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The Fruit Guys is the industry leader in providing farm-fresh produce to the American Workplace. The company was founded on the premise that bringing healthy brain food to the office can boost productivity, improve wellness and help companies improve their bottom lines.

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Corporate Wellness Programs

Our services include a wide range of wellness products & providers, allowing each organization to review and select the most appropriate level of involvement based on their budget and needs.

Our goal is to bring wellness into every organization and assist each business in developing a wellness initiative that will be effective for them.

Free or very low cost services allow all organizations to promote wellness and be able to grow the program as interest and results warrant.

• Custom Health Risk or Personal Health Assessments
• Wellness needs, interest surveys and assessments
• Employee wellness presentations, including Wellness Fairs & “Lunch and Learns” 
• HIPAA compliant weight management and biometric weight, blood pressure, BMI, and body fat testing. Optional uploads of cholesterol and blood sugar readings
• Biometric blood testing for cholesterol, blood sugar and other early disease detection in an affordable, convenient offering
• Managed Behavioral Health, Employee Assistance Programs, and HR consulting and personal guidance.

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The Very Best CBD For Stress And Anxiety

The Very Best CBD For Stress And Anxiety

Forget the meditation cushions and the mindfulness apps– if the coronavirus has actually got you feeling distressed nowadays, it may be time to consider including some CBD to your self-care regimen.

As cases of COVID-19 continue to spike across the country, so have cases of stress and anxiety. New data from the American Psychiatric Association last week discovered that nearly half of all Americans (48%) are nervous about the possibility of getting ill, with more than one-third saying that coronavirus is having a “ severe impact on their psychological health.“

The Stress And Anxiety and Anxiety Association of America says “capsized itinerary, indefinite seclusion, panic over limited resources and information overload” have actually likewise contributed to sensations of anxiety and seclusion.

While doctors continue to deal with a treatment for COVID-19, individuals are seeking to things like supplements and natural treatments to assist soothe and self-medicate. One way they’re handling the insaneness: cannabidiol, a.k.a. CBD.

CBD works by connecting with your body’s endocannabinoids system (ECS), which regulates a variety of functions and procedures in the body that consist of sleep, cravings, memory, and state of mind. Specialists say appropriate does can go a long way towards alleviating things like OCD and distressed behaviors by bring back balance in your ECS.

” This system has a crucial function in attempting to support and keep a sense of homeostasis (balance) in the body,” discusses Jason Mitchell, a naturopathic doctor and the Co-Founder and Co-CEO of wellness brand, HempFusion “CBD engages in such a method that can cause a relaxing impact in the body, and it does this in a way that is not drug-like or as a sedative.”

In other words: CBD might assist you relax, without getting you high.

According to a research study released last month by consumer insights firm Brightfield Group, 48%of cannabis users have actually stocked up or plan to equip up on CBD in the near future. The numbers associate to a spike in e-commerce sales of CBD, confirms Brightfield Group’s Handling Director, Bethany Gomez.

It’s important to note that while CBD might help suppress some of your anxiety, it’s not a catch-all treatment (the FDA says it’s continuing to screen and examine the effectiveness of CBD products in the market). “CBD supplements can help support a healthy reaction to particular conditions, including preserving typical levels of stress and anxiousness,” states Dr. Jeremy Stewart, the Chief Scientist and VP of Scientific Affairs at Gaia Herbs, whose line of products include supplements utilizing hemp extracts consisting of CBD.

Another thing to keep in mind: not all products labelled as “hemp” or “CBD” on the marketplace are the exact same. To get the complete results of cannabidiol, look for items utilizing hemp-derived CBD (or cannabis-derived, in legal states) which extracts the CBD compound from the leaves, stems and stalks of the hemp plant, utilizing its complete therapeutic advantages. If a product does not have the CBD label (say, these “ hemp oils” on Amazon), it’s because their ingredients are extracts of the hemp seed, and not the real plant. They’ll still offer some advantages, but they will not include any cannabinoids, consisting of CBD.

If you’re experiencing severe flare-ups of stress and anxiety, it’s finest to contact your physician or medical service provider. For everybody else, here are ten CBD products to try, to assist you handle your mood, stop your stress and anxiety and stay calm during this unmatched time.

1. Lord Jones Royal Oil

lord jones royal oil review

Courtesy Sephora

Lord Jones’ “Royal Oil” has actually won over fans in the beauty community as a nourishing oil for the face and body, but the broad-spectrum CBD formula can be taken as a cast too, to assist relieve stress and anxiety and promote a sense of calm. Each full dropper includes approximately 40 mg of CBD; each half dropper includes around 20 mg of CBD. Keep in mind: Because there are no additives or additional components, anticipate a more powerful scent of the cannabis plant. $100, Sephora.com

2. Papa & Barkley “Releaf” Capsules

papa barkley releaf capsules

Courtesy Papa & Barkley

Each pill contains 30 mg of CBD in a precisely-measured dosage.99, PapaandBarkley.com

3. Prismatic Plants Cast

prismatic-plants-good-day

Courtesy Prismatic Plants

Prismatic Plants’ “Good Day” cast integrates all the advantages of full-spectrum hemp oil and adaptogenic herbs in an easy-to-take tincture that consists of 10 mg of CBD (for stress and anxiety) and 3mg of CBDa (a naturally-occurring cannabidiolic acid that is stated to help with swelling). Bay Area-based Prismatic Plants combines cannabis with standard herbalism, and the adaptogens in this formula (generally plants stated to consist of healing properties) assist increase focus and calm, while reducing feelings of stress and anxiety. If you require something to assist you sleep, the company likewise makes a “Great Night” version that includes things like mood-bossting (however non-hallucinogenic) reishi mushrooms, and ashwagandha, an Indian root known for its pacifying homes. $70, PrismaticPlants.com

4. Healist Calm Infused Patch

healist patches

Courtesy Healist

If you’re feeling nervous, consider utilizing one of these CBD spots from the brand-new CBD and botanicals brand name, Healist. Each spot is infused with 10 mg of CBD, plus natural stress-relieving herbs and amino acids like ashwagandha and L-Theanine.

5. Kin Slips “Park Life” Sublingual Strips

kin slips review

Courtesy Kin Slips

Like a breath mint strip laced with CBD, these “Park Life” strips dissolve under the tongue for quicker, more direct relief than traditional edibles, which have actually to be absorbed before taking effect. In our experience, the strips have a near-immediacy of smoking cigarettes or vaping, and the 10:1 ratio of CBD to THC works well to help take the edge off.

6. Life Aspects CBD Bath Bomb

life elements bath bomb cbd

Courtesy Life Elements

Life Components says its “Mercury in Retrograde Bath Bomb” helps to “ward off cosmic chaos” with 250 mg of hemp-derived CBD and essential oils like frankincense, myrrh, and a touch of palo santo. Hokey language aside, this CBD bath bomb does wonders for aching muscles and mild cramps, in addition to assisting with tension and tension.

7. SMILE “Balance” CBD Gummies

smile cbd gummies

Courtesy Smile

One of the most convenient methods to add CBD into your daily regimen is through these multivitamins, which contain 10 mg of CBD per serving. The mix of essential vitamins and minerals (believe magnesium, vitamin B12, and zinc) helps to much better support your immune system and prevent adrenal fatigue, while the CBD helps to control your body’s response to stress.

8. Her Highness CBD Pre-Roll

her highness pre roll

Courtesy Her Highness

Prefer to smoke? This CBD pre-roll from female-fronted brand name, Her Highness, provides 0.5 g of Connecticut-sourced CBD per joint. The brand name states a couple puffs might assist to fight stress and anxiety, sleeping disorders, anxiety, discomfort and cramps. What we like: the smooth-settling formula eases you into a more mellow state, instead of striking you all at once. This set consists of a pre-rolled joint and gold lighter, which you’ll require to fill with your own butane before you light up. $15, HerHighnessCBD.com

9. KIVA “Freshly Squeezed” Gummies

kiva gummies review

Courtesy Kiva

KIVA is among the most popular names in edibles, and their newest release is a citrus-flavored gummy that promises a “more relaxed frame of mind.” This is one of the most healthy edibles we’ve tried, with the mix of CBD, terpines and ginseng gradually releasing over an hour or two, to provide you a slow, subtle “high.” Keep in mind: this has a CBD to THC ratio of 9:1. $20, KivaConfections.com(Currently available in California, Hawaii, Illinois, Michigan, and Nevada).

10 B GREAT Relax Shots

b great relax shot

Courtesy B Great

There are a ton of CBD-infused beverages on the market right now, from Sweet Factor(a sort of CBD-meets-La Croix beverage) to the party-ready G and Juice(based out of California, naturally). Each shot contains 20 mg of full-spectrum hemp CBD, along with melatonin, gingko biloba (a Chinese plant known for its therapeutic properties), and lavender water.

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Choose The Most Suitable CBD Oil

Choose The Most Suitable CBD Oil

Choose The Most Suitable CBD Oil

As the CBD market continues to increase, more and more sellers are associated with CBD brands. Because of the excellent healing properties that are associated with CBD oil, the therapeutic cannabis industry has grown significantly. That translates into a wide variety of CBD products available in the market, including different types of oils. Thus, it may not be easy for you to choose the most suitable CBD oil for your needs.

The truth is that buying CBD oil is not an easy task. Due to the increase in its popularity, it is possible to find a large amount of online information that is not always reliable. So how can we choose the most suitable CBD oil? You could spend a good amount of money and try different brands until you find the most suitable for you. But the most practical solution is to define certain criteria to filter the products until we find the one we like the most.

The contemporary market is full of CBD products that can make it difficult to choose the most suitable CBD oil. The quality and efficiency of an oil can vary greatly. That is why it is important to know what we are looking for. Other important factors that must be taken into account are taste, efficiency, ease of use, concentration, and price.

Decide why you want to use CBD oil

The first thing you have to decide is why you want to use CBD oil. Various health benefits are attributed to it, and several studies suggest that it could help treat from anxiety to pain, depression, or multiple sclerosis. At the moment, its effectiveness has been demonstrated as a treatment for two unusual forms of epilepsy.

Administering a few drops of CBD oil sublingually may be effective in relieving anxiety or muscle cramps. You have to know and understand what you want to achieve with the use of CBD in order to choose the most suitable CBD oil.

Choose CBD oil with the right concentration

Normally, concentration is the most important factor when choosing CBD oil or any other product with this cannabinoid. The concentration allows us to know how much CBD this product contains, and that helps us know its potency and its value.

CBD products sold in dropper bottles or capsules are available in different concentrations. The amount of CBD a bottle or capsule has is specified in the package. Many products with CBD oil show this information in milligrams, while others report the percentage concentration. Therefore, you can find products with 250 mg or 1000 mg of CBD, but also with 3% or 10% of CBD. The famous CBDistillery brand produces CBD oil available in potencies from 150mg to 5000mg of CBD.

High doses of CBD may have a more pronounced effect, but it is not advisable to start with oils or products with a very high concentration. You should keep in mind that each person is different and can react differently to CBD. There is no single answer to choose CBD oil with one or another concentration. Factors such as consumer weight, metabolism, and how a person interacts with a medication should be taken into account. A bottle of 250 mg CBD oil may work for some people, but others will need to consume more drops of that oil or drink a higher concentration oil.

That is why it is normally recommended to start with a moderate dose and, from there, increase it if necessary. Adjustments can be made as the effects of the product are observed. If you do not feel the desired effects in a few days, it will be necessary to increase the dose.

Look at the amount of THC in the product

It is something important if you want to avoid the effects associated with THC. Knowing how much THC a product contains is also essential for other reasons. For example, it is important to know its potential effectiveness. Some research suggests that CBD may be more effective in some individuals in combination with THC. This theory is related to the entourage effect we have talked about earlier.

However, this note is not yet proven, but it is a theory. In addition, with only a small amount of THC (0.3%), it is possible to increase the therapeutic effects of CBD. CBD products are manufactured from hemp that contains an amount of THC not exceeding 0.3%. Therefore, if you want a CBD oil that contains a little THC but not enough to produce psychoactive effects, you should choose organic hemp products.

Finding a CBD oil with a THC content greater than 0.3% can be a bit more difficult. 0.3% is the legal limit. Therefore, buying a CBD oil with high THC content can take a lot of effort. The good thing is that 0.3% THC seems to be more than enough to provide the benefits of the entourage effect.

What extraction method is used?

The two most common extraction methods to produce CBD oil are supercritical CO2 extraction and ethanol extraction. There are other methods of extraction, such as distillation and oil extraction, but they are much less common. Although each method has its advantages, supercritical CO2 extraction is considered the safest and most effective. Therefore, the extraction method used for oil production will affect your decision by choosing the most suitable CBD oil.

Not all extraction methods achieve a final product with the same purity and quality. Some companies manage to manufacture cheap CBD products thanks to the use of solvents such as butane and propane to obtain the extracts. Although these products are cheaper, the possible health risks of these substances mean that they are not worth trying.

The opinion that the best CBD oils are those obtained with CO2 extraction is widespread. This method relies on the use of carbon dioxide under pressure to isolate, conserve, and maintain the purity of CBD. It is a much more expensive process than the other extraction methods, but the CBD oil that is obtained is of a much higher quality. CO2 extraction does not require the use of toxic substances.

Analysis of independent laboratories

One of the most significant things to keep in mind when buying CBD oil or any other product with CBD is independent laboratory analysis. If a company performs these analyses, it will be available on its website.

If you don’t find these analyses, it can be for several reasons. This analysis may have been performed, but CBD oil does not contain the amount of cannabinoids specified. Or maybe the product contains harmful contaminants. But the company may not have updated the website with the corresponding analysis.

But, without a laboratory report, it is not possible to confirm what the CBD oil contains or if its use is safe. So, it is desirable to look for a Certificate of Analysis (laboratory report) before buying a CBD oil online.

Where does hemp come from?

Hemp is the main source from which CBD is extracted. The quality of hemp has a great impact on the quality of the final product. Although some brands have a close relationship with hemp producers to ensure the best quality of crops, there are also other companies that all they are looking for is a low price.

In some cases, companies buy wholesale isolated CBD without knowing where hemp comes from or how it is grown. In these cases, the distributors affirm to the new CBD companies with limited knowledge of the industry that their isolated CBD comes from organic hemp grown following best practices. However, when the company has no direct relationship with the farmer, it is impossible to certify these claims.

When choosing CBD oil, it is important to confirm the quality of the hemp from which it is extracted. First, check the provenance of hemp. It can be grown in Europe, in China or in the USA. Both Europe and the United States require high requirements to grow hemp organically.

It is also important to know what cultivation practices have been used. Proper cultivation practices, such as the use of hemp seeds from accredited groups, a balanced soil pH, or the absence of pesticides, are the basis of quality CBD products. Although it can be challenging to find this information, it is always a good sign that companies share their standards and principles related to hemp cultivation.

Image Source: Pexels.com

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The Unlikely Products Selling Out Due To The Fact That Of Coronavirus

The Unlikely Products Selling Out Due To The Fact That Of Coronavirus

The pandemic is altering short-term consumer habits– and retailers can’t keep up

Jennifer Alsever

T T he coronavirus lockdown has organisations reeling, with countless companies preparing for high sales declines and some whole markets at danger And yet some items are still flying off the racks in this new work-from-home (and do-everything-else-from-home) world– and it’s not just bathroom tissue and hand sanitizer. A wide variety of items, from sporting goods to devices, have all of a sudden ended up being hot ticket items.

Here are some of the surprising items that are selling out and what it says about the existing mindset of consumers.

You would not think a pandemic would be the time you ‘d begin shopping for home appliances, however plenty of people entered search of them this month. In particular, they desired freezers– the much better to stockpile food. Freezer searches climbed 440%this month compared to the very first two weeks of February according to data by Slickdeals, an online discount coupon business that monitors e-commerce shopping traffic.

When all the toilet tissue sold out at supermarket, buyers started hunting for another option: bidets. Searches for the bathroom component leapt 304%this month compared to the first 2 weeks of February according to Slickdeals. (The company’s data likewise showed searches for bathroom tissue were still high– up 7,000%.) At New York-based bidet startup Tushy, “Sales have been up about [tenfold], which is quite insane,” CEO Jason Ojalvo told the New York City Post

In San Francisco, company was brisk at weapon stores last week in the middle of the state’s shelter-in-place order to stem the tide of brand-new Covid-19 cases. And there are signs that sales of guns and ammo are increasing nationwide As one customer told the San Francisco Chronicle, “If society is unraveling, it’s up to us to secure ourselves.”

Likewise, archery and bowhunting site Archer’s Products witnessed a sudden spike in sales on various kinds of bows, crossbows, and other hunting equipment. Says Oleg Donets, CEO and creator of ODMsoft, a web marketing agency, “People are preparing for something unforeseen.”

With health clubs and in-person workout classes off-limits, consumers are snapping up home workout devices, consisting of accessories like kettlebells, which sold out on Amazon recently. Peloton is cranking out stationary bicycle to meet need (although the business canceled orders of its treadmill, which needed at home set up), and boxing devices company FightCamp saw its sales increase 4 to 5 times what they were in 2015. “It reveals no signs of slowing,” says Khalil Zahar, CEO of the California-based business. “We’re seeing comparable surges in purchasing now to what we would typically see on Black Friday or Cyber Monday.”

There’s also been a rush on virtual workouts. Local studios and gyms are scrambling to provide virtual classes via Zoom and one-on-one exercise assessments. Beachbody, which streams at-home workouts, saw a 330%jump in customers recently compared with the same time the year before, and the number of exercises streamed leapt 79%last week compared with the week previously.

Of course, people sought items to put in those freezers– primarily, meat. Nielsen reported huge sales jumps for all kinds of meat over the previous two weeks– even canned meat, which grew 187%recently compared with the same period the year before. On the other hand, U.S. sales of poultry climbed 51%. “Chicken is flying off the racks,” states Jim Perdue, owner of Perdue Chicken Company, based in Salisbury, Maryland. He says the business is working overtime to meet demand. (For the record, there was no big rush for vegetables and fruit however rather potato chips and pretzels, both of which saw impressive double-digit growth.)

School closures and the work-from-home mandate increased a severe run on computers, laptops, workplace chairs, and screens. Moms and dads tired of sharing computer systems with kids (who now should log online to find out) have caused an extraordinary surge in laptop computers and computer notebooks. As manufacturers battle with supply chain problems in China– which is only now recovering from the coronavirus– interfered with providers from shipping crucial elements. Dell Technologies is searching for alternative providers, and Lenovo Group has had more need for displays and headsets along with computer systems. Experts forecast need for laptop computers to continue to grow.

Individuals scooted to set up house offices, too. Web searches ballooned for desks (87%), displays (75%), and office chairs (65%) according to data by Slickdeals.

With all the festering stress and anxiety, sales are warming up for marijuana and CBD products, specifically in California, Washington, and Colorado, where pot is legal. In some areas that executed lockdown orders to avoid individuals from leaving their houses except to buy essentials, marijuana dispensaries (in addition to alcohol shops) made the cut to qualify as “essential organisations.”

House shipment, too, is escalating. Marijuana orders grew 229%this past week, according to Weedmaps, which lets people locate dispensaries and order online. Purchasers also spent more: They spent 100%more than they did recently when they purchased online and picked it up in the shop.

” Dispensaries in cities like Seattle, San Francisco, Los Angeles, and Denver have actually had a consistent stream of clients in their companies,” says John Kueber, CRO of Sorse Technology, a CBD business. “My THC partner, GreenMedLabs, which produces cannabis beverages, has seen their orders triple in the recently.”

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Green Growth Brands Announces Conclusion of Strategic Review Process, Consent to Receivership Appointment for CBD Business, and Continuation of Cannabis Business in Florida, Massachusetts, and Nevada

Green Growth Brands Announces Conclusion of Strategic Review Process, Consent to Receivership Appointment for CBD Business, and Continuation of Cannabis Business in Florida, Massachusetts, and Nevada

COLUMBUS, OH, April 3, 2020 /PRNewswire/ – Green Growth Brands Inc. (CSE: GGB) (OTCQB: GGBXF) (“GGB” or the “Company“) announced today that a special committee of the Board of Directors has concluded the previously announced strategic review process (the “Strategic Review Process” or “Process”)  related to the Company’s cannabidiol business (the “CBD Business”).  As a result of the Process, the Company has determined that appointment of a receiver is in the best interest of the Company and the creditors of the CBD Business.  The CBD Business is operated by six of the Company’s subsidiaries: Green Growth Brands LLC, GGB Beauty LLC, GGB Licenses LLC, Green Growth Brands Realty LLC, GGB Kiosks LLC, and GGB GN LLC (collectively, the “CBD Subsidiaries”).  Each of the CBD Subsidiaries will be subject to the receivership order. 

Green Growth Brands (CNW Group/Green Growth Brands)

Green Growth Brands (CNW Group/Green Growth Brands)

The conclusion of the Strategic Review Process follows the Company’s announcement on March 19, 2020 that it would be indefinitely suspending its CBD Business operations in light of the ongoing COVID-19 pandemic.  The consent to appointment of the receiver was filed on April 2, 2020 with the Franklin County Court of Common Pleas, in Franklin County, Ohio.  Materials related to the filing can be accessed via the Franklin County Clerk of Courts electronic docket, which can be found at https://fcdcfcjs.co.franklin.oh.us/CaseInformationOnline/.

The Company will continue to operate its cannabis business in Florida, Massachusetts, and Nevada (the “MSO Business”) through its subsidiaries Nevada Organic Remedies LLC (“NOR”), Henderson Organic Remedies LLC (“Henderson”), Wellness Orchards of Nevada LLC, Just Healthy LLC, and Spring Oaks Greenhouses Inc. (collectively, the “MSO Subsidiaries”).  NOR and Henderson operate the Company’s The+Source dispensaries in the Las Vegas, Nevada region, and have recently commenced delivery service in response to Nevada Governor Stephen Sisolak’s March 20, 2020 order limiting dispensary operations in the state.  None of the MSO subsidiaries nor any of their respective assets will be subject to the receivership order. 

About Green Growth Brands Inc.

Green Growth Brands creates remarkable experiences in cannabis. The company’s brands include CAMP, The+Source, and 8 Fold. GGB is expanding its cannabis operations throughout the U.S., via dispensaries in Nevada, Massachusetts and Florida. Learn more about the vision at  GreenGrowthBrands.com.

Cautionary Statements

Forward Looking Information 

Certain information in this news release constitutes forward-looking statements under applicable securities law. Any statements that are contained in this news release that are not statements of historical fact may be deemed to be forward-looking statements. Forward-looking statements are often identified by terms such as “may”, “should”, “anticipate”, “expect”, “intend”, “forecast” and similar expressions.  Forward-looking statements necessarily involve known and unknown risks, including, without limitation, risks associated with general economic conditions; adverse industry events; marketing costs; loss of markets; future legislative and regulatory developments involving medical and recreational marijuana; inability to access sufficient capital from internal and external sources, and/or inability to access sufficient capital on favorable terms; the marijuana industry in the United States, income tax and regulatory matters; the ability of the Company to implement its business strategies; competition; currency and interest rate fluctuations and other risks, including those factors described under the heading “Risks Factors” in (i) the Company’s Annual Information Form dated November 26, 2018 which is available on the Company’s issuer profile on SEDAR and (ii) the Company’s Short Form Prospectus dated August 15, 2019.

Readers are cautioned that the foregoing list is not exhaustive. Readers are further cautioned not to place undue reliance on forward-looking statements as there can be no assurance that the plans, intentions or expectations upon which they are placed will occur. Such information, although considered reasonable by management at the time of preparation, may prove to be incorrect and actual results may differ materially from those anticipated. The forward-looking statements contained in this release, including without limitation, the continuing operation of the Company’s cannabis business in Florida, Massachusetts, and Nevada, is made as of the date hereof and the Company is not obligated to update or revise any forward-looking information, whether as a result of new information, future events or otherwise, except as required by applicable securities laws. Forward-looking statements contained in this news release are expressly qualified by this cautionary statement.

Going Concern Risk

As previously disclosed, the continuing operations of the Company remain dependent upon its ability to continue to raise adequate financing, to commence profitable operations in the future, and repay its liabilities arising from normal business operations as they become due. Notwithstanding the receivership fiing of the CBD business, there remains a significant risk that the Company will be unable to realize sufficient cost savings, find sufficient sources of financing for on-going working capital requirements and maturing debt and other liabilities or to negotiate extensions or alternate payment terms in respect of such debt. These material uncertainties cast significant doubt upon the Company’s ability to meet its obligations as they come due and to continue as a going concern. The Company is working to negotiate a deferral of previously announced obligations related to amounts owed to MXY Holdings LLC and GA Opportunties Corp. and has previously announced short-term financing from certain of its key stakeholders in connection therewith.  The Company has drawn all amounts available to it under the previously announced working capital backstop commitment provided by All Js Greenspace LLC (“All Js“) and Chiron Ventures Inc. (collectively, the “Backstop Parties“) for purposes of funding the Company’s operations.  In addition, for purposes of funding the Company’s operations All Js advanced approximately US$1.5 million from its portion of the previously announced US$52.3 million debenture repayment backstop commitment.  Notwithstanding this US$1.5 million advance from All Js, there is no guarantee that either of the Backstop Parties will permit additional funds to be drawn from the debenture repayment backstop commitment for purposes of funding the Company’s operations.  Amounts drawn from the debenture backstop commitment to fund operations reduce the funds available to refinance the debentures upon maturity.  The Company is actively pursuing alternative financing sources but there can be no guarantee that any such financing will be consummated or if consummated on what terms.

Investors are cautioned that additional financing may not be available when needed or, if available, the terms of such financing might not be favourable to the Company and might involve substantial dilution to existing shareholders. Failure to raise capital when needed will have a material adverse effect on the Company’s ability to pursue its business strategy, and accordingly could negatively impact the Company’s business, financial condition and results of operations.  Failure to obtain sufficient debt or equity financing and/or to successfully executed on one or more strategic alternative transactions could result in the Company defaulting on its obligations and force the Company into reorganization, bankruptcy or insolvency proceedings.

US Securities Law Disclaimer

This announcement does not constitute an offer, invitation or recommendation to subscribe for or purchase any securities and neither this announcement nor anything contained in it shall form the basis of any contract or commitment. In particular, this announcement does not constitute an offer to sell, or a solicitation of an offer to buy, securities in the United States, or in any other jurisdiction in which such an offer would be illegal.

The securities referred to herein have not been and will not be registered under the Securities Act of 1933, as amended (the “Securities Act“) or under the securities laws of any state or other jurisdiction of the United States and may not be offered or sold, directly or indirectly, within the United States, unless the securities have been registered under the Securities Act or an exemption from the registration requirements of the Securities Act is available.

Cision

Cision

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SOURCE Green Growth Brands

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How CBD can assist you get an excellent night’s sleep (without the hangover)

How CBD can assist you get an excellent night’s sleep (without the hangover)

If you suffer from insomnia, PTSD, or other rest-inhibiting conditions, it’s likely that someone you understand has advised you try CBD oil to help you sleep. Not all CBD products are alike.

What is CBD?

Cannabidiol (CBD) is one of the main chemical components (or cannabinoids) found in the Marijuana sativa plant. Unlike THC (another cannabinoid), CBD is not psychedelic. Meaning, it won’t get you high or modify your understanding and it can be collected for farming purposes by means of the hemp plant.

How does CBD assist you sleep?

Its results, according to the British Medicinal Society Journals, can help relieve a vast array of signs including those connected with mood disorders, persistent pain, anxiety, seizures, and sleeping disorders. Nevertheless, since most CBD products are noted as supplements or natural sleep help (versus medications), both the products themselves and their impacts have actually not been regulated or substantiated by the FDA.

But how does CBD help you sleep? I’m getting to that.

Keep in mind how I pointed out CBD comes from a group of cannabinoids found in hemp and marijuana plants? This is necessary because it makes CBD among lots of chemical compounds that connect with our endocannabinoid systems, activating one of two receptors: CB1 or CB2. Considering that our focus is on CBD (and not CBG, CBA, CBN, and so on), I’m only going to focus on the impacted antenna– our Cannabinoid Type 1 (CB1) receptor.

CB1 receptors are discovered all over the body, more notably, they’re a popular subtype of the main nervous system(AKA our brain and spinal cord). Because of where most of these receptors are located, it’s safe for you to assume that they play some sort of role in controling mood, thought pattern, and other synaptic transmissions(or details sharing procedures).

full spectrum vs broad spectrum

Generally, assumptions are the wrong relocation but in this case, it’s alright because research studies have really connected the activation of CB1 receptors to both “short-term and long-term changes in the effectiveness of synaptic transmission.” In plain English, this implies that trials have actually shown setting off CB1 receptors shows to be an effective treatment for both short-term and long-term changes in behavioral patterns triggered by internal aspects (mental disorders, metabolism problems, you understand).

I might let you link the dots, but for precision’s sake, I’ll simply tell you that these are fantastic examples of “internal behavioral patterns” that have the prospective to be remedied by consistent CBD use ( scientists recommend taking CBD at least one hour before bed so it has time to take impact). User trials have likewise suggested that unlike other sleep aids and pain medication, taking the appropriate dose of CBD will not leave you in a haze the next early morning.

( Disclaimer: it is very important for you to talk with your medical professional prior to consuming any CBD products, as CBD is understood to disrupt specific medications and if you’re pregnant or breastfeeding the FDA encourages versus making use of any hemp or marijuana items).

What’s the right CBD oil dose for sleep?

Like the majority of things in life, this can differ person-to-person depending on a range of factors (weight, tolerance level, how you’re taking in the CBD, the particular advantages you are looking for, etc.). And like weed edibles, the effects of consuming CBD edibles aren’t immediate so it’s recommended that you wait at least six hours prior to re-dosing (or upping your dose).

Best CBD for sleep and where to buy it

If you’ve left your home or turned on your TV in the last couple of weeks, you might have discovered that everyone from vape and smoke shops to hairdressers and store retailers are pressing CBD products. I can not worry this enough, and any respectable business will offer third-party laboratory results for all its CBD products.

So to help you stay out of harm’s method, listed below are a few of my top choices that abide by strict ethical and safety requirements. You can find the majority of these products online, but if for some reason they’re unavailable or you want to shop regional, I suggest stopping at the CBD dispensary near you (yes, those exist) and see what the person behind the counter there would recommend.

1) Medterra CBD

.

cbd oil for sleep

Offered online and at getting involved retailers, Medterra CBD is among the most widely known and relied on brands in the space. All Medterra products are third-party laboratory evaluated therefore high in quality, Medterra actually operates in collaboration with the Hemp Pilot Research Study Program

Medterra offers all sorts of CBD items, including broad-spectrum and CBD items for pets. For those seeking to order online, the website offers complimentary shipping on orders $99 and 15%off for those who pick the membership option.

Finest item for promoting sleep: CBD Melatonin pills($5599)

2) JustCBD

cbd oil for sleep

JustCBD is another fantastic online CBD merchant. JustCBD uses more of a variety than Medterra, so if you want to try CBD in all of its forms this is absolutely the location to go.

Finest item for promoting sleep: JustCBD Watermelon Gummies(on sale for $3250, regularly $40)

3) Extract Labs

cbd oil for sleep

The madmen behind Extract Labs’ are actually an essential factor this things works so well. Instead of creating with heat (like standard processes call for), the designers whip all their basic and natural active ingredients together. By doing so, Extract Labs’ items are able to keep more of the helpful and highly popular compounds the hemp plant is understood for.

Finest product for promoting sleep: Sleep CBD Bath Bomb($16), Grandaddy Purp or G-Rilla CBD Shatter($45 each)

4) Select CBD

cbd oil for sleep

Select CBD is my go-to for CBD cast because it’s one of the couple of brands that not just nailed the taste but the consistency of the drops, too! Which is a huge deal for anyone who’s tried tincture previously, as you probably understand simply how tough it can be to discover a product that will not make you gag.

Select CBD is not for sale online and can only be bought at taking part retailers, so yeah, you’ll need to leave your house to get your hands on it, however it’s well worth the additional effort!

Best item for promoting sleep: Lavender or Peppermint CBD Tincture drops or Rest CBD Gel Pills(not readily available online, prices differ by retailer)

The Daily Dot may get a payment in connection with purchases of services or products featured in this post. Click here to read more.

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Your barista may be at home, but that doesn’t mean your coffee game should suffer

Your barista may be at home, but that doesn’t mean your coffee game should suffer

Gather round, young and old — and hear tales of bygone days. Back in olden times, citizens would mass at a house of coffee, wherein skilled java alchemists would concoct special blends and apply artisanal wizardry to make each steaming chalice an appointment for the taste buds.

Granted, said wizards, once known as baristas, were ungifted in the art of immaculate spelling —but their inspired, almost supernatural ways of the bean were legend.

People are sequestered in their homes now, but the myth of the fabled barista lives on. Assembled below, find assorted relics of the dark art of brewing, each dedicated to keeping the time-honored practice of drinkable beans alive for future generations. Spread the word of this epic saga and own such artifacts in your own home.

Gourmia Coffee Makers

Headquartered in Brooklyn, New York, upstart small appliance maker Gourmia has spent the past few years establishing itself as a name player in the boutique coffee making field and now have an array of makers available for all shades of coffee-loving activity.

For the basic set-it-and-forget-it crowd, the Gourmia GCM2865 12-Cup Programmable Coffee Maker ($49.99; originally $59.99) is equipped with a programmable timer to have up to 12 cups of steaming hot coffee ready the minute you get up each morning. And the Gourmia GCM3600 Single Serve Coffee and Tea Maker ($59.99; originally $119.99) easily brews either coffee or tea at the push of a button as well as serving up single-serve k cups as well.

If your tastes run toward the more pure, 12-hour slow soak of cold brew coffee, the Gourmia GCM6850 Digital Accelerated Cold Brew Coffee Maker ($59.99; originally $109.99) simulates that process in as little as 4 minutes, creating premium cold brew in four different brewing strengths. Meanwhile, the Gourmia GCM7800 Brewdini 5-Cup Cold Brew Coffee Maker ($149.99) refines the process down to only 2 minutes with a patented vacuum technology that suctions sugar, caffeine, and other elements out to preserve the bean’s delicate natural flavors.

While drip method coffee making gets the job done, many aficionados will tell you the pour-over produces a more flavorful cup every time. The Gourmia GCM3250 Dual Mode Pourfect Pour-Over Coffee Maker ($59.99) lets you choose either automatic or manual modes to control the precise amount of grinds and water needed for the pour-over you like best. And the Gourmia GCM3350 Pourista Fully Automatic Pour-Over Coffee Brewer ($129.99; originally $149.99) allows you to maintain precise water temperature throughout the pour process for optimal flavor and even replicate the action of a trained barista with its planetary pour pattern and authentic bloom pause to hit the flavor you want just right.

And since some lovers just don’t feel it’s right unless they grind the beans themselves, the Gourmia GCM4700 Coffee Maker with Built-In Grinder ($99.99; originally $139.99) combines a state of the art coffee grinder and brewer to deliver the freshest coffee possible.

Other brewers

Since Gourmia is far from the only player in the coffee game these days, FrankOne Cold Brew and Coffee Maker ($79; originally $99) offers their VacTec brewing process, which accelerates the extraction time to serve up an intense cold brew in four minutes, or a piping hot cup of the regular stuff in just 30 seconds.

Whether you go with beans or grounds, the Chefman 4-Cup Grind & Brew Coffee Maker ($75.99; originally $99.99) lets you quickly use its integrated grinder to create the freshest ingredients, preserving the bean’s oils and flavors for maximum taste.

The BeanPlus Cold Drip Brewer Premium Kit ($99.99; originally $130) is a smarter way to cold brew, with its own special drip method that shaves brewing time down to just four hours and a patented slow-drip valve for adjusting your coffee strength to your taste.

Behmor is making a pair of their factory refurbished premium brewers available at a fraction of their regular cost, including the 1.2L Connected Coffee Brewer ($79.99; originally $169.99), which lets you use the Behmor app to adjust your brew settings and create your own memory presets to achieve the perfectly personalized cup of coffee all from your phone.

Or you can save $300 on the supremely loaded Behmor Brazen Plus 2.0 Temperature Control Coffee Brewer ($99.99; originally $399.99). In addition to the personalized settings, this feature-heavy unit allow you to set your brew temperatures based on your elevation and use the pre-soak option so your coffee blooms before brewing for an even better flavor.

Finally, the Ratio Six Coffee Maker ($345) combines form and function for a brewer with a slimmer profile, lighter weight and brilliant simulated barista pour over process to measure your water flow with precision throughout the brew. And for the heights of simplicity, it all works with the push of a single button.

Accessories

To maintain freshness even long after the grind, the Turn-N-Seal Food Vacuum Container with 2-in-1 Brew Scoop ($24.99; originally $40.98) creates a strong vacuum inside, locking out air and moisture while retaining all of your beans natural properties.

You can get an expert brew anywhere in a pinch with the Palmpress Coffee Press ($42). This one-cup stainless steel filtering system lets you include your grounds, then control your own coffee-to-water ratio that never touches plastic or rubber for the best possible brew.

Some brew units have their own grinders, but for a true variety, you can’t beat the Gourmia GCG205 14-Oz Automatic 4-Mode Digital Conical Burr Grinder ($99.99). From French pass to espresso to just a primo cup of joe, this grinder has 39 different grind size options with its own built-in scale to measure precise amounts for the perfect cup.

Coffee flavors

Of course, the quality of a brewing system doesn’t matter much without quality beans and grounds to put inside. For Nespresso Original machine users, the Gourmesso Nite Edition Bundle of 90 High-Intensity Blends ($37.99; originally $42.21) brings an assortment of espresso capsule tastes, each graded by their intensity, so you can always match the perfect blend to your mood.

If you’d like to combine the effects of a responsibly sourced fresh brew with the restorative, non-psycho-active properties of CBD, Jane West CBD Coffee ($38.99; originally $48) delivers the best of both worlds. Farmed by female coffee growers in Costa Rica, the rich light-roasted beans are coupled with CBD to help relieve pain, reduce anxiety, alleviate cancer-related symptoms and more. Or you can try Buddha Beans CBD-Infused Whole Coffee Beans ($26.99; originally $33) which combines non-GMO CBD with Mexican beans with hints of chocolate, hazelnut and citrus for a truly unique taste.

But if you’re still a big fan of your Keurig, the Glorybrew 72 Compostable K-Cup Coffee Pod Bundle ($42.99; originally $50) offers a full selection of Glorybrew’s premium beans and flavors, all in pods that are 100 percent compostable and made from bio-based materials to ensure you’re not only drinking well, but remaining conscious of the environment.

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NewLeaf Brands Launches COVID-19 Relief Initiative for Laid-off Workers, and Sale of up to 50% Off on All Online Purchases at WeAreKured.com

NewLeaf Brands Launches COVID-19 Relief Initiative for Laid-off Workers, and Sale of up to 50% Off on All Online Purchases at WeAreKured.com

VANCOUVER, British Columbia, March 31, 2020 /PRNewswire/ — NewLeaf Brands Inc. (CSE: NLB) (OTC: NLBIF) (FSE: 0NF) (“NewLeaf Brands” or the “Company”) is pleased to announce its partnership with Herbfluence, Inc. (“Herbfluence”) and OnTheHouse App, LLC (“OnTheHouse”) in offering free CBD samples to residents in the State of Colorado, USA that have been laid-off from work due to the recent Coronavirus pandemic. The free sample pack will include three bags of TeaLief’s CBD infused tea, a seven day pack of ReLyfe’s 25mg CBD soft gels and a free Kured 500MG disposable vape pen, an information package on the benefits of CBD and a list of the Company’s various product offerings (the “Product Offering”).

The Company’s leadership team hopes that this free Product Offering will provide relief in anxiety, depression and or sleep issues that these laid-off workers may be experiencing. The Company’s colleagues at HemPup are also offering a sample of their CBD dog treats for our K9 friends who are also stuck in the house, anxious and need something to take the edge off.

The Company is offering up to 50% off on all products through their online store to non- Colorado residents. This offer has no approval requirements and also no limitations. The Company hopes these savings will help those in need of some relief during this unprecedented time. To take advantage of this offer please visit wearekured.com/shop.

Benjamin Martch, CMO of NewLeaf Brands, commented, “I have lived and worked in Denver as an entrepreneur for the last 15 years and I hope that this Product Offering will help those suffering from any anxiety during this difficult time. NewLeaf Brand’s CBD products will include the following: KURED vape pens, HemPup dog treats, TeaLief CBD tea, ReLyfe CBD capsules.”

For Colorado residents interested in this free Product Offering, please follow the link below to complete registration and the Company will be in touch with further details.

Sign up registration sheet – https://tinyurl.com/sa99b5m

About NewLeaf Brands

NewLeaf Brands, Inc. is an innovative Cannabidiol (“CBD”) lifestyle Company. Through the Company’s wholly-owned subsidiaries We are Kured, LLC, Drink Fresh Water, LLC, ReLyfe Brand, LLC and TeaLief Brand, LLC the Company’s main business activities encompass the development, marketing, and distribution of CBD products (including vaporizer pens/cartridges, hot/cold tea, softgel capsules and beverages) throughout North America, South America, and Europe. In addition, NewLeaf Brands, Inc. has extensive retail and cultivation land investments in Oregon, USA.

For further information about NewLeaf Brands, please consult the Company’s profile on SEDAR at www.sedar.com or visit the Company’s website at www.NABrandsInc.com. For further information about We Are Kured, please visit their website at www.wearekured.com.

The Canadian Securities Exchange has neither approved nor disapproved the contents of this news release and accepts no responsibility for the adequacy or accuracy hereof.

This news release contains forward-looking statements, which relate to future events or future performance and reflect management’s current expectations and assumptions. Such forward-looking statements reflect management’s current beliefs and are based on assumptions made by and information currently available to the Company. Readers are cautioned that these forward looking statements are neither promises nor guarantees, and are subject to risks and uncertainties that may cause future results to differ materially from those expected including, but not limited to completion of planned improvements at both the Canadian and US sites on schedule and on budget, the availability of financing needed to complete the Company’s planned improvements on commercially reasonable terms, planned occupancy by the tenant-growers, commencement of operations, differences in yield on expected harvests, delays in obtaining statutory approval for marijuana production plans, issues that may arise throughout the grow period, outdoor crops affected by weather, the ability to mitigate the risk of loss through appropriate insurance policies, and the risks presented by federal statutes that may contradict local and state legislation respecting legalized marijuana. These forward-looking statements are made as of the date hereof and the Company does not assume any obligation to update or revise them to reflect new events or circumstances save as required under applicable securities legislation. This news release does not constitute an offer to sell securities and the Company is not soliciting an offer to buy securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such jurisdiction.

This news release does not constitute an offer of securities for sale in the United States. These securities have not and will not be registered under United States Securities Act of 1933, as amended, or any state securities laws and may not be offered or sold in the United States or to a U.S. Person unless so registered, or an exemption from registration is relied upon.

On Behalf of the Board of Directors
Joshua Bartch
Chief Executive Officer
[email protected]

For Further Information Contact
Corporate Communications
[email protected]
+1-250-488-6728

We Are Kured Contact:
Benjamin Martch
Founder & CEO
www.wearekured.com

Cision

Cision

View original content: http://www.prnewswire.com/news-releases/newleaf-brands-launches-covid-19-relief-initiative-for-laid-off-workers-and-sale-of-up-to-50-off-on-all-online-purchases-at-wearekuredcom-301032405.html

SOURCE NewLeaf Brands Inc.

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Danica Patrick on Investing in CBD — and How She and Aaron Rodgers Are Handling Self-Isolation

Danica Patrick on Investing in CBD — and How She and Aaron Rodgers Are Handling Self-Isolation

Danica Patrick is all-in on promoting health and wellness — and now, she’s doing that by investing in something she says really works: CBD.

Patrick invested in company Beam, which sells pharmaceutical-grade products made with natural ingredients and THC-free CBD oil, she announced this week.

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“I just think that it’s part of investing in your health,” she says of her involvement in Beam.

Patrick says Beam is “special” because its founders Matt Lombardi and Kevin Moran are, too, ex-athletes — the former a hockey player and the latter a baseball player.

“The first thing I did was get on the phone with them and hear their story and what they wanted to do and all about the product,” the retired NASCAR driver explains. “I just really believe in them.”

RELATED: Danica Patrick Congratulates Boyfriend Aaron Rodgers on Packers Win — and His ’Hotness’

Continues Patrick, 38, “After I got the product and I realized just how legitimate and how effective it was, I went into the investment side of the company, as well. So not only am I helping promote the product and being an ambassador for them, but I also invested in the company. It’s just a really, really high-quality, effective product.”

Patrick mainly uses the company’s salve, the Fixer — which she says she rubs on sore muscles; the Beam’s oil, called the One — Patrick likes it for achieving a deeper sleep; and Dream, a CBD blend of “natural sleep agents” that helps you fall asleep.

She’s also a fan of the blend Clarity, which she says she sometimes mixes with yogurt or oatmeal to promote focus.

“When you have a high-quality CBD, I just think that your body is craving these natural medicines that exist, right?” says the former driver. “We don’t have to go to a lab and make something up. These things already exist in nature and I think our body just really responds well to natural things. The natural body responds to natural ingredients.”

Patrick — who hosts the Pretty Intense podcast — has been increasingly focused on wellness during the current coronavirus pandemic. She’s been hosting workouts live on Instagram to promote a sense of “community” and “connection” while most of the country quarantines or self-isolates at home to stop the spread of the virus.

“I really think that in this time it’s become obvious to me that it’s very natural to want to spend time with people and to connect and to have a community and to have a group of friends,” says Patrick. “I just think that in all of history we’ve seen that too. Has there ever been a time in history where it’s just all based on isolation? I don’t think so. So it’s about community and it’s about sharing what I have.”

Patrick has been self-isolating with boyfriend, Green Bay Packers quarterback Aaron Rodgers. The pair have been staying busy, taking online classes, cooking and catching up with friends and family through the phone.

“I’m learning a little bit more Spanish,” Patrick says. “Aaron got Rosetta Stone on his phone, so we’re learning languages.”

She continues, “I still got guitar on my list to practice, but I haven’t done that. So yeah, watching shows, watching movies. Like everyone else, we’ve watched Tiger King.”

Rodgers and Patrick are used to life on the move, so staying home for an extended period of time is unique. When the world eventually returns to normal, Patrick says, “There’s trips that have been canceled and things that have changed. What’s going to happen when it’s over? Do we have a plan? It’s just to pick up where we left off.”

RELATED: Girl Who Cried and Asked for 400 Popsicles from Aaron Rodgers While Under Anesthesia Gets Her Wish

In the meantime, she encourages others stuck at home amid the pandemic to focus on improving their health and wellness.

“What a good time to let this be a reminder to take care of our bodies,” says Patrick.

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Friday’s Best Deals: Children’s Books, Circular Lamp, Memory Foam Pillows, Onsen Towels, and More

Friday’s Best Deals: Children’s Books, Circular Lamp, Memory Foam Pillows, Onsen Towels, and More

Illustration for article titled Fridays Best Deals: Childrens Books, Circular Lamp, Memory Foam Pillows, Onsen Towels, and More

Best Deals of the DayBest Deals of the DayThe best deals from around the web, updated daily.

A large heating pad, Comixology Marvel sale, Instant Pot, and six months of Xbox Game Pass Ultimate lead off Friday’s best from around the web.

Bookmark Kinja Deals and follow us on Twitter to never miss a deal!

Pick up the latest Sonos One (2nd Generation) for a low $150, or the One SL for $129 right now. Both speakers AirPlay 2-ready, contribute multi-room audio solution for your entire house, and sound terrific. The big difference is the Sonos One can summon Alexa or Google Assistant, while the SL cannot.

But if you’re looking for an upgrade to your TV’s sound, The Sonos Beam is our readers’ favorite sound bar, and Amazon’s also discounting it to just $350.

We’re not in the apocalypse yet (at least, I don’t think we are), but if your power suddenly goes out and you don’t have a gas generator, perhaps you can fill up using solar energy. That’s possible thanks to RAVPower’s 24W solar charger. It carries an MSRP of $80 and usually hovers near the $50 mark, but with coupon code COME50, you’ll only need to part ways with $40. That includes free shipping, too.

There are five solar panels and three USB ports capable of 2.4A each. It can only convert up to 23.5% solar energy into power, so we’re not exactly sure how useful that is with the many fast-charging devices out today, but at least battery safety won’t be a concern: it delivers only the current you need with smart frequency technology.

Ah, 2014. The days before Apple decided to axe the ports we’d come to know and love in favor of USB-C, a faster and reversible standard that still isn’t exactly supported by all your favorite accessories. If you need to edit photos from your DSLR camera, for instance, well you’re basically fucked without one of these here dongles.

One of the best you can find, the 8-in-1 USB-C hub from Vava is half off using our exclusive promo code KinjaVa330 and by clipping the coupon on the Amazon listing page. Combined, that brings your total down from $40 to a mere 20 bells! That way, you can get your cake (a new MacBook) and eat it too (use ports) with three USB Type-A connections, HDMI-out, a Gigabit Ethernet jack, two SD card slots and USB-C power delivery.

Sure, your drinks might stay nice and cool while you’re doing your nightly Netflix binge, but if you want to take your spirits with you on your next stroll or hike, one of Brumate’s containers will come in handy. Right now, Brumate is giving Kinja readders 20% off their entire line of products, including the Hopsulator Slim, using code KINJA-20. Sure, the bars might be closed right now, but that doesn’t mean a cold beer won’t be a welcome companion at your post-hike sunset viewing.

Right now, Best Buy selling an Instant Pot Viva 6-quart 9-in-1 Multi-Use Pressure Cooker for a low $50. This multi-purpose device can replace numerous appliances in your home; it can act as a rice cooker, steamer, and a whole lot more. It’ll quickly make eggs, stews, and is a wonder for making stock.

There’s no shortage of recipe books and lifehacks to use with Instant Pots, so you’ll probably be able to make your meals for the week a breeze.

This current price is one of the lowest we’ve ever seen on this particular Instant Pot. But just remember, this is a one-day sale. So get yours before they run out.

In your quest to find the perfect night’s sleep, don’t forget to upgrade your pillows. Right now, you’ve got two, super-customizable memory foam options to get your sleeping posting just right: a $24 queen-sized foam pillow and a contoured pillow for $31. Both options have a removable middle layer to change up the height and thickness of your pillow.

For the contoured pillow, use the promo code uttupillow and for the more standard version, use the promo code uttuqueen at checkout.

Nowadays, the best part of my day is my long, hot shower. Free from noise and panic of the world, it’s one of the few times in my day I’m not bombarded with frightening news. Of course, no great bath would be complete without a super luxurious towel to cap off the entire experience.

Right now, Huckberry is dropping the price on a number of Onsen towels. Onsen’s waffle weave towels are made from environmentally-friendly cotton, and will get softer over the course of your ownership.

Add a modern, futuristic twist to your decor with this rad Aukey RGB Circle Table Lamp. In addition to its uncommon, attractive shape, this particular model offers six lighting modes, four lighting effect speeds, and four brightness levels. It also comes with a remote for a convenient way to customize your experience.

Make sure to use the promo code Y26FFDIG to get the best price.

You have tons of time on your hands, so why not spend that time with a bit of spring cleaning? For just $17, you can get your hands on a six-pack of foldable storage bins you can place basically anywhere in your home. Need to hide away all the mail sitting by your front door? Use a storage bin. Got a bunch of dog toys all over your floor? Use a storage bin. You get a storage bin, you get a storage bin, and YOU get a storage bin. They’re ready for you, just go ahead and buy one!

50% off Alara Technology iPhone Cases | Gadget Guard | Use code GIZMO50

Whether you’re really worried about cell phone radiation or you just like to have all your bases covered, a little extra protection for your phone is never a bad thing. Right now, Gadget Guard is giving Kinja readers 50% off its iPhone cases with Alara radiation-protective technology, using the promo code GIZMO50.

Man…life during quarantine is bleak and the nights are long. Why not make it more entertaining with not one, but TWO vibrators for a cheap $40 (it’s basically two for the price of ONE). First you’ll get a g-spot rabbit vibrator for dual stimulation that’ll make you see stars, and you’ll also get a traditional vibrator with seven tingly modes of vibration because why the hell not? The best thing about these sex toys though is that you can use them with or WITHOUT a quarantine buddy. So why not treat yourself to some bomb orgasms? You deserve it. Buy it while it’s hot!

Thanks to Lelo’s “Stay At Home” sale, you can get your hands on a Sona 2 Cruise for a decent $118. If you’re not familiar with Lelo products, they’re a luxury sex toy brand that provides sleek, and hella pleasurable toys to anyone with a vagina. It’s that simple. The Lelo Sona 2 Cruise is specifically designed with sensonic wave technology to offer constant pressure on all your private parts, as well as “cruise control” to increase pressure when you apply more force, or less depending on your mood. Grab this toy and you’ll be sure to climax again, again….and again!

Do you like to shave? Would you like to continue to even with a global pandemic? Well, you’re in luck! For only $9, you can get a Billie razor subscription. It includes the razor itself, as well as two replacements. Once you get on the website, you’ll be able to set the frequency of which you want razors to be delivered to your front door based on how much you actually shave! We love customizable plans! I’d go ahead and try this subscription service. What else do you have to lose?

Banish neck and back pain forever with this discounted BesDio XLarge Heating Pad. This particular model can be worn like a cape and is just $20 when use promo code KINJA3ZR at checkout. It’ll target and soothe your shoulders, neck and back with your choice of 10 heat settings.

To be honest, ever since I started working from home three weeks ago, my neck and back have been hurting. And I doubt I’m alone. If you have a particularly robust HR or acquisitions department, maybe ask them to order this for you.

If they say no, this is a worthy splurge in these troubled times.

Grab the popcorn, turn your bias light to eye-bleeding neon green, and watch one of the Matrix movies—or anything else that catches your eye in this Vudu weekend sale—for just $5. There’s also The Book of Eli, Ghostbusters, The Social Network, Spider-Man (2002), Men In Black, and more than 30 other films. Check out Vudu’s full selection here, and don’t forget that damn popcorn! (No kettle corn, please. Seriously, anyone who eats that stuff hates taste buds.)

Amazon is giving away three months of access to its increasingly impressive music service, after which you’ll be asked to pay $8 monthly to continue. That’s cheaper than most others, though, and you may like what you find after signup.

Amazon has one of the most extensive catalogs with over 60 million tracks, and the mobile app supports Alexa and all the devices she loves to dwell in, so you don’t have to move an inch in bed to start that morning routine playlist.

For some, the charm of a comic book brings the superheroes more to life than even the movies can, especially if those movies are based in the DC universe. (I still don’t forgive Warner Bros. for Batman v. Superman.) Thankfully, we’re talking about Marvel today, which has several comics up for grabs in Comixology’s latest BOGO offer. It’s simple: you buy one, and another one is yours at no additional cost. Just use coupon code MARVEL2020 at checkout.

Most issues on avail cost just $2, including 2019’s X-Men #1 and #2. You’ll also see a few Powers of X and House of X issues for $3.

With school seemingly out forever, you’ll need to find something to occupy your toddler’s mind that doesn’t involve toys, games, and pizza pockets. They might not like it, but you can get them some children’s books to at least pretend they’re using their time productively, and Amazon is helping out with up to 50% off a pretty sizable collection of them.

There aren’t a whole lot of recognizable titles here, but the artwork in some of these books is impressive, and with titles as cheap as $5, now’s a good time to stock up. I’m personally in love with Deborah Heiligman’s CoolDog, SchoolDog based on its description alone:

Tinka is a cool dog, a school dog, a breaking all the rules dog. A hall dog, a ball dog, a crash-into-the-wall dog.

My kind of dog.

Want a slew of decent-to-good indie games you might not otherwise pay for? Twitch Prime has your back, and you can sign up for a free 30-day trial right now to download full games like Turok, Etherborn, Kathy Rain, Earthlock, and Lightmatter this month.

Not only that, but you can take home fresh loot for your daily mainstays, too, like the DOOMicorn Slayer Master Collection DLC pack which, yes, turns your Doom Guy into an ass-kicking, head-ripping, guns-blazing PINK. WINGED. UNICORN. What’s more metal than that? Oh, I don’t know, maybe a Rainbow Six Siege skin that transforms Mozzie the operator into A PIZZA SLICE.

All that and more when you sign up for Prime which also includes, mind you, free movies like the excellent The Last Black Man In San Francisco, Mid90s, and The Florida Project, among other modern day classics.

It looks like this homebound lifestyle is going to be around a lot longer than we originally anticipated, so a lot of people are gaming right now. Whether you’re new to Xbox One or you’re nearing the end of your current subscription, Amazon is offering an excellent deal to add Xbox Game Pass Ultimate time to your account. You pay the usual $45 for three months, and Amazon will throw in another three months on top of that. You’re limited to one code per account and mailing address, too, so no hoarding—that’s what tissue is for.

Game Pass Ultimate is an insanely good deal. Not only do you get Xbox Live Gold access—which entitles you to multiplayer and free games each month—but you’ll also get instant access to the hundreds of games currently on offer via GamePass, including some heavy-hitting triple-A first-party titles on launch day like Gears of War 5.

P.S.: Microsoft is also running a pretty good deal of its own, giving you your first month of Game Pass Ultimate for just $1, after which your monthly bill jumps to the usual $15. This offer is only good for new subscribers.

I’m not really a pink kind of guy, but I might disregard my insecurities for this Xbox One Phantom Magenta special edition controller, which Amazon has on a $10 discount right now to bring its price down to $60.

That may seem like a lot considering it isn’t tied to any particular and there are no crazy designs on it, but the controller chassis starts as a solid magenta at the bottom and fades into a translucent pink toward the top, a much nicer take on see-through tech than the eye-gouging horrors we’ve lived through in the past ten decades.

Storage

Power

Audio

Home Theater 

Computers & Accessories 

PC Parts 

Mobile Devices

Photography

Home Goods 

Smart Home 

Kitchen

Tools & Auto

Apparel 

Beauty & Grooming 

Camping & Outdoors

Fitness

Movies & TV

Books & Comics

Gift Cards

Peripherals

PC 

PlayStation 4 

Xbox One 

Nintendo

Toys & Board Games

You never know when you’ll need a power bank. Whether the lights go out or you’re going on a remote hiking trip that’ll absolutely come with some Animal Crossing breaks along the way, the RAVPower 16750mAh packs enough umph to last you to your destination. Better yet, it costs just 18 bells with our exclusive promo code KINJA0331.

Plug it in at checkout and watch your savings soar. RAVPower claims its 2A ports reduce charging times by half and that its 16750 portable charger is 20% smaller than an iPhone 8. It also comes in white, but sadly this deal only extends to the plain black model.

If you’re looking to invest in a pair of truly wireless headphones, the TaoTronics SoundLiberty 53 are down to just $28 with our promo code KINJA987. In his review, Whitson Gordon says they have “no business being as good as they are for that low a price.” And he was referring to their $40 retail price.

I enjoyed my time with the TaoTronics quite a bit, and regularly found myself marveling at what you get for the price. If you value the convenience of true wireless earbuds over all else and keep your expectations in check just a little—don’t expect an AirPods-level experience—these are pretty solid earbuds for on-the-go tunes.

Getting outside for a movie night in the backyard could be the perfect way to combat cabin fever, and if you grab one within the next few days, you can take $80 off an Anker Nebula Capsule Max projector to help get the job done. Your total falls to $390 when using coupon code KINJA2423. Unfortunately its resolution tops out at 720p, but you can stretch the image up to 100 inches, it’s small enough to fit in a bag, and with Android on board, you can load up YouTube and Netflix right on the Capsule Max itself.

Have big plans to bake a sourdough this weekend? Start by investing $100 in this awesome Le Creuset Iron Handle Skillet. Highly regarded in kitchens everywhere, Le Creuset is synonymous with quality products and this 10.25″ skillet is no exception.

The big problem? Le Creuset products rarely see discounts. But we found a terrific one for this white model. This pan, no joke, hovers around $170. So this is a terrific bargain.

Le Creuset says their “improved enamel interior resists staining, dulling, and wear and tear” and doesn’t require additional seasoning, unlike other cast-iron cookware.

So you’ve finally graduated from Lipton’s and you’re ready to seep your own quality leaves, eh? You could do it in a regular old pot, but nothing does it like a tea kettle, and if you’re serving guests, you don’t want it looking like it came straight out of a medieval soup kitchen. Consider buying this 2-quart stainless steel tea kettle by All-Clad, which is down to $48 following discounts and virtual coupon clippings. You and that pesky mother-in-law who criticizes everything you do can thank me later.

If you miss your standing desk setup from the office, you can convert your dining room table desk into one for just 83 Bells today. Use the promo code KJDSK to knock 17 bells off the price. This riser sits on top of your existing cardboard box desktop and can be adjusted to go higher or lower depending on your preference.

This particular model has enough space for two monitors and offers a slot for your smartphone or tablet to sit up front. Plus, you have a little shelf for your mouse and keyboard which is super nice.

Just note that we’ve seen DailySteals stock run out quickly after posting, so don’t hesitate if you’ve been mulling one over.

Right now, you can save 15% off Bokksu subscriptions and gift boxes with our exclusive code, KINJA15. If you’re unfamiliar, Bokksu is a snack box subscription service that delivers “Japan-exclusive snacks to your door.”

When I first encountered Bokksu, I thought to myself, “Well, I don’t need that” since I consider myself an adventurous snacker and I’m currently living in Elmhurst, Queens where there are amazing Asian snacks abound.

However, I gave it a shot and was pleasantly surprised. There were plenty of treats included in the box that I’ve never seen before and I thoroughly enjoyed all of them. There was a varied selection of sweet and savory, so I never got tired of anything. Quite frankly, the Bokksu box I received was one of the best things to happen in recent weeks.

The best part? There’s a handy guide that gives you all the info you’d want on each treat (including allergy info) that removes a big barrier that often comes with trying new things with non-English labels.

That summer wardrobe isn’t going to build itself. Let PUMA help you out with its latest sale, where select shoes and apparel for men, women, and children get an extra 40% off using code SPRING40, and that includes free shipping for any orders over $35. There are way more shoes than anything in each category, and the styles are varied enough that—unless you’re Amish—you should be able to find something you like.

If you’re looking for an affordable, comfortable refresh to your springtime wardrobe, here’s your chance. JACHS NY is offering a ton of short-sleeve knit polos, henleys and t-shirts starting at just 15 bells.

The entire collection is basically what I love: upgraded basics. I, for one, am partial to the Jet Black Sueded Cotton Short Sleeve Henley. It’s just… so simple! And elegant.

So, if you’re looking to stay comfy in these particularly trying times, this is the deal to take advantage of. Our colleague Tommy says, “Those are in limited supply, so act fast if you’re serious.”

Just make sure to use the promo code SSK at checkout. And as always JACHS NY offers free returns, so go wild.

There’s a lot of discourse surrounding the benefits of CBD and whether the Cannabid sativa extract is actually beneficial to those experiencing chronic pain and anxiety or if it’s a placebo cleverly marketed as a cure-all antidote. Whatever you believe (I, myself, have seen the positive effects of a good batch), JustCBD is offering 25% off its entire selection of CBD gummies right now using our exclusive discount code KINJA25.

Chill out, maybe watch a movie and fall asleep halfway through. Gummies at CBD start at 8mg and cap out at 25mg/piece, so there’s a wide gamut of dosages to choose from. Especially right now, we need all the help we can get for our mental and physical health. To that extent, CBD is a proven aid, and gummies are the most fun way to consume it.

Released today, the new Mystery Ranch x Huckberry Mission Hybrid shoulder bag would normally set you back a whole $240. But for the next 72 hours, it’s down to $190. The wood wax-colored bag is perfect for taking on walks and isolated hiking trips.

Its three-way zip pocket lets you store “documents, valuables, and other gear” and is securely fastened in place while you’re moving around. A zippered and divided EDC department is perfect for essentials while a designated boot bag keeps your muddied-up boots away from the stuff you don’t want to get dirty, such as your laptop which also has its own sleeve.

Peak Design products are legendary among photographers and organization nerds. And right now, you can save up to 40% on Peak Design products, including retailer exclusives, over at Huckberry.

To sweeten the deal, Peak Design is offering 20% off all products (except Travel Tripod + tripod accessories) and 40% off all V1 Everyday Bags on its own site.

Expertly-designed and well-built, enthusiasts trust Peak Design products to carry and protect their valuables but prices have always been a barrier for most of us. These discounts, however, lower that barrier quite a bit.

The sitewide sale goes for one week only and ends April 6 while the Huckberry deal has no known expiration date. Supplies are limited, so act quickly before your bag gets shipped to someone else.

Looking to get some new workout gear or at least some super comfortable clothes to work from home in? Right now, you can save 20% off Olivers entire line of pants, shorts, tees and outerwear when you use the promo code INITTOGETHER at checkout.

If you’re unfamiliar, Olivers makes some of our favorite men’s activewear that doesn’t look like activewear,

We’ve written about the Olivers mystery boxes before and it’s been a super popular promotion. Olivers decided to go for a more traditional route this time around and pick out your own goodies. And it’s all good, so browse around and save.

We’re all spending a little more time inside right now, so it’s a good time to stock up on cozy loungewear, or maybe a new work from home uniform. Starting tomorrow, and going through Monday, Nordstrom Rack is having a “Buy More, Save More” sale on its entire online store.

Spending $100 will save you $15, $150 will get you $30 off, and you’ll save $60 when you spend $200. Plus, all orders qualify for free shipping.

Whether you’ve already lived through Forky’s (I still think he should have been named Sporky) cute-yet-maddeningly-sad identity crisis or you’re brand new to the Toy Story universe, Microsoft is giving you a prime opportunity to spend more time with your favorite plastic gang. The Toy Story four-film collection is 73% off, and that includes the 4K Ultra HD versions for just $22. You can also snag it in HD for $17.

Microsoft Store digital titles are viewable on PC, Xbox One, Xbox 360, Android, iOS, and even HoloLens. You’ll need an Xbox One S or Xbox One X to watch in 4K, however, so be sure to go for the HD version if you don’t have a console.

Looking for a way to help out in the COVID-19 efforts? I mean, more than just staying at home? Well, here’s your chance: Humble’s special one-week bundle features over $1,000 in incredible games for just $30. Humble says “100% of the proceeds from your bundle purchase go to support organizations responding to COVID-19.”

As an added bonus, there’s a ton of great games here including Superhot, Hollow Knight, Into the Breach, Undertale, Brothers, Tropico 4, and so much more. So do your part, send ‘em $30, stay home, and play video games.

Because that’s what heroes do.

The PlayStation 5 is almost here, but if you haven’t already, you should really give the PlayStation 4 a shot, and Woot’s latest offer might be the most enticing proposition for doing so. You can pay $250 for a PlayStation 4 Slim, and you’ll get three games alongside it: God of War, Horizon: Zero Dawn, and The Last of Us: Remastered, all of which I’ve played, and all of which I’d probably give a limb for if I couldn’t. OK, maybe it’s not that serious, but if you’re bored as shit and you’re willing to give the middle finger to productivity, it’s certainly worth the $250.

Soulcalibur VI’s shaky start didn’t help its long-term momentum, and now this perfectly good game is being sold dirt cheap. Amazon has the Xbox One version for $16. Our PlayStation 4 friends can also get it cheaper than normal at $19.

If you’ve played one Soulcalibur, you’ve played them all, but Soulcalibur VI shakes it up with new fighting mechanics, a fresh dual-pronged campaign, a versatile and flexible character creation that’s responsible for some of my worst nightmares, and some of the most realistic boob physics you’ll find in gaming. Sold? Hit those links below.

Oh no, I totally get it: that brutal ass beating you took in Mortal Kombat 11 was definitely because you were using your controller instead of a legit arcade stick. Let’s fix that: Amazon has Razer’s Panthera Evo tournament stick for $170, a $30 discount. It’s designed for use with PlayStation 4, has plug-and-play support on PC, and can even be used with the Nintendo Switch and Xbox One with some added hardware.

You’ll find 10 face buttons and an eight-direction joystick, which should be more than enough to make sure you don’t whiff another game-ending combo when it’s all on the line. It’s also fully moddable, so you can swap out the buttons and joystick once wear and tear eventually get their way.

Shep called this $19 shelf from Elevation Lab dumb. It is. But the good kind of dumb, like eating cheese despite being lactose sensitive, or telling your ex how you still value her friendship…

Um.

You know what’s not dumb? Using the promo code KINJASHELF to bring it down to just $19. In his review, Shep said:

In hindsight, the Elevation Shelf is about as simple and obvious as a product can be. And yet, there are surprisingly few low profile under-desk storage options out there, and those that do exist require drilling into your desk, which may be frowned upon your office. In fact, I’d say 99% of desk organization products are things that go on top of your desk, but for small items like your wallet and keys, utilizing the oft-wasted area under your desk is a much better use of space.

This is absolutely perfect for everyone WFH right now. But just a heads up, this sold out when we last posted about it. So get yours, or else we’ll know who the real dummy is. (It’s me, it’s always me.)

I’ve said it a million times and I’ll say it again: Mental health care IS health care, and therapy is a crucial part of treating your symptoms. You might be feeling down in the dumps right now, and that’s ok, you’re not alone. If you need to talk to someone but can’t leave your house, know that Talkspace is the number one online therapy service around and they’re offering $100 off your first month with the coupon code REMOTE100.

Considering it starts at $65/week, you’re basically getting a free 7-day trial and then some. As part of the service, Talkspace is currently promoting their COVID-19 stress and anxiety management program to all subscribers, including those taking advantage of this very discount. Try it out, and let me know how it is because I’m genuinely tempted to sign up myself.

There’s a shaky history behind antivirus software, mostly due to high cost, obtrusive ads, spyware, and a knack to gorge on system resources. Lots of programs have improved in all of those areas over time, such as Webroot, which makes an antivirus app designed specifically for gamers that’s $10 off at Amazon today. You’ll get a full year of coverage for one computer for that price.

Webroot combines its deep threat definitions and scanning with a lightweight UI, faster scans, and a system optimizer that helps keep your operating system running its best.

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The numbers on Connecticut’s newest crop: CBD hemp

The numbers on Connecticut’s newest crop: CBD hemp

hemp
Credit: CC0 Public Domain.

.

CBD hemp, a new crop in Connecticut, might earn farmers between $5,000 and almost $12,000 per acre, according to a report from UConn’s Zwick Center for Food and Resource Policy and Department of Agricultural and Resource Economics.

The study is the first of its kind to measure expenses and returns for CBD hemp in Connecticut. Since the death of the 2019 Farm Bill, farmers have actually aspired to grow the crop to meet market need for cannibidiol or CBD, a chemical compound that has gained popularity in a wide range of items over the previous numerous years.

Jeremy Jelliffe, a researcher in the Department of Agricultural and Resource Economics in the College of Agriculture, Natural Resources, and Health was lead author on the study. He says the vital need for the report became apparent in the spring of 2019.

” Hemp cultivation has been forbidden for so long and as an outcome there has actually been restricted research and info on it,” Jelliffe says. “Considering that Connecticut approved the pilot program so growers could start growing in 2019, there was a call for additional info.”

Jelliffe explains this report focuses only on the economic viability of CBD hemp farming.

But just like any new crop, there’s a lot that needs to be learned by farmers, from finest practices to overall economic practicality. The report tries to fill some of these knowledge gaps by taking a complete look at the crop, from the cost of startup, to the expense of growing the crop, and the possible returns.

” The first portion of the report is straightforward, we developed a budget design comparable to if we were going to start our own hemp production,” Jelliffe states. “We looked at the recommended technologies from agronomists,” states Jelliffe.

Jelliffe authored the report with professor Rigoberto Lopez and UConn extension teacher Shuresh Ghimire, who has actually been working carefully with the first wave of hemp growers in the state.

The scientists identified great management practices to present a model that growers can reference, Jelliffe states.

” What we provide is a bit different than what I would think of as common growing practices right now however what we anticipate to become more extensively embraced. Some practices we provide include utilizing plasticulture, drip watering, fencing, things that not everyone did (in the 2019 growing season) but after the first season I think more people will be inclined to do,” he states.

Jelliffe states the complete report describes criteria coming out of different research study hubs from around the nation.

” Other scientists have actually been taking a look at hemp intensively over the last numerous years, because the last Farm Bill from2014 With this report we integrate information from other reports to offer more information to the growers. In terms of expense and returns the reality sheet has a really great summary,” says Jelliffe.

The scientists approximate that it costs about $19,000 per acre to grow hemp, including $6,570 in fixed costs and $12,719 in variable expenses, meaning expenses that alter with the level of production. The yield per acre is dependent on lots of variables, such as regional rates, CBD content, and overall dried flower gathered.

At the prevailing local price, farmers can anticipate to earn approximately $24,375 in revenue per acre, for an earnings of between $5,086 and $11,656, depending on those variable costs

” Ultimately,” the scientists write, “the success of this business will depend upon technical abilities of private farmers (yield and CBD content) along with external market forces, predominately CBD rates.”

” We are estimating that the local price will continue to drop this year with the big supply that is out there, and finest case, we will see a cost of one dollar and twenty-five cents per pound, per portion of CBD, per acre,” states Jelliffe.

Though the price is not as high as some had actually hoped at the start of the 2019 growing season, Jelliffe states he believes that farmers are coming to face the truth in the market.

” The ones who make the most cash are the ones who can do it most effectively, produce the very best quality, and market it at a premium. Farmers know that is how it works no matter what the crop is and they are all attempting to produce the best they can. They stabilize this with the price they anticipate to be able to get.”

Jelliffe is hopeful the report will assist farmers get the most out of their growing business.

” It has been interesting to work with Connecticut growers that are learning more about this brand-new crop and how to finest grow it,” he says. “I believe there is a lot of capacity for profitability but I likewise believe there is a great deal of risk and unpredictability that we have seen with the drop in costs. Ultimately it is going to take a while for those who are actually committed to this brand-new crop to figure it out.”.

Citation:.
The numbers on Connecticut’s most recent crop: CBD hemp (2020, April 3).
obtained 4 April2020
from https://phys.org/news/2020-04- connecticut-crop-cbd-hemp. html.

This document undergoes copyright. Apart from any fair dealing for the function of private study or research study, no.
part may be reproduced without the written approval. The content is attended to information functions only.

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The best hotels in New Orleans

The best hotels in New Orleans

When you buy through our links, we may earn money from our affiliate partners. Learn more.

Best Hotels in New Orleans 4X3



Tripadvisor; Alyssa Powell/Business Insider


  • With its colorful festival culture, buzzy food and drink, vibrant music scene, and historic neighborhoods, New Orleans is an attractive destination year-round.
  • There are dozens of hotels from international chains to unique, independent inns and historic hotels that have been family-owned for generations. A new wave of trendier, design-forward hotels are springing up as well.
  • Outside of festival seasons, entry-level rooms can be found at four-star hotels under $100 a night, rising just to $350 for the top-tier properties. Our top hotels were chosen based on recent stays, expert insight, and reviews from trusted travel sites.
  • Read all Business Insider hotel reviews here.

A note from your Insider Reviews travel editor: Coronavirus has interrupted travel on a global scale forcing travelers to cancel and reassess plans in the coming weeks and months. We understand that right now is a challenging time to plan travel. But when this time passes and things return to normal, we know you’ll be eager to explore the world again.

Whenever that happens for you, and we know it will, we hope our travel content helps you make informed, useful, and inspiring choices on the best places and hotels to book. So whether you use our reviews now, bookmark them for the future, or simply need an escape from the news, we’ll continue to share the world with you. In the meantime, we encourage all travelers to stay safe, follow guidelines from the CDC website, and take precautions.

New Orleans remains one of North America’s most idiosyncratic cities. It is culturally rich and has — certainly in the French Quarter — one of the most alluring historic neighborhoods anywhere in the world. Add world-class music and culinary scenes, a year-round festival circuit, racially diverse heritage, and a bohemian reputation, and you have quite the destination.

The city has long been a hugely popular tourist destination with over 18 million annual visitors in recent years — a million and a half of these coming for the city’s biggest event, Mardi Gras. This, coupled with a healthy convention industry, has driven strong hotel growth.

Preservation restrictions forbid the construction of large hotels in the French Quarter itself, but a rash of new properties have opened up in the neighboring Central Business District (CBD), with many large national chains, as well as smaller, character-filled boutique properties in converted historic buildings. Many brands pick New Orleans to try out niche collections.

I’ve been visiting since 2001 and have lived in New Orleans since 2011, and the variety of hotels is impressive. I’ve stayed in every hotel on this list multiple times, through openings, rebrandings, and refurbishments. They all offer excellent value while maintaining very good standards of hospitality and are well-placed for business and tourism.

I’ve chosen properties based on my own experiences, with a starting price point under $100 rising to just shy of $350. All are well-rated on sites such as TripAdvisor and Booking.com. Most are newer, contemporary, and design-forward to create a real sense of place, though some are wonderful historic hotels, and others are familiar corporate brands. In their own ways, each reflects the culture of New Orleans.

Thanks to New Orleans’ healthy roster of huge festivals, prices can vary wildly. Rooms are very expensive around Mardi Gras (February to March) as well as Jazz Fest weekends (April to May), Essence Fest (July) and VooDoo Fest (October). The summer months are cheapest since the humid climate makes it a less comfortable time to visit.

New Orleans attracts a lot of visitors for a wealth of reasons, and everyone has a preference when it comes to hotels. Thankfully, the Crescent City’s properties appeal to all tastes, with value as strong and attractive as the city itself.

Traveling elsewhere? Read our list of the best hotels in other popular cities:

Keep reading to discover the best hotels in New Orleans, sorted by price from low to high.

Old 77 Hotel and Chandlery

Old77



TripAdvisor


Book Old 77 Hotel and Chandlery starting at $87 per night

It’s not every day you get to stay in a converted chandlery (maker of supplies for ships) but this art-forward, converted 19th-century warehouse in the CBD offers guests that exact opportunity.

The interior boasts refined dark wood fittings that contrast with exposed brickwork, and a rotating display of work from local and regional artists creates a reassuringly cultural space. There’s even a vending machine with miniature pieces of original art. 

The brickwork continues as a visual motif into guest rooms themselves, which also come with a pleasing amount of space and light. Expect some cheeky modern art, a very comfortable white-tiled bathroom with a walk-in shower, and the option to order a selection of pillows and inspirational books.

Downstairs, the Caribbean brasserie of Compere Lapin is one of the city’s most exciting restaurants, complemented by a bar with a well-curated craft cocktail menu. 

Trip Advisor Ranking: 83 out of 176 hotels in New Orleans

Booking.com Rating: 8.3 out of 10

Pros: The interior design is one of the most pleasing in the city, and having such a high-quality restaurant on-site is a real bonus. The comfortable rooms offer excellent value. 

Cons: There’s no swimming pool, though there is a small exercise room for keeping up those fitness regimens.

The Troubadour Hotel New Orleans

the troubadour



TripAdvisor


Book The Troubadour Hotel starting at $114 per night

This intriguing property lies at the far edge of the CBD, and outwardly, seems to be just a fairly nondescript 1960s office block. But through the doors is a different story, with a kaleidoscope of colorful, sleek retro interiors and patterns, striking sculptures of musical instruments, and design flourishes that switch between decades seamlessly. There are plentiful sofas for lounging on the ground floor and mezzanine, some nooks feel futuristic, others are straight out of a scene in Mad Men. 

The rooms are a delight and the entry-level Troubie King dazzles with floor-to-ceiling windows and visually exciting geometric patterns amid blues and gray tones. Light fittings are just shy of kitsch, as are the locally-sourced artworks, and there are aspects of both 1970s and contemporary luxury about the place. The self-service cocktail kit and huge walk-in shower feel decadently adult.

The rooftop bar, Monkey Board is as sexy as any in the city, with its taco stand and views, and restaurant Jayne has a great selection of elevated casual favorites.  

Trip Advisor Ranking: 75 out of 176 hotels in New Orleans

Booking.com Rating: 8.6 out of 10

Pros: Don’t let the lower Trip Advisor ranking fool you, the design-forward rooms offer some of the best value accommodations in the city. 

Cons: The rooftop bar space is crying out for a small pool, but sadly there isn’t one.

The Pontchartrain Hotel

pontchartrain



TripAdvisor


Book The Pontchartrain Hotel starting at $118 per night

This hotel reopened in 2016 after a 60-year hiatus and the refurbishment was a panoramic triumph. Though the hotel is away from Downtown in the Lower Garden District, it’s a true destination property with 1940s glamour that was lovingly recreated throughout the building. Details such as the gold leaf in the original elevators, staff uniforms, antique mirrors, curated art, and the cinematic period front desk that issues actual metal door keys to guests, all curate a retro aesthetic that is completely on point. 

Guest rooms are equally vintage feeling and unmatched in style in the city. European and Caribbean influences are apparent with tiki-style decor, velvet headboards, and chaise lounges that add to the plush feel. Antique medicine cabinets in immaculately-tiled bathrooms and original wardrobes complete the aesthetic.

Stand-out food and beverage options include the artfully decadent Jack Rose restaurant, but the real jewel is the rooftop bar, Hot Tin, which serves up the best views of the city alongside craft cocktails. 

Trip Advisor Ranking: 8 out of 176 hotels in New Orleans

Booking.com Rating: 9.1 out of 10

Pros: The attention to detail in the refurbishment is astounding, making The Pontchartrain Hotel one of the most evocative hotels in the city. 

Cons: The location is slightly away from the main action of Downtown, but some visitors may prefer the quieter ambiance the slight distance provides.

Hotel Peter & Paul

hotel peter and paul



TripAdvisor


Book Hotel Peter & Paul starting at $134 per night

The Marigny is a mostly residential neighborhood next to the French Quarter, and this hotel a considerate, discreet addition to its streets. Housed in a converted church, both the sacred space and the associated properties such as a school house, rectory, and convent were all repurposed to welcome guests.

The original architecture still very much on display and interiors pay dutiful homage to the former lives of the buildings. Stained glass windows and swathes of richly colored fabrics frame the spaces and there’s a casual holiness to the captivating ambiance. 

The rooms are spread across three of the buildings, and given that the original structures have been preserved, come in a wide array of styles and sizes. There’s a pastoral feel to most, with contemporary rustic decor and gingham furnishings. Religious iconography pops up, landing the rooms somewhere between a farmhouse and a seminary. 

The Elysian Bar is a destination spot with its decadent wall hangings and the striking curved and colorful columns of the bar itself. 

Trip Advisor Ranking: 13 out of 176 hotels in New Orleans

Booking.com Rating: 9.3 out of 10

Pros: The sense of place and former life of these buildings has been honored respectfully and thoughtfully, and it’s a truly memorable place to stay with affordable prices.

Cons: Due to the age and design of the original buildings, some of the rooms can feel quite small.

Read Business Insider’s full hotel review of Hotel Peter & Paul

Hotel Monteleone

monteleone



TripAdvisor


Book Hotel Monteleone starting at $149 per night

Operational since 1886, this hotel is one of the very few family-owned properties of its kind, now under fifth generation management. Exterior lights up Royal Street with elegant Italianate architecture, and the lobby feels alive with old-school European charm. Exhibition cases show off a proud literary history with artifacts from Truman Capote and Tennessee Williams. Service harks back to the Golden Age of travel, and the hotel’s famous Carousel Bar (literally designed around a slowly-rotating carousel bar) is a major tourist draw and has been welcoming guests and locals for cocktails for over 100 years. 

There’s a traditional, almost imperial feel to the rooms with brocaded curtains and striped wallpaper, but it’s the hotel’s public spaces that really shine. As well as the Carousel Bar, the flagship restaurant Criollo serves Southern Classic and live jazz. On the rooftop, one of the city’s best pools awaits guests, and the day spa, Aria, is also suitably welcoming. 

Trip Advisor Ranking: 21 out of 176 hotels in New Orleans

Booking.com Rating: 8.9 out of 10

Pros: The feeling of staying in a truly unique property is unmatched the access to Carousel Bar is a major advantage. Hotels like this one don’t really exist any more in the United States. 

Cons: The entry-level rooms are more functional than showstoppers, though the suites are among the best in town. 

The Hyatt Regency New Orleans

hyattregency



TripAdvisor


Book The Hyatt Regency New Orleans starting at $149 per night

This large convention hotel – still fresh from a $275 million renovation – lies in a plumb spot just behind the Louisiana Superdome. In terms of service and breadth of amenities, it stands alone in the city. Seven award-winning dining options and an outdoor saltwater pool are just a couple of the highlights. The interior is a symphony of glass and steel, with futuristic elevators and striking windows that are a work of art in themselves and stretch for several stories with views of the stadium beyond. 

There are 1,200 rooms, arranged in a horseshoe pattern around the central public space. They are cleaned to hypoallergenic standards and deliver everything you might expect from a successful international brand including a high standard for business design, with gold and ivory accents and a tech-forward feel.

The restaurants run the gamut of high-end to casual, with coffee shops, stores, and a 32nd-floor gym, meaning you don’t have to leave the property if you don’t need to. 

Trip Advisor Ranking: 81 out of 176 hotels in New Orleans

Booking.com Rating: 8.9 out of 10

Pros: Solid quality accommodations with so many amenities that leaving the hotel isn’t necessary. The Trip Advisor ranking belies how good the value of this hotel is.  

Cons: If it’s a sense of place and character you’re looking for, a smaller boutique property would be better. This is definitely a chain business and convention hotel and feels as traditional as you’d expect from a big name.

The Royal Sonesta

royalsonesta



TripAdvisor


Book The Royal Sonesta starting at $166 per night

There are odd touches of class to be found along New Orleans’ tackiest thoroughfare, Bourbon Street, and this grand dame of a hotel is one of them. Taking up a whole city block, stepping inside immediately transports you away from the neon and noise outside into an elegant Art Deco lobby, replete with floral arrangements and sleek sofas. The hotel boasts a 6,000-piece art collection, making it the most cultural spot on the street. 

Thanks to a 2016 complete renovation, the rooms feel fresh with royal blue bedding, maroon flourishes, and decor that feels whimsical without straying into pretension.

The hotel’s flagship restaurant, R’Evolution, is one of the finest in the city providing a gourmet romp through the best cuisine in the South. There’s an on-site jazz lounge for taking in the local music scene, and an outdoor heated pool that’s a blessing year-round. 

Trip Advisor Ranking: 51 out of 176 hotels in New Orleans

Booking.com Rating: 8.5 out of 10

Pros: Staying at Royal Sonesta places you right in the thick of the action, surrounded by the entertainment district of the French Quarter, without feeling overburdened by it.

Cons: Some guests might see the location as a minus, as it can be one of the noisier spots at peak times.

The Higgins Hotel New Orleans

higgins



TripAdvisor


Book The Higgins Hotel New Orleans starting at $170 per night

Not many hotels in the world can say they are the sister property to a museum, but that’s the case here at this unusual property. Neighboring the National World War II Museum, The Higgins reflects a retro 1940s chic feel. The imposing, Gothic exterior gives way to a glorious lobby, with Art Deco aesthetics and huge, floor-to-ceiling murals. Wartime artifacts and music from the period create an impressively evocative atmosphere, all designed to welcome the veterans and history buffs that make up most of the clientele. 

The entry-level rooms are impressive, with inviting royal blues and gold hues in King Rooms that complements the military precision of clean lines and general tidiness. There’s wartime-inspired artwork and kitsch posters as well as panoramic city views.

The hotel’s amenities continue the theme, with Kilroy’s lobby bar and rustic French restaurant Café Normandie both offering additional military aesthetics. Hilton Honors members can use the lounge, which boasts General Patton’s piano. 

Trip Advisor Ranking: 1 out of 176 hotels in New Orleans

Booking.com Rating: 9.2 out of 10

Pros: A truly interesting and memorable property that is right next door to the world-class National World War II Museum, and certainly takes inspiration from it. It’s a must for history buffs. 

Cons: Younger travelers may find the clientele on the mature side, but there’s every respect paid to veterans and servicemen and women.

The Roosevelt New Orleans

roosevelt



TripAdvisor


Book The Roosevelt New Orleans starting at $199 per night

One of the oldest hotels in New Orleans (it dates back to 1893), this magnificent building combines architectural styles from the Gilded Age, as well as Art Deco and Beaux-Arts flourishes. The block-long lobby is stunning, all done up in golden sophistication with murals, elaborate light fixtures, and period furniture. Uniformed lobby staff dart between guests, and there’s an ambiance of a grand, European hotel, including old-school touches such as a shoe-shine stand. 

Off the lobby are famed local institutions, such as the wood-paneled Sazerac Bar and legendary event space, The Blue Room, while live jazz music floats from The Fountain Bar. There’s a traditional feel to the rooms, with dark woods and floral patterns, and suites offering a particularly good value. On-site restaurant Domenica offers upscale Italian classics, and the Waldorf Astoria-branded spa and rooftop swimming pool are elegant relaxation areas. 

Trip Advisor Ranking: 45 of 176 hotels in New Orleans

Booking.com Rating: 8.8 out of 10

Pros: The wealth of amenities and services give guests a reassuring feel of a true full-service five-star hotel. 

Cons: Some of the walls in the standard rooms can be thin, but it’s not a hotel that books in many large parties of young people.

Soniat House Hotel

soniathouse



Soniat House


Book Soniat House Hotel starting at $245 per night

It’s easy to walk right past this early 19th-century complex of high-end Creole cottages tucked away on a tranquil, residential stretch of the French Quarter.

Stepping through the door, though, guests see flickering gas lamps and tropical foliage framing a stone-flagged courtyard. Wrought iron balconies and public spaces bedecked with period antiques hint at the levels of sophistication within, and the hotel serves as a timeless iteration of Southern elegance. 

The 31 accommodations differ in size and layout but all reflect a rustic sophistication. Entry-level cottages come with canopy beds, gold and green color palates, chandeliers, and antique ornaments. Doors open out onto the courtyard, where guests can enjoy freshly-baked biscuits, preserves, and freshly-squeezed orange juice for breakfast, and there’s also a well-stocked honor bar in a plush guest lounge for pre-dinner cocktails. 

Trip Advisor Ranking: 60 out of 176 hotels in New Orleans

Booking.com Rating: 9.1 out of 10

Pros: The feeling of privacy and exclusivity while still staying in the French Quarter is unmatched. 

Cons: With only a breakfast menu (though it is available for most of the day), guests have to rely on dining out options. Amenities on-site are quite limited.

Read Business Insider’s full hotel review of Soniat House Hotel

The Ritz Carlton New Orleans

ritzcarlton



TripAdvisor


Book The Ritz-Carlton New Orleans starting at $279 per night

The New Orleans branch of the global luxury brand dominates a city block on Canal Street and the edges of the French Quarter, in an imposing Beaux-Arts building. Once a high-end department store, it’s now a sprawling, five-star property with all the amenities and comforts visitors would expect of a brand such as The Ritz. The elevator to the lobby delivers a reassuring degree of exclusivity, and the lower floor is dedicated to the hotel’s high-end spa and gym. 

Rooms err on the traditional side, with opulent curtains, oversized embroidered headboards, and a plush blue velvet armchair that create a certain antebellum charm. There’s a club level in its own annex with even higher levels of indulgence.

M Bistro, the flagship restaurant, has a Southern menu that locks in a sense of place, and the Davenport Lounge sees local jazz trumpeter Jeremy Davenport entertain with classic songs for free on weekends. 

Trip Advisor Ranking: 44 out of 176 hotels in New Orleans

Booking.com Rating: 8.8 out of 10

Pros: There’s an assured confidence of booking into a Ritz Carlton property and the standards that come along with that. This outpost certainly does not disappoint.

Cons: The Ritz Carlton New Orleans is one of the more expensive options and the interiors don’t really reflect the city in a very noticeable way.

Windsor Court Hotel

windsorcourt



TripAdvisor


Book Windsor Court Hotel starting at $305 per night

For an unlikely slice of British refinement in the CBD, this 5-star hotel comes complete with afternoon tea service and fine art depicting hunting scenes and high society.

The exterior is unswervingly modern, but inside offers a traditionally luxurious experience following a $22 million refurbishment. The public spaces feel like a private members club with leather sofas and a lingering air of refinement and the heated pool is easily the most alluring in the city. 

The suites (it’s an all-suite hotel) scream classic English vogue, with blue and gold overtones accentuating traditional patterns and views of the river from small private balconies. The all-marble bathrooms elevate the ambiance even more, and though the rooms are decidedly unflashy, they reflect a high standard of design.

The restaurant, The Grill Room, is one of the highest-rated in the South, with its murals and leather-backed chairs, and the Polo Lounge is a sophisticated spot for an after-dinner cocktail. 

Trip Advisor Ranking: 9 out of 176 hotels in New Orleans

Booking.com Rating: 9.4 out of 10

Pros: A high-end, full-service hotel that instantly delivers a real sense of refinement and elegance. 

Cons: Windsor Court is very traditional, and fans of modern design may feel it’s on the stuffy side.

Read Business Insider’s full hotel review of Windsor Court Hotel

Maison de la Luz

maison de la luz



TripAdvisor


Book Maison de la Luz starting at $341 per night

This new (opened 2019) luxury hotel is a side venture from the Ace Hotel brand, and The Ace Hotel New Orleans is just across the street.

This newer concept, however, is not like the minimal mod Ace properties you’ve come to know. Rather, it’s far more exclusive and luxurious. The 67-room property feels like you’ve slipped into the townhouse of a global traveler, who returned to New Orleans and decorated her property with curios she collected. The lobby is framed by glorious twin staircases and retro Art Deco flourishes complete the look. 

The rooms enjoy expert interior design, as well as indulgent amounts of daylight with high ceilings and huge windows. Quirky touches such as zodiac-themed coffee tables and sculpted snakes for shower door handles ramp up the visual curiosity, while stand-alone tubs and high-end mini-bar liquor reflects the 5-star status.

The lounge and restaurant downstairs evoke feelings of an Egyptian museum and French brasserie respectively, and the scarlet library of front bar Marilou is a decadent escape that also houses a secret bar within a bar behind a bookshelf for hotel guests. 

Trip Advisor Ranking: 2 out of 176 hotels in New Orleans

Booking.com Rating: 9.8 out of 10

Pros: The hotel has truly elevated the level of exclusive luxury in the city, and there are no properties quite like it in town. 

Cons: Maison de la Luz is priced higher than most New Orleans hotels, and besides the bar and restaurant, there are no real amenities. For a pool or exercise room, guests need to use those at the Ace Hotel, though this is only a minute’s across the road.

Read Business Insider’s full hotel review of Maison de la Luz

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Disclosure: This post is brought to you by the Insider Reviews team. We highlight products and services you might find interesting. If you buy them, we get a small share of the revenue from the sale from our commerce partners. We frequently receive products free of charge from manufacturers to test. This does not drive our decision as to whether or not a product is featured or recommended. We operate independently from our advertising sales team. We welcome your feedback. Email us at [email protected]

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2 Cannabis Stocks to Buy in the Brand New Bear Market

2 Cannabis Stocks to Buy in the Brand New Bear Market

The COVID-19 pandemic can’t stop these two marijuana companies.

Prosper Junior Bakiny

It’s a scary time to be an investor. Due to fears surrounding the COVID-19 pandemic, the stock market has been hammered over the past few weeks. On March 11, the Dow Jones slid by 5.9% and closed more than 20% down from its most recent all-time high, thus officially entering bear market territory.

With that said, the worst thing investors can do is panic. There are still scores of excellent stocks to consider buying, and now may be an especially opportune time, since many of these stocks are cheaper than they were at the beginning of the year. Here are two cannabis stocks investors should buy right now and hold through the bear market: Charlotte’s Web (OTC:CWBHF) and Innovative Industrial Properties (NYSE:IIPR). 

1. Charlotte’s Web 

Charlotte’s Web is the leader in the U.S. market for cannabidiol (CBD) products. And while this market presents some opportunities, it also comes with its share of challenges. Most notably, the U.S. Food and Drug Administration (FDA) recently warned consumers about the dangers of CBD-based products. According to the health industry regulator, CBD can cause side effects including liver injury. The FDA also said there hasn’t been enough research done about CBD, and the claims regarding its alleged therapeutic benefits remain unproven.

Despite this challenge — and others — I believe Charlotte’s Web is worth buying; let’s consider three reasons why. First, the company has a strong retail presence in the U.S., with its products in about 11,000 retail locations around the country. It is worth noting that the company recently made an acquisition that will further expand its retail presence. On March 23, Charlotte’s Web announced it was acquiring Abacus Health Products in an all-stock transaction valued at approximately 99 million Canadian dollars. 

Per the agreement between the two companies, each of Abacus’s shareholders will receive 0.85 share of Charlotte’s Web for each share of Abacus owned. The transaction is expected to close in the second quarter. Abacus Health offers a suite of over-the-counter hemp products (hemp is derived from CBD) and has a strong retail presence in the U.S. Also, Abacus Health boasts a network of about 16,500 healthcare practitioners. Thanks to this acquisition, Charlotte’s Web’s presence will expand to “15,000 unique doors.”

Second, Charlotte’s Web is currently in the process of significantly ramping up its production capacity. The company is building a 137,000 square foot production facility in Colorado that will multiply its output capacity by a factor of 10. The facility should be up and running by the end of the year. Lastly, Charlotte’s Web is attractively valued, at least when compared to many of its peers in the cannabis industry. Since Charlotte’s Web isn’t yet consistently profitable, let’s compare the company’s price to sales ratio with that of Canopy Growth (NYSE:CGC) and Aurora Cannabis (NYSE:ACB). 

ACB PS Ratio (Forward) Chart

ACB PS Ratio (Forward) data by YCharts

Charlotte’s Web’s comparatively attractive valuation — coupled with its strong retail presence and leading position in the U.S. CBD market — makes the company one of the best investment options in the cannabis industry. 

2. Innovative Industrial Properties

Innovative Industrial Properties is a real estate investment trust (REIT) that focuses on leasing spaces to companies within the medical cannabis market. Let’s consider two reasons why this company is worth investing in. First, Innovative Industrial Properties currently owns 51 properties in 15 states with an average lease length of 15.6 years.

There are many more states in which medical uses of cannabis are approved (there are more than 30 states that have legalized medical uses of marijuana); given that Innovative Industrial Properties is the leading REIT that focuses on leasing properties to state-licensed medical cannabis companies, the company will likely continue its expansion to more states.

A bear and a bull on financial numbers

Image Source: Getty Images

Second, few marijuana companies have been able to post consistent profits, and others have recorded profits thanks to one-time adjustments or other things that had nothing to do with their core operations. For instance, during the fourth quarter of its fiscal year 2020, Aurora Cannabis recorded a net income of CA$10.4 million, but this included unrealized gains on derivative liability of CA$143.8 million.

By contrast, Innovative Industrial Properties has consistently recorded profits. During the fourth quarter of 2019, the company’s net income was $9.6 million, up from $2.3 million compared to the year-ago period. For the full year, Innovative Industrial Properties recorded a net income of $22.1 million, up by 292.7% compared to the fiscal year 2018. Innovative Industrial Properties’ ability to post recurring profits is a major selling point given that few of its competitors are doing the same. 

Innovative Industrial Properties is performing significantly better than the broader market so far this year. Year to date, the company’s shares are up by 11.7%, while the S&P 500 is down by 18.6%. In my view, Innovative Industrial Properties will continue to outperform the market and most other cannabis companies, making it a good cannabis stock to buy right now. 


Prosper Junior Bakiny owns shares of Aurora Cannabis Inc. The Motley Fool owns shares of and recommends Innovative Industrial Properties. The Motley Fool recommends Charlotte’s Web. The Motley Fool has a disclosure policy.”>

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3 Surprises in Cronos Group’s Delayed Q4 Earnings Update

3 Surprises in Cronos Group’s Delayed Q4 Earnings Update

Many investors probably didn’t see these things coming for the Canadian cannabis producer.

Keith Speights

Cronos Group (NASDAQ:CRON) was originally scheduled to report its Q4 results on Feb. 27, 2020. However, the company delayed this update because of a review by the Audit Committee of its board of directors into the recognition of revenue related to wholesale bulk resin purchases and sales.

It took a while, but Cronos Group finally joined its peers in reporting its results for the quarter ending Dec. 31, 2019. The Canadian cannabis producer announced its 2019 fourth-quarter and full-year results after the market closed on Monday. 

Unsurprisingly, Cronos said that it would need to restate its financial results for the first, second, and third quarters of 2019 based on the committee’s findings. But there were several surprises in Cronos’ Q4 update, including these three, in particular.

Three cannabis leaves

Image source: Getty Images.

1. Major revenue shortfall

Analysts surveyed by Zacks expected Cronos to report Q4 net revenue of $12.5 million. The company announced actual Q4 net revenue of only $7.3 million — well below what analysts were looking for. 

Cronos Group’s Q4 net revenue reflected a 71% year-over-year jump. However, its revenue was lower than the $7.64 million recorded in the previous quarter (after its restatement of revenue).

The company reported $2.7 million in revenue during the fourth quarter from its U.S. segment, which consists of the Redwood business acquired last year. Cronos’ rest of world segment, which includes its core business in the Canadian cannabis market, generated Q4 net revenue of $4.6 million.

2. A tidy profit (but don’t get excited about it)

While Cronos Group’s top line disappointed, the company reported a profit of $61.6 million, or $0.16 per diluted share. The consensus analysts’ estimate was for a loss of $0.04 per share. But don’t get too excited about this surprise.

The only reason behind Cronos’ positive bottom line was that the company recorded a gain of $118.8 million on the revaluation of derivative liabilities associated with Altria‘s (NYSE:MO) investment. This accounting gain stemmed from Cronos Group stock sinking during the fourth quarter.

A better number to look at to determine how Cronos fared in Q4 is its adjusted earnings before interest, taxes, depreciation, and amortization (EBITDA). The company posted an adjusted EBITDA loss in Q4 of $51.9 million, a significant deterioration from the adjusted EBITDA losses of $5.8 million in the prior-year period.

3. CBD pause

In November, Cronos Group CEO Michael Gorenstein spoke excitedly in the company’s Q3 conference call about the launch of its new PEACE+ hemp-derived CBD tinctures in the U.S. market. He said that Cronos would use Altria’s sales and distribution network to build sales for its hemp CBD products.

That was then. On Monday, Cronos stated that it decided to “pause” the distribution of PEACE+ CBD tinctures through Altria’s sales and distribution network. The company said that it “will continue to evaluate other product formats and categories that we believe may be more suitable for the PEACE+ brand in the evolving environment.”

Looking ahead

The main issue for Cronos Group right now is the same one that impacts nearly every company in North America and across the world: the novel coronavirus pandemic. All of Cronos’ facilities remain in operation, though. Cannabis has been designated as an essential business in areas where the company operates. However, Cronos acknowledged that it could be impacted by the COVID-19 crisis.

This viral outbreak will likely dampen the anticipated growth in Canada’s Cannabis 2.0 market for cannabis derivatives products over the short term. As a result, Cronos’ revenue growth in 2020 could be a lot lower than hoped.

But the company claims something that most marijuana stocks don’t, namely a strong balance sheet. Thanks to Altria’s investment, Cronos’ cash stockpile totaled $1.5 billion at the end of 2019. That should be more than enough for the company to weather the storm caused by COVID-19.

Editor’s note: A previous version of this article incorrectly referenced Cronos Group’s financial results in Canadian dollars instead of U.S. dollars. The Fool regrets the error.


Keith Speights has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.”>

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Our Editors’ All-Time Favorite CBD Products

Our Editors’ All-Time Favorite CBD Products





By now, the entire world seems to have hopped onto the CBD bandwagon—even your mom is probably sipping on CBD soda in the afternoon—and it’s for a good reason. It has a reputation for delivery calming effects in a natural, accessible, and simple way.

If you aren’t familiar with CBD (or don’t know the specifics), it’s short for Cannabidiol, which is known for its anti-inflammatory, pain-reducing, and mind-lifting effects. It’s part of the hemp plant that you can take for its calming effects, but without the high that THC gives you. If you’re afraid of CBD because you associate it with marijuana, fear not: by definition, marijuana needs to have 0.3 percent THC or higher—which hemp does not.

Another perk of CBD? It can be taken in a variety of forms—from capsules to drops to creams to, yes, even drinks. There’s a form of it for everyone, and after months of trial and error, our team has found the product that works the best for each of us (and what we’re looking to get out of CBD) with the help of Equilibria. Instead of blindly picking up the same CBD oil your friend has, Equilibria take the guess-work out of the process by providing you with products and dosage tailored to you. 

Our editors all started with the Brilliance Box and with the help of Equilibria’s Dosage Specialist, found a routine that works best for them. No more Googling how many drops you should be taking and winging it—this process is literally made for you.

Equilibria

Brilliance Box

use code THEEVERYGIRL for 20% off your first order

A well-rounded and effective CBD routine includes a combination of all three products. But today we’re focusing soleley on the one (yes, only one!) product they consider their holy grail. Read on to see which must-have they can’t stop reaching for:















Equilibria

Relief Cream

I’ve seen physical therapists and chiropractors pretty regularly since I was in high school—as a runner, former athlete, and current neck-stress-holder, I’ve frequently sought relief from muscle pain and sports-related injuries. Now that I’m an adult, I’m constantly on the lookout for products to help with my tight neck, shoulder, back, and leg muscles. This cream is an absolute gamechanger—I rub it on my neck at least once a day as I hunch over my computer while working, and I like to rub it on sore muscles and joints after a long run (or even just when waking up stiff from a weird night of sleep). Additionally, I love slathering it all over my lower stomach before and during my period—it soothes my cramps SO well (and I don’t say that lightly—I really mean it!).















Equilibria

Daily Softgels

As I’m sure many of you can relate, my stress levels have been a bit higher than normal in recent weeks. Of course that is the opposite of what you want for yourself when you’re trying to stay healthy. In an effort to keep myself feeling good physically and emotionally, I started taking Equilibria’s daily capsules every morning along with my vitamins. The capsules are fat soluble and I have avocado almost every morning, so it works perfectly. The slow release helps me maintain a much-needed calm throughout my day, allowing me to focus on work and my family, and less on spiraling thoughts about the current state of the world.







Equilibria

Daily Drops

When I tried Equilibria, I wasn’t new to CBD; however, I was so intrigued to try their products for my endometriosis pain. I started with the Flavored Daily Drops at night, and then I tried them in the morning. I ended up loving them so much that I take one drop before bed and one before I start work in the morning. I notice a slight difference in my endo pain, but it’s everything else that has made me love them. In the morning, I notice I have less anxiety toward the day, and I have more focus at work. At night, I fall asleep faster and stay asleep longer rather than tossing and turning endlessly all night. Overall, having less anxiety and better sleep does help my endometriosis, which I often notice is exacerbated by stress. My favorite of the Flavored Drops is the mint—Unflavored CBD tastes like hemp and my palette just can’t handle it (sorry not sorry). The mint helps balance the hemp flavor and makes the drops more enjoyable to take.















Equilibria

Daily Softgels

I’ve been a CBD-user for quite some time, but my biggest problem is always laziness. I always forget to take CBD from a dropper, and the relatively nasty taste doesn’t encourage me either. Enter: these miracle capsules. I keep them next to my coffee pot and take them in the morning with my breakfast (they’re fat-soluable), and remember to take them every. single. day. It’s by far the easiest and most convenient way to take CBD, and I feel overall much calmer and at-ease since I’ve gotten into a routine with them.











Equilibria

Relief Cream

I have been a loyal user of the Equilibria products—specifically the pain cream—for almost 18 months. One of the reasons I love this product so much is its versatility. I use it regularly for the aches and pains from lugging my 27-pound toddler around, for sore muscles after running and working out, for my endometriosis pain (I rub the cream on my abdomen), and to help with sleep and stress. Rubbing this cream on various body parts for all of these problems has helped relieve pain and make me feel better on a daily basis.

Use code THEEVERYGIRL for 20% off your first order!

As per FDA guidelines, Equilibria CBD is not intended to diagnose, treat, cure or prevent any disease or ailment. As always, consult with your physician before starting any new program that may interact with your current health plan.

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‘Like Avon but for CBD’: the endometriosis sufferers propping up CBD MLMs

‘Like Avon but for CBD’: the endometriosis sufferers propping up CBD MLMs

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Endometriosis 3

A new strain of multi-level marketing schemes is infiltrating the blossoming CBD industry, with chronic pain sufferers in their ranks

The UK CBD industry is booming. Products are being sold everywhere from B&M bargains for £1 to boutiques where CBD skincare can set you back up to £60 a tube. The most visible part of CBD’s upward trend may be wellness, but it’s also being used to help manage the symptoms of chronic illnesses. 

A recent report from the Centre for Medical Cannabis found 41 per cent of those using CBD in the past year did so for medicinal purposes. And beyond using CBD to help with symptoms, those with chronic conditions are beginning to sell it too.

As someone with endometriosis, I’ve noticed an uptick in CBD products packaged as ‘treatments’ for pelvic pain and in endometriosis sufferers taking and selling CBD. The five women I spoke to who have endometriosis and sell CBD first tried it as an alternative to painkillers like naproxen, tramadol, codeine, and even morphine they previously required but are now unable to. 

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CBD MLM advertisement

Heart & Body Naturals, a CBD MLM

Jo Biggerstaffe Charlseton, a distributor for a CBD company, says painkillers are becoming more difficult to acquire on the NHS. “There’s so many people out there that are taking shedloads of meds (and) are having them cut because of the (risk of an) opioid crisis. The doctor goes: ‘Sorry we’re cutting down your codeine tablets, we’re cutting down your morphine’. They need to find alternatives.” And even when obtainable, painkillers have side-effects which makes long-term use unappetising, if not impossible. 

No wonder CBD, which is non-addictive and seems like a more natural and sustainable option, is attractive, as Dr Yewande Okuleye, Cannabis Medicine Health Strategist at the University of Leicester explains: “This isn’t a new phenomenon. It’s the latest iteration of self-medication in a different patient group, which has come to our attention because of the increased popularity of CBD as an alternative treatment.”

Lack of regulation means brands can make misleading claims with little consequence. The UK’s Centre for Medical cannabis found 62 per cent of high street CBD products did not contain the amount of CBD claimed. And according to current guidelines, companies shouldn’t say their CBD product helps with any medical issue, but I’ve seen countless claiming to soothe, alleviate, treat and even cure everything from minor ailments to serious illnesses. 

Frankie Penfold, a team manager for a multi-level marketing CBD company who describes her job as “like Avon but for CBD” says: “It’s pretty horrendous when it comes to find(ing) out information. I reckon it took me a year to understand it enough to be confident with how to find good oil.” Meanwhile, Jo tested 11 different CBD brands before finding one she feels works. 

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Endometriosis CBD

Once they have found a product they feel is effective, endometriosis sufferers naturally want to spread the word to save others money and time. And after recommending, for many, selling seems like a logical next step.

Sally Davies*, who isn’t allowed to talk publicly about the CBD company she works for, says: “I believed in it so much that I signed up to be a distributor. So many of my friends have medical issues and pain issues. I’m not one for fads like Slim Fast – I get on my high horse. But I said to them, you know me well enough to know I would not be talking to you about something if I didn’t absolutely believe it.”

For those I spoke to, money wasn’t their main motivator in selling. As Frankie notes: “Helping people is my main priority, the money is a bonus.” However, setting up one’s own business or working for companies which allow flexible/home-working is an understandably attractive prospect for chronic pain sufferers, especially those with children.

“When it comes to multi-level marketing, unless you know the founders, you’re a number in the system”

In the CBD industry, multi-level marketing schemes proliferate. Though they aren’t as new (established companies like Avon and Body Shop at Home are MLMs), like CBD they are on the rise, and their legitimacy has proven more than a little dubious.

To join an MLM as a distributor (a non-salaried, commission-based role) you’ll usually have to pay a joining fee or buy several products. Some companies may even require distributors to do so regularly, and, if expensive, those involved can easily get into debt. Companies use distributors to help them tap into their pre-existing networks. Women with endometriosis are frequently part of social media support groups or have friends with chronic illnesses. From what we know of the prevailing MLM blueprint – from supplements, cosmetic brands, and clothing lines like Herbalife and Mary Kay – they prey on stay-at-home mothers and the unemployed, people at their most vulnerable, in need of relief, community, and cash.

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Endrometriosis CBD

Product sales are often not how distributors make serious money, but by signing up other sellers beneath them whose sales they then get a percentage of. Those who are “downline” (further down the MLM food chain) may find it hard to make anywhere near as much money as those upline, and many similar schemes have made headlines when distributors’ experiences don’t live up to expectations. 

The defined difference between MLMs and pyramid schemes is that MLMs centre on a product, whereas with pyramid schemes, it’s usually just the promise of one, and  it relies on recruitment overall. As both the CBD industry and CBD MLMs are so new, most of the women I spoke to were not far downline, which makes potential earnings higher and experiences – so far – more positive. It means all the women I speak to reject any notion that they’re in disadvantageous positions.

Frankie, who makes her entire salary selling CBD, said she isn’t pressured to sell, but acknowledges that’s not always the case. “You can sign up and do nothing. I know that (with) so many companies, you have to have orders and you’re forking out money when you shouldn’t be. When it comes to multi-level marketing, unless you know the founders, you’re a number in the system.”

She continues: “Thankfully with (the current) company, because we’re so small still, and it’s so young, I have first hand communication with the founders. I’m doing well and I’m classed as a team manager so I’ve got most of the UK in my team which is great. I think I’ve really hit the jackpot with this company.” Frankie adds that she has worked for another MLM whose operations were not all above board. She tells me: “I had a bad experience because they were sending (the CBD product) illegally to the UK, and there was a lot of false advertising from the top dogs, from head office. That’s something that I really regret.”

“Although self-medication might provide relief for chronic pain, the potency and purity of wellness CBD products requires closer scrutiny”

As CBD industry MLMs remain so new, problematic trends and widespread contentious practices are yet to be seriously documented. Investigations into individual CBD companies in the US have however drawn concerning conclusions – Hempworx, which began life as My Daily Choice before its sudden pivot to CBD-focused products, has been found to have made over 100 illegitimate health claims by The Extract. The company was also reportedly found to be inflating the numbers sellers were earning – around $5,000 a month, unproved figures. Other brands, such as Kannaway, Dose of Nature, and First Fitness Nutrition, have been criticised for a range of issues, including lack of lab testing and low income potential – 22 MLMs, including Dose of Nature, were issued with FDA official warning lettters in the US last year. In the UK, the Food Standards Agency ruled in February that CBD products – from oils to drinks and food – had to be registered by March 2021 or they would be pulled from shelves. As they move to combat misleading market claims, high prices, and health concerns, the work to regulate the market could significantly impact the CBD MLMs.

Previous bad experiences with doctors can lead those with endometriosis to mistrust the medical system, so sufferers rely on their network for information in the absence of other guidance. Dr Okuleye notes: “Although self-medication might provide relief for chronic pain, the potency and purity of wellness CBD products requires closer scrutiny to ensure patients can maximise the therapeutic potential of medical cannabis. Ideally, this should be within a research setting which evaluates efficacy, safety, and dosage.”

The presence of distributors within Facebook support groups is contentious. They are often discouraged from promoting products and many group rules warn that promotional posts will be deleted and repeat offenders blocked.

Alex Cohen, who runs the small, independent company CBD Buddy, is suspicious of MLMs. “I’m not interested in building a huge conglomerate. I’m also not interested in MLM schemes, which, frankly, I think, are dangerous. I want to do (something) legitimate and uncomplicated.” She says she has friends who have worked for beauty MLMs like Arbonne, adding: “There’s something slightly not right about the fact that you do have to do this extra marketing. I think it’s counterproductive. If you have a product that is legitimately good and helping people, I just don’t think it’s necessary.”

Cohen has some advice which may be helpful for those trying to navigate both the complicated world of buying and selling CBD: “If it seems too good to be true, it probably is.” 

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Is This the Next Big Cannabis IPO?

Is This the Next Big Cannabis IPO?

Bruce Linton isn’t staying away from the pot industry.

David Jagielski

It may not be an appropriate time for business to go public, but don’t tell that to former Canopy Development ( NYSE: CGC) CEO Bruce Linton. Linton is still associated with the cannabis industry through Vireo Health ( OTC: VREOF), and he’s also seeking to make a much bigger splash with the launch of a brand-new company called Collective Development. Given the success he attained in making Canopy Growth into a market leader, financiers may want to keep a close watch on his latest organisation.

The business might be on the Nasdaq very soon

On March 2, Collective Growth submitted to note on the Nasdaq exchange. The company is seeking to raise $150 million that it prepares to use through 15 million systems priced at $10 each. If authorized, Collective Growth would trade under the ticker sign CGROU.

The company is eyeing the hemp and cannabidiol (CBD) markets. It remains the Canadian-based cannabis company’s best way to permeate the U.S. market, where the federal government restricts cannabis products with tetrahydrocannabinol (THC) levels in excess of 0.3%.

Marijuana leaf showing on a green traffic signal.

Image source: Getty Images.

Nevertheless, in his most recent endeavor, Linton is looking at more than simply hemp-derived CBD items. He informed Yahoo Financing, “What we wish to take is the entire plant and produce a make money from every aspect of it.” While he didn’t provide specifics as to what the business was going to do, he did recommend that they might be taking a look at acquiring some companies, specifying that “we have a terrific management team and we think we can find some truly excellent targets.”

Part of that management team consists of former Canopy Growth CFO Tim Saunders, and Geoff Whaling, who is a chairman at the National Hemp Association.

Currently, there’s no word on when the brand-new stock may begin trading. Nevertheless, offered the sell-offs that have actually occurred in the markets of late due to fears surrounding the coronavirus, it would not be surprising if Linton and his management team chose to hold back on the listing in the meantime.

Could Linton’s new business be a bargain for marijuana investors?

The advantage that Linton has is that he knows the marijuana market well and can likely find great deals of worth in this bear market. Where investors may have concerns is that Canopy Development had a hard time to stay out of the red and his brand-new business might require deep pockets. Canopy Development has Constellation Brands as an essential investor that can assist the pot manufacturer. It also didn’t injure that Constellation offered the business an influx of money with a $4 billion financial investment.

It’s a much different climate in the marijuana market today, and financiers are more concerned about profits and capital than they are almost sales growth and capacity. That’s why Linton’s new business might encounter challenges raising cash. Even concentrating on hemp isn’t much of a much safer strategy anymore. Charlotte’s Web ( OTC: CWBHF) is a leader in that segment, and its stock is down around 80%in the past year, which remains in line with how the Marijuana Life Sciences ETF has performed throughout that time.

Without using investors something new or an engaging method, it’s hard to see why Collective Development will be able to prevent the downward path lots of pot stocks have been on for the past 12 months. He may find it more difficult to do in the middle of so much negativeness in the cannabis sector as business struggle to fulfill investors’ expectations.

Another issue investors might have about Linton is his focus. Between Vireo, Collective Development, and backing Mind Medicine– a business in neuro-pharmaceuticals, or psychedelics– Linton’s associated with numerous different organisations, and his attention may not be completely on this new venture.

Secret takeaway for financiers

Collective Development is an up-and-coming business to keep an eye on, however with no distinguishable reason regarding why this company will be a better financial investment than the pot stocks that are currently out there, investors may not see a reason to buy the stock when it appears. Investors would be better off waiting to see some concrete arise from Collective Growth prior to thinking about purchasing shares of the company. The market remains extremely risky, and a new issue might be particularly vulnerable to the marketplace’s unstable swings.


David Jagielski has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Constellation Brands. The Motley Fool recommends Charlotte’s Web. The Motley Fool has a disclosure policy.”> David Jagielski has no position in any of the stocks pointed out. The Motley Fool owns shares of and recommends Constellation Brands. The Motley Fool advises Charlotte’s Web. The Motley Fool has a disclosure policy“>

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Today in Gear: Full-Spectrum CBD Oil, the very best Time to Purchase a New Ford Mustang & More

Today in Gear: Full-Spectrum CBD Oil, the very best Time to Purchase a New Ford Mustang & More

We ‘d enjoy to hear from you at [email protected]

Even on an excellent day, it can be tough to completely unwind when it’s time to evacuate shop. And let’s face it, times are a bit difficult. There has been a lot of noise about CBD Oil supplements in the marketplace and it can be a confusing area to research. Sunsoil, a Vermont-based seed to rack business, is doing CBD the right way. Sunsoil’s full-spectrum CBD oil is made from full-plant licensed natural hemp extracts. Lab-tested at 3 independent labs at several phases of processing, you can rest assured that Sunsoil’s full-spectrum CBD is tested for pureness and potency. Plus, they are among the lowest price/mg of CBD out there and be available in liquid oil drops, soft gels, vegetarian pills and CBD coconut oil– so you have a lot of alternatives for how to use it. Today, you can grab 30 percent off with the code EQUIPMENT30 so you can stockpile on all your CBD needs throughout these demanding days.

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CBD Oil, Cannabinoid Doesn’t Have To Be Hard. Read These 9 Tips
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Up Your CBD Knowledge: Hemp Industry Education With Max Simon, CEO Green Flower Media

Up Your CBD Knowledge: Hemp Industry Education With Max Simon, CEO Green Flower Media

Terrell Davis, CBD, Hemp Training, Hemp Education, Agriculture,

Max Simon, CEO Greenflower


Green Flower Media

With CBD slated to grow 107%annually over the next 4 years , the need for technicians in the CBD market is immediate; yet no U.S. college, trade school or university uses a full-fledged course on Hemp or educates on how to succeed in various locations of the market. Likewise, different state and federal regulators have actually sent out blended messages as to what the precise laws surrounding hemp are.

Go Into Green Flower – a CBD education platform that offers students an affordable alternative to college, enhancing education amongst various locations of the industry and empowering the hemp economy.

Just recently I took a seat with Max Simon, the CEO and Co-Founder of Green Flower Media to get his take on CBD education, workplace and state regulations surrounding hemp production and sales, in addition to how people are getting involved in this growing service.

Max, tell us about Green Flower’s objective.

Our mission is to educate the world about how to succeed in CBD. We do that by producing industry-leading educational programs featuring the world’s leading experts that cover every aspect of CBD today, including growing, extraction, compliance, and far more.

How have things altered given that the passing of the 2018 United States Farm Costs, in regards to CBD regulative matters? Has it had a positive or unfavorable impact?

There has actually been an absolute surge of new CBD services and items that have actually struck the market trying to capitalize on the Farm Costs’s newly legalized status of hemp. While there is a frustrating amount of interest and excitement for this new chapter of legal CBD from hemp, there is also a palpable level of uncertainty and confusion about what a genuinely legal and regulated CBD market will look like.

Is CBD legal in every state?

Presently, 47 States totally permit the sale and usage of hemp obtained CBD, and the only S. Dakota, Nebraska, and Idaho have restrictions or flat out bans on the sale or usage of CBD.

For anybody who uses CBD everyday, are there any workplace or legal problems that may affect your employment?

Because lots of CBD items do not need stringent laboratory testing to ensure accuracy of ingredients, many CBD items really include greater portions of THC. CBD items polluted with THC are the only genuine risk for somebody’s work, so, if this is a potential problem for you – look for CBD business that have actually totally gotten rid of THC from their products.

How do you educate employers and towns about CBD usage, effectiveness and security?

Green Flower is an online education company, so our programs can be distributed to any employer or municipality around the nation. This is how we are spreading out trusted CBD education around the globe.

How is hemp-derived CBD extracted and produced?

CBD can be extracted through lots of different extraction approaches consisting of CO2, Ethanol, MCT-oil infusion, and more.

Are different kinds of CBD better for various types of items?

Types of CBD normally refers to the distinction in between “whole plant CBD” and “CBD isolate”. It’s not proven unquestionably yet, the large bulk of anecdotal proof suggests that if you’re looking for a CBD item that actually supplies a significant benefit, you will want to find entire plant CBD items because the science suggests that this promotes something called “The Entourage Effect”– essentially a symphony of particles that work together to supply the maximum benefit. If you are taking in a CBD product that lacks that herbaceous note, it’s likely a CBD isolate product and it may not supply the very same healing advantages.

What steps can an individual take if they have an interest in going into the CBD market?

The CBD industry is complete of opportunity, but it’s also really complex and there is a lot to discover. To get involved, you’ll want to get educated on the regulations, the different product types, how CBD is being dispersed, how you can and can not market CBD, and which companies are building great brand names.

Inform us about a Green Flower Media success story. What are they doing now?

One of my preferred success stories is Dr. Kerklann, who was a chiropractic physician searching for his next huge thing. He signed up for a Green Flower program, found out everything about the progressing Hemp industry, utilized that understanding and motivation to build a new line of CBD topicals, and now his products are distributed nationally and growing like insane. A fantastic success story!

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Canna Bizfair Offers Proprietary Virtual Trade Expo Platform, at Cost, to Legalized Cannabis & CBD Event Organizers Around the World to Ensure Business Continuity

Canna Bizfair Offers Proprietary Virtual Trade Expo Platform, at Cost, to Legalized Cannabis & CBD Event Organizers Around the World to Ensure Business Continuity

– Legalized cannabis and CBD businesses rely heavily on global trade shows to create brand awareness and drive product sales

– The Canna Bizfair virtual trade expo platform provides a boundary-less online marketplace that presents opportunities for strong business partnerships and also brings the best brands to end consumer

LONDON, March 18, 2020 /PRNewswire/ — Due to the global COVID-19 pandemic, social distancing is a necessity across many countries. As per local government directives, many cannabis & CBD related events and trade shows have been postponed or cancelled. As a result, CBD businesses will likely miss out on the much needed exposure and global partnerships during its growth phase. While safeguarding employees, vendors and customers, a sunrise CBD industry should ensure that the business growth is not adversely affected.

“Our online trade expo platform presents a unique opportunity for cannabis & CBD brands to create awareness about genuine products from trustworthy brands on a global scale. It builds live market places which bring buyers directly to exhibiting brands. Using our platform, you can exhibit at or attend the virtual trade expo from anywhere in the world, whether you’re at office or home and from any device. We sincerely hope and pray that people stay safe during this difficult situation and hence we have decided to offer the platform, at cost, to industry stakeholders and those who want to grow the industry,” said Rishi Kudale, Marketing Director, Canna Bizfair.

Online retail is an important channel for legal cannabis & CBD businesses. Every day consumers are discovering new products through social media, online stores, influencers, reviews and word of mouth. This conversational commerce keeps the customer engaged and wanting for more. However, promotional restrictions from Google, Facebook and obscure regulations make it harder for businesses to properly educate their consumers. Hence, the virtual trade shows will not just be a necessity but it will become a norm in the cannabis & CBD industry in couple of years.

Benefits of the Canna Bizfair Virtual Expo platform –

  • Event organizers can create an online extension of their existing events or a completely online trade exhibition. The unified platform allows exhibitor and attendee management, creating expo hall layouts and detailed reporting at event and exhibitor level.

  • Exhibiting brands can create hyper-real expo stalls with interactive branding panels which can be updated with marketing collateral and promo videos in real-time.

  • Engage exhibitors, wholesale buyers, partners and retail customers from around the world through live chat

  • Industry delegates can showcase expertise and thought leadership through informative webinars that cover regulatory nuances to enter a new markets and latest technology trends.

  • Expo ROI and impact measurement with granular reporting metrics such as number of visitors, average time spent, number of document views, number of cards exchanged, etc.

“We have a pilot event CBD+VAPE WORLD 2020 coming up in May to showcase efficacy and impact of our virtual trade show platform and to on-board more event organizers. It is a 3-day online fiesta on a massive scale focused on bringing the entire CBD vape ecosystem on a single platform. You can not only explore demand in different markets but also meet reliable vendors and suppliers. There is an array of numerous benefits that exhibitors can expect from the platform,” continued Rishi Kudale, during the press announcement. “We have an exciting Canna Bizfair Partner Program and have already partnered with an established event company in APAC to use our platform. We’re in talks with few more from Europe & North America.“

Canna Bizfair has extended the proprietary virtual trade expo platform, at cost till 31st August 2020, that can accommodate hundreds of thousands of visitors around the world. The platform can be used by established event organizers focused on CBD, vaping, cannabis ancillary sub-domains like packaging, software technology, investment, insurance, logistics, etc.

Interested parties can write to [email protected].

About Canna Bizfair:

Canna Bizfair provides a cutting-edge platform to plan, design, create & manage business focused online trade expos for legalised cannabis and CBD industry. The event organizers can build live ecosystems where business can grow and make meaningful connections from across the globe. Our events attract buyers, entrepreneurs and professionals from all over the world as well as your day to day consumer. Now deliver successful trade show while staying clear of expensive event logistics

You can attend world class events from anywhere, anytime and on any device.

Our proprietary Canna Bizfair Virtual Expo Center. An expansive 8,640 SqM expo arena is loaded with all the essential features to host successful cannabis trade expos and more. Exhibitors can choose from various customization options to create dynamic and hyper-real booths. Our 3D booths are equipped with interactive branding panels, so that you can showcase your products in the best manner.

For more details, please visit https://www.cannabizfair.com/

CBD+VAPE WORLD, May 8-10, 2020: https://www.cannabizfair.com/cbd-vape-world/

Exhibitor Features & Benefits: https://www.cannabizfair.com/exhibitor-brochure.pdf

Canna Bizfair Partner Program Dossier: https://www.cannabizfair.com/partner-brochure.pdf

Write to [email protected]

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SOURCE Canna Bizfair

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NewLeaf Brands Announces Complete Sell Through of Gen 1 Fresh Water and Launch of Newly Revamped High PH, Electrolyte-infused, 25mg Alkaline Water

NewLeaf Brands Announces Complete Sell Through of Gen 1 Fresh Water and Launch of Newly Revamped High PH, Electrolyte-infused, 25mg Alkaline Water

VANCOUVER, British Columbia, March 3, 2020 /PRNewswire/ — NewLeaf Brands Inc.’s (CSE: NLB) (OTC: NLBIF) (FSE: 0NF) (“NewLeaf Brands” or the “Company”) wholly-owned subsidiary Drink Fresh CBD, LLC (“Drink Fresh”) is pleased to announce that it has sold out of their Fresh premium CBD water bottles (“Premium CBD Water”). The 16.9 fluid ounce bottle contains 5MG of nano-amplified CBD per bottle. The order was placed by Colorado’s largest nightclub group.

Fresh’s Premium CBD Water will now come in a new 12 fluid ounce sleek can.

Fresh’s Premium CBD Water will now come in a new 12 fluid ounce sleek can.

Drink Fresh’s Premium CBD Water will now come in a new 12 fluid ounce sleek can. Premium CBD Water is high PH and contains electrolyte-infused alkaline water with 25MG of CBD.

Benjamin Martch CMO of NewLeaf Brands commented, “We have established distribution partnerships with companies that specialize in beverage distribution to variety of vendors. Additionally, the switch to an aluminum can from a plastic bottle was an environmental move to a more recyclable alternative.”

About NewLeaf Brands

NewLeaf Brands, Inc. is an innovative Cannabidiol (“CBD”) lifestyle Company. Through the Company’s wholly-owned subsidiaries We are Kured, LLC, Drink Fresh Water, LLC, ReLyfe Brand, LLC and TeaLief Brand, LLC the Company’s main business activities encompass the development, marketing, and distribution of CBD products (including vaporizer pens/cartridges, hot/cold tea, softgel capsules and beverages) throughout North America, South America, and Europe. In addition, NewLeaf Brands, Inc. has extensive retail and cultivation land investments in Oregon, USA.

For further information about NewLeaf Brands, please consult the Company’s profile on SEDAR at www.sedar.com or visit the Company’s website at www.NABrandsInc.com. For further information about We Are Kured, please visit their website at www.wearekured.com.

The Canadian Securities Exchange has neither approved nor disapproved the contents of this news release and accepts no responsibility for the adequacy or accuracy hereof.

This news release contains forward-looking statements, which relate to future events or future performance and reflect management’s current expectations and assumptions. Such forward-looking statements reflect management’s current beliefs and are based on assumptions made by and information currently available to the Company. Readers are cautioned that these forward looking statements are neither promises nor guarantees, and are subject to risks and uncertainties that may cause future results to differ materially from those expected including, but not limited to completion of planned improvements at both the Canadian and US sites on schedule and on budget, the availability of financing needed to complete the Company’s planned improvements on commercially reasonable terms, planned occupancy by the tenant-growers, commencement of operations, differences in yield on expected harvests, delays in obtaining statutory approval for marijuana production plans, issues that may arise throughout the grow period, outdoor crops affected by weather, the ability to mitigate the risk of loss through appropriate insurance policies, and the risks presented by federal statutes that may contradict local and state legislation respecting legalized marijuana. These forward-looking statements are made as of the date hereof and the Company does not assume any obligation to update or revise them to reflect new events or circumstances save as required under applicable securities legislation. This news release does not constitute an offer to sell securities and the Company is not soliciting an offer to buy securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such jurisdiction.

This news release does not constitute an offer of securities for sale in the United States. These securities have not and will not be registered under United States Securities Act of 1933, as amended, or any state securities laws and may not be offered or sold in the United States or to a U.S. Person unless so registered, or an exemption from registration is relied upon.

On Behalf of the Board of Directors
Joshua Bartch
Chief Executive Officer
[email protected]

For Further Information Contact:
Corporate Communications
[email protected]  
+1-250-488-6728

We Are Kured Contact:
Benjamin Martch
Founder & CEO
www.wearekured.com

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SOURCE NewLeaf Brands Inc.

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[ASAP] Strategies for Design of Potential Singlet Fission Chromophores Utilizing a Combination of Ground-State and Excited-State Aromaticity Rules

[ASAP] Strategies for Design of Potential Singlet Fission Chromophores Utilizing a Combination of Ground-State and Excited-State Aromaticity Rules

Research on solar energy harvesting is one of the most active areas within chemistry, and photovoltaics technology is one of the main directions for turning solar energy into electricity. Today, three different generations of photovoltaics exist.(1,2) The third and most recent generation includes materials able to overcome the Shockley–Queisser limit (∼33%).(3,4) This generation includes singlet exciton fission photovoltaics, or shortly singlet fission, i.e., a process where one photon of light, absorbed by a molecule, is used to create two excitons of triplet multiplicity in two molecules or in two chromophores linked intramolecularly.(5,6)

In singlet fission, a molecule in its first singlet excited-state (S1) kickbacks some of its energy, transferring it to a neighboring ground-state (S0) molecule, and both end up in the lowest triplet state (T1). For this process, one needs molecules with their lowest excited states arranged according to at least two key criteria: the S1 state and second triplet excited (T2)-state should have energies higher than twice that of the T1 state, i.e., 2E(T1) E(S1) and 2E(T1) E(T2). The first criterion guarantees that the singlet fission is exergonic and the second that the T1 + T1 → T2 annihilation is slow and endergonic.(5−7) Ideally, E(S1) should also lie 0.1–0.2 eV above 2E(T1). Desirably, the T2 state should be at an energy higher than the S1 state, i.e., E(S1) E(T2), so as to hamper intersystem crossing from S1 to T2.(8) Combined, this means that 2E(T1) E(S1) E(T2) for a singlet fission chromophore. Finally, to maximize the efficiency in energy conversion, E(T1) should preferably be close to or slightly above 1 eV as this facilitates triplet exciton transfer and charge injection from the molecule into a silicon electrode, which has a bandgap of 1.11 eV.(9) Such a process was recently accomplished by tetracene (E(T1)=1.25 eV), enabling a combined exciton yield of 133% ± 13%.(10) This and several other recent studies reveal that efficient combinations of singlet exciton fission with semiconductor technology can be accomplished to achieve triplet exciton harvesting and charge injection into electrodes, inducing photocurrents.(11−15)

A number of aspects need to be taken into account for the enhanced design of singlet fission solar cells.(16−18) We need, for example, deepened mechanistic understanding of the exciton fission process, better control of intra- and intermolecular singlet fission rates, and improved understanding of how singlet fission chromophores interact with each other as well as with a semiconductor surface or quantum dot. To fit many different technological setups we should also compose a library of compounds that expands outside the acenes suitable for singlet fission, and chromophores with higher E(T1) than the present ones should be identified.(17,18) However, how can further chromophores with the desired characteristics be discovered?

The search for materials suitable for singlet fission is not a straightforward task, particularly as the experimental determination of E(T1) is less facile than for E(S1). However, with the help of quantum chemical analyses, the search has evolved considerably over the last years.(8,19−27) The first experimental evidence of efficient singlet fission was observed for anthracene crystals, and research then expanded to tetracene and pentacene materials.(28−30) 1,3-Diphenylisobenzofuran (DPB) was the first compound observed to undergo singlet fission that had been predicted by theoretical modeling.(31,32)

Recently, Bronstein, Musser, Friend, and co-workers used for the first time the concept of T1-state Baird-aromaticity(33−36) to analyze singlet fission chromophores.(37) They studied indolonaphthyridine thiophene (INDT) derivatives, which they described as influenced by a resonance structure with a 4π-electron Baird-aromatic cycle. On the basis of quantum chemical computations of nearly 10000 INDT derivatives, they concluded that a significant part of these are influenced by aromaticity to various extents in their T1 states and have the appropriate relative arrangement of E(T1) and E(S1) to function in singlet fission photovoltaics. Significantly higher photostabilities of two INDT derivatives compared to TIPS-pentacene were also observed,(37) a feature of excited-state aromatic molecules with 4nπ-electron cycles earlier noted by Wan and Shukla for dibenz[b,f]oxepins.(38,39)

Now, what are the explicit scopes of T1-state Baird-aromaticity for the design of singlet fission chromophores, and what are the limitations? It was argued by Ryerson et al.,(40) when analyzing the INDT compounds by Fallon et al.,(37) that the intermediate triplet-state aromaticity yielding the E(S1)=2E(T1) situation needs to be found through inspection of calculated adiabatic excitation energies. Thus, a qualitative tool should be desirable. Herein, we report on approaches for the correlated tuning of the E(T1) and E(S1) of Baird-aromatic chromophores by exploiting an earlier observed similarity in the electronic structures of the T1 and S1 states of Baird-aromatic molecules.(39,41) Are their ways by which E(T1) and E(S1) can be tuned predictably in a similar manner while E(T2) is left unaffected or changes in another way than E(T1) and E(S1)? How are compounds with E(T1) slightly above 1 eV identified, allowing for the combination of the singlet fission process with existing silicon solar cell technology? We develop a general design strategy by combining qualitative theory on excited-state Baird- and ground-state Hückel-aromaticity with quantum chemical computations. We arrive at approaches that could be applied broadly to identify a plethora of excited-state Baird-aromatic compounds and compound classes potentially suitable for singlet fission photovoltaics.

Design Strategies

Molecules with Baird-aromatic T1 states in general have a low E(T1), as the aromatic character leads to a stabilization of that state relative to the S0 state, which is Hückel anti- or nonaromatic.(35,39,41) Cyclobutadiene (CBD), which is T1-state Baird-aromatic, fulfills the first criterion as E(S1)/E(T1)=2.84.(42) The opposite applies to benzene (T1-state Baird-antiaromatic) because E(S1)/E(T1)=1.35.(43) Thus, one should search for (moderately) Baird-aromatic compounds with E(T1) that are approximately double the E(T1) of CBD (0.59 eV)(42) to achieve an E(T1) similar to the band gap of silicon (1.11 eV). If one can identify compound classes influenced by Baird-aromaticity and throughout which the S1 and T1 states are described by the same HOMO → LUMO singly excited electron configuration (except for a spin-flip), it should be possible to find specific compounds that fit the requirements. In such compound classes, the absolute changes in E(T1) and E(S1) should be similarly large because the two states will be influenced in the same manner by, for example, electronic or steric effects caused by substituents. Throughout the compound class, the energy difference between the two states will then equal twice the exchange integral, i.e., ΔE(S1 – T1)=2Kij=2KH,L (i and j=orbitals involved in excitation, H=HOMO and L=LUMO).

Now, if the E(T1) and E(S1) of the various specific compounds in the compound class are plotted against an (anti)aromaticity index (∼coordinate), one can tentatively determine a threshold degree of (anti)aromaticity between the compounds that satisfy the singlet fission criterion and those that do not (Figure 1). At that threshold, E(S1) will equal twice E(T1), and potential singlet fission chromophores will be found on the right side of the threshold (orange region in Figure 1). However, the hypothesis summarized in Figure 1 assumes that 2KH,L is constant over the interval, but even if HOMO and LUMO keep their respective symmetries throughout a compound class, their spatial localization may shift; as a result, 2KH,L will change in size. The importance of colocalization of the HOMO and LUMO to the same atoms for a large 2KH,L becomes clear through a comparison of naphthalene with azulene: naphthalene with a HOMO and LUMO colocalized to the same atoms has an ΔE(S1 – T1) of 1.7 eV, while azulene, where the HOMO and LUMO are not fully colocalized and somewhat polarized toward different ends of the molecule, has an ΔE(S1 – T1) of 0.5 eV.(44) Similarly, the ΔE(S1 – T1) of individual compounds within a compound class will vary if there is a change in the spatial distribution of HOMO and/or LUMO throughout the class.

Figure 1

Figure 1. Desired arrangement of the lowest electronic states within a particular compound class that encompasses both S0 aromatic (T1/S1 antiaromatic) compounds and S0 antiaromatic (T1/S1 aromatic) compounds. Compounds within the orange region have 2E(T1) E(S1).

We first test our design strategy on substituted fulvenes (pentafulvenes) being a compound class with E(T1) and E(S1) that span a large part of the region between the corresponding excited-state energies of benzene and CBD.(45−49) This feature is a result of the “aromatic chameleon” character of fulvenes, meaning that they can adapt to the different aromaticity rules in different electronic states: Baird’s rule in T1 and S1 and Hückel’s rule in S0.(50) π-Electron withdrawing groups (EWGs) at the exocyclic position lead to low-lying T1 and S1 states, as they enhance the Baird-aromatic character of these states (Figure 2A). Computations have shown that fulvenes and related compounds with triplet ground (T0) states are possible,(50,51) explained by the fact that the cyclopentadienyl cation (Cp+) has a triplet ground state.(52−54) Assuming that the T1 and S1 states are described by the same electron configuration, except for the multiplicity difference, this means that a particular EWG at the exocyclic position of a fulvene will have the same stabilizing effect in S1 as in T1 when compared to the parent fulvene as a reference.

Figure 2

Figure 2. (A) Postulated (idealized) variation in excitation energies of fulvenes as one goes from electron donating groups (EDGs) to electron withdrawing groups (EWGs). The figure displays the ideally constant energy difference between E(T1) and E(S1) (ΔE(S1 – T1)=2Kij), upon which our hypothesis is based. (B) E(S1)/E(T1) ratio for four experimentally investigated fulvene derivatives, i.e., TClDCF, TClDMF, DMF, and TClDPF (see refs (46) and (47)).

Indeed, the tunability of E(T1) and E(S1) was earlier observed experimentally for four fulvene derivatives: 1,2,3,4-tetrachloro-6,6-dipyrrolidinofulvene (TClDPF), 1,2,3,4-tetrachloro-6,6-dimethylfulvene (TClDMF), 1,2,3,4-tetrachloro-6,6-dicyanofulvene (TClDCF), and 6,6-dimethylfulvene (DMF) (Figure 2B).(45,46) For singlet fission, it is rewarding that the experimental E(S1)/E(T1) ratio increases when going from TClDPF to TClDCF (Figure 2B) so that E(S1) in TClDCF is (at least) nearly twice larger than E(T1). With TClDCF being a stable organic compound, together with the recently reported INDT derivatives,(37) it is revealed that a large number of chromophores, which to various extents are influenced by aromaticity in their T1 states, are awaiting to be discovered and used in singlet fission photovoltaics. In fact, the experimental ΔE(S1 – T1) values for the four fulvenes displayed in Figure 2B are similar for three compounds (TClDPF, TClDMF, and DMF) yet are possibly higher for TClDCF, as only an upper limit of E(T1) was assessed for the latter compound (1.45, 1.50, 1.52, and E(S1)/E(T1) ratio of TClDCF, which is 1.95 or higher, suggests that this compound may indeed function as a singlet fission chromophore.

The design strategy outlined for fulvenes in Figure 2A utilizes electronic substituent effects, but altered steric congestion can also change E(T1) and E(S1). Again, this effect can be exemplified on fulvenes by altering the CC bond lengths in silico. This modulates the energies of the HOMO and LUMO (Figure 3A) by changing the strength of either the bonding or the antibonding character of an orbital at a particular bond. If the T1 and S1 states are HOMO → LUMO single excitations, this allows for tuning of the E(T1) and E(S1). As seen for the parent fulvene (Figure 3B), the relevant states change in energy as a function of CC bond lengths, and the absolute energy changes for the T1 and S1 states in each of the two types of distortions. Specifically, the energies of the two states decrease by 0.81 and 0.68 eV when the r2,3 bond is shortened from 1.54 to 1.38 Å, and they decrease in energy by 0.98 and 0.86 eV when the r1,2=r3,4 distances are elongated from 1.35 to 1.45 Å. Thus, ΔE(S1 – T1) remains rather constant if there is no gradual shift in the location of the HOMO relative to the LUMO along the distortion coordinate. The T2 state in the distorted parent fulvene, on the other hand, displays smaller changes (0.19 and 0.48 eV, respectively). Indeed, molecular contortion (bending and twisting) has recently been shown to be one means for altering E(T1) and E(S1) so as to improve singlet fission performance of an existing chromophore.(55)

Figure 3

Figure 3. (A) Plots of HOMO and LUMO of the parent fulvene, and (B) two plots showing how E(T1)v, E(S1)v, and E(T2)v vary as functions of the CC bond lengths marked in red. Calculations at TD-M06-2X/6-311+G(d,p) level.

A further design approach is to combine Baird’s rule with Clar’s rule,(56−58) as that particular isomer among a series of isomeric polycyclic antiaromatic hydrocarbons (PAAHs) that maximizes the total number of aromatic monocycles in the T1 state (one Baird π-quartet or π-octet plus Clar π-sextets) has the lowest E(T1) value.(59) By selecting the proper isomer, it should be possible to identify the T1-state Baird-aromatic compounds with E(T1)=1.1–1.2 eV, which fulfill the singlet fission criteria. However, it is important to note that the isomer, which is ideal for singlet fission, is not necessarily the one that is the most strongly Baird-aromatic in its T1 state, as also concluded by Ryerson et al.(40) Another more established approach for the design of singlet fission chromophores is the diradical character-based design.(6,20,24,26,60−62) It has been found that molecules with the proper amount of open-shell singlet diradical character often satisfy the singlet fission criteria,(26,63) and a connection between the diradical character and aromaticity has been described for heteroacenes.(24) A link to our approach based on Baird-aromaticity can likely be formulated, yet the extent of diradical character in the S0 state may not necessarily reflect Baird-aromaticity in the T1 state (vide infra).

Finally, it should be noted that our design strategies are approaches for identification of candidate chromophores for singlet fission. The strategies do not take into consideration, for example, nonradiative decay processes from the S1 state to the S0 state. Indeed, it has earlier been observed that some 4nπ-electron compounds can have very short excited-state lifetimes (less than 1 ns),(64) a feature that could limit the applicability of Baird-aromatic chromophores in singlet fission photovoltaics. We calculated spin–orbit coupling (SOC) elements as a means to determine the probability for intersystem crossings; however, photophysical processes that are limiting for singlet fission performance are likely best probed experimentally. Thus, further careful design is needed, for example, to constrain the molecules into rigid frameworks, hampering the geometric distortions that open pathways for nonradiative decay.

The validity of the design strategy is first examined on fulvenes (pentafulvenes), as they represent a compound class in which the (anti)aromatic character of both the S0 state and the T1 and S1 states can be varied extensively.(45−49) Our computations were mostly run with DFT at (U)M06-2X and TD-M06-2X levels,(65) but CASPT2//CASSCF multireference computations were also performed.(66) We primarily used a computational scheme derived by Zeng, Hoffmann, and Ananth (ZHA), which uses adiabatic excitations to the T1 state and vertical excitations to the S1 (T2) states from the S0 (T1) optimized structures. This approach gives the correct ordering of the T1, S1, and T2 states of pentacene,(67) and it gives the E(S1)/E(T1) ratios for pentacene and DPB above or close to 2 (2.33 and 1.96 with M06-2X, see Table S1). However, at times, we also used either (i) vertically excited E(T1), labeled as E(T1)v as opposed to the adiabatic ones labeled E(T1)a, or (ii) adiabatically excited E(S1) labeled as E(S1)a. When evaluated against the experimental E(T1) and E(S1) of pentacene, tetracene, DPB, and the four fulvenes of Figure 2, it becomes clear that the approach with vertical E(T1) and E(S1) underestimates E(S1)/E(T1) when compared to experiments while the ZHA approach exaggerates the ratio. The extent of geometric relaxation in the S1 versus T1 states is important to take into consideration, as this varies between the compound classes.

Kaupp and co-workers previously used a TD-DFT-based protocol for the screening of singlet fission chromophores and, provided there is no evidence of multireference character, they proposed vertical excitation energies computed with local hybrid functionals.(68) However, M06-2X was found to perform similarly. For the T1 energies and optimized geometries of substituted fulvenes, we recently observed a good agreement between CASPT2 and M06-2X,(49) and we therefore used (U)M06-2X. For method assessments on CBD, benzene, DPB, and pentacene, see the Supporting Information. In short, the T1-, S1-, and T2-state orderings are the same with (TD-)M06-2X and CASPT2, and the E(S1)v/E(T1)a with the two methods using the ZHA scheme resemble each other. The (anti)aromatic character of fulvenes was determined through nucleus-independent chemical shifts (NICSs)(69,70) computed with the GIAO method(71) in the S0 and T1 states at optimized geometries. NICS calculations in the S1 state are cumbersome, and we instead used the electronic multicenter index (MCI)(72) for selected compounds. The geometry-based HOMA index(73,74) is not ideal for small T1 aromatic molecules (HOMA equals 0.73 for 3Cp+ and 0.45 for 3CBD, thus not reflecting the aromatic ideal of 1.0), and we avoid it for the fulvenes. In contrast, HOMA was used to assess the aromaticity of individual 4nπ-electrons rings of polycyclic compounds as the extent of aromaticity of individual rings in such systems cannot be determined by NICS as each ring is influenced by several diatropic or paratropic circuits.

Design Strategy Tested on Substituted Model Fulvenes

As pointed out by Zeng et al.,(25) the parent fulvene cannot be used for singlet fission applications since it has a low-lying T2 state, and it also undergoes efficient S1/S0 radiationless decay via two possible conical intersections (one planar and one twisted).(75,76) As seen below, the first of the two drawbacks is overcome by utilizing electronic substituent effects. The second drawback can likely be alleviated by benzannelation, leading to a rigidification of the molecular structure. We explored fulvenes substituted at the exocyclic 6-position (substituents X, Figure 4) and/or at the endocyclic 2- and 5-positions (substituents Y). The substituents X and Y were selected as electron neutral, electron donating, and electron withdrawing. With the chosen substituents, we span fulvenes with calculated E(T1)a in the range 0.10–2.81 eV. We did not consider fulvenes substituted at the 3- and 4-positions because substituents at these positions have only weak electronic impact due to steric hindrance, which twists the substituents out of conjugation with the 5-membered ring.(49) It should also be emphasized that the fulvenes of Figure 4 are model compounds (many are experimentally unrealistic) that allow us to explore the design hypothesis of Figures 1 and 2A. The initial set included 225 fulvenes, but 2 had triplet ground states (T0), 15 rearranged to an isomeric compound in the S0 and/or T1 state, and 49 had a HOMO and/or LUMO not analogous to those of the parent fulvene. These 66 were not further analyzed, whereby the set included 159 fulvenes (Table S2), i.e., 71% of the initial set.

Figure 4

Figure 4. Di- and tetrasubstituted fulvene derivatives included in this work.

Throughout the fulvenes with the T1 and S1 states described as singly excited HOMO → LUMO excitations, there are still complications. This is exemplified through two fulvenes that represent limiting cases with, respectively, high and low E(T1) and E(S1) values (Figure S1). The first fulvene with X=NH2 and Y=CN has E(T1)v=2.92 eV, E(T1)a=2.49 eV, and E(S1)v=4.19 eV, while the second fulvene with X=CN and Y=NH2 has a triplet ground (T0) state −0.17 eV below the lowest singlet state and E(S1)v=1.45 eV. Although the HOMO and LUMO each are analogous in the two compounds, there is a marked difference in the spatial distribution of LUMO that impact KH,L (Figure S1). As a consequence, ΔE(S1 – T1)v,v equals 1.66 eV for the first of these fulvenes while 0.66 eV for the second. The ΔE(S1 – T1)v,a of the two fulvenes are fortuitously very similar (1.70 and 1.62 eV, respectively), while the ΔE(S1 – T1)a,a could not be computed as it was not possible to locate the relaxed S1-state geometries of the fulvenes with neither TD-DFT or CASSCF.

The two fulvenes above further represent limiting cases with regard to singlet and triplet aromaticity because the first one is strongly 6π-electron Hückel-aromatic in its S0 state (Baird-antiaromatic in T1 and S1), while the second one is 4π-electron Baird-aromatic in its T0 state (Hückel-antiaromatic in the lowest singlet state). For the fulvene with X=NH2 and Y=CN, NICS(1)zz,S0=−24.8 ppm and NICS(1)zz,T1=23.8 ppm, while for the fulvene with X=CN and Y=NH2, NICS(1)zz,S0=27.4 ppm and NICS(1)zz,T0=−11.9 ppm. Noteworthy, the strongly Baird-aromatic cyclopentadienyl cation in its T0 state,(77,78) representing the limiting Baird-aromatic resonance structure of a fulvene in its triplet state,(49) has a NICS(1)zz,T0 value of −26.3 ppm. In its lowest singlet state, the cyclopentadienyl cation is also strongly diradical, as evidenced by a y0 value of 0.96. However, the fulvene with X=CN and Y=NH2, having a T0 state, is not extensively diradical in its lowest singlet state (y0=0.09), and other fulvenes with low E(T1) have even lower diradical character (Table S10). This should be compared with the reported diradical characters of tetracene and pentacene (y0=0.28 and 0.42, respectively).(63) Thus, although increased Baird-aromatic character of the T1 state lowers the E(T1) of fulvenes, it is not followed by increased diradical character of the S0 states until one has reached fulvenes with inverted order between the lowest singlet and triplet states.

For the fulvenes in Figure 4, the changes in (anti)aromaticity when going from S0 to T1, as given by ΔNICS(1)zz,T1–S0, correlate to a reasonable extent with E(T1) (R2=0.82, Figure S3), similar to what we found earlier.(49) However, when regarding E(T1) in dependence of Baird (anti)aromaticity in the T1 state (NICS(1)zz,T1) the correlation is lower (R2=0.68, Figure S4). It is noteworthy that fulvenes with E(T1)a in the range of 1.1–1.2 eV have NICS(1)zz,T1 values in the range of −4 to −2 ppm, i.e., they are nonaromatic in their T1 states. In the S1 state, we did not run NICS calculations due to computational complications, yet calculations using the MCI in the S1 and T1 states for selected fulvenes reveal that the two states for each of the investigated fulvenes are similarly (anti)aromatic (see Table S6).

In Figure 5A and B, we plot E(T1)v, E(T1)a, and E(S1)v against NICS(1)zz,S0, thereby revealing that the computed S0-state aromaticity, which is the easiest to calculate, led to good correlations. Similar correlations were also found when plotting these energies against the difference between the NICS in T1 and S0, ΔNICS(1)zz,T1–S0 (Figure S3), which should be the NICS index that best matches E(T1). Importantly, and in support of our hypothesis outlined above (Figures 1 and 2A), it is clear in Figure 5A that E(T1)v, E(T1)a, and E(S1) vary with NICS(1)zz,S0 in essentially identical ways. However, when plotting ΔE(S1 – T1) against NICS(1)zz,S0, it is revealed that only when both E(S1) and E(T1) are vertically excited energies is there a reasonable fit with the mean average deviation (MAD) from the least-squares fitted trendline of 0.10 eV (Figure 5C). Here, it is also notable that ΔE(S1 – T1) is gradually lowered as one goes to fulvenes that are S0 antiaromatic/T1 aromatic, a feature explained by the shift in the spatial distribution of the HOMO and LUMO, leading to small KH,L.

Figure 5

Figure 5. Plots of excited-state energies and energy differences against degree of (anti)aromaticity in S0. (A) E(T1)v and E(S1)v versus NICS(1)zz,S0, (B) E(T1)a and E(S1)v versus NICS(1)zz,S0. (C) The energy difference between the S1 and T1 states versus NICS(1)zz,S0 (D) E(T2)v and E(S1)v versus NICS(1)zz,S0 for tetrasubstituted fulvenes. R2 is the squared correlation coefficient. NICS(1)zz,S0 computed at GIAO/(U)M06-2X/6-311+G(d,p) level. In (A), the parent fulvene is indicated by red marks.

Now, how do these plots agree with the hypothesis presented in Figure 2? Clearly, when based on the ZHA scheme, the 2E(T1)a=E(S1)v threshold is reached at fulvenes with NICS(1)zz,S0=−13.5 ppm (dashed line in Figure 5B), while when based on the approach with E(T1)v, the threshold appears at the extrapolated value of 45.2 ppm. As the ZHA scheme exaggerates E(S1)/E(T1) while the approach with vertically excited E(T1) underestimates the ratio, it can be concluded that the 2E(T1)=E(S1) threshold is placed along the aromaticity coordinate represented by NICS(1)zz,S0. If the threshold is placed in the middle between the two limiting values then it is placed at NICS(1)zz,S0=15.8 ppm, i.e., at fulvenes that are rather strongly Hückel-antiaromatic in S0 and Baird-aromatic in T1.

With regard to the second threshold, E(S1) E(T2), it is clear in Figure 5D that E(T2) shows no correlation with NICS(1)zz,S0 (R2=0.00). Because most substituted fulvenes have E(T2) in the range 2.2–3.5 eV, it is gradually more probable that the criterion E(S1) E(T2) is met for fulvenes with NICS(1)zz,S0 above 2.5 ppm, as the trendlines for E(T2) and E(S1) cross at this value. Obviously, the fulvenes with NICS(1)zz,S0 values at ∼15 ppm will also satisfy the second criterion, but their E(T1) will likely be far below 1 eV.

As found above, by changing the bonding or antibonding character of the HOMO and LUMO through geometric distortions (Figure 3), one can tune E(S1) and E(T1) of the parent fulvene simultaneously and similarly since the S1 and T1 excitations are described by the same singly excited configuration except for the spin flip. Thus, ΔE(S1 – T1) is constant along the distortion coordinate. However, ΔE(S1 – T1) does not have the same value if one goes between differently substituted fulvenes as the spatial (de)localization of the HOMO and LUMO vary between the fulvenes. Hence, we analyzed how the E(T1) and E(S1) values change upon distortion in four substituted fulvenes in which the ΔE(S1 – T1) values at the minimum geometry vary from 0.84 to 1.41 eV (Figure 6). Upon distorting the C2–C3 bond length, the E(T1) and E(S1) values change simultaneously and similarly in three of the four fulvenes. The exception is 6,6-diaminofulvene (Figure 6B) in which the S1 state at several of the geometries is described by a different configuration than the T1 state, revealing the importance of having the S1 and T1 states described by the same configuration.

Figure 6

Figure 6. Variations in E(T)v, E(S1)v, and E(T2)v dependence on the C2–C3 bond length (red) in four fulvenes. Data points marked correspond to other excitations than that of the singly excited HOMO–LUMO configuration of the parent fulvene.

The calculations show that the hypothesis on the rational tuning of E(T1) and E(S1) utilizing excited-state Baird- and ground-state Hückel-aromaticity is valid with TD-DFT. However, is that also the case at the CASPT2 level? The latter calculations disclose potential multireference character and whether the fulvenes exhibit double excitation character in certain excited states or not. Table S7 lists the excitations at CASPT2 and TD-M06-2X levels for a few fulvenes for which the two criteria are met (or nearly met). In short, the E(T1) at the CASPT2 level are similar or slightly higher (0.2 eV) than those calculated with M06-2X. With regard to the E(S1), the CASPT2 energies are higher in all cases except one and sometimes 0.4 eV higher than those at M06-2X level. For the lowest S0 and T1 states, the CASSCF calculations reveal one predominant configuration with a weight between 0.80 and 0.93, revealing good agreement with %TAEe([T]) (Table S9) for the first of these states. We observe that almost all of the compounds preserve the energy order of the different states and fulfill the singlet fission criteria (Table S7). The exceptions are the two model fulvenes with X=BF2, Y=F and with X=CN and Y=SiH3. For these fulvenes, E(S1) and E(T2) are very close in energy, a feature that can lead to an S1/T2 intersystem crossing. However, one still cannot discard the possibility for singlet exciton fission because the calculated SOC for S1/T2 is merely 1.7 cm–1, i.e., –1, which indicates a very weak coupling,(79) despite some cases with similarly small SOCs are large enough for ISC.(80) Further results on SOC elements, which generally are small, and T1/S0 intersystem crossing are given in the Supporting Information, yet ISC also depends on the Franck–Condon weighted density of states according to the Fermi Golden Rule,(81) which is not considered in the present work.

Earlier Experimentally Investigated Fulvenes

We next considered the dicyanofulvenes (DCFs) that earlier have been synthesized by Finke et al.(82) We chose to explore six of these DCFs using our strategy. The TD-M06-2X calculations using the ZHA scheme point out that these compounds could serve as singlet fission chromophores (Figure 7); however, the S1 and T2 states are close in energy for DClDPDCF. Importantly, the adiabatic E(T1) are rather close to 1 eV, despite with M06-2X all are below. Similarly as seen for the model fulvenes, CASPT2 gives E(T1)a, which are higher than those of M06-2X, with 0.2–0.4 eV. In their S0 states, DClDPDCF and TClDCF are influenced by Hückel-antiaromaticity, evident by NICS(1)zz,S0 values of 10.1 and 23.1 ppm, respectively. On the other hand, they are nonaromatic in the T1 states, as the NICS(1)zz,T1 values are −0.2 and 1.3 ppm, respectively. Substituted fulvenes and fulvenoid species, which are clearly Baird-aromatic in their T1 states, have been designed computationally, but these have E(T1) which are far below 1 eV.(50)

Figure 7

Figure 7. T1, S1, and T2 energies (in eV) of six previously synthesized fulvenes computed at TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) (normal print) and CASPT2(14in14)/ANO-RCC-VDZP//M06-2X/6-311+G(d,p) (italics) levels.

Interestingly, the calculated E(S1)v/E(T1)a ratios of DClDPDCF and TClDCF are well above 2, despite that they are nonaromatic in T1. The other four DCFs in Figure 7 fulfill the E(S1)/E(T1)> 2 criterion, yet only three of them fulfill the E(S1) E(T2) criterion. The three DCFs that were also calculated at the CASPT2 level have E(S1)/E(T1) ratios that are similar to those at the M06-2X level.

A potential caveat for fulvenes is their nonrigidity, as they can relax geometrically in the S1 and T1 state, making it difficult to predict their usefulness as singlet fission chromophores. Pentacene, tetracene, and DPB relax less in energy in their T1 states compared to fulvenes (Table S8). Interestingly, from the two ratios of E(S1)v/E(T1)v and E(S1)v/E(T1)a (Table S8), one can conclude that the relative degree of energy relaxation is smaller in the established singlet fission chromophores than in the fulvenes investigated here.

Application to Other Compound Classes

Numerous additional compound classes, which to various extents are influenced by Baird-aromaticity in their T1 and S1 states and have the potential to be suitable for singlet fission photovoltaics, can be listed. For that reason we explored if a similar design strategy for fulvenes can be used to identify and tailor CBDs, pentalenes, and their benzannelated derivatives as suitable singlet fission chromophores. We showed earlier that E(T1) of isomeric PAAHs vary with the number of aromatic monocycles in the T1 state.(59) In short, the isomer with the lowest E(T1) has the maximum number of disjoint aromatic monocycles (one triplet diradical Baird-aromatic π-quartet/π-octet plus closed-shell Hückel-aromatic π-sextets). In other words, it is described by Clar’s rule(56−58) in an extended version that incorporates Baird’s 4n rule.(59) Provided the S1 state is influenced similarly as the T1 state, we argue that the benzannelation approach can be used to identify new singlet fission chromophores since E(T1) and E(S1) will be changed in energy by comparable amounts (cf. Figure 1).

The parent CBD has the correct arrangement of its T1, S1, and T2 states for singlet fission (E(T1)=0.51, E(S1)=2.70 and E(T2)=4.69 eV with M06-2X, Figure 8). However, it is exceedingly unstable, and E(T1) is too low. Instead, three substituted CBDs (SCBD1–SCBD3), which are persistent at room temperature,(83,84) were explored. Additionally, we probed an experimentally unexplored silyl-substituted CBD (SCBD4) with a more suitable energy level arrangement than the three persistent CBDs. All four substituted CBDs fulfill the fundamental singlet fission criteria, except the E(T1) of each one is too low.

Figure 8

Figure 8. Parent and substituted cyclobutadienes and their excitation energies (in eV) computed at TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) level.

For the three tetrasilyl-substituted CBDs (SCBD2–SCBD4), there is a correlation (R2=0.97) between E(T1)a and the difference in aromaticity between S0 and T1, as measured by ΔNICS(1)zz,T1-S0 (Figure S7). However, the CBD with tBu substituents (SCBD1) does not correlate with them, revealing that both electronic and geometric factors contribute to the E(T1)a of substituted CBDs. Moreover, in the silyl-substituted CBDs, the T1 and S1 states follow similar trends (Figure S7) because the E(T1)a of SCBD3 and SCBD4 increases by 0.21 and 0.42 eV when compared to the E(T1)a of SCBD2, while E(S1)v increases by 0.32 and 0.52 eV, respectively. In contrast, the E(T2)v of SCBD3 and SCBD4, within the ZHA scheme, is lower in energy by 0.34 and 0.71 eV, respectively, when compared to that of SCBD2.

Pentalenes as 8π-electron compounds were examined next, and in the Supporting Information, we also discuss results for indacenes being 12π-electron compounds. In particular, we looked at substituents that induce geometry changes to see if they alter the E(T1)a, E(S1)v, and E(T2)v to any significant extents (Figure 9). Pentalenes are strongly T1-state Baird-aromatic,(59) but according to our calculations, the parent compound only satisfies the 2E(T1)a E(S1)v criterion. Two further drawbacks are the calculated E(T1)a of ∼0.6 eV and the exceptionally low stability of the parent pentalene; however, persistent substituted pentalenes have been reported.(85,86) One could argue that substituents can tune E(T1) because the HOMO and LUMO have opposing nodal features at the formal C–C single bonds. However, substituents at the 1,2- and 4,5-positions change E(T1)a minutely, even when they are bulky. Rewardingly, the singlet fission criteria according to the ZHA scheme are satisfied for all three substituted pentalenes.

Figure 9

Figure 9. Parent and substituted pentalenes and their excitation energies (in eV) computed at the TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) level.

Because CBD has the correct state ordering while benzene does not (Figure 1), it should be possible to tailor compounds with the proper ordering of E(T1), E(S1), and E(T2) through fusion of benzene and CBD rings in certain proportions and with certain connectivities. That said, how should CBD optimally be benzannelated to arrive at suitable singlet fission chromophores? Also, can sterically congestive substituents alter the excited-state energy levels of the larger benzannelated CBD compounds? A selection of benzannelated CBDs were examined (Figure 10). The same reasoning and questions were applied to pentalenes (vide infra).

Figure 10

Figure 10. Benzannelated cyclobutadiene compounds and their excitation energies (in eV) computed at TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) and CASPT2/ANO-RCC-VDZP//CASSCF(n,m)/ANO-RCC-VDZP (italics, n=m=8 for BENZCBD1 and n=m=12, for BENZCBD2) levels. The compounds for which both singlet fission criteria are satisfied are marked in green. For full compound names, see Figure S20.

Indeed, fusion of one CBD and one benzene ring into benzocyclobutadiene (BENZCBD1) yields a compound that, according to computations, has the correct state ordering for singlet fission. The calculated E(T1)a is slightly higher than ideal, yet BENZCBD1 is still a highly reactive species and may also, as a result of the small CBD ring, decay nonradiatively to the S0 state. Among the three isomers with one CBD and two benzene rings, only one isomer satisfies the two singlet fission criteria: BENZCBD2. Using the extended version of Clar’s rule,(59) it becomes clear that this isomer is the only isomer among the three that can be described by two aromatic monocycles in its T1 state: one triplet diradical Baird-aromatic π-quartet and one closed-shell Hückel-aromatic π-sextet (see Figure S19 for ACID plots).(59) In the S0 state, it is notable that the diradical character increases somewhat when going from BENZCBD1 (y0=0.11, Table S10) to BENZCBD2 (y0=0.23).

An interesting aspect of the E(T1)a, E(S1)v, and E(T2)v of the two naphtoCBDs is the fact that when going from BENZCBD2 to BENZCBD3 the T1 and S1 states increase in energy by near-identical amounts (0.86 and 0.84 eV, respectively), while the T2 state goes up by much less (0.18 eV). This suggests that the T1 and S1 states in the two compounds are described by the same electron configuration (except for the multiplicity), following Figure 1. Indeed, according to TD-DFT computations, the S1 states of both compounds are singly excited HOMO → LUMO excitations (see Table S18). Here, it can be noted that when increasing the molecular size from BENZCBD1 to the dibenzannelated BENZCBD2–BENZCBD4, the energy differences between the vertical and adiabatic excited-state energies decrease, both in T1 and S1 (Table S26).

One can tune E(T1) and E(S1) in two ways: through benzannelation and through C–C bond length distortions (or generally, geometric contortions).(55) As seen below, the first provides for larger tunings of the excited-state energies of PAAHs because C–C bond length distortions in BENZCBD2, a small PAAH, lead to variations in E(T1) and E(S1) in the range of 0.1–0.2 eV (see Figure S15). In larger benzannelated PAAHs, where HOMO and LUMO are delocalized over further atoms, the energy tunings will be even smaller. Tuning through benzannelation should therefore be the preferred means to broadly identify PAAHs that satisfy the singlet fission criteria, while bond length changes provide fine-tuning of E(T1) and E(S1). When fusing a benzene ring onto BENZCBD2, leading to BENZCBD5, the T1 and S1 states are lowered in energy by 0.24 and 0.22 eV, respectively, while the T2 state increases by 0.10 eV. Thus, E(S1)v follows the pattern of E(T1)a when going from BENZCBD2 to BENZCBD5, in line with the hypothesis outlined in Figure 1 providing a general means for singlet fission chromophore design. Indeed, with BENZCBD5, we identify a PAAH that satisfies the two singlet fission criteria; however, it is a truly unstable compound(87) with some diradical character in S0 (y0=0.28).

Several interesting patterns emerge when going to more extensively benzannelated CBDs. Benzobiphenylene (BENZCBD6), when compared to biphenylene (BENZCBD4), has E(T1) and E(S1), which are lower by 0.52 and 0.56 eV, respectively, while E(T2) is lower by 0.30 eV. Hence, the E(S1)v/E(T1)a ratio upon fusion of one benzene ring onto biphenylene in an angular manner increases from 1.57 to 1.73, while extending in a linear way to BENZPENT7 lowers it to 1.32. Further angular benzannelation to trans-dinaphthoCBD (BENZCBD9) brings E(T1)a well below E(S1)v, but the E(S1)v/E(T1)a ratio is still smaller than 2. Here, it should be noted that the connectivity is crucial because BENZCBD9 has a higher E(S1)v/E(T1)a ratio than the isomeric BENZCBD8. Going to the penta- and hexabenzannelated CBDs, BENZCBD10 and BENZCBD11, both singlet fission criteria become satisfied within the ZHA scheme. According to M06-2X, the first of these compounds has E(T1)a in the ideal energy range. Another feature of importance is the oscillator strengths for transitions to S1 in the benzannelated CBDs, which are suitable for singlet fission. Indeed, transitions to this state are weakly allowed in BENZCBD5, BENZCBD7, and BENZCBD8 (Table S19), and one of these compounds (BENZCBD5) is in theory interesting for singlet fission.

The Baird-aromatic character of a benzannelated 4nπ-electron compound in its T1 state increases with the possibility to form local aromatic monocycles (one Baird- and several Hückel-aromatic ones).(59) Still, the Hückel-antiaromatic character of these compounds in their S0 states is significant, in line with an often observed low stability, and NICS-XY scans indicate that it is even accentuated in BENZCBD5 when compared to the other two (Figure 11). However, the T1-state Baird-aromaticity in the CBD ring in this compound is more apparent according to NICS-XY; but a weak global diatropic circuit also exists, as indicated by the ACID plot (Figure S19). Interestingly, the CBD unit in BENZCBD5 in the T1 state seems equally aromatic as in BENZCBD10 and BENZCBD11 but less aromatic to that of BENZCBD9 (Figure S17). However, the assessment of the aromaticity of the CBD ring based on NICS is not suitable, as the NICS value in a PAAH is a composite of ring currents in several 4nπ-electron circuits. HOMA, a geometry-based aromaticity index,(73,74) is more suited, and it indeed shows that the aromaticity of the CBD ring in BENZCBD5 (HOMA=0.41), which is close to that of the T1-state CBD (HOMA=0.45), is higher than in BENZCBD9–BENZCBD11 (HOMA=0.13, 0.21, and 0.27, respectively). Here, it is notable that the HOMA of the T1 state of CBD is low, as the C–C bond lengths (1.434 Å) are considerably longer than the reference value (Ropt=1.388 Å) that results in a HOMA of 1.0.

Figure 11

Figure 11. NICS-XY scans of (A) BENZCBD1, (B) BENZCBD2, (C) BENZCBD5, (D) BENZPENT1, (E) BENZPENT3, and (F) BENZPENT7 in their S0 and T1 states calculated at GIAO/M06-2X/6-311+G(d,p) level.

Similar patterns upon benzannelation to the CBDs are found for pentalenes. A drawback with pentalenes is their transitions to the S1 state, which are forbidden or very weakly allowed (for calculated oscillator strengths, see Table S23); however, the excitation to the S2 state in a 5,10-bis(styryl)-substituted dibenzo[a,e]pentalene has shown to provide an entry point to singlet fission.(88) The monobenzannelation in BENZPENT1 increases E(T1) when compared to the parent pentalene (Figure 12), similar to what was found for CBD and BENZCBD1, but BENZPENT1 is less ideal for singlet fission as E(S1) ≈ E(T2). On the other hand, the energy relaxation in the S1 state, calculated as E(S1)v – E(S1)a, is much smaller in BENZPENT1 than in BENZCBD1 (Figure S26), and E(S1)a/E(T1)a equals 2.06.

Figure 12

Figure 12. Benzannelated pentalenes and their excitation energies (in eV) computed at TD-M06-2X/def2-TZVPD//(U)M06-2X/6-311+G(d,p) (normal print) and CASPT2/ANO-RCC-VDZP//CASSCF(12,12)/ANO-RCC-VDZP (italics) levels. The compounds for which both singlet fission criteria are satisfied are marked in green. Additional benzannelated pentalenes are found in the Supporting Information. The at the E(S1)v of BENZPENT10 indicates the two-configurational character of the S1 state.

With a more isolated T1-state Baird-aromatic pentalene unit, BENZPENT3 satisfies the singlet fission criteria according to the ZHA scheme but with a slightly low E(T1). Interestingly, dibenzo[a,e]pentalene (BENZPENT5), which corresponds to the core of the compound that experimentally undergoes singlet fission when excited to S2, satisfies none of the singlet fission criteria, yet the bis(styryl)-substitution brings down E(T1) whereby the experimentally explored compound fulfills the criteria (see Figure S22 for a comparison of dibenzo[a,e]pentalene with 5,10-bis(styryl)dibenzo[a,e]pentalene). Noteworthy, the 5,10-bis(styryl) substitution introduces a new conjugation path, 1,8-diphenyl-octa-1,3,5,7-tetraene (see Figure S22), and the diradical spin density of the T1 state is concentrated to this segment. The S1 state, in contrast, is not lowered as much as the T1 state, yet this state is potentially unsuitable for TD-DFT, as it is known that the S1 state in 1,8-diphenyloctatetraene has double-excitation character.(89−91) Opposing dibenzo[a,e]pentalene (BENZPENT5), dibenzo[a,f]pentalene (BENZPENT6), the much less stable dibenzopentalene isomer,(92) satisfies both criteria, but its E(T1) is very low.

The T1 and S1 states of all benzannelated pentalenes except one are described by singly excited HOMO–LUMO excitations (the exception being BENZPENT10 with an S1 state described as HOMO–2 → LUMO (63%) plus HOMO → LUMO (37%)). Thus, several trends can be observed when expanding to larger benzannelated pentalenes. However, an important feature to note in the four panels of Figure 13 is the fact that E(T1) and E(S1) follow each other closely when the benzannelation is changed. For that reason, one should compare ΔE(S1 – T1) in a selection of compounds that follow one type of benzannelation. For example, in Figure 13A, the ΔE(S1 – T1)v,a spans from 0.94 to 1.11 eV, while ΔE(S1 – T1)v,v spans from 0.39 to 0.63 eV, indicating a similar 2KH,L within the specific selection of the compound. The first trend to note is a gradual and similar lowering of E(T1) and E(S1) found when going successively from BENZPENT5 to the hexabenzannelated BENZPENT19 (Figure 13A), following the angular connectivity that maximizes the number of aromatic monocycles in T1.(59) With BENZPENT19, a compound that has been synthesized and further investigated experimentally,(93) one has reached a point where 2E(T1) E(S1), i.e., one is within the orange region of Figure 1. Interestingly, BENZPENT19 has very similar E(T1)a, E(S1)v and E(T2)v values to those of BENZPENT3, and it contains four angular segments (∼BENZPENT3).

Figure 13

Figure 13. Variation in E(T1)a, E(S1)v, and E(T2)v calculated using the ZHA approach as a function of benzannelation in selected benzannelated pentalenes. Compounds that satisfy the singlet fission criteria are represented by yellow bars. Computations at TD-M06-2X/def2-TZVPD//(U)M06-2X/6-311+G(d,p) level. The at E(S1)v of BENZPENT10 indicates the two-configurational character of the S1 state. Further comparisons are given in Figure S23. Results of T1-aromaticity assessments are found in Figures S25–S28.

When instead going from the parent pentalene to the linear dinaphtho[a,e]pentalene (BENZPENT16), both E(T1)a and E(S1)v increase, the E(S1)v/E(T1)a ratio becomes successively smaller, and E(T2)v is placed gradually further below E(S1)v (Figure 13B). Interestingly, the ΔE(S1 – T1)v,a of BENZPENT10, having a two-configurational S1 state (vide supra), is smaller than that of the other four compounds in Figure 13B (1.12 vs 1.26–1.34 eV). The linear connectivity, which is undesirable for singlet fission chromophores, is further evidenced from the isomeric tetrabenzopentalenes BENZPENT12–BENZPENT16 (Figure S23). Also, on the basis of NICS as well as HOMA, the T1-state aromatic character of the pentalene unit decreases when going from BENZPENT13 and BENZPENT14 to BENZPENT15 and BENZPENT16, i.e., from angular-benzannelated to linear-benzannelated compounds. In the case of BENZPENT15, we have an intermediate situation as the molecule is a combination of linear and angular connectivities. Again, the inclusion of angular-benzannelated segments leads to tuning of E(S1)/E(T1) toward higher values while linear ones do the opposite.

However, there is also another route to benzannelated pentalenes that satisfy the singlet fission criteria. Further benzannelation of dibenzo[a,f]pentalene BENZPENT6 yields BENZPENT11 and BENZPENT17, which both recently were synthesized.(94) The first two satisfy the singlet fission criteria (Figures 12 and 13C) but with low E(T1)a values and high diradical characters (y0=0.48 and 0.60, respectively). Finally, BENZPENT3 and BENZPENT7, similar to BENZCBD2 and BENZCBD5, respectively, satisfy the singlet fission criteria. Now, starting at BENZPENT3 and fusing a benzene ring or a naphthalene unit to the opposite side of the pentalene unit, one obtains benzonaphthopentalene (BENZPENT8) and trans-dinaphthopentalene (BENZPENT14), respectively, for which E(T1)a and E(S1)v increase by significant amounts and the E(S1)v/E(T1)a ratio drops well below 2 (Figure 13D). The same is found when going from BENZPENT7 to BENZPENT12, revealing that a singlet fission chromophore can be ruined by overbenzannelation. It is only when at the hexabenzannelated pentalene BENZPENT19 with four angular segments that the singlet fission criteria again are satisfied, a compound in which the T1 state can be described with a markedly Baird-aromatic central 8π-electron pentalene moiety (HOMA=0.75) and four Hückel-aromatic 6π-electron units.(59) Interestingly, when gradually building up the four angular segments going from BENZPENT8 (HOMA=0.47), BENZPENT14 (HOMA=0.67), and BENZPENT18 (HOMA=0.70) to BENZPENT19, the Baird-aromatic character of the pentalene unit increases. Thus, benzannelation together with an attention to connectivity can be used to simultaneously tune E(T1) and E(S1) to similar extents such that one reaches a situation where 2E(T1) E(S1) E(T2).

The General Design Approach and Its Limitations

As the design approach applies to compound classes in which the extent of excited-state Baird-(anti)aromatic character varies among the individual compounds, E(T1) and E(S1) will change similarly along the aromaticity tuning coordinate, while E(T2) should remain more constant or change differently. The model further assumes that throughout an investigated compound class, (i) HOMO and LUMO each keep the same character (∼symmetry), (ii) the T1 and S1 states are described by singly excited HOMO → LUMO excitations, and (iii) the spatial distributions of HOMO and LUMO are similar. The model is not applicable to compound classes in which these requirements do not hold (for example, triafulvenes, vida infra), or it is only applicable to a part of the compound class.

Information on the E(T1) and ΔE(S1 – T1)=2KH,L of the parent compound is needed for the most simple back-of-an-envelope design using the model. A third parameter to consider is the slope, i.e., the extent by which E(T1) and E(S1) change in response to altered (anti)aromaticity, but a few different compounds within the compound class must be computed for this information. At the singlet fission threshold, E(T1)=ΔE(S1 – T1)=2KH,L. Thus, if the parent compounds in two compound classes have the same E(T1) but different 2KH,L then the compound class with the larger 2KH,L will have the threshold placed at a less T1 aromatic compound than what is the case in the compound class with a smaller 2KH,L (Figure 14A and B). A series of further situations are exemplified in Figure S37. Here it should be noted that the additional fulfilment of the E(S1) E(T2) criterion may restrict the useful region, pushing it toward increased Baird-aromaticity.

Figure 14

Figure 14. (A and B) Schematic drawings of the changes in E(T1) and E(S1) as functions of increased T1 and S1 aromatic character for a compound class with (A) large KH,L and (B) small KH,L. Slopes of E(T1) and E(S1) as well as the position and E(T1) of the parent compound (marked as 0 on the x-axis) are kept constant in the two plots. (C) 1,1-Disubstituted siloles with X and Y=H, Me, CF3, F, SiH3, and SiMe3 as high-E(T1) singlet fission chromophores (for explicit energies, see Figure S33). (D) Benzannelated pentalenes where the terminal benzo rings have been exchanged for thiopheno rings (for explicit energies, see Figure S36). A comparison against the completely benzannelated pentalenes is given in the Supporting Information.

The E(T1) of the parent compound depends on its extent of T1 aromaticity; if the parent compound is strongly (weakly) influenced by Baird-aromaticity it will have a low (high) E(T1). The KH,L depends on the extent of colocalization of HOMO and LUMO, as exemplified by naphthalene and azulene with 2KH,L values of 1.7 and 0.5 eV, respectively.(44) Extrapolating from this observation, by strict localization of HOMO and LUMO to different atoms, one can, together with spin-polarization, design a molecule (heptazine) that has its S1 state at a lower energy than its T1 state,(95) i.e., a negative ΔE(S1 – T1). To instead achieve a large positive 2KH,L, the HOMO and LUMO should be localized to the same atoms, ideally a small number (see siloles below).

However, as noted above, ΔE(S1 – T1) is not constant for fulvenes (Figure 5A), as it decreased for fulvenes with EWGs as exocyclic substituents, which lead to a polarization of LUMO toward the substituents, and consequently, a lowered 2KH,L and ΔE(S1 – T1). On the other hand, the model applies well to 1,1-disubstituted siloles, i.e., 1-silacyclopenta-2,4-dienes, which are cross-hyperconjugated “aromatic chameleons”.(47) For the latter compounds, ΔE(S1 – T1) varies within the narrow interval of 2.14–2.34 eV (Figure 14C). Rewardingly, siloles may provide access to singlet fission chromophores with high E(T1) (∼2 eV) according to our computations, and the 2KH,L is high due to colocalizations of HOMO and LUMO to mainly the four C atoms of the diene unit (Figure S35). As siloles are already extensively explored in experiments,(96,97) they may provide interesting targets as singlet fission chromophores.

Although the design approach had complications with pentafulvenes, the tria- and heptafulvenes are even more complex. The parent tria- and heptafulvenes have E(T1) at 2.71 and 1.41 eV, respectively, and 2KH,L at 1.87 and 1.54 eV, respectively. Thus, the parent heptafulvene, but not the triafulvene, fulfils the 2E(T1) E(S1) criterion. To lower E(T1), exocyclic electron donating substituents X are needed in both compound classes,(45) but several substituted triafulvenes in their T1 and S1 states are described by other electron configurations than the singly excited HOMO → LUMO configuration that corresponds to the T1 and S1 states in the parent compound (see Figure S31). In heptafulvene, the 2E(T1) E(S1) criterion is satisfied, but one needs to step toward increased T1 aromaticity in order to achieve heptafulvenes that also satisfy the E(S1) E(T2) criterion. However, the E(T1) and ΔE(S1 – T1) values vary extensively among substituted heptafulvenes (see Figure S32 and Table S28), and their nonplanar structures in S0 and/or T1 are dilemma. Thus, the model also fails when large conformational changes occur within a compound class, either along the (anti)aromaticity coordinate in the S0 and/or T1 states or upon excitation.

Our design approach also applies to the benzannelated pentalenes (Figure 13). The parent pentalene is strongly Baird-aromatic in T1, and it has an E(T1)a of 0.63 eV and 2KH,L of 1.26 eV. Thus, the singlet fission threshold should be placed at benzannelated pentalenes that are less T1 Baird-aromatic than the parent pentalene (BENZPENT3 or BENZPENT4 are computed to be close to the threshold, Figure 12). Now, as the NICS values of BENZPENT3 and BENZPENT4 are composites of 8π-, 12π- and 16π-electron circuits, NICS is not a suitable method for the assessment of the T1 aromaticity of a pentalene subunit within a benzannelated pentalene. HOMA is a better aromaticity index, and we indeed find the pentalene units in BENZPENT3 and BENZPENT4 to be less aromatic (HOMA=0.72 and 0.73, respectively) than the parent pentalene (HOMA=0.86). The design approach also applies to thieno-annelated benzopentalenes (see Figure S36). In regard to these, they have E(T1) that are slightly higher than the purely benzannelated pentalenes (Figures 14D and S36), revealing the impact of the incorporation of heterocycles as a means for fine-tuning E(T1). Thieno-annelated benzopentalenes could be synthetically feasible, and also, these could be interesting targets for research on singlet fission photovoltaics.

Excited-state Baird-aromaticity in combination with Hückel ground-state aromaticity can be used in the design of singlet fission chromophores, but it is a double-edged sword. While several compounds that formally can be written with Baird-aromatic resonance structures fulfill the singlet fission criteria, the specific compound within a certain compound class that is most suitable, having an E(T1) of ∼1 eV, is not always strongly T1-state Baird-aromatic. In order to identify the compounds within a certain compound class that satisfy the singlet fission criteria and that have E(T1) in a suitable energy range, we have developed a general and qualitative design model.

If the T1 and S1 states throughout a compound class are (i) dominated by the singly excited HOMO → LUMO configuration, (ii) HOMO and LUMO each are of the same character, and (iii) distributed spatially in the same manner then the energy difference between the two states equals twice the exchange integral, ΔE(S1 – T1)=2KH,L (H=HOMO and L=LUMO). As a result, the relative energies of the two states are influenced by substituents (electronic or steric) and benzannelation to similar extents. With this, we develop a geometric model to identify a region along a tuning coordinate (an ∼aromaticity/antiaromaticity scale or increased benzannelation), within which 2E(T1) E(S1) (orange region, Figure 1). It is noteworthy that when E(T1) goes below a certain threshold, the E(S1) E(T2) criterion generally becomes satisfied (Figures 5B and 13A). However, the model also has its limitations, the most notable being variations in KH,L and thus ΔE(S1 – T1), among individual compounds in a compound class.

Taken together, our study outlines the scope, limitations, and complications in the usage of T1-state Baird-aromaticity for the design of new singlet fission chromophores. The design approach and the qualitative (geometric) model developed provide a novel design rational. We show that through careful selection of (stable) compound classes influenced by Baird-aromaticity in T1 to various extents and with suitable E(T1) and 2KH,L, one can tailor many new candidates for novel types of singlet fission chromophores.

All S0– and T1-optimized geometries were obtained using the M06-2X functional(65) and 6-311+G(d,p) basis set.(98) Additionally, for benzene and CBD, CASPT2 optimizations were carried out using the atomic natural orbital (ANO-RCC-VDZP) basis set with a contraction [B, C, N, O, F/3s2p1d, Si/4s3p2d, H/2s1p].(99−101) For vertical excitations of the substituted fulvenes, two methods were used: TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) and CASPT2-SA3/ANO-RCC-VDZP//M06-2X/6-311+G(d,p) at the S0– or T1-optimized geometries. As a multiconfigurational indicator, the percentage of the perturbative triplet correction (T) to the total CCSD(T) atomization energy (%TAEe[(T)])(102) was evaluated at the CCSD(T)/aug-cc-pVDZ//M06-2X/6-311+G(d,p) level. Spin–orbit coupling (SOC) elements were computed within the TD-M06-2X framework using PySOC(80) DFT, TD-DFT, and CCSD(T) calculations performed using Gaussian 16 revision B.01,(103) and CASPT2 computations were carried out with OpenMolcas packages.(101) Aromaticity was evaluated in terms of the nucleus-independent chemical shift (NICS),(69) ACID plots,(104) harmonic oscillator model of aromaticity (HOMA),(73,74) and multicenter index (MCI)(72) computed at the M06-2X/6-311+G(d,p) optimized geometries. NICS values were calculated at 1.0 Å above the ring centers (NICS(1)zz)(70) using the gauge-independent atomic orbital (GIAO) method.(71) NICS-XY scans were performed using the Aroma package, scanning from 1.7 Å above the plane of the molecule.(105) Distinctly negative NICS(1)zz values indicate the aromatic character, values close to one indicate the nonaromatic character, and distinctly positive values indicate the antiaromatic character. For six PAAHs, NICS-XY scans were also computed using B3LYP-(106) and CAM-B3LYP-(107) optimized geometries (see Figures S19 and S18). MCI is an electronic index that provides a measure of electron sharing among the atoms considered: the higher the MCI value, the more aromatic the ring. MCI values were retrieved with the ESI-3D program(108) using the overlaps between the occupied molecular orbitals obtained by AIMAll.(109) The diradical and tetraradical character have been calculated using the spin-projected spin-unrestricted Hartree–Fock (PUHF) proposed by Yamaguchi(110) (see more details in the Supporting Information).

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.9b12435.

  • Tables with absolute relative energies, excitation energies, aromaticity data (MCI, HOMA, NICS(1)zz), and diradical character. Plots of excitation energies versus HOMA and NICS(1)zz, molecular orbitals, and NICS-XY scans. List of compounds include the following: substituted fulvenes, substituted CBDs, substituted pentalenes, substituted indacenes, benzannelated CBDs, benzannelated pentalenes, triafulvenes, heptafulvenes, siloles, and thieno-benzannelated pentalenes (PDF)

The authors declare no competing financial interest.

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We are grateful to M. Abrahamsson and G. London for interesting discussions on the manuscript and to L. Karas, N. Proos Vedin, and J. Toldo for technical assistance. We acknowledge the Wenner–Gren Foundation for a postdoctoral fellowship of O.E.B., the Swedish Research Council (grant 2015-04538) for financial support, and the Swedish National Infrastructure for Computing via the National Supercomputer Center in Linköping, Sweden for generous allotment of computer time. J.R.S. would like to thank the Swedish Fulbright Commission, the American Scandinavian Foundation, and the HSU College of Natural Resources and Science for supporting his time at UU.

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    ISSN: 1932-7447.

    (American Chemical Society)

    Singlet fission (SF), the generation of two triplet excitons per the absorption of one photon, is a promising strategy for increasing the efficiency of solar cells beyond the theor. Shockley-Queisser limit of 34%. Upon photon absorption by a SF mol., the initially created singlet excited state (S1) interacts with a neighboring chromophore and is first transformed into a triplet pair (TT), which can be subsequently sepd. into independent triplet excitons (2T1). These independent triplet excitons can be harvested through triplet charge extn. or triplet energy transfer to an acceptor. Research on SF systems has revealed rates and efficiencies of triplet formation and triplet pair decorrelation that are strongly dependent on interchromophore coupling, which is dictated by mol. structure and the resulting geometrical arrangement of chromophores adopted in covalent (e.g., dimers) and noncovalent (e.g., films and crystals) systems. Incorporation of SF materials into realistic device architectures introduces a host of new challenges to consider regarding the efficient extn. of triplets generated through SF. In this Feature Article, we review our work that has led to some degree of understanding and control of inter- and intramol. SF rates placed in the context of solar energy harvesting architectures, including dye-sensitized solar cells, conjugated polymer films, and ligand-exchanged quantum dots. We emphasize the importance of understanding and manipulating interactions between SF mols. with each other and with the charge or energy collectors across an interface in order to strike a kinetic balance that leads to efficient utilization of triplet excitons.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitFGgsL0%253D&md5=d2e9383954aec4be5cb9c269b4455ec9

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    Krishnapriya, K. C.; Musser, A. J.; Patil, S. Molecular Design Strategies for Efficient Intramolecular Singlet Exciton Fission. ACS Energy Lett. 2019, 4, 192– 202, DOI: 10.1021/acsenergylett.8b01833

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    Molecular Design Strategies for Efficient Intramolecular Singlet Exciton Fission

    Krishnapriya, K. C.; Musser, Andrew J.; Patil, Satish

    ACS Energy Letters
    (2019),
    4
    (1),
    192-202CODEN:
    AELCCP;
    ISSN: 2380-8195.

    (American Chemical Society)

    The process of carrier multiplication via singlet fission can potentially exceed the Shockley-Queisser limit on the efficiency of single-junction photovoltaics. In the recent past, theor. anal. provided the principal guidelines on mol. design strategies for singlet fission. In this Perspective, we focus instead on correlating exptl. results for different classes of reported singlet fission materials to identify principles to aid in the design of new mols. for efficient intramol. singlet fission. Building on an evaluation of several series of multichromophoric and polymeric singlet fission materials, we ext. new suggested strategies for mol. design.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlWhtL%252FK&md5=d36cf31ac171611a9e6cf6c8ec1a1189

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    Basel, B. S.; Papadopoulos, I.; Thiel, D.; Casillas, R.; Zirzlmeier, J.; Clark, T.; Guldi, D. M.; Tykwinski, R. R. Pentacenes: A Molecular Ruler for Singlet Fission. Trends in Chem. 2019, 1, 11– 21, DOI: 10.1016/j.trechm.2019.02.002

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    Ito, S.; Nagami, T.; Nakano, M. Molecular Design for Efficient Singlet Fission. J. Photochem. Photobiol., C 2018, 34, 85– 120, DOI: 10.1016/j.jphotochemrev.2018.01.002

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    Molecular design for efficient singlet fission

    Ito, Soichi; Nagami, Takanori; Nakano, Masayoshi

    Journal of Photochemistry and Photobiology, C: Photochemistry Reviews
    (2018),
    34
    (),
    85-120CODEN:
    JPPCAF;
    ISSN: 1389-5567.

    (Elsevier B.V.)

    A review. Singlet fission is a photophys. process in mols. and mol. aggregates, in which a singlet exciton generated by irradn. splits into two triplet excitons. Recently, singlet fission has attracted a great deal of attention from the viewpoint of applications in org. photovoltaic cells, where singlet fission has a possibility of improving the photoelec. conversion efficiency. Although singlet fission was first obsd. about 50 years ago in anthracene crystals, and the mechanism has been investigated in detail for a small no. of mol. systems such as tetracene and pentacene crystals, the relationships between mol. or crystal structures and singlet fission efficiency are yet to be precisely clarified. Thus, mol. structure – singlet fission relationships and mol. or crystal design guidelines for efficient singlet fission are intensely desired for realizing efficient photovoltaic energy conversion, and exptl. and theor. investigations advance rapidly. We introduce three investigation steps, which are based on bottom-up theor. modeling from a mol. to a mol. aggregate or crystal. The modeling involves energy level matching at the mol. level, electronic coupling at the aggregate level, and singlet fission dynamics including exciton-phonon (vibronic) coupling, by emphasizing the importance of interplay between each step. From the modeling, we present several design guidelines for efficient singlet fission, which is together with practical mol. structures, chem. modifications and mol. configurations.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXivFCku74%253D&md5=4f57ac0f40a9bc49a0b6f79ad9533fb9

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    Minami, T.; Ito, S.; Nakano, M. Fundamental of Diradical-Character-Based Molecular Design for Singlet Fission. J. Phys. Chem. Lett. 2013, 4, 2133– 2137, DOI: 10.1021/jz400931b

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    Fundamental of Diradical-Character-Based Molecular Design for Singlet Fission

    Minami, Takuya; Ito, Soichi; Nakano, Masayoshi

    Journal of Physical Chemistry Letters
    (2013),
    4
    (13),
    2133-2137CODEN:
    JPCLCD;
    ISSN: 1948-7185.

    (American Chemical Society)

    The fundamental of diradical-character-based mol. design for singlet fission is clarified through the correlation between the diradical character, the first singlet (S1) and triplet (T1) excitation energies, the frontier orbital energy gap, and the energy level matching condition (2E(T1) – E(S1) ≈ 0 or

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXptlCgsr4%253D&md5=4395e6adc01babfe1515a66d311512d7

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    Zeng, T.; Goel, P. Design of Small Intramolecular Singlet Fission Chromophores: An Azaborine Candidate and General Small Size Effects. J. Phys. Chem. Lett. 2016, 7, 1351– 1358, DOI: 10.1021/acs.jpclett.6b00356

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    Design of Small Intramolecular Singlet Fission Chromophores: An Azaborine Candidate and General Small Size Effects

    Zeng, Tao; Goel, Prateek

    Journal of Physical Chemistry Letters
    (2016),
    7
    (7),
    1351-1358CODEN:
    JPCLCD;
    ISSN: 1948-7185.

    (American Chemical Society)

    We report the first attempt to design small intramol. singlet fission chromophores, with the aid of quantum chem. and explicitly simulating the time evolution of state populations using quantum dynamics method. We start with three previously proposed azaborine-substituted intermol. singlet fission chromophores. Through analyzing their frontier orbital amplitudes, we select a BN-substituted azulene as the building block. Covalently connecting two such monomers and tuning their relative configuration, we examine three dimers. One dimer is found to be an eminent candidate: the triplet-pair state is quickly formed within 1 silicon::polycryst.,, and the two triplets are ready to be disentangled. We elucidate the general small size effects in intramol. singlet fission and focus on specific aspects which should be taken care of when manipulating the fission rate through steric hindrance.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XkslGqt70%253D&md5=bdb0554f3fc3eb17b45c7664b3d8ebb1

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    Match, C.; Perkins, J.; Schreckenbach, G. Simple Computational Screening of Potential Singlet Fission Molecules. Theor. Chem. Acc. 2018, 137, 109, DOI: 10.1007/s00214-018-2290-4

  23. 23

    Nakano, M. Open-Shell-Character-Based Molecular Design Principles: Applications to Nonlinear Optics and Singlet Fission. Chem. Rec. 2017, 17, 27– 62, DOI: 10.1002/tcr.201600094

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    Open-Shell-Character-Based Molecular Design Principles: Applications to Nonlinear Optics and Singlet Fission

    Nakano, Masayoshi

    Chemical Record
    (2017),
    17
    (1),
    27-62CODEN:
    CRHEAK;
    ISSN: 1528-0691.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    Open-shell character, e.g., diradical character, is a quantum chem. well-defined quantity in ground-state mol. systems, which is not an observable but can quantify the degree of effective bond weakness in the chem. sense or electron correlation strength in the phys. sense. Because this quantity also correlates to specific excited states, physicochem. properties concerned with those states are expected to strongly correlate to the open-shell character. This feature enables us to open a new path to revealing the mechanism of these properties as well as to realizing new design principles for efficient functional mol. systems. This account explains the open-shell-character-based mol. design principles and introduces their applications to the rational design of highly efficient nonlinear optical and singlet fission mol. systems.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtlShurfE&md5=1b07f1a1af532cc83425079f045d2cdc

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    Ito, S.; Nakano, M. Theoretical Molecular Design of Heteroacenes for Singlet Fission: Tuning the Diradical Character by Modifying π-Conjugation Length and Aromaticity. J. Phys. Chem. C 2015, 119, 148– 157, DOI: 10.1021/jp5103737

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    Theoretical Molecular Design of Heteroacenes for Singlet Fission: Tuning the Diradical Character by Modifying π-Conjugation Length and Aromaticity

    Ito, Soichi; Nakano, Masayoshi

    Journal of Physical Chemistry C
    (2015),
    119
    (1),
    148-157CODEN:
    JPCCCK;
    ISSN: 1932-7447.

    (American Chemical Society)

    A theor. mol. design for efficient singlet fission (SF) is performed for several heteroacene models involving nitrogen (N) atoms based on the diradical character criterion of the energy level matching conditions. This criterion is found to be closely related to the relative contributions of diradical and zwitterionic resonance structures of the heteroacenes, i.e., the aromaticity of the central ring(s). From the anal. of the diradical characters of these heteroacene models, the increase in the aromaticity of the central ring(s) is found to prefer the diradical form to the zwitterionic form. From the comparison of the excitation energies evaluated by multireference second-order perturbation theory calcns., two promising candidates, chosen based on the diradical character criterion, are found to satisfy the energy level matching conditions and to possess high triplet energies of ∼1.1 eV, which are suitable for an application in org. photovoltaic cells. The proposed two candidates are shown to have mutually different types of the first excited singlet states, which are distinguished by the primary excitation configurations. These results suggest that the proposed two candidates exhibit different singlet fission dynamics due to the different amplitude of the electronic coupling.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitV2ju7fE&md5=ae8b1b61f3c332de221cecaede8c7113

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    Zeng, T.; Ananth, N.; Hoffmann, R. Seeking Small Molecules for Singlet Fission: A Heteroatom Substitution Strategy. J. Am. Chem. Soc. 2014, 136, 12638– 12647, DOI: 10.1021/ja505275m

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    Seeking Small Molecules for Singlet Fission: A Heteroatom Substitution Strategy

    Zeng, Tao; Ananth, Nandini; Hoffmann, Roald

    Journal of the American Chemical Society
    (2014),
    136
    (36),
    12638-12647CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    We design theor. small mol. candidates for singlet fission chromophores, aiming to achieve a balance between sufficient diradical character and kinetic persistence. We develop a perturbation strategy based on the captodative effect to introduce diradical character into small π-systems. Specifically, this can be accomplished by replacing pairs of not necessarily adjacent C atoms with isoelectronic and isosteric pairs of B and N atoms. Three rules of thumb emerge from our studies to aid further design: (i) Lewis structures provide insight into likely diradical character; (ii) formal radical centers of the diradical must be well-sepd.; (iii) stabilization of radical centers by a donor (N) and an acceptor (B) is essential. Following the rules, we propose candidate mols. Employing reliable multireference calcns. for excited states, we identify three likely candidate mols. for SF chromophores. These include a benzene, a naphthalene, and an azulene, where four C atoms are replaced by a pair of B and a pair of N atoms.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVSnsrfP&md5=252ab72cf2c676144b0f4e7d0d05f51f

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    Ito, S.; Minami, T.; Nakano, M. Diradical Character Based Design for Singlet Fission of Condensed-Ring Systems with 4nπ Electrons. J. Phys. Chem. C 2012, 116, 19729– 19736, DOI: 10.1021/jp3072684

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    Diradical Character Based Design for Singlet Fission of Condensed-Ring Systems with 4nπ Electrons

    Ito, Soichi; Minami, Takuya; Nakano, Masayoshi

    Journal of Physical Chemistry C
    (2012),
    116
    (37),
    19729-19736CODEN:
    JPCCCK;
    ISSN: 1932-7447.

    (American Chemical Society)

    By applying the diradical character based mol. design guideline for singlet fission (SF), we investigate the feasibility of efficient SF in condensed-ring π-conjugated mols. with 4nπ electrons (n=4, 5, …), i.e., antiarom. polycyclic hydrocarbons composed of five- and six-membered rings. The multiple diradical character (yi), which takes a value between 0 (closed shell) and 1 (pure open shell), is defined as the occupation no. of the lowest unoccupied natural orbital (LUNO) + i (i=0, 1, …) calcd. using the approx. spin-projected spin-UHF method. The excitation energies are also evaluated using the tuned long-range cor. time-dependent d. functional theory method with the Tamm-Dancoff approxn. to examine the energy level matching conditions for SF: (i) 2E(T1) – E(S1) ∼ 0 or ≤ 0 and (ii) 2E(T1) – E(T2)

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xht1KmsL7E&md5=71e724b13bea11298ec80ba071215c44

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    Chen, Y.; Shen, L.; Li, X. Effects of Heteroatoms of Tetracene and Pentacene Derivatives on Their Stability and Singlet Fission. J. Phys. Chem. A 2014, 118, 5700– 5708, DOI: 10.1021/jp503114b

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    Effects of Heteroatoms of Tetracene and Pentacene Derivatives on Their Stability and Singlet Fission

    Chen, Yuhan; Shen, Li; Li, Xiyou

    Journal of Physical Chemistry A
    (2014),
    118
    (30),
    5700-5708CODEN:
    JPCAFH;
    ISSN: 1089-5639.

    (American Chemical Society)

    The effects of the introduction of an sp2-hybridized nitrogen atom (=N-) and thiophene ring on the structure geometries, frontier MO energies, and excited state energies related to singlet fission (SF) for some tetracene and pentacene derivs. were theor. investigated by quantum chem. methods. The introduction of a nitrogen atom significantly decreases the energies of frontier MOs and hence improves their stabilities in air and light illumination. More importantly, it is helpful for reducing the energy loss of the exothermic singlet fission of pentacene derivs. For fused benzene-thiophene structures, the (α, β) connection pattern could stabilize the frontier MOs, while the (β, β) connection pattern can promote the thermodn. driving force of singlet fission. These facts provide a theor. ground for rational design of SF materials.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFens7bN&md5=2e6ee780697588cecb98355257bf03d9

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    Singh, S.; Jones, W. J.; Siebrand, W.; Stoicheff, B. P.; Schneider, W. G. Laser Generation of Excitons and Fluorescence in Anthracene Crystals. J. Chem. Phys. 1965, 42, 330– 342, DOI: 10.1063/1.1695695

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    Laser generation of excitons and fluorescence in anthracene crystals

    Singh, S.; Jones, W. J.; Siebrand, W.; Stoicheff, B. P.; Schneider, W. G.

    Journal of Chemical Physics
    (1965),
    42
    (1),
    330-42CODEN:
    JCPSA6;
    ISSN: 0021-9606.

    Exptl. and theoretical studies are reported of the short-lived and delayed fluorescence of anthracene single crystals, excited by single- and double-proton absorption. A giant-pulse ruby laser provides the primary source of radiation of 14,400 cm.-1 (up to 1027 photons/cm.2 sec.) and is also used to generate 2nd-harmonic radiation from adenosine 5′-diphosphate, as well as stimulated Raman radiation of 12,800 and 17,500 cm.-1 from liquid O. The time dependence of the fluorescence intensity is studied as a function of laser intensity, crystal temp., and excitation wavelength. The very intense fast fluorescence with a half-life of 30 nsec. at 300°K., characteristic of singlet exciton decay, and the relatively weak delayed fluorescence which involves intermediate triplet states, are sepd. by using sectored disks. The triplet state at 14,750 cm.-1 can be populated (1) by direct absorption of laser photons, involving an activation energy of 350 cm.-1; (2) via 2-photon absorption, presumably leading to a vibrationally excited state of the 1B2u exciton, followed by intersystem crossing; (3) via 1-photon (2nd-harmonic) excitation from levels ≥700 cm.-1 into the singlet absorption band, followed by conversion of the singlet exciton into a triplet pair. The latter process is suggested by the observed activation energy of 700 cm.-1 In agreement with these interpretations, the delayed fluorescence intensity varies with the 2nd to 4th power of the laser intensity, depending on the exptl. conditions. Also, light of 17,500 cm.-1 leads exclusively to process (1), light of 12,800 cm.-1 exclusively to (2). Triplet lifetimes from 2-17 msec. are obtained, depending on crystal purity, which indicates that unimol. triplet decay is an extrinsic, radiationless process. A singlet-triplet intersystem crossing rate const. of ∼3 × 10-5 sec.-1 is estd. The triplet-triplet annihilation rate const. is ∼5 × 10-11 cm.3 sec.-1 This value, considered together with the triplet-pair creation process, suggests a triplet exchange rate ⪆1013 sec.-1 and a triplet diffusion const. ⪆5 × 10-4 cm.2/sec.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaF2MXhvFyjtQ%253D%253D&md5=7a939ac766c41d53bcc49f62422007a6

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    Groff, R. P.; Avakian, P.; Merrifield, R. E. Coexistence of Exciton Fission and Fusion in Tetracene Crystals. Phys. Rev. B 1970, 1, 815– 817, DOI: 10.1103/PhysRevB.1.815

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    Burgos, J.; Pope, M.; Swenberg, Ch. E.; Alfano, R. R. Heterofission in Pentacene-Doped Tetracene Single Crystals. Phys. Status Solidi B 1977, 83, 249– 256, DOI: 10.1002/pssb.2220830127

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    Heterofission in pentacene-doped tetracene single crystals

    Burgos, J.; Pope, M.; Swenberg, C. E.; Alfano, R. R.

    Physica Status Solidi B: Basic Research
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    83
    (1),
    249-56CODEN:
    PSSBBD;
    ISSN: 0370-1972.

    The magnetic field and the temp. dependence of both guest and host fluorescence in pentacene-doped tetracene single crystals was studied. From an anal. of the exptl. results pentacene enters substitutionally into the host lattice sites and thermally activated heterofission is site-dependent with activation energies ≈ (0.13 ± 0.01) eV and .ltorsim.0.06 eV. From a kinetic fit to the temp. dependence of the green and red fluorescence, a thermally activated host singlet exciton diffusion coeff. of ≈ 2 × 10-2 cm2/s is inferred; its activation energy is (0.018 ± 0.001) eV. The heterofission rate of ≈ (4.7 ± 0.5) × 10-10 cm3 s-1 was detd. and location of the pentacene triplet level is found at (0.86 ± 0.03) eV.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2sXlslGjtL0%253D&md5=934556b5642fb2fe13cd77706d3b48c9

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    Johnson, J. C.; Nozik, A. J.; Michl, J. High Triplet Yield from Singlet Fission in a Thin Film of 1,3-Diphenylisobenzofuran. J. Am. Chem. Soc. 2010, 132, 16302– 16303, DOI: 10.1021/ja104123r

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    High Triplet Yield from Singlet Fission in a Thin Film of 1,3-Diphenylisobenzofuran

    Johnson, Justin C.; Nozik, Arthur J.; Michl, Josef

    Journal of the American Chemical Society
    (2010),
    132
    (46),
    16302-16303CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    Direct observation of triplet absorption and ground-state depletion upon pulsed excitation of a polycryst. thin solid film of 1,3-diphenylisobenzofuran at 77 K revealed a 200 ± 30% triplet yield, which was attributed to singlet fission.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlOnsLvM&md5=e715b469a3c20c180c8fa1819457801e

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    Schrauben, J. N.; Ryerson, J. L.; Michl, J.; Johnson, J. C. Mechanism of Singlet Fission in Thin Films of 1,3-Diphenylisobenzofuran. J. Am. Chem. Soc. 2014, 136, 7363– 7373, DOI: 10.1021/ja501337b

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    Mechanism of Singlet Fission in Thin Films of 1,3-Diphenylisobenzofuran

    Schrauben, Joel N.; Ryerson, Joseph L.; Michl, Josef; Johnson, Justin C.

    Journal of the American Chemical Society
    (2014),
    136
    (20),
    7363-7373CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    In order to elucidate the mechanism of singlet fission in thin films of 1,3-diphenylisobenzofuran (1) the authors have performed ultrafast transient absorption spectroscopy as a function of sample temp. and excitation fluence on polycryst. thin films composed of two polymorphs. The authors earlier investigations revealed that films enriched in a particular polymorph of 1 displayed near 200% efficiency for triplet formation at 77 K, while films composed primarily of a second polymorph had a very low triplet quantum yield. Present data confirm the triplet yield disparities in the two polymorphs and demonstrate the distinct fates of the initially prepd. singlets in films of different structure. Singlet fission is inhibited in the more stable polymorph due to rapid excimer formation and trapping. The less stable polymorph undergoes highly efficient singlet fission with a dominant time const. of 10-30 ps and without strong thermal activation. Transient absorption measurements with varying excitation fluence indicate that singlet-singlet annihilation is a primary competitor of singlet fission at higher fluence and that fission from higher-lying states can also contribute to the triplet formation process. Measurements employing different excitation energies and sample temps. reveal the role that trapping processes play in attenuating the triplet quantum yield to produce the complex temp. dependence of the singlet fission yield. The rate consts. for singlet fission itself are essentially temp. independent.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmt1SgsL8%253D&md5=ec61c22a867d92d4100c371d0a6b692c

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    Baird, N. C. Quantum organic photochemistry. II. Resonance and Aromaticity in the Lowest 3 ππState of Cyclic Hydrocarbons. J. Am. Chem. Soc. 1972, 94, 4941– 4948, DOI: 10.1021/ja00769a025

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    Quantum organic photochemistry. II. Resonance and aromaticity in the lowest 3ππstate of cyclic hydrocarbons

    Baird, N. Colin

    Journal of the American Chemical Society
    (1972),
    94
    (14),
    4941-8CODEN:
    JACSAT;
    ISSN: 0002-7863.

    The concepts of aromaticity, antiaromaticity, and Dewar resonance energy are extended to the lowest ππtriplet state of conjugated hydrocarbons by comparing the bonding energy of triplets to the most stable biradical ref. structure. Arguments based upon simple perturbation theory indicate that the rules for ground state aromaticity are reversed in the 3ππstate (4n rings display “aromatic” character whereas 4n + 2 systems display “antiaromaticity”). Semiempirical SCF-LCAO-MO calcns. by the neglect-of-nonbonded-differential-overlap method confirm these predictions, and predict transition, bonding, and stabilization energies for a wide range of triplets including those for cyclobutadiene and derivs., cyclooctatetraene and derivs., nonclassical polyenes, 3-7-membered rings contg. exocyclic C atoms, benzenoid hydrocarbons, butalene, azulene, and cyclodecapentaene. The preference of certain hydrocarbon triplets for a completely planar rather than 90° twisted structure (such as methylenecyclo-propene, fulvene, and heptafulvene) is analyzed by perturbation theory. The consequences of aromatic and antiaromatic character to the exothermicity of ortho addn. are explored for several hydrocarbon triplets.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE38XkslCksb0%253D&md5=fd74d4499d8dfcca1fe6d296285623a6

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    Ottosson, H. Organic photochemistry: Exciting Excited-State Aromaticity. Nat. Chem. 2012, 4, 969– 971, DOI: 10.1038/nchem.1518

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    Organic photochemistry Exciting excited-state aromaticity

    Ottosson, Henrik

    Nature Chemistry
    (2012),
    4
    (12),
    969-971CODEN:
    NCAHBB;
    ISSN: 1755-4330.

    (Nature Publishing Group)

    In 1972, Baird published rules describing aromaticity and antiaromaticity in the lowest triplet excited states of annulenes. The fortieth anniversary of Baird’s rules – which are the reverse of Hueckel’s rules for aromaticity and antiaromaticity in the ground state – ought to be celebrated before 2012 comes to an end.

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    Rosenberg, M.; Dahlstrand, C.; Kilså, K.; Ottosson, H. Excited State Aromaticity and Antiaromaticity: Opportunities for Photophysical and Photochemical Rationalizations. Chem. Rev. 2014, 114, 5379– 5425, DOI: 10.1021/cr300471v

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    Excited State Aromaticity and Antiaromaticity: Opportunities for Photophysical and Photochemical Rationalizations

    Rosenberg, Martin; Dahlstrand, Christian; Kilsaa, Kristine; Ottosson, Henrik

    Chemical Reviews (Washington, DC, United States)
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    114
    (10),
    5379-5425CODEN:
    CHREAY;
    ISSN: 0009-2665.

    (American Chemical Society)

    In this review the authors described the development of the excited state aromaticity concept over time, a development which has progressed slowly over several decades and in different branches of chem. As a result, the concept has not been as visible to the chem. community as desirable. This review provides accumulative collection of studies that strongly support the existence of aromaticity and antiaromaticity effects in the lowest excited states of cyclic π-conjugated mols. The excited state (anti)aromaticity effects could be equally useful for understanding of excited state properties and processes as ground state aromaticity is useful for rationalization of ground state properties and processes.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXlsl2ks7s%253D&md5=4f1023c0fa4c093032d1bc71d30885db

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    Oh, J.; Sung, Y. M.; Hong, Y.; Kim, D. Spectroscopic Diagnosis of Excited-State Aromaticity: Capturing Electronic Structures and Conformations upon Aromaticity Reversal. Acc. Chem. Res. 2018, 51, 1349– 1358, DOI: 10.1021/acs.accounts.7b00629

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    36

    Spectroscopic Diagnosis of Excited-State Aromaticity: Capturing Electronic Structures and Conformations upon Aromaticity Reversal

    Oh, Juwon; Sung, Young Mo; Hong, Yongseok; Kim, Dongho

    Accounts of Chemical Research
    (2018),
    51
    (6),
    1349-1358CODEN:
    ACHRE4;
    ISSN: 0001-4842.

    (American Chemical Society)

    A review. Aromaticity, the special energetic stability derived from cyclic [4n + 2]π-conjugated electronic structures, has been the topic of intense interest in chem. because it plays a crit. role in rationalizing mol. stability, reactivity, and phys./chem. properties. Recently, the pioneering work by Colin Baird on aromaticity reversal, postulating that arom. (antiarom.) character in the ground state reverses to antiarom. (arom.) character in the lowest excited triplet state, has attracted much scientific attention. The completely reversed aromaticity in the excited state provides direct insight into understanding the photophys./chem. properties of photoactive materials. In turn, the application of arom. mols. to photoactive materials has led to numerous studies revealing this aromaticity reversal. However, most studies of excited-state aromaticity have been based on the theor. point of view. The exptl. evaluation of aromaticity in the excited state is still challenging and strenuous because the assessment of (anti)aromaticity with conventional magnetic, energetic, and geometric indexes is difficult in the excited state, which practically restricts the extension and application of the concept of excited-state aromaticity. Time-resolved optical spectroscopies can provide a new and alternative avenue to evaluate excited-state aromaticity exptl. while observing changes in the mol. features in the excited states. Time-resolved optical spectroscopies take advantage of ultrafast laser pulses to achieve high time resoln., making them suitable for monitoring ultrafast changes in the excited states of mol. systems. This can provide valuable information for understanding the aromaticity reversal.This Account presents recent breakthroughs in the exptl. assessment of excited-state aromaticity and the verification of aromaticity reversal with time-resolved optical spectroscopic measurements. To scrutinize this intriguing and challenging scientific issue, expanded porphyrins have been utilized as the ideal testing platform for investigating aromaticity because they show distinct arom. and antiarom. characters with aromaticity-specific spectroscopic features. Expanded porphyrins exhibit perfect arom. and antiarom. congener pairs having the same mol. framework but different nos. of π electrons, which facilitates the study of the pure effect of aromaticity by comparative analyses. On the basis of the characteristics of expanded porphyrins, time-resolved electronic and vibrational absorption spectroscopies capture the changes in electronic structure and mol. conformations driven by the change in aromaticity and provide clear evidence for aromaticity reversal in the excited states. The approaches described in this Account pave the way for the development of new and alternative exptl. indexes for the evaluation of excited-state aromaticity, which will enable overarching and fundamental comprehension of the role of (anti)aromaticity in the stability, dynamics, and reactivity in the excited states with possible implications for practical applications.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjvVSksLc%253D&md5=8e24d0c31644703531f08b314da63df7

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    Fallon, K. J.; Budden, P.; Salvadori, E.; Ganose, A. M.; Savory, C. N.; Eyre, L.; Dowland, S.; Ai, Q.; Goodlett, S.; Risko, C.; Scanlon, D. O.; Kay, C. W. M.; Rao, A.; Friend, R. H.; Musser, A. J.; Bronstein, H. Exploiting Excited-State Aromaticity to Design Highly Stable Singlet Fission Materials. J. Am. Chem. Soc. 2019, 141, 13867– 13876, DOI: 10.1021/jacs.9b06346

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    37

    Exploiting excited-state aromaticity to design highly stable singlet fission materials

    Fallon, Kealan J.; Budden, Peter; Salvadori, Enrico; Ganose, Alex M.; Savory, Christopher N.; Eyre, Lissa; Dowland, Simon; Ai, Qianxiang; Goodlett, Stephen; Risko, Chad; Scanlon, David O.; Kay, Christopher W. M.; Rao, Akshay; Friend, Richard H.; Musser, Andrew J.; Bronstein, Hugo

    Journal of the American Chemical Society
    (2019),
    141
    (35),
    13867-13876CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    Singlet fission, the process of forming two triplet excitons from one singlet exciton, is a characteristic reserved for only a handful of org. mols. due to the atypical energetic requirement for low energy excited triplet states. The predominant strategy for achieving such a trait is by increasing ground state diradical character; however, this greatly reduces ambient stability. Herein, we exploit Baird’s rule of excited state aromaticity to manipulate the singlet-triplet energy gap and create novel singlet fission candidates. We achieve this through the inclusion of a [4n] 5-membered heterocycle, whose electronic resonance promotes aromaticity in the triplet state, stabilizing its energy relative to the singlet excited state. Using this theory, we design a family of derivs. of indolonaphthyridine thiophene (INDT) with highly tunable excited state energies. Not only do we access novel singlet fission materials, they also exhibit excellent ambient stability, imparted due to the delocalized nature of the triplet excited state. Spin-coated films retained up to 85% activity after several weeks of exposure to oxygen and light, while analogous films of TIPS-pentacene showed full degrdn. after 4 days, showcasing the excellent stability of this class of singlet fission scaffold. Extension of our theor. anal. to almost ten thousand candidates reveals an unprecedented degree of tunability and several thousand potential fission-capable candidates, while clearly demonstrating the relationship between triplet aromaticity and singlet-triplet energy gap, confirming this novel strategy for manipulating the exchange energy in org. materials.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFSku73L&md5=0a0a7bc43984992df2b7883fde556f2f

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    Shukla, D.; Wan, P. Evidence for a Planar Cyclically Conjugated 8π System in the Excited State: Large Stokes Shift Observed for Dibenz[b,f]oxepin Fluorescence. J. Am. Chem. Soc. 1993, 115, 2990– 2991, DOI: 10.1021/ja00060a063

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    38

    Evidence for a planar cyclically conjugated 8π system in the excited state: large Stokes shift observed for dibenz[b,f]oxepin fluorescence

    Shukla, Deepak; Wan, Peter

    Journal of the American Chemical Society
    (1993),
    115
    (7),
    2990-1CODEN:
    JACSAT;
    ISSN: 0002-7863.

    The fluorescence emissions of dibenz[b,f]oxepin (I, X=O) and dibenzo[b,f]thiepin (I, X=S) exhibit unexpectedly large Stokes shifts (≈4720 cm-1). The equil. geometries of I on the excited-state surface are planar and are the fluorescent states. The driving force for torsional twisting to a planar geometry is believed to be the attainment of a conjugated 8π cyclic array in the central ring, which would be highly unfavorable (antiarom.) in the ground state. The vibrational fine structure (progression of ≈1500 cm-1) and relatively long lifetime of the emission band obsd. for I (X=O), along with corroborating reactivity data, indicate that these compds. exhibit the characteristics of a planar and arom. mol. in S1.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXitlegt78%253D&md5=dacbf0e58476739b6f9ba604f61a1482

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    Toldo, J.; El Bakouri, O.; Solà, M.; Norrby, P.-O.; Ottosson, H. Is Excited-State Aromaticity a Driving Force for Planarization of Dibenzannelated 8π-Electron Heterocycles?. ChemPlusChem 2019, 84, 712– 721, DOI: 10.1002/cplu.201900066

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    Is Excited-State Aromaticity a Driving Force for Planarization of Dibenzannelated 8π-Electron Heterocycles?

    Toldo, Josene; El Bakouri, Ouissam; Sola, Miquel; Norrby, Per-Ola; Ottosson, Henrik

    ChemPlusChem
    (2019),
    84
    (6),
    712-721CODEN:
    CHEMM5;
    ISSN: 2192-6506.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    Compds. with dibenzannelated heterocycles with eight π-electrons are found in a range of applications. These mols. often adopt a bent structure in the ground state (S0) but can become planar in the first excited states (S1 and T1) because of the cyclically conjugated 4nπ central ring, which fulfils the requirements for excited state aromaticity. We report on a quantum chem. investigation of the arom. character in the S1 and T1 states of dibenzannelated seven- and six-membered heterocycles with one, two, or three heteroatoms in the 8π-electron ring. These states could have ππor nπcharacter. We find that compds. with one or two heteroatoms in the central ring have ππstates as their S1 and T1 states. They are to a significant degree influenced by excited state aromaticity, and their optimal structures are planar or nearly planar. Among the heteroatoms, nitrogen provides for the strongest excited state aromaticity whereas oxygen provides for the weakest, following the established trend of the S0 state. Yet, dibenzannelated seven-membered-ring compds. with N=N bonds have non-arom. nπstates with strongly puckered structures as their S1 and T1 states.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXotl2rsbw%253D&md5=1e0da0b30c73875f80df7c775be455ab

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    Ryerson, J. L.; Zaykov, A.; Aguilar
    Suarez, L. E.    ; Havenith, R. W. A.; Stepp, B. R.; Dron, P. I.; Kaleta, J.; Akdag, A.; Teat, S. J.; Magnera, T. F.; Miller, J. R.; Havlas, Z.; Broer, R.; Faraji, S.; Michl, J.; Johnson, J. C. Structure and Photophysics of Indigoids for Singlet Fission: Cibalackrot. J. Chem. Phys. 2019, 151, 184903, DOI: 10.1063/1.5121863

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    Structure and photophysics of indigoids for singlet fission: Cibalackrot

    Ryerson, Joseph L.; Zaykov, Alexandr; Aguilar Suarez, Luis E.; Havenith, Remco W. A.; Stepp, Brian R.; Dron, Paul I.; Kaleta, Jiri; Akdag, Akin; Teat, Simon J.; Magnera, Thomas F.; Miller, John R.; Havlas, Zdenek; Broer, Ria; Faraji, Shirin; Michl, Josef; Johnson, Justin C.

    Journal of Chemical Physics
    (2019),
    151
    (18),
    184903/1-184903/16CODEN:
    JCPSA6;
    ISSN: 0021-9606.

    (American Institute of Physics)

    We report an investigation of structure and photophysics of thin layers of cibalackrot, a sturdy dye derived from indigo by double annulation at the central double bond. Evapd. layers contain up to three phases, two cryst. and one amorphous. Relative amts. of all three have been detd. by a combination of X-ray diffraction and FT-IR reflectance spectroscopy. Initially, excited singlet state rapidly produces a high yield of a transient intermediate whose spectral properties are compatible with charge-transfer nature. This intermediate more slowly converts to a significant yield of triplet, which, however, does not exceed 100% and may well be produced by intersystem crossing rather than singlet fission. The yields were detd. by transient absorption spectroscopy and cor. for effects of partial sample alignment by a simple generally applicable procedure. Formation of excimers was also obsd. In order to obtain guidance for improving mol. packing by a minor structural modification, calcns. by a simplified frontier orbital method were used to find all local maxima of singlet fission rate as a function of geometry of a mol. pair. The method was tested at 48 maxima by comparison with the ab initio Frenkel-Davydov exciton model. (c) 2019 American Institute of Physics.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitFOls77L&md5=baac68449b6fc5222a85530d568fd2cc

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    Ueda, M.; Jorner, K.; Sung, Y. M.; Mori, T.; Xiao, Q.; Kim, D.; Ottosson, H.; Aida, T.; Itoh, Y. Energetics of Baird Aromaticity Supported by Inversion of Photoexcited of Chiral [4n]Annulene Derivatives. Nat. Commun. 2017, 8, 346, DOI: 10.1038/s41467-017-00382-1

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    Energetics of Baird aromaticity supported by inversion of photoexcited chiral [4n]annulene derivatives

    Ueda Michihisa; Xiao Qi; Aida Takuzo; Itoh Yoshimitsu; Jorner Kjell; Ottosson Henrik; Sung Young Mo; Kim Dongho; Mori Tadashi; Aida Takuzo

    Nature communications
    (2017),
    8
    (1),
    346
    ISSN: .

    For the concept of aromaticity, energetic quantification is crucial. However, this has been elusive for excited-state (Baird) aromaticity. Here we report our serendipitous discovery of two nonplanar thiophene-fused chiral [4n]annulenes (Th4) COT Saddle and (Th6) CDH Screw , which by computational analysis turned out to be a pair of molecules suitable for energetic quantification of Baird aromaticity. Their enantiomers were separable chromatographically but racemized thermally, enabling investigation of the ring inversion kinetics. In contrast to (Th6) CDH Screw , which inverts through a nonplanar transition state, the inversion of (Th4) COT Saddle , progressing through a planar transition state, was remarkably accelerated upon photoexcitation. As predicted by Baird’s theory, the planar conformation of (Th4) COT Saddle is stabilized in the photoexcited state, thereby enabling lower activation enthalpy than that in the ground state. The lowering of the activation enthalpy, i.e., the energetic impact of excited-state aromaticity, was quantified experimentally to be as high as 21-22 kcal mol(-1).Baird’s rule applies to cyclic π-conjugated molecules in their excited state, yet a quantification of the involved energetics is elusive. Here, the authors show the ring inversion kinetics of two nonplanar and chiral [4n]annulenes to support Baird’s rule from an energetic point of view.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1cbhsVKgtQ%253D%253D&md5=825b23cf4008a0a4fb10e38653618bb3

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    Eckert-Maksić, M.; Vazdar, M.; Barbatti, M.; Lischka, H.; Maksić, Z. B. Automerization Reaction of Cyclobutadiene and Its Barrier Height: An Ab Initio Benchmark Multi-reference Average-Quadratic Coupled Cluster Study. J. Chem. Phys. 2006, 125, 064310, DOI: 10.1063/1.2222366

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    Automerization reaction of cyclobutadiene and its barrier height: An ab initio benchmark multireference average-quadratic coupled cluster study

    Eckert-Maksic, Mirjana; Vazdar, Mario; Barbatti, Mario; Lischka, Hans; Maksic, Zvonimir B.

    Journal of Chemical Physics
    (2006),
    125
    (6),
    064310/1-064310/9CODEN:
    JCPSA6;
    ISSN: 0021-9606.

    (American Institute of Physics)

    The problem of the double bond flipping interconversion of the two equiv. ground state structures of cyclobutadiene (CBD) is addressed at the multireference av.-quadratic coupled cluster level of theory, which is capable of optimizing the structural parameters of the ground, transition, and excited states on an equal footing. The barrier height involving both the electronic and zero-point vibrational energy contributions is 6.3 kcal mol-1, which is higher than the best earlier theor. est. of 4.0 kcal mol-1. This result is confirmed by including into the ref. space the orbitals of the CC σ bonds beyond the std. π orbital space. It places the present value into the middle of the range of the measured data (1.6-10 kcal mol-1). An adiabatic singlet-triplet energy gap of 7.4 kcal mol-1 between the transition state 1Btg and the first triplet 3A2g state is obtained. A low barrier height for the CBD automerization and a small ΔE(3A2g,1B1g) gap bear some relevance on the highly pronounced reactivity of CBD, which is briefly discussed.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xotl2itbw%253D&md5=7bd50762674678b87933cda1da6505e3

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    Bryce-Smith, D.; Gilbert, A. The Organic Photochemistry of Benzene – I. Tetrahedron 1976, 32, 1309– 1326, DOI: 10.1016/0040-4020(76)85002-8

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    Bryce-Smith, D.; Gilbert, A.

    Tetrahedron
    (1976),
    32
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    1309-26CODEN:
    TETRAB;
    ISSN: 0040-4020.

    A review with 113 refs.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2sXltVej&md5=4f5b65d8510cec636484fa2f5bb63355

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    Michl, J.; Thulstrup, E. W. Why is Azulene Blue and Anthracene White? A Simple MO Picture. Tetrahedron 1976, 32, 205– 209, DOI: 10.1016/0040-4020(76)87002-0

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    Why is azulene blue and anthracene white? A simple MO picture

    Michl, J.; Thulstrup, E. W.

    Tetrahedron
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    32
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    205-9CODEN:
    TETRAB;
    ISSN: 0040-4020.

    The longest wavelength singlet-singlet absorption band which dets. the color of the title compds. (I and II, resp.) is due to HOMO→LUMO excitation. The large difference between the lowest singlet-singlet excitation energies of I and II, which have almost identical ionization potentials and electron affinities, was interpreted by the explicit introduction of an electron repulsion term into the simple Hueckel picture in which excitation energies are expressed as orbital energy differences. The differences in the magnitude of the singlet-triplet splitting and the structural features responsible for differences between I and II are discussed.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE28XhsFSjtLk%253D&md5=50db8207db1eed4acb0ee141c2795230

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    Ottosson, H.; Kilså, K.; Chajara, K.; Piqueras, M. C.; Crespo, R.; Kato, H.; Muthas, D. Scope and Limitations of Baird’s Theory on Triplet State Aromaticity: Application to the Tuning of Singlet-Triplet Energy Gaps in Fulvenes. Chem. – Eur. J. 2007, 13, 6998– 7005, DOI: 10.1002/chem.200700362

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    Scope and limitations of Baird’s theory on triplet state aromaticity: application to the tuning of singlet-triplet energy gaps in fulvenes

    Ottosson, Henrik; Kilsa, Kristine; Chajara, Khalil; Carmen Piqueras, Mari; Crespo, Rauel; Kato, Haruhisa; Muthas, Daniel

    Chemistry – A European Journal
    (2007),
    13
    (24),
    6998-7005, S6998/1-S6998/23CODEN:
    CEUJED;
    ISSN: 0947-6539.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    Utilizing Baird’s theory on triplet state aromaticity, we show that the singlet-triplet energy gaps (ΔEST) of pentafulvenes are easily varied through substitution by as much as 36 kcal mol-1. This exploits the fact that fulvenes act as arom. chameleons in which the dipoles reverse on going from the singlet ground state (S0) to the lowest ππtriplet state (T1); thus, their electron distributions are adapted so as to achieve some aromaticity in both states. The results are based on quantum chem. calcns. with the OLYP d. functional theory method and the CASPT2 ab initio method, as well as spectroscopic detn. of ΔEST by triplet sensitization. The findings can also be generalized to fulvenes other than the pentafulvenes, even though the effect is attenuated as the size of the fulvene increases. Our studies thus reveal that triplet-state aromaticity can greatly influence the properties of conjugated compds. in the T1 state.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtVWhu7nE&md5=f6aae8f28ca97d01bda50455b2e3056f

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    Rosenberg, M.; Ottosson, H.; Kilså, K. Influence of Excited State Aromaticity in the Lowest Excited Singlet States of Fulvene Derivatives. Phys. Chem. Chem. Phys. 2011, 13, 12912– 12919, DOI: 10.1039/c0cp02821e

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    Influence of excited state aromaticity in the lowest excited singlet states of fulvene derivatives

    Rosenberg, Martin; Ottosson, Henrik; Kilsa, Kristine

    Physical Chemistry Chemical Physics
    (2011),
    13
    (28),
    12912-12919CODEN:
    PPCPFQ;
    ISSN: 1463-9076.

    (Royal Society of Chemistry)

    The absorption spectra and excited state dipole moments of four differently substituted fulvenes have been investigated both exptl. and computationally. The results reveal that the excited state dipole moment of fulvenes reverses in the first excited singlet state when compared to the ground state. The oppositely polarized electron d. distributions, which dominate the ground state and the first excited singlet state of fulvenes, resp., reflect the reversed π-electron counting rules for aromaticity in the two states (4n + 2 vs. 4n, resp.). The results show that substituents indeed influence the polarity of fulvenes in the two states, however, cooperative interactions between the substituents and the fulvene moiety are most pronounced in the ground state.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXosVWju7w%253D&md5=a98bb2bea600d477e5aa074422c890ad

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    Jorner, K.; Emanuelsson, R.; Dahlstrand, C.; Tong, H.; Denisova, A. V.; Ottosson, H. Impact of Ground and Excited State Aromaticity on Silole and Cyclopentadiene Excitation Energies and Excited State Polarities. Chem. – Eur. J. 2014, 20, 9295– 9303, DOI: 10.1002/chem.201402577

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    Impact of Ground- and Excited-State Aromaticity on Cyclopentadiene and Silole Excitation Energies and Excited-State Polarities

    Jorner, Kjell; Emanuelsson, Rikard; Dahlstrand, Christian; Tong, Hui; Denisova, Aleksandra V.; Ottosson, Henrik

    Chemistry – A European Journal
    (2014),
    20
    (30),
    9295-9303CODEN:
    CEUJED;
    ISSN: 0947-6539.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    A new qual. model for estg. the properties of substituted cyclopentadienes and siloles in their lowest ππexcited states is introduced and confirmed through quantum chem. calcns., and then applied to explain earlier reported exptl. excitation energies. According to model, which is based on excited-state aromaticity and antiaromaticity, siloles and cyclopentadienes are cross-hyperconjugated arom. chameleons that adapt their electronic structures to conform to the various aromaticity rules in different electronic states (Hueckel’s rule in the π2 electronic ground state (S0) and Baird’s rule in the lowest ππexcited singlet and triplet states (S1 and T1)). By using pen-and-paper arguments, one can explain polarity changes upon excitation of substituted cyclopentadienes and siloles, and one can tune their lowest excitation energies by combined considerations of ground- and excited-state aromaticity/antiaromaticity effects. Finally, the arom. chameleon model can be extended to other monocyclic compd. classes of potential use in org. electronics, thereby providing a unified view of the S0, T1, and S1 states of a range of different cyclic cross-π-conjugated and cross-hyperconjugated compd. classes.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFWns7%252FP&md5=dbf6a578035ae514213747fe5e5745fb

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    Yu, D.; Rong, C.; Lu, T.; De Proft, F.; Liu, S. Baird’s Rule in Substituted Fulvene Derivatives: An Information-Theoretic Study on Triplet-State Aromaticity and Antiaromaticity. ACS Omega 2018, 3, 18370– 18379, DOI: 10.1021/acsomega.8b02881

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    Baird’s Rule in Substituted Fulvene Derivatives: An Information-Theoretic Study on Triplet-State Aromaticity and Antiaromaticity

    Yu, Donghai; Rong, Chunying; Lu, Tian; De Proft, Frank; Liu, Shubin

    ACS Omega
    (2018),
    3
    (12),
    18370-18379CODEN:
    ACSODF;
    ISSN: 2470-1343.

    (American Chemical Society)

    Originated from the cyclic delocalization of electrons resulting in extra stability and instability, aromaticity and antiaromaticity are important chem. concepts whose appreciation and quantification are still much of recent interest in the literature. Employing information-theoretic quantities can provide us with more insights and better understanding about them, as we have previously demonstrated. In this work, we examine the triplet-state aromaticity and antiaromaticity, which are governed by Baird’s 4n rule, instead of H.ovrddot.uckel’s 4n + 2 rule for the singlet state. To this end, we have made use of 4 different aromaticity indexes and 8 information-theoretic quantities, examd. a total of 22 substituted fulvene derivs., and compared the results both in singlet and triplet states. It is found that cross-correlations of these two categories of mol. property descriptors enable us to better understand the nature and propensity of aromaticity and antiaromaticity for the triplet state. Our results have not only demonstrated the existence and validity of Baird’s rule but also shown that H.ovrddot.uckel’s rule and Baird’s rule indeed share the same theor. foundation because with these cross-correlation patterns we are able to distinguish them from each other simultaneously in both singlet and triplet states. Our results should provide new insights into the nature of aromaticity and antiaromaticity in the triplet state and pave the road toward new ways to quantify this pair of important chem. concepts.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisF2gurfP&md5=513803bf6d3f6f51b1197bd2eeabe5dc

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    Yadav, S.; El Bakouri, O.; Jorner, K.; Tong, H.; Dahlstrand, C.; Solà, M.; Ottosson, H. Exploiting the Aromatic Chameleon Character of Fulvenes for Computational Design of Baird-Aromatic Triplet Ground State Compounds. Chem. – Asian J. 2019, 14, 1870– 1878, DOI: 10.1002/asia.201801821

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    Exploiting the Aromatic Chameleon Character of Fulvenes for Computational Design of Baird-Aromatic Triplet Ground State Compounds

    Yadav, Sangeeta; El Bakouri, Ouissam; Jorner, Kjell; Tong, Hui; Dahlstrand, Christian; Sola, Miquel; Ottosson, Henrik

    Chemistry – An Asian Journal
    (2019),
    14
    (10),
    1870-1878CODEN:
    CAAJBI;
    ISSN: 1861-4728.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    Due to the reversal in electron counts for aromaticity and antiaromaticity in the closed-shell singlet state (normally ground state, S0) and lowest ππtriplet state (T1 or T0), as given by Hueckel’s and Baird’s rules, resp., fulvenes are influenced by their substituents in the opposite manner in the T1 and S0 states. This effect is caused by a reversal in the dipole moment when going from S0 to T1 as fulvenes adapt to the difference in electron counts for aromaticity in various states; they are arom. chameleons. Thus, a substituent pattern that enhances (reduces) fulvene aromaticity in S0 reduces (enhances) aromaticity in T1, allowing for rationalizations of the triplet state energies (ET) of substituted fulvenes. Through quantum chem. calcns., we now assess which substituents and which positions on the pentafulvene core are the most powerful for designing compds. with low or inverted ET. As a means to increase the π-electron withdrawing capacity of cyano groups, we found that protonation at the cyano N atoms of 6,6-dicyanopentafulvenes can be a route to on-demand formation of a fulvenium dication with a triplet ground state (T0). The five-membered ring of this species is markedly Baird-arom., although less than the cyclopentadienyl cation known to have a Baird-arom. T0 state.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXislCitLg%253D&md5=56b200076c5a89ac4cb327de5d0f6fc7

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    Möllerstedt, H.; Crespo, R.; Piqueras, M. C.; Ottosson, H. Fulvenes, Fulvalenes, and Azulene: Are They Aromatic Chameleons?. J. Am. Chem. Soc. 2004, 126, 13938– 13939, DOI: 10.1021/ja045729c

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    50

    Fulvenes, fulvalenes, and azulene: are they aromatic chameleons?

    Mollerstedt Helene; Piqueras Mari Carmen; Crespo Raul; Ottosson Henrik

    Journal of the American Chemical Society
    (2004),
    126
    (43),
    13938-9
    ISSN: 0002-7863.

    On the basis of the theory of Baird on reversal of Huckel’s rule for aromaticity and antiaromaticity of annulenes when going from the electronic ground state (S0) to the lowest pipitriplet state (T1) (J. Am. Chem. Soc. 1972, 94, 4941), we argue that fulvenes, fulvalenes, and azulene are “aromatic chameleons”. The dipole moments of fulvenes in T1 should be of comparable magnitude to those of S0, but due to the reversal of Huckel’s aromaticity rule in T1, their dipole should be in the opposite direction. Thereby, they are capable of adopting some aromaticity in both the T1 and S0 states as they adapt their dipolar resonance structures. The same applies to fulvalenes and azulene in their lowest quintet states (Q1) when compared to S0. Our hypothesis on chameleon behavior is supported by quantum chemical OLYP, CASSCF, and CASPT2 calculations of dipole moments, pi-orbital populations, and energies.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2crmtlSnsw%253D%253D&md5=6ada97f5aed47cd51272b76fd46cec4f

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    Solel, E.; Kozuch, S. Tuning the Spin, Aromaticity, and Quantum Tunneling in Computationally Designed Fulvalenes. J. Org. Chem. 2018, 83, 10826– 10834, DOI: 10.1021/acs.joc.8b01541

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    Tuning the Spin, Aromaticity, and Quantum Tunneling in Computationally Designed Fulvalenes

    Solel, Ephrath; Kozuch, Sebastian

    Journal of Organic Chemistry
    (2018),
    83
    (18),
    10826-10834CODEN:
    JOCEAH;
    ISSN: 0022-3263.

    (American Chemical Society)

    Pentafulvalene is a sym. unsatd. hydrocarbon built from two five-membered rings connected by an exocyclic double bond, where each ring is one electron short of being a 6π-electron arom. system. Here, we show computationally that by selectively introducing electron withdrawing and donating substituents, we can design pentafulvalene derivs. that exhibit tunable aromaticity properties. Pentafulvalene can be shaped into a species with connected arom.-antiarom. rings, which can also achieve π-bond shifting by carbon tunneling. We propose an NMR technique that can exptl. prove such tunneling mechanism. In addn., we devised a doubly arom. fulvalene involving both H.ovrddot.uckel and Baird aromaticities. These results can open possibilities to create novel mols. in terms of spin state, aromaticity, and reactivity by quantum tunneling.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsFejsL3L&md5=befaf110854ae53c7119a7a3d89f16b3

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    Breslow, R.; Chang, H. W.; Hill, R.; Wasserman, E. Stable Triplet States of Some Cyclopentadienyl Cations. J. Am. Chem. Soc. 1967, 89, 1112– 1119, DOI: 10.1021/ja00981a015

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    Stable triplet states of some cyclopentadienyl cations

    Breslow, Ronald; Chang, Hai Won; Hill, Roger; Wasserman, Edel

    Journal of the American Chemical Society
    (1967),
    89
    (5),
    1112-19CODEN:
    JACSAT;
    ISSN: 0002-7863.

    A no. of cyclopentadienyl cations have been prepd. in soln., and for all of them a triplet state has been detected. This is the ground state for the pentachloro cation (I), a low-lying excited state for the pentaphenyl cation (II, R=Ph), and a somewhat higher state for less sym. cations (II, R=p-MeOC6H4, p-ClC6H4 Me, β-naphthyl, p-MeC6H4). The methods used for detection include E.S.R. spectra of frozen solns., magnetic susceptibility detns., and an N.M.R. method. 20 references.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaF2sXmsV2ltQ%253D%253D&md5=50f42b99fe9594c840b83d3e1b010a1e

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    Antiaromaticity

    Breslow, Ronald

    Accounts of Chemical Research
    (1973),
    6
    (12),
    393CODEN:
    ACHRE4;
    ISSN: 0001-4842.

    A review with 38 refs.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2cXis1eqsQ%253D%253D&md5=090a552d977463ce6175e9c2823840b1

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    Wörner, H. J.; Merkt, F. Photoelectron Spectroscopic Study of the First Singlet and Triplet States of the Cyclopentadienyl Cation. Angew. Chem., Int. Ed. 2006, 45, 293– 296, DOI: 10.1002/anie.200503032

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    Photoelectron spectroscopic study of the first singlet and triplet states of the cyclopentadienyl cation

    Worner, Hans Jakob; Merkt, Frederic

    Angewandte Chemie, International Edition
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    45
    (2),
    293-296CODEN:
    ACIEF5;
    ISSN: 1433-7851.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    The pulsed-field ionization zero-kinetic-energy photoelectron spectrum of the C5H5 radical is recorded after direct excitation from the ~X 2E”1 ground state and two-photon excitation via the ~A 2A”2 electronically excited state. The intensity distributions of the spectra enables the characterization of the energetics, symmetry, and structure of the lowest two electronic states of the cation.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xlslyksg%253D%253D&md5=ab491b0b14470afb559019afeae7b4ef

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    Conrad-Burton, F. S.; Liu, T.; Geyer, F.; Costantini, R.; Schlaus, A. P.; Spencer, M. S.; Wang, J.; Sanchez, R. H.; Zhang, B.; Xu, Q.; Steigerwald, M. L.; Xiao, S.; Li, H.; Nuckolls, C. P.; Zhu, X. Controlling Singlet Fission by Molecular Contortion. J. Am. Chem. Soc. 2019, 141, 13143– 13147, DOI: 10.1021/jacs.9b05357

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    Controlling singlet fission by molecular contortion

    Conrad-Burton, Felisa S.; Liu, Taifeng; Geyer, Florian; Costantini, Roberto; Schlaus, Andrew P.; Spencer, Michael S.; Wang, Jue; Sanchez, Raul Hernandez; Zhang, Boyuan; Xu, Qizhi; Steigerwald, Michael L.; Xiao, Shengxiong; Li, Hexing; Nuckolls, Colin P.; Zhu, Xiaoyang

    Journal of the American Chemical Society
    (2019),
    141
    (33),
    13143-13147CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    Singlet fission, the generation of two triplet excited states from the absorption of a single photon, may potentially increase solar energy conversion efficiency. A major roadblock in realizing this potential is the limited no. of mols. available with high singlet fission yields and sufficient chem. stability. Here, we demonstrate a strategy for developing singlet fission materials in which we start with a stable mol. platform and use strain to tune the singlet and triplet energies. Using perylene diimide as a model system, we tune the singlet fission energetics from endoergic to exoergic or iso-energetic by straining the mol. backbone. The result is an increase in the singlet fission rate by 2 orders of magnitude. This demonstration opens a door to greatly expanding the mol. toolbox for singlet fission.

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    Forty years of Clar’s aromatic π-sextet rule

    Sola Miquel

    Frontiers in chemistry
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    1
    (),
    22
    ISSN: 2296-2646.

    In 1972 Erich Clar formulated his aromatic π-sextet rule that allows discussing qualitatively the aromatic character of benzenoid species. Now, 40 years later, Clar’s aromatic π-sextet rule is still a source of inspiration for many chemists. This simple rule has been validated both experimentally and theoretically. In this review, we select some particular examples to highlight the achievement of Clar’s aromatic π-sextet rule in many situations and we discuss two recent successful cases of its application.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2cflvVGmuw%253D%253D&md5=9fe5e8101921ef264034c40046a70b9d

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    El
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    Ayub, R.; Bakouri, O. E.; Jorner, K.; Solà, M.; Ottosson, H. Can Baird’s and Clar’s Rules Combined Explain Triplet State Energies of Polycyclic Conjugated Hydrocarbons with Fused 4nπ- and (4n+2)π-Rings?. J. Org. Chem. 2017, 82, 6327– 6340, DOI: 10.1021/acs.joc.7b00906

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    Can Baird’s and Clar’s Rules Combined Explain Triplet State Energies of Polycyclic Conjugated Hydrocarbons with Fused 4nπ- and (4n + 2)π-Rings?

    Ayub, Rabia; El Bakouri, Ouissam; Jorner, Kjell; Sola, Miquel; Ottosson, Henrik

    Journal of Organic Chemistry
    (2017),
    82
    (12),
    6327-6340CODEN:
    JOCEAH;
    ISSN: 0022-3263.

    (American Chemical Society)

    Compds. that can be labeled as “arom. chameleons” are π-conjugated compds. that are able to adjust their π-electron distributions so as to comply with the different rules of aromaticity in different electronic states. We used quantum chem. calcns. to explore how the fusion of benzene rings onto arom. chameleonic units represented by biphenylene, dibenzocyclooctatetraene, and dibenzo[a,e]pentalene modifies the first triplet excited states (T1) of the compds. Decreases in T1 energies are obsd. when going from isomers with linear connectivity of the fused benzene rings to those with cis- or trans-bent connectivities. The T1 energies decreased down to those of the parent (isolated) 4nπ-electron units. Simultaneously, we observe an increased influence of triplet state aromaticity of the central 4n ring as given by Baird’s rule and evidenced by geometric, magnetic, and electron d. based aromaticity indexes (HOMA, NICS-XY, ACID, and FLU). Because of an influence of triplet state aromaticity in the central 4nπ-electron units, the most stabilized compds. retain the triplet excitation in Baird π-quartets or octets, enabling the outer benzene rings to adapt closed-shell singlet Clar π-sextet character. Interestingly, the T1 energies go down as the total no. of arom. cycles within a mol. in the T1 state increases.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXot1yntr4%253D&md5=cb8d23972464cea417558c657e9332ae

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    Paci, I.; Johnson, J. C.; Chen, X.; Rana, G.; Popović, D.; David, D. E.; Nozik, A. J.; Ratner, M. A.; Michl, J. Singlet Fission for Dye-Sensitized Solar Cells: Can a Suitable Sensitizer Be Found?. J. Am. Chem. Soc. 2006, 128, 16546– 16553, DOI: 10.1021/ja063980h

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    Singlet Fission for Dye-Sensitized Solar Cells: Can a Suitable Sensitizer Be Found?

    Paci, Irina; Johnson, Justin C.; Chen, Xudong; Rana, Geeta; Popovic, Duska; David, Donald E.; Nozik, Arthur J.; Ratner, Mark A.; Michl, Josef

    Journal of the American Chemical Society
    (2006),
    128
    (51),
    16546-16553CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    Improvements in the efficiency of dye-sensitized photovoltaic cells are possible by using dyes capable of singlet fission into 2 triplets, thus producing 2 electron-hole pairs from a single photon. In addn. to derivs. of large alternant hydrocarbons, those of biradicals are also candidates for a favorable ordering of excited-state energy levels, E(T2), E(S1)> 2E(T1). A large no. of favorable structures was examd. by the semiempirical PPP method and some also by the time-dependent DFT method. Several candidates were identified for exptl. examn.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlWmur3E&md5=1209f57bd46e51e21e69c84b2c350bfb

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    Akdag, A.; Havlas, Z.; Michl, J. Search for a Small Chromophore with Efficient Singlet Fission: Biradicaloid Heterocycles. J. Am. Chem. Soc. 2012, 134, 14624– 14631, DOI: 10.1021/ja3063327

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    Search for a Small Chromophore with Efficient Singlet Fission: Biradicaloid Heterocycles

    Akdag, Akin; Havlas, Zdenek; Michl, Josef

    Journal of the American Chemical Society
    (2012),
    134
    (35),
    14624-14631CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    Of the five small biradicaloid heterocycles whose S1, S2, T1, and T2 adiabatic excitation energies were examd. by the CASPT2/ANO-L-VTZP method, two have been found to meet the state energy criterion for efficient singlet fission and are recommended to the attention of synthetic chemists and photophysicists.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFOisr7L&md5=41828188421bf220751c941b25e216bf

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    Minami, T.; Nakano, M. Diradical Character View of Singlet Fission. J. Phys. Chem. Lett. 2012, 3, 145– 150, DOI: 10.1021/jz2015346

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    Diradical Character View of Singlet Fission

    Minami, Takuya; Nakano, Masayoshi

    Journal of Physical Chemistry Letters
    (2012),
    3
    (2),
    145-150CODEN:
    JPCLCD;
    ISSN: 1948-7185.

    (American Chemical Society)

    The feasibility conditions of singlet fission on the excitation energy differences are revealed as functions of the multiple diradical characters yi [defined by the occupation nos. of the LUNO (=Lowest Unoccupied Natural Orbital) + i (i=0, 1, …), where 0 ≤ yi ≤ 1 and yi ≥ yj (i> j)] using the linear H4 full CI model. The diradical characters suited for singlet fission are found to lie in the region with y0> 0.10 except for y0 ∼ y1, though its energy efficiency is better in case of smaller y0, to which diradical and multiradical compds. with low/intermediate diradical characters such as open-shell singlet polycyclic arom. hydrocarbons belong. These findings indicate that the multiple diradical character is an effective indicator for exploring mol. systems for efficient singlet fission.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1Ojur3L&md5=76b624a9c479e109deb646a65856640e

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    Ito, S.; Nagami, T.; Nakano, M. Diradical Character-Based Design for Singlet Fission of Bisanthene Derivatives: Aromatic-Ring Attachment and π-Plane Twisting. J. Phys. Chem. Lett. 2016, 7, 3925– 390, DOI: 10.1021/acs.jpclett.6b01885

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    Diradical Character-Based Design for Singlet Fission of Bisanthene Derivatives: Aromatic-Ring Attachment and π-Plane Twisting

    Ito, Soichi; Nagami, Takanori; Nakano, Masayoshi

    Journal of Physical Chemistry Letters
    (2016),
    7
    (19),
    3925-3930CODEN:
    JPCLCD;
    ISSN: 1948-7185.

    (American Chemical Society)

    We demonstrate a diradical character-based mol. design for singlet fission using polycyclic arom. hydrocarbons, bisanthene derivs. Two types of chem. modifications-arom.-ring attachment and π-plane twisting-are examd. in order to satisfy the energy level matching condition for singlet fission. Detailed anal. of the electronic structures of the model mols. using nucleus-independent chem. shift, MOs, and their energies has demonstrated the usefulness of the relationship between the resonance structure and aromaticity and that between nonplanarity of π-conjugated systems and redn. of orbital overlap for tuning the diradical character. This result provides a novel design guideline for polycyclic arom. hydrocarbons toward efficient singlet fission.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsFWqtrbK&md5=4d4096d1b63c0045d5517449a4ee6136

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    Wirz, J. Electronic Structure and Photophysical Properties of Planar Conjugated Hydrocarbons with a 4n-Membered Ring, Part II. Jerusalem Symposia on Quantum Chemistry and Biochemistry 1977, 10, 283– 294, DOI: 10.1007/978-94-010-1273-7_24

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    Electronic structure and photophysical properties of planar conjugated hydrocarbons with a 4n-membered ring

    Wirz, Jakob

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    283-94CODEN:
    JSQCA7;
    ISSN: 0075-3696.

    The UV of I through VI, which exhibit systematic features which differ radically from the pattern obsd. with benzenoid hydrocarbons, are assigned using a PDP-SCF-CI calcn. The assignments are corroborated by polarization measurements on III through V. The triplet rate absorption spectra and energies of III, V, and VI are detd. by flash photolysis and energy transfer expts. The fluorescence and triplet yield trends are an example of the photophys. consequences of an avoided hypersurface crossing.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE1cXhsFWrsbo%253D&md5=b3c9bf58088a0af108b358c4c37c31d4

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    Zhao, Y.; Truhlar, D. G. The M06 Suite of Density Functionals for Main Group Thermochemistry, Thermochemical Kinetics, Noncovalent Interactions, Excited States, and Transition Elements: Two New Functionals and Systematic Testing of Four M06-class Functionals and 12 Other Function. Theor. Chem. Acc. 2008, 120, 215– 241, DOI: 10.1007/s00214-007-0310-x

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    The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals

    Zhao, Yan; Truhlar, Donald G.

    Theoretical Chemistry Accounts
    (2008),
    120
    (1-3),
    215-241CODEN:
    TCACFW;
    ISSN: 1432-881X.

    (Springer GmbH)

    We present two new hybrid meta exchange-correlation functionals, called M06 and M06-2X. The M06 functional is parametrized including both transition metals and nonmetals, whereas the M06-2X functional is a high-nonlocality functional with double the amt. of nonlocal exchange (2X), and it is parametrized only for nonmetals. The functionals, along with the previously published M06-L local functional and the M06-HF full-Hartree-Fock functionals, constitute the M06 suite of complementary functionals. We assess these four functionals by comparing their performance to that of 12 other functionals and Hartree-Fock theory for 403 energetic data in 29 diverse databases, including ten databases for thermochem., four databases for kinetics, eight databases for noncovalent interactions, three databases for transition metal bonding, one database for metal atom excitation energies, and three databases for mol. excitation energies. We also illustrate the performance of these 17 methods for three databases contg. 40 bond lengths and for databases contg. 38 vibrational frequencies and 15 vibrational zero point energies. We recommend the M06-2X functional for applications involving main-group thermochem., kinetics, noncovalent interactions, and electronic excitation energies to valence and Rydberg states. We recommend the M06 functional for application in organometallic and inorganometallic chem. and for noncovalent interactions.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXltFyltbY%253D&md5=c31d6f319d7c7a45aa9b716220e4a422

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    Second-order perturbation theory with a complete active space self-consistent field reference function

    Andersson, Kerstin; Malmqvist, Per Aake; Roos, Bjoern O.

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    96
    (2),
    1218-26CODEN:
    JCPSA6;
    ISSN: 0021-9606.

    The recently implemented second-order perturbation theory based on a complete active space SCF ref. function has been extended by allowing the Fock-type one-electron operator, which defines the zeroth-order Hamiltonian to have nonzero elements also in nondiagonal matrix blocks. The computer implementation is now less straightforward and more computer time will be needed in obtaining the second-order energy. The method is illustrated in a series of calcns. on N2, NO, O2, CH3, CH2, and F-.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XptFKhsw%253D%253D&md5=9b11f4ec21a64ab3f5cfd44355156b1a

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    Zeng, T.; Hoffmann, R.; Ananth, N. The Low-Lying Electronic States of Pentacene and Their Roles in Singlet Fission. J. Am. Chem. Soc. 2014, 136, 5755– 5764, DOI: 10.1021/ja500887a

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    The Low-Lying Electronic States of Pentacene and Their Roles in Singlet Fission

    Zeng, Tao; Hoffmann, Roald; Ananth, Nandini

    Journal of the American Chemical Society
    (2014),
    136
    (15),
    5755-5764CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    We present a detailed study of pentacene monomer and dimer that serves to reconcile extant views of its singlet fission. We obtain the correct ordering of singlet excited-state energy levels in a pentacene mol. (E (S1)

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXktlens7o%253D&md5=f7a7f04cad176c35966c447e4ae956c9

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    Grotjahn, R.; Maier, T. M.; Michl, J.; Kaupp, M. Development of a TDDFT-Based Protocol with Local Hybrid Functionals for the Screening of Potential Singlet Fission Chromophores. J. Chem. Theory Comput. 2017, 13, 4984– 4996, DOI: 10.1021/acs.jctc.7b00699

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    Development of a TDDFT-Based Protocol with Local Hybrid Functionals for the Screening of Potential Singlet Fission Chromophores

    Grotjahn, Robin; Maier, Toni M.; Michl, Josef; Kaupp, Martin

    Journal of Chemical Theory and Computation
    (2017),
    13
    (10),
    4984-4996CODEN:
    JCTCCE;
    ISSN: 1549-9618.

    (American Chemical Society)

    Chromophores suitable for singlet fission need to meet specific requirements regarding the relative energies of their S0, S1, and T1 (and T2) electronic states. Accurate quantum-chem. computations of the corresponding energy differences are highly desirable for materials design. Methods based on d. functional theory (DFT) have the advantage of being applicable to larger, often more relevant systems compared to more sophisticated post-Hartree-Fock methods. However, most exchange-correlation functionals do not provide the needed accuracy, in particular, due to an insufficient description of the T1 state. Here the authors use a recent singlet fission chromophore test set to evaluate a wide range of DFT-based methods, with an emphasis on local hybrid functionals with a position-dependent exact-exchange admixt. New ref. vertical CC2/CBS benchmark excitation energies for the test set were generated, which exhibit somewhat more uniform accuracy than the previous CASPT2-based data. These CC2 ref. data were used to evaluate a wide range of functionals, comparing full linear-response TDDFT, the Tamm-Dancoff approxn. (TDA), and ΔSCF calcns. Two simple 2-parameter local hybrid functionals and the more empirical M06-2X global meta-GGA hybrid provide the overall best accuracy. Due to its lower empiricism and wide applicability, the Lh12ct-SsifPW92 local hybrid is suggested as the main ingredient of an efficient computational protocol for prediction of the relevant excitation energies in singlet fission chromophores. Full TDDFT for the S1, S2, and T2 excitations is combined with ΔSCF for the T1 excitations. Making use also of some error compensation with suitable DFT-optimized structures, even the most crit. T1 excitations can be brought close to the target accuracy of 0.20 eV, while the other excitation energies are obtained even more accurately. This fully DFT-based protocol should become a useful tool in the field of singlet fission.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVelu7vJ&md5=6c0e0f9703d2e210438c1029ea0900c7

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    Schleyer, P. v. R.; Maerker, C.; Dransfeld, A.; Jiao, H.; van Eikema
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    Nucleus-independent chemical shifts: a simple and efficient aromaticity probe

    Schleyer, Paul v.R.; Maerker, Christoph; Dransfeld, Alk; Jiao, Haijun; van Eikema Hommes, Nicolaas J. R.

    Journal of the American Chemical Society
    (1996),
    118
    (26),
    6317-6318CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    Nucleus-independent chem. shifts (NICS), the neg. of the abs. magnetic shieldings (in ppm) computed at the ab initio GIAO-HF/6-31 + Glevel at ring centers (non-weighted means of the heavy atom coordinates), are proposed as a simple and efficient magnetic probe for characterizing aromaticity and antiaromaticity. For a series of five membered heterocycles, NICS correlate with arom. stabilization energies, magnetic susceptibility exaltations, and geometric criteria of aromaticity. Arom. compds. have neg. NICS (e.g., -9.7 for benzene and -15.1 for pyrrole), whereas antiarom. systems, in contrast, exhibit pos. NICS values (18.1 for pentalene and 27.6 for cyclobutadiene). In addn., NICS can characterize the individual rings in polycyclic arom. (e.g., -19.7 and -7.0 for the five- and seven-membered rings in azulene) and antiarom. (e.g., -2.5 and 22.5 for the six- and four-membered rings in benzocyclobutadiene) systems as well as the spherical aromaticity of cage compds., e.g., closo-B12H122- (-34.4) and the 1,3-dehydro-5,7-adamantanediyl dication (-50.1). The C60 NICS confirm that the 5-rings are paramagnetic and the 6-rings are diamagnetic, but the magnitudes are not large.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XjsFCis7Y%253D&md5=fd205be78733a8f593307d4863afb340

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    Fallah-Bagher-Shaidaei, H.; Wannere, C. S.; Corminboeuf, C.; Puchta, R.; Schleyer, P. v. R. Which NICS Aromaticity Index for Planar π Rings Is Best?. Org. Lett. 2006, 8, 863– 866, DOI: 10.1021/ol0529546

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    Which NICS Aromaticity Index for Planar π Rings Is Best?

    Fallah-Bagher-Shaidaei, Hossein; Wannere, Chaitanya S.; Corminboeuf, Clemence; Puchta, Ralph; Schleyer, Paul v. R.

    Organic Letters
    (2006),
    8
    (5),
    863-866CODEN:
    ORLEF7;
    ISSN: 1523-7060.

    (American Chemical Society)

    Five increasingly sophisticated aromaticity indexes, based on nucleus-independent chem. shifts (NICS), were evaluated against a uniform set of arom. stabilization energies (ASE) for 75 mono- and polyheterocyclic five-membered rings. While acceptable statistical correlations were given by all of the NICS methods, the most fundamentally grounded index, NICS(0)πzz (based on the π contribution to the out-of-plane zz tensor component), performed best statistically (cc=0.980) and in practice. The easily computable NICS(1)zz index is a useful alternative (cc=0.968).

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XpsVKgtQ%253D%253D&md5=c83cb9ff9c976543f65e5c7f05ec92d6

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    Efficient implementation of the gauge-independent atomic orbital method for NMR chemical shift calculations

    Wolinski, Krzysztof; Hinton, James F.; Pulay, Peter

    Journal of the American Chemical Society
    (1990),
    112
    (23),
    8251-60CODEN:
    JACSAT;
    ISSN: 0002-7863.

    An implementation of the gauge independent at. orbital (GIAO) method for the ab initio SCF calcn. of NMR chem. shifts is described. By using modern techniques borrowed from anal. deriv. methods, the efficiency of the GIAO method was significantly improved. Results with several basis sets, some of them large, are presented for methane, Me fluoride, cyclopropene, cyclopropane, oxirane, benzene, carbon disulfide, the sulfate and thiosulfate anions, di-Me sulfide, DMSO, and di-Me sulfone. Computer timings for energy and chem. shielding calcns. are given for a few large org. mols. Comparisons are made with the individual gauge for localized orbitals method of Schindler and Kutzelnigg, and with the localized orbital/local origin method of Hansen and Bouman. The GIAO method appears to converge faster than the localized techniques, i.e., it provides the same accuracy with a smaller basis, particularly for the individual tensor components. The computational effort for the ab initio calcn. of the NMR chem. shifts is only ∼2.5 times that of the energy calcn.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXmtFWjsrY%253D&md5=f035182721ab4eda4de3976200ace538

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    Bultinck, P.; Rafat, M.; Ponec, R.; Van Gheluwe, B.; Carbó-Dorca, R.; Popelier, P. Electron Delocalization and Aromaticity in Linear Polyacenes: Atoms in Molecules Multicenter Delocalization Index. J. Phys. Chem. A 2006, 110, 7642– 7648, DOI: 10.1021/jp0609176

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    Electron Delocalization and Aromaticity in Linear Polyacenes: Atoms in Molecules Multicenter Delocalization Index

    Bultinck, Patrick; Rafat, Michel; Ponec, Robert; Van Gheluwe, Bart; Carbo-Dorca, Ramon; Popelier, Paul

    Journal of Physical Chemistry A
    (2006),
    110
    (24),
    7642-7648CODEN:
    JPCAFH;
    ISSN: 1089-5639.

    (American Chemical Society)

    Mol. aromaticity in the linear polyacenes is studied using an atoms in mols. based six center index (SCI-AIM) which measures the electron delocalization. SCI-AIM values for the linear polyacenes indicate decreasing aromaticity going from outer to inner rings in the polyacene series. The SCI-AIM approach is compared to a Mulliken-like approach, and a crit. comparison to the PDI index is made.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XkvFGltrY%253D&md5=8cefc19e4f1e2ddea2ae2e1d65e5d072

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    Krygowski, T. M. Crystallographic Studies of Inter- and Intramolecular Interactions Reflected in Aromatic Character of π-Electron Systems. J. Chem. Inf. Model. 1993, 33, 70– 78, DOI: 10.1021/ci00011a011

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    Krygowski, T. M.; Cyranski, M. K. Structural Aspects of Aromaticity. Chem. Rev. 2001, 101, 1385– 1419, DOI: 10.1021/cr990326u

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    Structural Aspects of Aromaticity

    Krygowski, Tadeusz Marek; Cyranski, Michal Ksawery

    Chemical Reviews (Washington, D. C.)
    (2001),
    101
    (5),
    1385-1419CODEN:
    CHREAY;
    ISSN: 0009-2665.

    (American Chemical Society)

    A review, with 240 refs. in which the importance of a notion in the chem. vocabulary and an outline of the criteria of aromaticity is discussed.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXhs1agtbs%253D&md5=07e609d634f0d166211f284b7ce73f1c

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    Bearpark, M. J.; Bernardi, F.; Olivucci, M.; Robb, M. A.; Smith, B. R. Can Fulvene S1 Decay Be Controlled? A CASSCF Study with MMVB Dynamics. J. Am. Chem. Soc. 1996, 118, 5254– 5260, DOI: 10.1021/ja9542799

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    Can Fulvene S1 Decay Be Controlled? A CASSCF Study with MMVB Dynamics

    Bearpark, Michael J.; Bernardi, Fernando; Olivucci, Massimo; Robb, Michael A.; Smith, Barry R.

    Journal of the American Chemical Society
    (1996),
    118
    (22),
    5254-5260CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    CASSCF and CASMP2 calcns. show that the min. on the fulvene S1 potential energy surface is an S0/S1 conical intersection with a 90° twisted methylene group. We have also located a distinct planar azulene-like crossing point at higher energy, where the methylene is free to twist. The fulvene intersection – which exists for all twist angles – leads to efficient, irreversible radiationless decay and explains the lack of obsd. S1 fluorescence. We have modeled the femtosecond excited state motion leading to ultrafast decay that would be initiated by exciting the 0-0 and higher vibrational levels using semiclassical mol. dynamics with a hybrid quantum-mech./force-field potential (MMVB). Our simulation suggests that, with increased vibrational energy, decay occurs in the planar crossing region before relaxation by twisting can take place, and that isomerization might only be seen by pumping the 0-0 transition in laser studies.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XivFyntb0%253D&md5=6b2b454acfba778a7c8b5928cd9c738c

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    Mendive-Tapia, D.; Lasorne, B.; Worth, G. A.; Bearpark, M. J.; Robb, M. A. Controlling the Mechanism of Fulvene S1/S0 Decay: Switching Off the Stepwise Population Transfer. Phys. Chem. Chem. Phys. 2010, 12, 15725– 15733, DOI: 10.1039/c0cp01757d

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    Controlling the mechanism of fulvene S1/S0 decay: switching off the stepwise population transfer

    Mendive-Tapia, David; Lasorne, Benjamin; Worth, Graham A.; Bearpark, Michael J.; Robb, Michael A.

    Physical Chemistry Chemical Physics
    (2010),
    12
    (48),
    15725-15733CODEN:
    PPCPFQ;
    ISSN: 1463-9076.

    (Royal Society of Chemistry)

    Direct quantum dynamics simulations were performed to model the radiationless decay of the first excited state S1 of fulvene. The full space of thirty normal mode nuclear coordinates was explicitly considered. By default, ultrafast internal conversion takes place centered on the higher-energy planar region of the S1/S0 conical intersection seam, giving the stepwise population transfer characteristic of a sloped surface crossing, and leading back to the ground state reactant. Two possible schemes for controlling whether stepwise population transfer occurs or not-either altering the initial geometry distribution or the initial momentum compn. of the photo-excited wavepacket-were explored. In both cases, decay was successfully induced to occur in the lower-energy twisted/peaked region of the crossing seam, switching off the stepwise population transfer. This absence of re-crossing is a direct consequence of the change in the position on the intersection at which decay occurs (our target for control), and its consequences should provide an exptl. observable fingerprint of this system.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVyrt7jF&md5=ea4a9b217937390b6bd4f72f6f814b5b

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    Gogonea, V.; Schleyer, P. v. R.; Schreiner, P. R. Consequences of Triplet Aromaticity in 4nπ-Electron Annulenes: Calculation of Magnetic Shieldings for Open-Shell Species. Angew. Chem., Int. Ed. 1998, 37, 1945– 1948, DOI: 10.1002/(SICI)1521-3773(19980803)37: 13/143.0.CO;2-E

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    Consequences of triplet aromaticity in 4nπ-electron annulenes: calculation of magnetic shieldings for open-shell species

    Gogonea, Valentin; Schleyer, Paul von Rague; Schreiner, Peter R.

    Angewandte Chemie, International Edition
    (1998),
    37
    (13/14),
    1945-1948CODEN:
    ACIEF5;
    ISSN: 1433-7851.

    (Wiley-VCH Verlag GmbH)

    This paper presents evidence that triplet states of 4nπ-electron annulenes are arom. The first comprehensive ab initio [B3LYP and CCSD(T) levels] calcns. of adiabatic singlet-triplet sepns., arom. stabilization energies, and the magnetic properties of six neutral or charged 4nπ-electron annulenes are reported. Chem. shifts, magnetic susceptibilities, and magnetic susceptibility exaltations for singlet and triplet species were calcd. at the GIAO-SCF level.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXlsFWgsbY%253D&md5=2a97a2b3c22e35a0acf48aef37565c94

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    Villaume, S.; Fogarty, H. A.; Ottosson, H. Triplet-State Aromaticity of 4n -Electron Monocycles: Analysis of Bifurcation in the π Contribution to the Electron Localization Function. ChemPhysChem 2008, 9, 257– 264, DOI: 10.1002/cphc.200700540

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    Triplet-state aromaticity of 4nπ-electron monocycles: analysis of bifurcation in the π contribution to the electron localization function

    Villaume, Sebastien; Fogarty, Heather A.; Ottosson, Henrik

    ChemPhysChem
    (2008),
    9
    (2),
    257-264CODEN:
    CPCHFT;
    ISSN: 1439-4235.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    The π contribution to the electron localization function (ELF) is used to compare 4nπ- and (4n + 2)π-electron annulenes, with particular focus on the aromaticity of 4nπ-electron annulenes in their lowest triplet state. The anal. is performed on the electron d. obtained at the level of OLYP d. functional theory, as well as at the CCSD and CASSCF ab initio levels. Two criteria for aromaticity of all-carbon annulenes are set up: the span in the bifurcation values ΔBV(ELFπ) should be small, ideally zero, and the bifurcation value for ring closure of the π basin RCBV(ELFπ) should be high (≥ 0.7). From these criteria, nearly all 4nπ-electron annulenes are arom. in their lowest triplet states, similar to (4n + 2)π-electron annulenes in their singlet ground states. For singlet biradical cyclobutadiene and cyclooctatetraene constrained to D4h and D8h symmetry, resp., the RCBV(ELFπ) at the CASSCF level is lower (0.531 and 0.745) than for benzene (0.853), even though they have equal proportions of α- and β-electrons.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXltVKqsbk%253D&md5=d1ec85d8d39aed6e2f4b99aa836c630e

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    Gao, X.; Bai, S.; Fazzi, D.; Niehaus, T.; Barbatti, M.; Thiel, W. Evaluation of Spin-Orbit Couplings with Linear-Response Time-Dependent Density Functional Methods. J. Chem. Theory Comput. 2017, 13, 515– 524, DOI: 10.1021/acs.jctc.6b00915

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    Evaluation of Spin-Orbit Couplings with Linear-Response Time-Dependent Density Functional Methods

    Gao, Xing; Bai, Shuming; Fazzi, Daniele; Niehaus, Thomas; Barbatti, Mario; Thiel, Walter

    Journal of Chemical Theory and Computation
    (2017),
    13
    (2),
    515-524CODEN:
    JCTCCE;
    ISSN: 1549-9618.

    (American Chemical Society)

    A new versatile code based on Python scripts was developed to calc. spin-orbit coupling (SOC) elements between singlet and triplet states. The code, named PySOC, is interfaced to third-party quantum chem. packages, such as Gaussian 09 and DFTB+. SOCs are evaluated using linear-response (LR) methods based on time-dependent d. functional theory (TDDFT), the Tamm-Dancoff approxn. (TDA), and time-dependent d. functional tight binding (TD-DFTB). The evaluation employs Casida-type wave functions and the Breit-Pauli (BP) spin-orbit Hamiltonian with an effective charge approxn. For validation purposes, SOCs calcd. with PySOC are benchmarked for several org. mols., with SOC values spanning several orders of magnitudes. The computed SOCs show little variation with the basis set, but are sensitive to the chosen d. functional. The benchmark results are in good agreement with ref. data obtained using higher-level spin-orbit Hamiltonians and electronic structure methods, such as CASPT2 and DFT/MRCI. PySOC can be easily interfaced to other third-party codes and other methods yielding CI-type wave functions.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVKqtbrK&md5=875811e61c508533165946a658d2e29a

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    Samanta, P. K.; Kim, D.; Coropceanu, V.; Brédas, J. L. Up-Conversion Intersystem Crossing Rates in Organic Emitters for Thermally Activated Delayed Fluorescence: Impact of the Nature of Singlet vs Triplet Excited States. J. Am. Chem. Soc. 2017, 139, 4042– 4051, DOI: 10.1021/jacs.6b12124

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    Up-Conversion Intersystem Crossing Rates in Organic Emitters for Thermally Activated Delayed Fluorescence: Impact of the Nature of Singlet vs. Triplet Excited States

    Samanta, Pralok K.; Kim, Dongwook; Coropceanu, Veaceslav; Bredas, Jean-Luc

    Journal of the American Chemical Society
    (2017),
    139
    (11),
    4042-4051CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    The rates for up-conversion intersystem crossing (UISC) from the T1 state to the S1 state are calcd. for a series of org. emitters with an emphasis on thermally activated delayed fluorescence (TADF) materials. Both the spin-orbit coupling and the energy difference between the S1 and T1 states (ΔEST) are evaluated, at the d. functional theory (DFT) and time-dependent DFT levels. The calcd. UISC rates and ΔEST values are in good agreement with available exptl. data. The authors’ results underline that small ΔEST values and sizable spin-orbit coupling matrix elements have to be simultaneously realized to facilitate UISC and ultimately TADF. Importantly, the spatial sepn. of the highest occupied and lowest unoccupied MOs of the emitter, a widely accepted strategy for the design of TADF mols., does not necessarily lead to a sufficient redn. in ΔEST; in fact, either a significant charge-transfer (CT) contribution to the T1 state or a minimal energy difference between the local-excitation and charge-transfer triplet states is required to achieve a small ΔEST. Also, having S1 and T1 states of a different nature is found to strongly enhance spin-orbit coupling, which is consistent with the El-Sayed rule for ISC rates. Overall, the authors’ results indicate that having either similar energies for the local-excitation and charge-transfer triplet states or the right balance between a substantial CT contribution to T1 and somewhat different natures of the S1 and T1 states, paves the way toward UISC enhancement and thus TADF efficiency improvement.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjsFaltbc%253D&md5=178d3a35f1c218c9a3e2d69ef9b8a97c

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    Marian, C. M. Spin-Orbit Coupling and Intersystem Crossing in Molecules. Wiley Interdiscip. Rev. Comput. Mol. Sci. 2012, 2, 187– 203, DOI: 10.1002/wcms.83

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    Spin-orbit coupling and intersystem crossing in molecules

    Marian, Christel M.

    Wiley Interdisciplinary Reviews: Computational Molecular Science
    (2012),
    2
    (2),
    187-203CODEN:
    WIRCAH;
    ISSN: 1759-0884.

    (Wiley-Blackwell)

    A review. Many light-induced mol. processes involve a change in spin state and are formally forbidden in non-relativistic quantum theory. To make them happen, spin-orbit coupling (SOC) has to be invoked. Intersystem crossing (ISC), the nonradiative transition between two electronic states of different multiplicity, plays a key role in photochem. and photophysics with a broad range of applications including mol. photonics, biol. photosensors, photodynamic therapy, and materials science. Quantum chem. has become a valuable tool for gaining detailed insight into the mechanisms of ISC. After a short introduction highlighting the importance of ISC and a brief description of the relativistic origins of SOC, this article focusses on approx. SOC operators for practical use in mol. applications and reviews state-of-the-art theor. methods for evaluating ISC rates. Finally, a few sample applications are discussed that underline the necessity of studying the mechanisms of ISC processes beyond qual. rules such as the El-Sayed rules and the energy gap law.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjs1Kltrk%253D&md5=86c7360557a3d0c769f984b41edc6406

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    Finke, A. D.; Jahn, B. O.; Saithalavi, A.; Dahlstrand, C.; Nauroozi, D.; Haberland, S.; Gisselbrecht, J.-P.; Boudon, C.; Mijangos, E.; Schweizer, W. B.; Ott, S.; Ottosson, H.; Diederich, F. The 6,6-Dicyanopentafulvene Core: A Template for the Design of Electron-Acceptor Compounds. Chem. – Eur. J. 2015, 21, 8168– 8176, DOI: 10.1002/chem.201500379

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    The 6,6-Dicyanopentafulvene Core: A Template for the Design of Electron-Acceptor Compounds

    Finke, Aaron D.; Jahn, Burkhard O.; Saithalavi, Anas; Dahlstrand, Christian; Nauroozi, Djawed; Haberland, Sophie; Gisselbrecht, Jean-Paul; Boudon, Corinne; Mijangos, Edgar; Schweizer, W. Bernd; Ott, Sascha; Ottosson, Henrik; Diederich, Francois

    Chemistry – A European Journal
    (2015),
    21
    (22),
    8168-8176CODEN:
    CEUJED;
    ISSN: 0947-6539.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    The electron-accepting ability of 6,6-dicyanopentafulvenes (DCFs) can be varied extensively through substitution on the five-membered ring. The redn. potentials for a set of 2,3,4,5-tetraphenyl-substituted DCFs, with varying substituents at the para-position of the Ph rings, strongly correlate with their Hammett σp-parameters. By combining cyclic voltammetry with DFT calcns. ((U)B3LYP/6-311+G(d)), using the conductor-like polarizable continuum model (CPCM) for implicit solvation, the abs. redn. potentials of a set of twenty DCFs were reproduced with a mean abs. deviation of 0.10 eV and a max. deviation of 0.19 eV. The exptl. studied DCFs have redn. potentials within 3.67-4.41 eV, however, the computations reveal that DCFs with exptl. redn. potentials ≤5.3 eV could be achieved, higher than that of F4-TCNQ (5.02 eV). Thus, the DCF core is a template that allows variation in the redn. potentials by ∼1.6 eV.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnt1Wjurw%253D&md5=d9b28a1b3a701cf5b914c1229bc96f82

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    Sekiguchi, A.; Tanaka, M.; Matsuo, T.; Watanabe, H. From a Cyclobutadiene Dianion to a Cyclobutadiene: Synthesis and Structural Characterization of Tetrasilyl-Substituted Cyclobutadiene. Angew. Chem., Int. Ed. 2001, 40, 1675– 1677, DOI: 10.1002/1521-3773(20010504)40:93.0.CO;2-G

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    From a cyclobutadiene dianion to a cyclobutadiene: synthesis and structural characterization of tetrasilyl-substituted cyclobutadiene

    Sekiguchi, Akira; Tanaka, Masanobu; Matsuo, Tsukasa; Watanabe, Hidetoshi

    Angewandte Chemie, International Edition
    (2001),
    40
    (9),
    1675-1677CODEN:
    ACIEF5;
    ISSN: 1433-7851.

    (Wiley-VCH Verlag GmbH)

    Lithiation of tetrasilyl cyclobutadiene cobalt complex I with lithium in THF followed by reaction with BrCH2CH2Br gave cyclobutadiene deriv. II which on photolysis gave cyclododecadiyne III. The crystal structure of II was detd.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjslChurY%253D&md5=135e594aa9c206992860456c9e19a014

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    Maier, G.; Neudert, J.; Wolf, O. Tetrakis(Trimethylsilyl)Cyclobutadiene and Tetrakis(Trimethylsilyl)Tetrahedrane. Angew. Chem., Int. Ed. 2001, 40, 1674– 1675, DOI: 10.1002/1521-3773(20010504)40:93.0.CO;2-I

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    Tetrakis(trimethylsilyl)cyclobutadiene and tetrakis(trimethylsilyl)tetrahedrane

    Maier, Gunther; Neudert, Jorg; Wolf, Oliver

    Angewandte Chemie, International Edition
    (2001),
    40
    (9),
    1674-1675CODEN:
    ACIEF5;
    ISSN: 1433-7851.

    (Wiley-VCH Verlag GmbH)

    Coupling reaction of tris(trimethylsilyl)cyclopropenylium hexachloroantimonate with lithiated (trimethylsilyl)diazomethane gave 11% trimethylsilyl[1,2,3-tris(trimethylsilyl)-2-cyclopropen-1-yl]diazomethane which on thermolysis at 50° gave tetrakis(trimethylsilyl)cyclobutadiene (8) along-with Me3SiN:C:C(SiMe3)C(SiMe3):C:NSiMe3. Irradn. of a mixt. of 8 gave title tetrakis(trimethylsilyl)tetrahedrane.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjslChurg%253D&md5=1e142ee8dd1c2b5ad6bc00ced811cae2

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    Hafner, K.; Süss, H. U. 1,3,5-Tri- Tert-Butylpentalene. A Stabilized Planar 8π-Electron System. Angew. Chem., Int. Ed. Engl. 1973, 12, 575– 577, DOI: 10.1002/anie.197305751

  86. 86

    Levi, Z. U.; Tilley, T. D. Versatile Synthesis of Pentalene Derivatives via the Pd-Catalyzed Homocoupling of Haloenynes. J. Am. Chem. Soc. 2009, 131, 2796– 2797, DOI: 10.1021/ja809930f

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    Versatile Synthesis of Pentalene Derivatives via the Pd-Catalyzed Homocoupling of Haloenynes

    Levi, Zerubba U.; Tilley, T. Don

    Journal of the American Chemical Society
    (2009),
    131
    (8),
    2796-2797CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    A palladium-catalyzed, reductive homocoupling of haloenynes, e.g. ArC≡CPh (Ar=2-BrC6H4, 2-Br-3-thienyl), yields a diverse range of polysubstituted pentalene derivs., including annulated dibenzopentalenes, e.g. I, and dithienylpentalenes, e.g. II.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFKhur0%253D&md5=a07efe544c93fe3d1dafc743fcb840db

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    Miyamoto, T.; Odaira, Y. The Reaction of Phenanthro[ζ]cyclobutadiene. Tetrahedron Lett. 1973, 14, 43– 46, DOI: 10.1016/S0040-4039(01)95572-8

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    Wu, Y.; Wang, Y.; Chen, J.; Zhang, G.; Yao, J.; Zhang, D.; Fu, H. Intramolecular Singlet Fission in an Antiaromatic Polycyclic Hydrocarbon. Angew. Chem., Int. Ed. 2017, 56, 9400– 9404, DOI: 10.1002/anie.201704668

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    Intramolecular singlet fission in an antiaromatic polycyclic hydrocarbon

    Wu, Yishi; Wang, Yuancheng; Chen, Jianwei; Zhang, Guanxin; Yao, Jiannian; Zhang, Deqing; Fu, Hongbing

    Angewandte Chemie, International Edition
    (2017),
    56
    (32),
    9400-9404CODEN:
    ACIEF5;
    ISSN: 1433-7851.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    Singlet fission (SF), in which one singlet exciton (S1) splits into two triplets (T1) on adjacent mols. through a correlated triplet-pair 1(TT) state, requires precise but difficult tuning of exciton energetics and intermol. electronic couplings in the solid state. Antiarom. 4nπ dibenzopentalenes (DPs) are demonstrated as a new class of single-chromophore-based intramol. SF materials that exhibit an optically allowed S2 state with E(S2)> 2 × E(T1) and an optically forbidden S1 state. Ultrafast population transfer from a high-lying S2 state to a 1(TT) state was obsd. in monomeric soln. of styryl-substituted DP (SDP) on a sub-picosecond timescale. There is evidence of exciton diffusion (ED) of the 1(TT) state to yield two individual long-lived triplets in SDP thin film. The overall triplet yield via intramol. SF and subsequent triplet-pair diffusion can be as high as 142 ± 10 % in thin film.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFensr3J&md5=eadbf6ec7c2d393250af8570cee6fb44

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    Hudson, B. S.; Kohler, B. E. Polyene Spectroscopy: The Lowest Energy Excited Singlet State of Diphenyloctatetraene and Other Linear Polyenes. J. Chem. Phys. 1973, 59, 4984– 5002, DOI: 10.1063/1.1680717

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    Polyene spectroscopy. Lowest energy excited singlet state of diphenyloctatetraene and other linear polyenes

    Hudson, Bruce S.; Kohler, Bryan E.

    Journal of Chemical Physics
    (1973),
    59
    (9),
    4984-5002CODEN:
    JCPSA6;
    ISSN: 0021-9606.

    Optical absorption and emission spectra at liq. He temps. of solns. of all-trans-1,8-diphenyloctatetraene in single crystals of bibenzyl and polycryst. n-paraffin matrixes are presented which show an excited singlet state at a lower energy than the 1Bu state responsible for the strong absorption of all linear polyenes. The transition from the ground state to this level has an oscillator strength of ∼0.05. The location of this low-energy weak transition removes a no. of discrepancies between the expected and obsd. fluorescence properties of diphenyloctatetraene. The obsd. vibronic pattern is consistent with the Raman spectrum which is also reported. Substantial indirect evidence is presented which indicates that many, and perhaps all, linear polyenes have a similar ordering of excited states. A review of the available information on diphenylpolyenes is presented.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2cXhtFCntbo%253D&md5=0bff3b4e7d5e93be75e968d5fb5cb65f

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    Holtom, G. R.; McClain, W. M. Two-photon excitation spectra of the low energy excited states of diphenylhexatriene and diphenyloctatetraene. Chem. Phys. Lett. 1976, 44, 436– 439, DOI: 10.1016/0009-2614(76)80699-9

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    Two-photon excitation spectra of the low energy excited states of diphenylhexatriene and diphenyloctatetraene

    Holtom, G. R.; McClain, W. M.

    Chemical Physics Letters
    (1976),
    44
    (3),
    436-9CODEN:
    CHPLBC;
    ISSN: 0009-2614.

    All-trans-diphenylhexatriene and diphenyloctatetraene in soln. show a very strong 2-photon absorption beginning at about the same energy as the one-photon spectrum. This supports the postulated presence of a low-lying 1Ag electronic state.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2sXmtlSisg%253D%253D&md5=d4c0ade0dc5e7a0a6955f4e9f4047d33

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    Fiedor, L.; Dudkowiak, A.; Pilch, M. The Origin of the Dark S1 State in Carotenoids: A Comprehensive Model. J. R. Soc., Interface 2019, 16, 20190191, DOI: 10.1098/rsif.2019.0191

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    91

    The origin of the dark S1 state in carotenoids: a comprehensive model

    Fiedor, Leszek; Dudkowiak, Alina; Pilch, Mariusz

    Journal of the Royal Society, Interface
    (2019),
    16
    (158),
    20190191/1-20190191/11CODEN:
    JRSICU;
    ISSN: 1742-5662.

    (Royal Society)

    A review. In carotenoids, by analogy to polyenes, the symmetry of the π-electron system is often invoked to explain their peculiar electronic features, in particular the inactivity of the S0 → S1 transition in one-photon excitation. In this review, we verify whether the mol. symmetry of carotenoids and symmetry of their π-electron system are supported in exptl. and computational studies. We focus on spectroscopic techniques which are sensitive to the electron d. distribution, including the X-ray crystallog., electronic absorption, two-photon techniques, CD, NMR, Stark and vibrational spectroscopies, and on this basis we seek for the origin of inactivity of the S1 state. We come across no exptl. and computational evidence for the symmetry effects and the existence of symmetry restrictions on the electronic states of carotenoids. They do not possess an inversion center and the C2h symmetry approxn. of carotenoid structure is by no means justified. In effect, the application of symmetry rules (and notification) to the electronic states of carotenoids in this symmetry group may lead to a wrong interpretation of exptl. data. This conclusion together with the results summarized in the review allows us to advance a consistent model that explains the inactivity of the S0 → S1 transition. Within this model, S1 is never accessible from S0 due to the neg. synergy of (i) the contributions of double excitations of very low probability, which elevate S1 energy, and (ii) a non-verticality of the S0 → S1 transition, due to the breaking of Born-Oppenheimer approxn. Certainly, our simple model requires a further exptl. and theor. verification.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXms1yjtQ%253D%253D&md5=9b6ee2db80fe0577ed2d5282481f95bc

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    Baker, W.; McOmie, J. F. W.; Parfitt, S. D.; Watkins, D. A. M. 799. Attempts to Prepare New Aromatic Systems. Part VI. 1:2–5:6-Dibenzopentalene and Derivatives. J. Chem. Soc. 1957, 0, 4026– 4037, DOI: 10.1039/JR9570004026

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    92

    Attempts to prepare new aromatic systems. VI. 1,2,5,6-Dibenzopentalene and derivatives

    Baker, Wilson; McOmie, J. F. W.; Parfitt, S. D.; Watkins, D. A. M.

    Journal of the Chemical Society
    (1957),

    (),
    4026-37CODEN:
    JCSOA9;
    ISSN: 0368-1769.

    2-Benzylideneindan-1,3-dione was added to PhMgBr (from 8.3 g. PhBr) in Et2O, boiled 1 hr., poured into dil. HCl, and on elution from Al2O3 with alc. gave 2-diphenylmethyl-3-phenylinden-1-one (I), m. 154° [differs from Kohler’s (C.A. 1, 1849) conclusion that 3,4-dihydro-3-oxo-4-phenyl-1,2,5,6-dibenzopentalene (II) was formed]; 2,4-dinitrophenylhydrazone, m. 249°; oxime, m. 159-62°. 2-(Diphenylmethyl)indan-1,3-dione (III), m. 128-9°, was similarly prepd. by using increased amts. of reagents. III and PhMgBr gave I. I with Cr2O3 in HOAc gave Ph2CO and 2-PhCOC6H4CO2H while III gave Ph2CO, Ph2CHCO2H, and phthalic acid. Ph2CHCH(CO2H)2 (2 g.) was heated with 20 g. polyphosphoric acid at 120° 1 hr., poured into H2O, and crystd. from C6H6 to give 3,4,7,8-tetrahydro-3,4-dioxo-1,2,5,6-dibenzopentalene (IV), m. 259°, sol. in hot but not cold aq. NaOH, gives a CHCl3 sol. green Cu deriv., gives no color with alc. FeCl3, and remains unchanged by Na in hot ethylene glycol; mono-2,4-dinitrophenylhydrazone, m. 297° (decompn.); mono-4-toluenesulfonylhydrazone, m. 116°. 3-Phenylindan-1-one (V) (2,4-dinitrophenylhydrazone, m. 209-10°) and Ph2CHCH2CO2H were prepd. from cinnamic acid and AlCl3. V (21 g.) in 50 cc. (EtO)2CO (VI) was added slowly to 150 cc. VI in which 2.3 g. Na was dissolved and heated at 150° to give trans-Et 1-oxo-3-phenylindan-2-carboxylate (VII), m. 103-4°; 2,4-dinitrophenylhydrazone, m. 179°. The ester prepd. by Yost (C.A. 45, 2928i) was probably the cis isomer. VII (2 g.) was heated at 160° 3 min. with excess polyphosphoric acid and poured into H2O to give IV. V (10 g.), 9 g. (CO2Et)2, and 40 cc. EtOH was added with stirring to 100 cc. warm EtOH contg. 10 g. Na and poured into dil. HCl giving 1-oxo-3-phenyl-2-indanylglyoxylic acid (VIII), m. 213°, and probably 3-phenyl-2-(3-phenyl-1-indenylidene)indan-1-one, m. 185°; Me ester of VIII, m. 148°. Cyclization of VIII with polyphosphoric acid gave IV. IV (1.0 g.), 6 g. Zn-Hg, 20 cc. H2O, 50 cc. concd. HCl, 1 cc. HOAc, and 5 cc. MePh was refluxed 40 hrs. giving 3,4,7,8-tetrahydro-1,2,5,6-dibenzopentalene (IX), m. 95°. IX (0.2 g. and 0.3 g. chloranil was boiled in 10 cc. C6H6 14 hrs., poured into dil. NaOH, and extd. with Et2O to give 3(or 7)-(2,3,5,6-tetrachloro-4-hydroxyphenoxy)-1,2,5,6-dibenzopentalene (X), m. 210°. Sublimation of X at 230°/12 mm. gave IX. IV (0.5 g.) and 5 g. PCl5 was heated at 100° 5 min. to give 3,3,4,4,7,8-hexachloro-3,4,7,8-tetrahydro-1,2,5,6-dibenzopentalene, m. 207°, and 8(or 7)-chloro-3,4,7,8-tetrahydro-3,4-dioxo-1,2,5,6-dibenzopentalene, m. 172°. IV with LiAlH4 gave 2 stereoisomers of 3,4,7,8-tetrahydro-3,4-dihydroxy-1,2,5,6-dibenzopentalene: isomer A, m. 262° (di-Ac deriv., m. 109-10°; Bz deriv., m. 169°); isomer B, m. 200° (di-Ac deriv., m. 158°). IV (1 g.) in Et2O was boiled with MeMgI and 3,4,7,8-tetrahydro-3-methylene-4-oxo-1,2,5,6-dibenzopentalene (XI), m. 156°; sepd. XI gives a red soln. with concd. H2SO4. 2-Benzylidene-3-phenylindan-1-one (XIa) (5 g.), 200 cc. C6H6, and 50 g. AlCl3 was refluxed 6 hrs. and poured into H2O giving 3,4,7,8-tetrahydro-3-oxo-4-phenyl-1,2,5,6-dibenzopentalene (XII), m. 132°; 2,4-dinitrophenylhydrazone, m. 271°. To 2.5 g. XII in a warm soln. of 1 g. Na in 50 cc. ethylene glycol was added pure N2H4, the mixt. refluxed 20 hrs., poured into H2O, and extd. with Et2O to give 3,4,7,8-tetrahydro-3-phenyl-1,2,5,6-dibenzopentalene (XIII), m. 112°. XII (10 g.) and 10 g. PCl5 in 100 cc. C6H6 was boiled 10 hrs., distd. to dryness in vacuo, and crystd. from light petr. giving 3,3-dichloro-3,4,7,8-tetrahydro-4-phenyl-1,2,5,6-dibenzopentalene (XIV), m. 151°, which hydrolyzes in damp air or alc. KOH or reacts with Ag2O in anhyd. C6H6 to give XII. XIV with Zn-HCl gave XIII. When XIV is melted under reduced pressure or boiled in pyridine 45 min., 3,3,4(or 7)-trichloro-3,4,7,8-tetrahydro-4-phenyl-1,2,5,6-dibenzopentalene, m. 214° (decompn.), is obtained. The 4-toluenesulfonylhydrazone of XII, m. 204°, reacts with Na in ethylene glycol to give 3,4,7,8-tetrahydro-3-(2-hydroxyethoxy)-4-phenyl-1,2,5,6-dibenzopentalene, m. 147°, and similarly replacing glycol with cyclohexanol as solvent XII gave 3-cyclohexyloxy-3,4,7,8-tetrahydro-4-phenyl-1,2,5,6-dibenzopentalene, m. 133°. XII with LiAlH4 gave 3,4,7,8-tetrahydro-3-hydroxy-4-phenyl-1,2,5,6-dibenzopentalene (XV), m. 176-8° (Ac deriv., m. 151°), while reduction with Al(OCHMe2)3 gave a 2nd isomer (XVI) of XV, m. 148°; Ac deriv., m. 145°. The Ac derivs. of XV and XVI do not decomp. on heating alone or with anhyd. K2CO3. XV (1 g.) and 1 g. anhyd. CuSO4 was boiled 4 hrs. in 30 cc. xylene, then filtered, and the residue washed with Et2O. Evapn. of the filtrate and washings gave 4,7(?)-dihydro-4-phenyl-1,2,5,6-dibenzopentalene (XVII), m. 178-80°, and an unknown compd. (XVIII), m. 158-9°. XVII and XVIII were also prepd. by heating XV with anhyd. CuSO4 7 hrs., but after 10 hrs. only XVIII was isolated. A similar dehydration of XVI gave XVII after 1.5 hrs. and XVIII after 3 hrs. boiling. When either XV or XVI was heated with P2O5 in C6H6 a substance was formed which melted at about 60°, solidified at about 80°, and then m. 154°, ν 745 and 702 cm.-1 Dry air contg. Br and CHCl3 passed through a CHCl3 soln. of XII yielded 3,4-dihydro-3-oxo-4-phenyl-1,2,5,6-dibenzopentalene (XIX), m. 266-9° (decompn.). IV and PhMgBr refluxed 1 hr. gave 3,4,7,8-tetrahydro-3-hydroxy-4-oxo-3-phenyl-1,2,5,6-dibenzopentalene (XX), m. 120°. Similarly, IV and excess PhMgBr or PhLi gave XIX and XX. The epoxide of XIa (XXI), m. 164°, was prepd. by the reaction of H2O2 with XIa in the presence of NaOH. 1,3-Dihydroxy-2,4-diphenylnaphthalene, n. 163-5°, was prepd. by the reaction of XXI with polyphosphoric acid at 160° and 192°, by heating with excess concd. HCl 3 hrs., or by reaction with BF3. XII and PhMgBr in Et2O boiled 5 hrs. gave 3,4,7,8-tetrahydro-3-hydroxy-3,4-diphenyl-1,2,5,6-dibenzopentalene (XXII), m. 160°. Dehydration of XXII with anhyd. CuSO4 gave 4,7-dihydro-3,4-diphenyl-1,2,5,6-dibenzopentalene (XXIII), m. 202-4°. XXIII in CCl4 with oxides of N prepd. from fuming HNO3, H2SO4, and As2O3 gave a cryst. addn. compd., C28H20N2O4, m. 242°.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaG1cXisFCnuw%253D%253D&md5=4d4659ba869a3fbe16dfcf2bd812856d

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    Oshima, H.; Fukazawa, A.; Yamaguchi, S. Facile Synthesis of Polycyclic Pentalenes with Enhanced Hückel Antiaromaticity. Angew. Chem., Int. Ed. 2017, 56, 3270– 3274, DOI: 10.1002/anie.201611344

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    93

    Facile Synthesis of Polycyclic Pentalenes with Enhanced Hueckel Antiaromaticity

    Oshima, Hiroya; Fukazawa, Aiko; Yamaguchi, Shigehiro

    Angewandte Chemie, International Edition
    (2017),
    56
    (12),
    3270-3274CODEN:
    ACIEF5;
    ISSN: 1433-7851.

    (Wiley-VCH Verlag GmbH & Co. KGaA)

    Pentalenes represent highly reactive Hueckel antiaroms. with 8π electrons. Usually, pentalenes are stabilized by incorporation of two benzene rings in a fused fashion. In dibenzo[a,e]pentalenes, however, the high aromaticity of the fused benzene rings compromises the inherent antiaromaticity of the pentalene core. Herein, the authors disclose that this forfeited antiaromaticity can be restored by fusing four addnl. arom. rings onto the peripheral positions of dibenzo[a,e]pentalenes. Such polycyclic pentalenes were prepd. by successive transannular cyclizations via in situ-generated tetrakisdehydro[16]annulenes. The thus obtained compds. showed intriguing properties, for example, characteristic absorptions in the visible-to-near-IR (NIR) region and low redn. potentials. These results hence afford a design principle to produce highly antiarom. yet stable pentalenes. The antiaromaticity of the pentalene core can be widely tuned via the degree of aromaticity of the peripherally fused rings.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXlsVyltg%253D%253D&md5=896814635a6672ca1309b0416ded7118

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    Konishi, A.; Okada, Y.; Kishi, R.; Nakano, M.; Yasuda, M. Enhancement of Antiaromatic Character via Additional Benzoannulation into Dibenzo[a,f]Pentalene: Syntheses and Properties of Benzo[a]Naphtho[2,1-f]Pentalene and Dinaphtho[2,1-a,f]Pentalene. J. Am. Chem. Soc. 2019, 141, 560– 571, DOI: 10.1021/jacs.8b11530

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    94

    Enhancement of Antiaromatic Character via Additional Benzoannulation into Dibenzo[a,f]pentalene: Syntheses and Properties of Benzo[a]naphtho[2,1-f]pentalene and Dinaphtho[2,1-a,f]pentalene

    Konishi, Akihito; Okada, Yui; Kishi, Ryohei; Nakano, Masayoshi; Yasuda, Makoto

    Journal of the American Chemical Society
    (2019),
    141
    (1),
    560-571CODEN:
    JACSAT;
    ISSN: 0002-7863.

    (American Chemical Society)

    Understanding the structure-property relationships in antiarom. mols. is crucial for controlling their electronic properties and designing new org. optoelectronic materials. Dibenzo[a,f]pentalene, a structural isomer of dibenzopentalene, displays open-shell and antiarom. character harmonization, which is not shared by the well-known isomer, dibenzo[a,e]pentalene. The next questions of interest concern the topol. effects of the π-extension on the harmonization of the open-shell and antiarom. character in the dibenzo[a,f]pentalene π-system. Herein, we describe the synthesis and characterization of the π-extended (bis)annulated analogs, benzo[a]naphtho[2,1-f]pentalene 4 and dinaphtho[2,1-a,f]pentalene 5. The solid-state structures and the magnetic and optoelectronic properties characterized these π-extended analogs as closed-shell antiarom. mols., in sharp contrast with dibenzo[a,f]pentalene 2. In these π-extended analogs, the open-shell character was annihilated whereas the antiarom. character was retained. The fusion of addnl. hexagons into 2 shifted the main 4nπ-conjugated circuit from a global to a local system. Further investigations into magnetic ring currents using gauge-including magnetically induced current (GIMIC) calcns. suggested that an enhanced local paratropic ring current appeared in the pentalene core of 5. The preservation of the benzenoid character in the addnl. fused hexagons confined the paratropicity to the pentalene subunit, and the inherent presence of an o-quinoidal structure highlighted the 4nπ-electron delocalization on the pentalene unit. The antiaromaticity of 4 and 5 was characterized by their small HOMO-LUMO energy gap. Both exptl. and computational results demonstrated that the [a,f]-type ring fusion of the pentalene core effectively enhanced the antiarom. character compared with the [a,e]-type ring fusion in the reported bisannulated[a,e]pentalenes. The findings of this study could potentially be used for the rational design of optoelectronic devices based on novel antiarom. mols.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisVKrsbzO&md5=a1ce6ec35e7e45013c274dbfc1442461

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    Ehrmaier, J.; Rabe, E. J.; Pristash, S. R.; Corp, K. L.; Schlenker, C. W.; Sobolewski, A. L.; Domcke, W. Singlet-Triplet Inversion in Heptazine and in Polymeric Carbon Nitrides. J. Phys. Chem. A 2019, 123, 8099– 8108, DOI: 10.1021/acs.jpca.9b06215

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    95

    Singlet-Triplet Inversion in Heptazine and in Polymeric Carbon Nitrides

    Ehrmaier, Johannes; Rabe, Emily J.; Pristash, Sarah R.; Corp, Kathryn L.; Schlenker, Cody W.; Sobolewski, Andrzej L.; Domcke, Wolfgang

    Journal of Physical Chemistry A
    (2019),
    123
    (38),
    8099-8108CODEN:
    JPCAFH;
    ISSN: 1089-5639.

    (American Chemical Society)

    According to Hund’s rule, the lowest triplet state (T1) is lower in energy than the lowest excited singlet state (S1) in closed-shell mols. The exchange integral lowers the energy of the triplet state and raises the energy of the singlet state of the same orbital character, leading to a pos. singlet-triplet energy gap (ΔST). Exceptions are known for biradicals and charge-transfer excited states of large mols. in which the HOMO and the LUMO are spatially sepd., resulting in a small exchange integral. In the present work, we discovered with ADC(2), CC2, EOM-CCSD, and CASPT2 calcns. that heptazine (1,3,4,6,7,9,9b-heptaazaphenalene or tri-s-triazine) exhibits an inverted S1/T1 energy gap (ΔST ≈ -0.25 eV). This appears to be the first example of a stable closed-shell org. mol. exhibiting S1/T1 inversion at its equil. geometry. The origins of this phenomenon are the nearly pure HOMO-LUMO excitation character of the S1 and T1 states and the lack of spatial overlap of HOMO and LUMO due to a unique structure of these orbitals of heptazine. The S1/T1 inversion is found to be extremely robust, being affected neither by substitution of heptazine nor by oligomerization of heptazine units. Using time-resolved photoluminescence and transient absorption spectroscopy, we investigated the excited-state dynamics of 2,5,8-tris(4-methoxyphenyl)-1,3,4,6,7,9,9b-heptaazaphenalene (TAHz), a chem. stable heptazine deriv., in the presence of external heavy atom sources as well as triplet-quenching oxygen. These spectroscopic data are consistent with TAHz singlet excited state decay in the absence of a low-energy triplet loss channel. The absence of intersystem crossing and an exceptionally low radiative rate result in unusually long S1 lifetimes (of the order of hundreds of nanoseconds in nonaq. solvents). These features of the heptazine chromophore have profound implications for org. optoelectronics as well as for water-splitting photocatalysis with heptazine-based polymers (e.g., graphitic carbon nitride) which have yet to be systematically explored and exploited.

    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs12jsbbK&md5=09a33ee027b0f9ba2631e3cc0df26355

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    Corey, J. Y. Siloles. Part 1: Synthesis, Characterization, and Applications. Adv. Organomet. Chem. 2011, 59, 1– 180, DOI: 10.1016/B978-0-12-378649-4.00001-0

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    96

    Siloles: part 1: synthesis, characterization, and applications

    Corey, Joyce Y.

    Advances in Organometallic Chemistry
    (2011),
    59
    (),
    1-180CODEN:
    AOMCAU;
    ISSN: 0065-3055.

    (Academic Press)

    A review. This review focuses on the synthesis, characterization, and uses of siloles.

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    (Wiley-VCH Verlag GmbH & Co. KGaA)

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    • Abstract

      Figure 1

      Figure 1. Desired arrangement of the lowest electronic states within a particular compound class that encompasses both S0 aromatic (T1/S1 antiaromatic) compounds and S0 antiaromatic (T1/S1 aromatic) compounds. Compounds within the orange region have 2E(T1) E(S1).

      Figure 2

      Figure 2. (A) Postulated (idealized) variation in excitation energies of fulvenes as one goes from electron donating groups (EDGs) to electron withdrawing groups (EWGs). The figure displays the ideally constant energy difference between E(T1) and E(S1) (ΔE(S1 – T1)=2Kij), upon which our hypothesis is based. (B) E(S1)/E(T1) ratio for four experimentally investigated fulvene derivatives, i.e., TClDCF, TClDMF, DMF, and TClDPF (see refs (46) and (47)).

      Figure 3

      Figure 3. (A) Plots of HOMO and LUMO of the parent fulvene, and (B) two plots showing how E(T1)v, E(S1)v, and E(T2)v vary as functions of the CC bond lengths marked in red. Calculations at TD-M06-2X/6-311+G(d,p) level.

      Figure 4

      Figure 4. Di- and tetrasubstituted fulvene derivatives included in this work.

      Figure 5

      Figure 5. Plots of excited-state energies and energy differences against degree of (anti)aromaticity in S0. (A) E(T1)v and E(S1)v versus NICS(1)zz,S0, (B) E(T1)a and E(S1)v versus NICS(1)zz,S0. (C) The energy difference between the S1 and T1 states versus NICS(1)zz,S0 (D) E(T2)v and E(S1)v versus NICS(1)zz,S0 for tetrasubstituted fulvenes. R2 is the squared correlation coefficient. NICS(1)zz,S0 computed at GIAO/(U)M06-2X/6-311+G(d,p) level. In (A), the parent fulvene is indicated by red marks.

      Figure 6

      Figure 6. Variations in E(T)v, E(S1)v, and E(T2)v dependence on the C2–C3 bond length (red) in four fulvenes. Data points marked correspond to other excitations than that of the singly excited HOMO–LUMO configuration of the parent fulvene.

      Figure 7

      Figure 7. T1, S1, and T2 energies (in eV) of six previously synthesized fulvenes computed at TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) (normal print) and CASPT2(14in14)/ANO-RCC-VDZP//M06-2X/6-311+G(d,p) (italics) levels.

      Figure 8

      Figure 8. Parent and substituted cyclobutadienes and their excitation energies (in eV) computed at TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) level.

      Figure 9

      Figure 9. Parent and substituted pentalenes and their excitation energies (in eV) computed at the TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) level.

      Figure 10

      Figure 10. Benzannelated cyclobutadiene compounds and their excitation energies (in eV) computed at TD-M06-2X/def2-TZVPD//M06-2X/6-311+G(d,p) and CASPT2/ANO-RCC-VDZP//CASSCF(n,m)/ANO-RCC-VDZP (italics, n=m=8 for BENZCBD1 and n=m=12, for BENZCBD2) levels. The compounds for which both singlet fission criteria are satisfied are marked in green. For full compound names, see Figure S20.

      Figure 11

      Figure 11. NICS-XY scans of (A) BENZCBD1, (B) BENZCBD2, (C) BENZCBD5, (D) BENZPENT1, (E) BENZPENT3, and (F) BENZPENT7 in their S0 and T1 states calculated at GIAO/M06-2X/6-311+G(d,p) level.

      Figure 12

      Figure 12. Benzannelated pentalenes and their excitation energies (in eV) computed at TD-M06-2X/def2-TZVPD//(U)M06-2X/6-311+G(d,p) (normal print) and CASPT2/ANO-RCC-VDZP//CASSCF(12,12)/ANO-RCC-VDZP (italics) levels. The compounds for which both singlet fission criteria are satisfied are marked in green. Additional benzannelated pentalenes are found in the Supporting Information. The at the E(S1)v of BENZPENT10 indicates the two-configurational character of the S1 state.

      Figure 13

      Figure 13. Variation in E(T1)a, E(S1)v, and E(T2)v calculated using the ZHA approach as a function of benzannelation in selected benzannelated pentalenes. Compounds that satisfy the singlet fission criteria are represented by yellow bars. Computations at TD-M06-2X/def2-TZVPD//(U)M06-2X/6-311+G(d,p) level. The at E(S1)v of BENZPENT10 indicates the two-configurational character of the S1 state. Further comparisons are given in Figure S23. Results of T1-aromaticity assessments are found in Figures S25–S28.

      Figure 14

      Figure 14. (A and B) Schematic drawings of the changes in E(T1) and E(S1) as functions of increased T1 and S1 aromatic character for a compound class with (A) large KH,L and (B) small KH,L. Slopes of E(T1) and E(S1) as well as the position and E(T1) of the parent compound (marked as 0 on the x-axis) are kept constant in the two plots. (C) 1,1-Disubstituted siloles with X and Y=H, Me, CF3, F, SiH3, and SiMe3 as high-E(T1) singlet fission chromophores (for explicit energies, see Figure S33). (D) Benzannelated pentalenes where the terminal benzo rings have been exchanged for thiopheno rings (for explicit energies, see Figure S36). A comparison against the completely benzannelated pentalenes is given in the Supporting Information.

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        JAPIAU;
        ISSN: 0021-8979.

        In order to find an upper theoretical limit for the efficiency of p-n junction solar energy converters, a limiting efficiency, called the detailed balance limit of efficiency, has been calcd. for an ideal case in which the only recombination mechanism of hole-electron pairs is radiative, as required by the principle of detailed balance. The efficiency is also calcd. for the case in which radiative recombination is only a fixed fraction fc of the total recombination, the rest being nonradiative. Efficiencies at the matched loads were calcd. with band gap and fc as parameters, the sun and cell being assumed to be black bodies with temps. of 6000°K. and 300°K., resp. The max. efficiency is 30% for an energy gap of 1.1 e.v. and fc=1. Actual junctions do not obey the predicted current-voltage relation, and reasons for the difference and its relevance to efficiency are discussed.

        https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaF3MXpslGqsQ%253D%253D&md5=bfba68acf98577c50912406e2cd24c13

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        Nelson, C. A.; Monahan, N. R.; Zhu, X. Y. Exceeding the Shockley–Queisser Limit in Solar Energy Conversion. Energy Environ. Sci. 2013, 6, 3508, DOI: 10.1039/c3ee42098a

        [ Crossref], [