Organic thermally activated delayed fluorescence (TADF) compounds used in photocatalysis

Chemical Society Reviews, Год журнала: 2021, Номер 50(13), С. 7587 - 7680

Опубликована: Янв. 1, 2021

Organic compounds that show Thermally Activated Delayed Fluorescence (TADF) have become wildly popular as next generation emitters in organic light-emitting diodes (OLEDs), but since 2016, received significant and increasing attention photocatalysts.

Язык: Английский

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Visible-light induced dearomatization reactions

Chemical Society Reviews, Год журнала: 2022, Номер 51(6), С. 2145 - 2170

Опубликована: Янв. 1, 2022

This review provides an overview of visible-light induced dearomatization reactions classified based on the manner in which aromaticity is disrupted.

Язык: Английский

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Unveiling Extreme Photoreduction Potentials of Donor–Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(33), С. 13266 - 13273

Опубликована: Авг. 16, 2021

Since the seminal work of Zhang in 2016, donor–acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied photoredox catalysis and used excellent metal-free alternatives to noble metal Ir- Ru-based photocatalysts. However, all reported reactions involving this chromophore family are based on harnessing energy from a single visible light photon, with limited range redox potentials −1.92 +1.79 V vs SCE. Here, we document unprecedented discovery that fluorophores can undergo consecutive photoinduced electron transfer (ConPET) achieve very high reduction potentials. One newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN•–*, which be activate reductively recalcitrant aryl chlorides (Ered ≈ −1.9 −2.9 SCE) under mild conditions. The resultant radicals engaged synthetically valuable aromatic C–B, C–P, C–C bond formation furnish arylboronates, arylphosphonium salts, arylphosphonates, spirocyclic cyclohexadienes.

Язык: Английский

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Acridinium Salts and Cyanoarenes as Powerful Photocatalysts: Opportunities in Organic Synthesis

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(36), С. 19526 - 19549

Опубликована: Апрель 22, 2021

The use of organic photocatalysts has revolutionized the field photoredox catalysis, as it allows access to reactivities that were traditionally restricted transition-metal photocatalysts. This Minireview reports recent developments in acridinium ions and cyanoarene derivatives synthesis. activation inert chemical bonds well late-stage functionalization biorelevant molecules are discussed, with a special focus on their mechanistic aspects.

Язык: Английский

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Recent Advances in the Construction of Spiro Compounds via Radical Dearomatization

Advanced Synthesis & Catalysis, Год журнала: 2020, Номер 362(21), С. 4446 - 4461

Опубликована: Июль 15, 2020

Abstract The field in dearomatization of aromatic compounds for the construction spirocycle has been developed rapidly over last two decades and it provides alternative synthetic method without using extra stoichiometric amounts chemical oxidants or reductants. In addition, radical cascade reactions alkenes alkynes that produce multiple bonds one‐step are significant direct efficient building complex molecules. By combining these concepts, opens a new powerful avenue accessing These have well explored past decade. As result, we summarize recent eventful advances this growing area as review, which typical examples listed mechanism also discussed. magnified image

Язык: Английский

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Visible Light Assisted Radical‐Polar/Polar‐Radical Crossover Reactions in Organic Synthesis

Advanced Synthesis & Catalysis, Год журнала: 2021, Номер 363(13), С. 3146 - 3169

Опубликована: Апрель 10, 2021

Abstract Chemists are generally familiar with polar reactions and radical reactions, in comparison, underdeveloped. In the last few years, however, novel concept of amalgamation above two form radical‐polar crossover (RPCO) polar‐radical (PRCO) has emerged as a valuable powerful tool. This methodology tends to bridge gap between well overcomes limitations both traditional chemistry. By bringing together unorthodox chemistry radicals orthodox carbocations carbanions, green quotient such is significantly improved. The development shaping up this area years synthetically important transformations summarised review. magnified image

Язык: Английский

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Photoredox catalysis on unactivated substrates with strongly reducing iridium photosensitizers

Chemical Science, Год журнала: 2021, Номер 12(11), С. 4069 - 4078

Опубликована: Янв. 1, 2021

Photoredox catalysis has emerged as a powerful strategy in synthetic organic chemistry, but substrates that are difficult to reduce either require complex reaction conditions or not amenable at all photoredox transformations. In this work, we show strong bis-cyclometalated iridium photoreductants with electron-rich β-diketiminate (NacNac) ancillary ligands enable high-yielding transformations of challenging very simple only single sacrificial reagent. Using blue green visible-light activation demonstrate variety reactions, which include hydrodehalogenation, cyclization, intramolecular radical addition, and prenylation via radical-mediated pathways, optimized the photocatalyst reductant/hydrogen atom donor. Many these reactions involve organobromide organochloride past have had limited utility catalysis. This work paves way for continued expansion substrate scope

Язык: Английский

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Asymmetric Intramolecular Dearomatization of Nonactivated Arenes with Ynamides for Rapid Assembly of Fused Ring System under Silver Catalysis

Journal of the American Chemical Society, Год журнала: 2020, Номер 143(2), С. 604 - 611

Опубликована: Дек. 31, 2020

Arene dearomatization is a straightforward method for converting an aromatic feedstock into functionalized carbocycles. Enantioselective dearomatizations of chemically inert arenes, however, are quite limited and underexplored relative to those phenols indoles. We developed diazo-free generation silver-carbene species from ynamide applied it the nonactivated arenes. Transiently generated norcaradiene could be trapped by intermolecular [4 + 2] cycloaddition, synthesizing polycycles with five consecutive stereogenic centers. This protocol constitutes first highly enantioselective reaction based on species. Mechanistic investigations revealed followed two different classes pericyclic reactions, as well origin chemo- enantioselectivity.

Язык: Английский

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Convergent Synthesis of 1,4-Dicarbonyl Z-Alkenes through Three-Component Coupling of Alkynes, α-Diazo Sulfonium Triflate, and Water

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(11), С. 4952 - 4965

Опубликована: Март 11, 2022

We report a general protocol for the convergent synthesis of 1,4-dicarbonyl Z-alkenes form alkynes using α-diazo sulfonium triflate and water. The C═O, C═C, C–H bonds are formed under mild conditions with wide range functional groups tolerated. reaction exhibits excellent Z-selectivity complete regioselectivity. resulting can smoothly undergo follow-up conversion to variety heteroaromatic scaffolds. Moreover, also provides facile access corresponding deuterated heteroarenes high level deuterium incorporation (90–97% D-inc.) by directly D2O, thus rendering method highly valuable. comprehensive mechanistic studies indicate that free carbyne radical intermediate is via photocatalytic single electron transfer process, KH2PO4 plays crucial role in significant improvements on yield selectivity based density-functional theory calculations, providing new direction coupling reactions diazo compounds.

Язык: Английский

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Organophotocatalytic Mechanisms: Simplicity or Naïvety? Diverting Reactive Pathways by Modifications of Catalyst Structure, Redox States and Substrate Preassemblies

ChemCatChem, Год журнала: 2023, Номер 15(11)

Опубликована: Фев. 21, 2023

Abstract Photocatalysis is a powerful tool to assemble diverse chemical scaffolds, yet bottleneck on its further development the understanding of multitude possible pathways when practitioners rely only oversimplified thermodynamic and optical factors. Recently, there growing number studies in field that exploit, inter alia , kinetic parameters organophotocatalysts are synthetically more programmable terms their redox states opportunities for aggregation with target substrate. Non‐covalent interactions play key role enables access new generation reactivities such as those open‐shell organophotocatalysts. In this review, we discuss how targeted structural modifications influence organophotocatalytic mechanisms together underlying principles. We also highlight benefits strategies preassembly static quenching overcome common reactivity issues (e. g., diffusion rate limits energetic limits).

Язык: Английский

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