The Golden Age of Thermally Activated Delayed Fluorescence Materials: Design and Exploitation

Chemical Reviews, Год журнала: 2024, Номер unknown

Опубликована: Дек. 12, 2024

Since the seminal report by Adachi and co-workers in 2012, there has been a veritable explosion of interest design thermally activated delayed fluorescence (TADF) compounds, particularly as emitters for organic light-emitting diodes (OLEDs). With rapid advancements innovation materials design, efficiencies TADF OLEDs each primary color points well white devices now rival those state-of-the-art phosphorescent emitters. Beyond electroluminescent devices, compounds have also found increasing utility applications numerous related fields, from photocatalysis, to sensing, imaging beyond. Following our previous review 2017 (

Язык: Английский

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Overcoming Photochemical Limitations in Metallaphotoredox Catalysis: Red-Light-Driven C–N Cross-Coupling

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(49), С. 22409 - 22415

Опубликована: Ноя. 23, 2022

Aryl amination is an essential transformation for medicinal, process, and materials chemistry. In addition to classic Buchwald–Hartwig conditions, blue-light-driven metallaphotoredox catalysis has emerged as a valuable tool C–N cross-coupling. However, blue light suffers from low penetration through reaction media, limiting its scalability industrial purposes. addition, enhances unwanted side-product formation in catalysis, namely hydrodehalogenation. Low-energy light, such deep red (DR) or near-infrared (NIR), offers solution this problem it can provide enhanced media compared higher-energy wavelengths. Herein, we show that low-energy also enhance the desired reactivity by suppressing We hypothesize reduced side product formed direct photolysis of aryl–nickel bond high-energy leading generation aryl radicals. Using deep-red osmium photocatalyst, demonstrate scope (hetero)aryl bromides amine-based nucleophiles with minimal hydrodehalogenation byproducts.

Язык: Английский

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Electron‐Poor Acridones and Acridiniums as Super Photooxidants in Molecular Photoelectrochemistry by Unusual Mechanisms

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(44)

Опубликована: Авг. 16, 2023

Abstract Electron‐deficient acridones and in situ generated acridinium salts are reported as potent, closed‐shell photooxidants that undergo surprising mechanisms. When bridging acyclic triarylamine catalysts with a carbonyl group (acridones), this completely diverts their behavior away from open‐shell, radical cationic, ‘beyond diffusion’ photocatalysis to closed‐shell, neutral, diffusion‐controlled photocatalysis. Brønsted acid activation of dramatically increases excited state oxidation power (by +0.8 V). Upon reduction protonated acridones, they transform electron‐deficient even more potent (* E 1/2 =+2.56–3.05 V vs SCE). These oxidize arenes where conventional salt have thusfar been limited electron‐rich arenes. Surprisingly, upon photoexcitation these appear two electron reductive quenching form acridinide anions, spectroscopically‐detected forms. This new behaviour is partly enabled by catalyst preassembly the arene, contrasts SET salts. Critically, study illustrates how redox active chromophoric molecules initially considered photocatalysts can during reaction catalytically species different spectroscopic properties.

Язык: Английский

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Lessons learnt in photocatalysis – the influence of solvent polarity and the photostability of the photocatalyst

Chemical Science, Год журнала: 2024, Номер 15(10), С. 3741 - 3757

Опубликована: Янв. 1, 2024

The triplet energies and redox properties of eight photocatalysts were found to vary a function solvent polarity. Irrespective solvent, the photodegraded under PET reaction conditions, but not PEnT conditions.

Язык: Английский

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A Semi‐Automated, High‐Throughput Approach for the Synthesis and Identification of Highly Photo‐Cytotoxic Iridium Complexes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(18)

Опубликована: Фев. 26, 2024

The discovery of new compounds with pharmacological properties is usually a lengthy, laborious and expensive process. Thus, there increasing interest in developing workflows that allow for the rapid synthesis evaluation libraries aim identifying leads further drug development. Herein, we apply combinatorial to build library 90 iridium(III) complexes (81 which are new) over two synthesise-and-test cycles, potential agents photodynamic therapy. We demonstrate power this approach by highly active well-tolerated dark but display very low nM phototoxicity against cancer cells. To detailed structure-activity relationship class have used density functional theory (DFT) calculations determine some key electronic parameters study correlations experimental data. Finally, present an optimised semi-automated protocol obtain multiplex data within 72 hours.

Язык: Английский

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Synthesis, Characterization, and Catalytic Activity of Ni(0) (DQ)dtbbpy, an Air-Stable, Bifunctional Red-Light-Sensitive Precatalyst

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Фев. 5, 2025

Despite a well-established and growing body of work on nickel(0) precatalysts, the potential complexes as bifunctional precatalysts remains underexplored. In this study, we synthesized, characterized, evaluated catalytic activity (Ni(0)(DQ)dtbbpy), bifunctional, red-light-sensitive, air-stable complex. Owing to its unique photophysical properties, it effectively catalyzed etherification amination aryl bromides under 620–630 nm light irradiation, functioning both photocatalyst an active metal catalyst. Mechanistic studies density functional theory (DFT) calculations further confirmed exceptional absorption properties Ni(0)(DQ)dtbbpy in red-light region, well electron transfer process triggered by irradiation.

Язык: Английский

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Extending Photocatalyst Activity through Choice of Electron Donor

The Journal of Organic Chemistry, Год журнала: 2023, Номер 88(10), С. 6445 - 6453

Опубликована: Янв. 11, 2023

Sacrificial additives are commonly employed in photoredox catalysis as a convenient source of electrons, but what occurs after electron transfer is often overlooked. Tertiary alkylamines initially form radical cations following transfer, which readily deprotonate to strongly reducing, neutral α-amino radicals. Similarly, the oxalate anion (C2O4•-) rapidly decomposes CO2•- (E0 ≈ -2.2 V vs SCE). We show that not only these reactive intermediates formed under conditions, they can also impact desired photochemistry, both positively and negatively. Photoredox systems using an donor able engage substrates with greater energy demands, extending reactivity past limits single multiphoton transition metal catalysts. Furthermore, offers better chemoselectivity than triethylamine when reducing moderate requirements.

Язык: Английский

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Reconceptualizing the Ir^III Role in Metallaphotoredox Catalysis: From Strong Photooxidant to Potent Energy Donor

ACS Catalysis, Год журнала: 2024, Номер 14(15), С. 11378 - 11388

Опубликована: Июль 16, 2024

Dual IrIII/LnNiII metallaphotoredox catalyzed C(sp3)–C(sp2) cross-coupling reactions are widely assumed to proceed by photoinduced single electron transfer steps due the highly oxidizing IrIII* excited state (IrIII = [Ir(dF(CF3)ppy)2(dtbbpy)]+[PF6]−; dF(CF3)ppy 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine; Ln dtbbpy 4,4′-di-tert-butyl-2,2′-bipyridine). Using time-resolved absorption and emission spectroscopy, we reveal that energy between various LnNiII precatalysts intermediates with kq ≥ 108 M–1 s–1 also drives catalysis. Specifically, states of dihalide precatalysts/organometallic accessible appear drive bond homolysis, halogen radical elimination, reductive elimination facilitate formation cross-coupled products. Energy dynamics consequently circumvent need for transfer, thereby extending substrate scopes coupling partners cannot be oxidized IrIII*. Within a cross-electrophile model reaction 4-bromobenzotrifluoride bromocyclohexane, activates precatalyst at early times before nucleophilic reductants present. In absence IrIII, direct excitation LnNiII(Br)2 form LnNiII(Br)(Aryl) intermediate. To compare kinetics, determined rate constants quenching Br– (kSET 4.1 × s–1) subsequent from reduced IrIII•– 107 using Stern-Volmer analysis pulse radiolysis, respectively. competitive is parallel pathway within Exploiting mechanism, demonstrate selective 4-chlorobenzotrifluoride bromocyclohexane exclusively product. With alkyl-trifluoroborate nucleophiles do not reductively quench emission, transmetalation LnNiII(Br/Cl)(Aryl) followed Similarly, rather than NiII oxidation C(sp2)–OR despite strongly ability total, these processes in catalysis can unlock alternative reactive pathways.

Язык: Английский

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Degradation Behavior of Donor‐acceptor Cyanoarenes‐based Organic Photocatalysts

ChemCatChem, Год журнала: 2023, Номер 15(16)

Опубликована: Июнь 28, 2023

Abstract Visible‐light photocatalysis has emerged as a powerful tool for organic transformations in recent years. The traditional reliance on transition metal‐based complexes photocatalysts raised concerns regarding their toxicity and the sustainability of precious metals, leading to exploration photocatalysts. Organic offer high structural diversity eliminate need metal removal, addressing aforementioned concerns. Notably, donor−acceptor cyanoarenes, originally developed thermally activated delayed fluorescence emitters, have gained significant attention due unique properties with efficiency. Consequently, understanding stability these catalysts become essential further enhancing performance. This review provides comprehensive overview studies focusing Key issues such photodegradation interactions active species are discussed, offering insights into durability Furthermore, we aim present current status while also identifying important directions future research.

Язык: Английский

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Photocatalytic synthesis of 2,3-diamines from anilines and DIPEA via C–N bond cleavage and C–C bond formation

Green Chemistry, Год журнала: 2023, Номер 26(1), С. 300 - 305

Опубликована: Дек. 5, 2023

2,3-Diamines are skeleton structures widely found in natural products and drug molecules can also be used as ligands transition metal catalysis.

Язык: Английский

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