Cage escape governs photoredox reaction rates and quantum yields

Nature Chemistry, Год журнала: 2024, Номер 16(7), С. 1151 - 1159

Опубликована: Март 18, 2024

Abstract Photoredox catalysis relies on light-induced electron transfer leading to a radical pair comprising an oxidized donor and reduced acceptor in solvent cage. For productive onward reaction occur, the must escape from that cage before they undergo spontaneous reverse transfer. Here we show decisive role plays three benchmark photocatalytic reactions, namely, aerobic hydroxylation, reductive debromination aza-Henry reaction. Using ruthenium(II)- chromium(III)-based photocatalysts, which provide inherently different quantum yields, determined quantitative correlations between rates of photoredox product formation yields. These findings can be largely rationalized within framework Marcus theory for

Язык: Английский

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Oxidative two-state photoreactivity of a manganese(IV) complex using near-infrared light

Nature Chemistry, Год журнала: 2024, Номер 16(5), С. 827 - 834

Опубликована: Фев. 8, 2024

Язык: Английский

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Charge‐Transfer and Spin‐Flip States: Thriving as Complements

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(15)

Опубликована: Окт. 4, 2022

Abstract Transition metal complexes with photoactive charge‐transfer excited states are pervasive throughout the literature. In particular, [Ru(bpy) 3 ] 2+ (bpy=2,2′‐bipyridine), its metal‐to‐ligand emission, has been established as a key complex. Meanwhile, interest in so‐called spin‐flip metal‐centered risen dramatically after molecular ruby [Cr(ddpd) 2 3+ (ddpd= N , ′‐dimethyl‐ ′‐dipyridin‐2‐yl‐pyridine‐2,6‐diamine) led to design principles access strong, long‐lived emission from photostable chromium(III) complexes. This Review contrasts properties of emissive and by using prototypical examples. We discuss relevant states, tunability their energy lifetimes, response external stimuli. Finally, we identify strengths weaknesses applications such photocatalysis circularly polarized luminescence.

Язык: Английский

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Zinc(II) Complexes with Triplet Charge-Transfer Excited States Enabling Energy-Transfer Catalysis, Photoinduced Electron Transfer, and Upconversion

JACS Au, Год журнала: 2022, Номер 2(10), С. 2367 - 2380

Опубликована: Окт. 11, 2022

Many CuI complexes have luminescent triplet charge-transfer excited states with diverse applications in photophysics and photochemistry, but for isoelectronic ZnII compounds, this behavior is much less common, they typically only show ligand-based fluorescence from singlet π–π* states. We report two closely related tetrahedral which intersystem crossing occurs appreciable quantum yields leads to the population of intraligand (ILCT) character. In addition showing their initially 1ILCT states, these new compounds therefore undergo triplet–triplet energy transfer (TTET) 3ILCT consequently can act as sensitizers photo-isomerization reactions annihilation upconversion blue ultraviolet spectral range. The photoactive state furthermore facilitates photoinduced electron transfer. Collectively, our findings demonstrate that mononuclear photophysical photochemical properties reminiscent well-known are accessible suitable ligands potentially amenable many different applications. Our insights seem relevant greater context obtaining based on abundant transition metals, complementing precious-metal-based luminophores photosensitizers.

Язык: Английский

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Improved transition metal photosensitizers to drive advances in photocatalysis

Chemical Science, Год журнала: 2023, Номер 15(1), С. 77 - 94

Опубликована: Ноя. 24, 2023

To function effectively in a photocatalytic application, photosensitizer's light absorption, excited-state lifetime, and redox potentials, both the ground state excited state, are critically important. The absorption profile is particularly relevant to applications involving solar harvesting, whereas potentials lifetimes determine thermodynamics, kinetics, quantum yields of photoinduced processes. This perspective article focuses on synthetic inorganic organometallic approaches optimize these three characteristics transition-metal based photosensitizers. We include our own work areas, which has focused extensively exceptionally strong cyclometalated iridium photoreductants that enable challenging reductive photoredox transformations organic substrates, more recent led improved harvesting charge-transfer copper(i) chromophores, an emerging class earth-abundant compounds solar-energy applications. also highlight many other complementary strategies for optimizing parameters representative examples from literature. It remains significant challenge simultaneously all at once, since improvements one often come detriment others. These inherent trade-offs obviate or circumvent them discussed throughout.

Язык: Английский

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Halide Noninnocence and Direct Photoreduction of Ni(II) Enables Coupling of Aryl Chlorides in Dual Catalytic, Carbon–Heteroatom Bond-Forming Reactions

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(22), С. 12293 - 12304

Опубликована: Май 19, 2023

Recent mechanistic studies of dual photoredox/Ni-catalyzed, light-driven cross-coupling reactions have found that the photocatalyst (PC) operates through either reductive quenching or energy transfer cycles. To date, reports invoking oxidative cycles are comparatively rare and direct observation such a event has not been reported. However, when PCs with highly reducing excited states used (e.g., Ir(ppy)

Язык: Английский

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Photosensitized activation of diazonium derivatives for C–B bond formation

Chem Catalysis, Год журнала: 2023, Номер 3(2), С. 100490 - 100490

Опубликована: Янв. 5, 2023

Язык: Английский

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The great strides of iron photosensitizers for contemporary organic photoredox catalysis: On our way to the holy grail?

Coordination Chemistry Reviews, Год журнала: 2023, Номер 500, С. 215522 - 215522

Опубликована: Ноя. 9, 2023

Язык: Английский

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Visible‐Light Induced Fixation of SO₂ into Organic Molecules with Polypyridine Chromium(III) Complexes

ChemCatChem, Год журнала: 2023, Номер 15(6)

Опубликована: Янв. 23, 2023

Abstract Incorporation of sulfur dioxide into organic compounds is achieved by a photocatalytic approach using sensitizers made from earth‐abundant chromium(III) ions and visible light leading to sulfones sulfonamides. We employed three different [Cr(ddpd) 2 ] 3+ , [Cr(bpmp) [Cr(tpe) with long excited state lifetimes ground redox potentials as well varying stability under the reaction conditions (ddpd= N N’ ‐dimethyl‐ ’‐dipyridin‐2‐yl‐pyridine‐2,6‐diamine; bpmp=2,6‐bis(2‐pyridylmethyl)pyridine; tpe=1,1,1‐tris(pyrid‐2‐yl)ethane). Key steps catalytic cycles are identified electrochemical, luminescence quenching, photolysis, laser flash photolysis experiments delivering detailed picture challenges in these transformations. The reactivity reduced chromium complex was key property explain outcomes. Initial cage escape yield determinations revealed that desired photoreactions occur unusually high quantum efficiencies, whereas side reactions almost unproductive.

Язык: Английский

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Dicationic Acridinium/Carbene Hybrids as Strongly Oxidizing Photocatalysts

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(5), С. 3416 - 3426

Опубликована: Янв. 24, 2024

A new design concept for organic, strongly oxidizing photocatalysts is described based upon dicationic acridinium/carbene hybrids. highly modular synthesis of such hybrids presented, and the dications are utilized as novel, tailor-made photoredox catalysts in direct oxidative C-N coupling. Under optimized conditions, benzene even electron-deficient arenes can be oxidized coupled with a range

Язык: Английский

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