Triplet–triplet annihilation photon upconversion-mediated photochemical reactions

Nature Reviews Chemistry, Journal Year: 2024, Volume and Issue: 8(4), P. 238 - 255

Published: March 21, 2024

Language: Английский

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

Nature Chemistry, Journal Year: 2024, Volume and Issue: 16(5), P. 827 - 834

Published: Feb. 8, 2024

Language: Английский

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Two Birds, One Stone: Microsecond Dark Excited-State Lifetime and Large Cage Escape Yield Afforded by an Iron–Anthracene Molecular Dyad

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

Iron photosensitizers represent a holy grail in photochemistry, but their widespread implementation is limited by short excited-state lifetimes and poor cage escape yields. Here, the introduction of an anthracene moiety appended to iron(III) complex allowed solve both limitations generate novel dyad exhibiting extraordinary lifetime 11.5 μs. The key achieving this remarkably long depopulation short-lived iron-centered emissive excited state populate dark triplet located on anthracene-like with spin-forbidden deactivation. Population only occurs ∼10% efficiency acetonitrile still allows expansion scope reactivity accessible iron-based photosensitizers, which now encompasses energy transfer 3O2. In addition, proof-of-principle investigation methyl viologen as electron acceptor, population drastic ten-fold increase yield from 4.5% for unsubstituted 42% molecular dyad. Hence, new provides complementary approach complexes based first-row transition metals alternatives well-established analogues precious metals. We believe that further spectroscopic investigations synthetic modifications acceptor linkage photosensitizer will be use these innovative dyads applications near future.

Language: Английский

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Iron(III) Complexes with Luminescence Lifetimes of up to 100 ns to Enhance Upconversion and Photocatalysis

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

Iron is the most abundant transition metal element and would be ideal replacement for noble metals in many applications that rely on luminescent long-lived electronically excited states. We show efficient reversible energy transfer between doublet states of iron complexes triplet organic ligands improves storage by up to 350-fold. As a result, luminescence lifetimes 100 ns are achieved, upconversion from red blue light becomes 68 times more yield benchmark photoredox reactions significantly improved. These advances make coordination compounds promising candidates lighting, solar conversion photocatalysis.

Language: Английский

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Efficient Triplet‐Triplet Annihilation Upconversion Sensitized by a Chromium(III) Complex via an Underexplored Energy Transfer Mechanism

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(27)

Published: March 28, 2022

Sensitized triplet-triplet annihilation upconversion (sTTA-UC) mainly relies on precious metal complexes thanks to their high intersystem crossing (ISC) efficiencies, excited state energies, and lifetimes, while of abundant first-row transition metals are only rarely utilized with often moderate UC quantum yields. [Cr(bpmp)

Language: Английский

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

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(15)

Published: Oct. 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.

Language: Английский

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Shedding Light on the Oxidizing Properties of Spin-Flip Excited States in a Cr^III Polypyridine Complex and Their Use in Photoredox Catalysis

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(31), P. 14181 - 14194

Published: Aug. 1, 2022

The photoredox activity of well-known RuII complexes stems from metal-to-ligand charge transfer (MLCT) excited states, in which a ligand-based electron can initiate chemical reductions and metal-centered hole trigger oxidations. CrIII polypyridines show similar properties, although they have fundamentally different electronic structures. Their photoactive state is spin-flip nature, differing the ground merely by change one spin, but with otherwise identical d-orbital occupancy. We find that driving-force dependence for photoinduced 10 donors to complex very polypyridine, thereby validate concept estimating redox potential d3 states analogous manner as MLCT d6 compounds. Building on this insight, we use our photocatalytic reactions not previously explored compound class, including aerobic bromination methoxyaryls, oxygenation 1,1,2,2-tetraphenylethylene, hydroxylation arylboronic acids, vinylation N-phenyl pyrrolidine. This work contributes understanding fundamental photochemical properties first-row transition-metal comparison well-explored precious-metal-based photocatalysts.

Language: Английский

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Sensitizer-controlled photochemical reactivityviaupconversion of red light

Chemical Science, Journal Year: 2022, Volume and Issue: 14(1), P. 149 - 161

Published: Dec. 1, 2022

By combining the energy input from two red photons, chemical reactions that would normally require blue or ultraviolet irradiation become accessible. Key advantages of this biphotonic excitation strategy are light usually penetrates deeper into complex reaction mixtures and causes less photo-damage than direct illumination in ultraviolet. Here, we demonstrate primary light-absorber a dual photocatalytic system comprised transition metal-based photosensitizer an organic co-catalyst can completely alter outcome. Photochemical reductions achieved with copper(i) presence sacrificial electron donor, whereas oxidative substrate activation occurs osmium(ii) photosensitizer. Based on time-resolved laser spectroscopy, changeover photochemical reactivity is due to different underlying mechanisms. Following triplet transfer 9,10-dicyanoanthracene (DCA) subsequent triplet-triplet annihilation upconversion, fluorescent singlet excited state DCA triggers activation, which initiates

Language: Английский

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Blue‐to‐UVB Upconversion, Solvent Sensitization and Challenging Bond Activation Enabled by a Benzene‐Based Annihilator

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(8)

Published: Nov. 18, 2022

Several energy-demanding photoreactions require harsh UV light from inefficient sources. The conversion of low-energy visible to high-energy singlet states via triplet-triplet annihilation upconversion (TTA-UC) could offer a solution for driving such reactions under mild conditions. We present the first annihilator with an emission maximum in UVB region that, combined organic sensitizer, is suitable blue-to-UVB upconversion. was successfully employed as energy donor subsequent FRET activations aliphatic carbonyls. This hitherto unreported UC-FRET reaction sequence directly monitored using laser spectroscopy and applied mechanistic irradiation experiments demonstrating feasibility Norrish chemistry. Our results provide clear evidence novel blue light-driven substrate or solvent activation strategy, which important context developing more sustainable light-to-chemical systems.

Language: Английский

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Direct Observation of Triplet States in the Isomerization of Alkenylboronates by Energy Transfer Catalysis

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(39), P. 21576 - 21586

Published: Sept. 20, 2023

Alkenylboronates are versatile building blocks for stereocontrolled synthesis owing to the traceless nature of boron group that can be leveraged achieve highly selective geometric isomerization. Using thioxanthone as an inexpensive photocatalyst, photoisomerization these species continues provide expansive platform stereodivergent synthesis, particularly in construction bioactive polyenes. Although mechanistic investigations consistent with light-driven energy transfer, direct experimental evidence remains conspicuously absent. Herein, we report a rigorous investigation using two widely used alkenylboronates alongside relevant reference compounds. Through combination irradiation experiments, transient absorption spectroscopic studies, kinetic modeling, and DFT calculations all isomers model compounds, it has been possible unequivocally detect characterize perpendicular triplet generated by transfer. Our results serve not only blueprint studies challenging organic sensitizers, but guidelines delineated have also enabled development more sustainable reaction conditions: first time, efficient organocatalytic isomerization under sunlight become feasible.

Language: Английский

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