Visible Light-Induced Transition Metal Catalysis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 1543 - 1625

Published: Oct. 8, 2021

In recent years, visible light-induced transition metal catalysis has emerged as a new paradigm in organic photocatalysis, which led to the discovery of unprecedented transformations well improvement known reactions. this subfield complex serves double duty by harvesting photon energy and then enabling bond forming/breaking events mostly via single catalytic cycle, thus contrasting established dual photocatalysis an exogenous photosensitizer is employed. addition, approach often synergistically combines catalyst–substrate interaction with photoinduced process, feature that uncommon conventional photoredox chemistry. This Review describes early development advances emerging field.

Language: Английский

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Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2487 - 2649

Published: Nov. 9, 2021

Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do and catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) enable bond formations not constrained by rules ionic 2 electron (e) mechanisms. Instead, they 1e mechanisms capable bypassing electronic steric limitations protecting group requirements, thus enabling chemists disconnect molecules in new different ways. However, while providing similar intermediates, differ several physical chemistry principles. Understanding those differences can be key designing transformations forging disconnections. This review aims highlight these similarities between comparing their underlying principles describing impact electrochemical photochemical methods.

Language: Английский

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Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(8), P. 4237 - 4352

Published: Jan. 24, 2023

The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C–H functionalization approaches that make use low energy photons as a controllable source. Compared to traditional strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- chemoselectivities. Merging compelling benefits with workflow offers potentially unmatched arsenal tackle drug development campaigns beyond. This Review highlights photocatalytic strategies small-molecule drugs, agrochemicals, natural products, classified according targeted bond newly formed one. Emphasis is devoted identifying, describing, comparing main mechanistic scenarios. draws critical comparison between established ionic chemistry photocatalyzed radical-based manifolds. aims establish current state-of-the-art illustrate key unsolved challenges be addressed in future. authors aim introduce general readership functionalization, specialist practitioners evaluation methodologies, potential for improvement, future uncharted directions.

Language: Английский

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Visible‐Light‐Induced Homolysis of Earth‐Abundant Metal‐Substrate Complexes: A Complementary Activation Strategy in Photoredox Catalysis

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(39), P. 21100 - 21115

Published: Feb. 18, 2021

Abstract The mainstream applications of visible‐light photoredox catalysis predominately involve outer‐sphere single‐electron transfer (SET) or energy (EnT) processes precious metal Ru II Ir III complexes organic dyes with low photostability. Earth‐abundant metal‐based M n L ‐type (M=metal, =polydentate ligands) are rapidly evolving as alternative photocatalysts they offer not only economic and ecological advantages but also access to the complementary inner‐sphere mechanistic modes, thereby transcending their inherent limitations ultrashort excited‐state lifetimes for use effective photocatalysts. generic process, termed visible‐light‐induced homolysis (VLIH), entails formation suitable light‐absorbing ligated metal–substrate (M ‐Z; Z=substrate) that can undergo homolytic cleavage generate n−1 Z . further transformations.

Language: Английский

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Ligand‐to‐Metal Charge Transfer (LMCT) Photochemistry at 3d‐Metal Complexes: An Emerging Tool for Sustainable Organic Synthesis

ChemCatChem, Journal Year: 2022, Volume and Issue: 14(19)

Published: Aug. 11, 2022

Abstract Despite the rich photochemistry of 3d‐metal complexes, utilization excited‐state reactivity these compounds in organic synthesis has been historically overlooked. The advent photoredox catalysis changed perception synthetic chemists towards photochemistry, and nowadays potential photoinduced, outer‐sphere single‐electron transfer events is widely recognized. More recently, an emerging new mode photoactivation taken spotlight, based on inner‐sphere triggered by population ligand‐to‐metal charge‐transfer (LMCT) excited states. Contrarily to photoredox, LMCT‐activation does not rely matching redox potentials, offers unique profiles particularly well suited Earth‐abundant metal complexes. Those appealing features are propelling development methods using this blueprint generate highly reactive open‐shell species under mild conditions. aim contribution provide a didactical tool for comprehension concept facilitate methodologies achieve sustainable chemical transformations.

Language: Английский

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UV/Chlorine Process: An Efficient Advanced Oxidation Process with Multiple Radicals and Functions in Water Treatment

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(3), P. 286 - 297

Published: Jan. 13, 2022

ConspectusBecause of the deterioration global water quality, occurrence chemical and microbial contaminants in raises serious concerns for health population. Identifying developing effective environmentally friendly treatment technologies are critical to obtain clean water. Among various purification water, ultraviolet photolysis chlorine (UV/chlorine), an emerging advanced oxidation process (AOP), has multiple functions control via production hydroxyl radicals (HO·) reactive species (RCS), such as Cl·, ClO·, Cl2·–.This Account centers around radical chemistry RCS HO· different matrices their roles mechanisms abatement contaminants. The concentrations Cl2·– comparable or higher than those (10–14 10–13 M). reactivities more selective with a broader range second-order rate constants (k). k values Cl· toward most aromatics similar compared HO·, while ClO· less but containing electron-donating functional groups. Their major reaction electron transfer addition, primarily involve transfer. As aliphatics, both much lower aromatics. them hydrogen abstraction, except olefins, which addition. In greatly contribute inactivation contaminants.Toward future application, UV/chlorine pros cons. Compared traditional HO·-based AOP UV/H2O2, is efficient energy-saving disinfection, its efficiency affected by matrix components. However, formation toxic byproducts limits application scenarios. dissolved organic matter (DOM)-rich halogenated enhanced UV/chlorine. presence ammonia, nitrogen (RNS) (e.g., ·NO ·NO2) involved, highly nitro(so) products nitro(so)-phenolics N-nitrosodimethylamine generated. For niche recommended be utilized low levels DOM ammonia.Strategies should developed make full use (RCS HO·) target reduce byproducts. example, can used tandem other treatments create barriers safe halogen very important ecosystems well areas medical therapy synthesis. homogeneous system generate radicals, thus it provides perfect investigate fates interdisciplinary research.

Language: Английский

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Chemical Upcycling of Commercial Polystyrene via Catalyst-Controlled Photooxidation

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(13), P. 5745 - 5749

Published: March 23, 2022

Chemical upcycling of polystyrene into targeted small molecules is desirable to reduce plastic pollution. Herein, we report the benzoyl products, primarily benzoic acid, using a catalyst-controlled photooxidative degradation method. FeCl3 undergoes homolytic cleavage upon irradiation with white light generate chlorine radical, abstracting an electron-rich hydrogen atom on polymer backbone. Under oxygen-rich environment, high MW (>90 kg/mol) degrades down <1 kg/mol and produces up 23 mol % products. A series mechanistic studies showed that radicals promoted via hydrogen-atom abstraction. Commercial efficiently in our method, showing compatibility system fillers. Finally, demonstrated potential scaling approach photoflow process convert gram quantities PS acid.

Language: Английский

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Photoactive Copper Complexes: Properties and Applications

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(22), P. 16365 - 16609

Published: Nov. 9, 2022

Photocatalyzed and photosensitized chemical processes have seen growing interest recently become among the most active areas of research, notably due to their applications in fields such as medicine, synthesis, material science or environmental chemistry. Among all homogeneous catalytic systems reported date, photoactive copper(I) complexes been shown be especially attractive, not only alternative noble metal complexes, extensively studied utilized recently. They are at core this review article which is divided into two main sections. The first one focuses on an exhaustive comprehensive overview structural, photophysical electrochemical properties mononuclear typical examples highlighting critical structural parameters impact being presented enlighten future design complexes. second section devoted application (photoredox catalysis organic reactions polymerization, hydrogen production, photoreduction carbon dioxide dye-sensitized solar cells), illustrating progression from early current state-of-the-art showcasing how some limitations can overcome with high versatility.

Language: Английский

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Radical C(sp3)–H functionalization and cross-coupling reactions

Nature Reviews Chemistry, Journal Year: 2022, Volume and Issue: 6(6), P. 405 - 427

Published: May 17, 2022

Language: Английский

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Convenient C(sp³)–H bond functionalisation of light alkanes and other compounds by iron photocatalysis

Green Chemistry, Journal Year: 2021, Volume and Issue: 23(18), P. 6984 - 6989

Published: Jan. 1, 2021

A practical and green iron-catalyzed photoredox system for C–H functionalization of ethane, propane, other light alkanes was developed.

Language: Английский

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