Mechanisms of Photoredox Catalysis Featuring Nickel–Bipyridine Complexes

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(11), P. 9055 - 9076

Published: May 29, 2024

Metallaphotoredox catalysis can unlock useful pathways for transforming organic reactants into desirable products, largely due to the conversion of photon energy chemical potential drive redox and bond transformation processes. Despite importance these processes cross-coupling reactions other transformations, their mechanistic details are only superficially understood. In this review, we have provided a detailed summary various photoredox mechanisms that been proposed date Ni-bipyridine (bpy) complexes, focusing separately on photosensitized direct excitation reaction By highlighting multiple key findings, depict how mechanisms, which ultimately define substrate scope, themselves defined by ground- excited-state geometric electronic structures Ni-based intermediates. We further identify knowledge gaps motivate future studies development synergistic research approaches spanning physical, organic, inorganic chemistry communities.

Language: Английский

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Red Light–Blue Light Chromoselective C(sp²)–X Bond Activation by Organic Helicenium-Based Photocatalysis

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(12), P. 7922 - 7930

Published: March 18, 2024

Chromoselective bond activation has been achieved in organic helicenium (nPr-DMQA+)-based photoredox catalysis. Consequently, control over chromoselective C(sp2)–X multihalogenated aromatics demonstrated. nPr-DMQA+ can only initiate the halogen atom transfer (XAT) pathway under red light irradiation to activate low-energy-accessible C(sp2)–I bonds. In contrast, blue initiates consecutive photoinduced electron (conPET) more challenging C(sp2)–Br Comparative reaction outcomes have demonstrated α-arylation of cyclic ketones with and lights. Furthermore, red-light-mediated selective bonds activated iodobromoarenes keep bromo functional handle untouched. Finally, strength catalysis highlighted two-fold functionalization using both photo-to-transition metal photo-to-photocatalyzed transformations.

Language: Английский

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Selectivity‐Enhanced Near‐Infrared Photocatalytic Dehydrogenation and C─N Coupling via Lanthanide Nanocrystal‐Mediated Photosensitization

Advanced Functional Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

Abstract Near‐infrared (NIR) light‐driven photocatalysis provides a promising solution to the inherent limitations of conventional ultraviolet (UV) and visible‐light photocatalysis, such as shallow penetration, photodamage from high‐energy irradiation, limited selectivity. However, effective strategies for achieving NIR remain scarce. Here, novel strategy that achieves with significantly enhanced selectivity is reported through lanthanide nanocrystal‐mediated photosensitization. A composite nanocatalyst, comprising NaNdF 4 nanocrystals Zn(II) phthalocyanine organic photosensitizers designed, where absorb 808 nm light transfer energy directly via lanthanide‐mediated triplet sensitization. This approach enables selective functionalization substrates increased yields reduced side‐product formation compared UV/visible excitation. The arises controlled generation superoxide anions (O 2 − ) reactive oxygen species (ROS) minimized substrate photoactivation. targeted dehydrogenation C─N coupling reactions diverse N‐heterocyclic substrates, including halogen‐substituted compounds are typically prone undesired side reactions. findings establish versatile improving in photocatalytic transformations, opening new opportunities light‐sensitive synthesis sustainable catalysis.

Language: Английский

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Red light excitation: illuminating photocatalysis in a new spectrum

Beilstein Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: 21, P. 296 - 326

Published: Feb. 7, 2025

Red-light-activated photocatalysis has become a powerful approach for achieving sustainable chemical transformations, combining high efficiency with energy-saving, mild conditions. By harnessing the deeper penetration and selectivity of red near-infrared light, this method minimizes side reactions typical higher-energy sources, making it particularly suited large-scale applications. Recent advances highlight unique advantages both metal-based metal-free catalysts under red-light irradiation, broadening range possible reactions, from selective oxidations to complex polymerizations. In biological contexts, enables innovative applications in phototherapy controlled drug release, exploiting its tissue low cytotoxicity. Together, these developments underscore versatility impact photocatalysis, positioning as cornerstone green organic chemistry significant potential synthetic biomedical fields.

Language: Английский

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Red-Light-Active N,C,N-Pincer Bismuthinidene: Excited State Dynamics and Mechanism of Oxidative Addition into Aryl Iodides

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

Published: Feb. 10, 2025

Despite the progress made in field of synthetic organic photocatalysis over past decade, use higher wavelengths, especially those deep-red portion electromagnetic spectrum, remains comparatively rare. We have previously disclosed that a well-defined N,C,N-pincer bismuthinidene (1a) can undergo formal oxidative addition into wide range aryl electrophiles upon absorption low-energy red light. In this study, we map out photophysical dynamics 1a and glean insights nature excited state responsible for activation electrophiles. Transient emission techniques reveal that, irradiation with light, complex undergoes direct S0 → S1 metal-to-ligand charge transfer (MLCT) transition, followed by rapid intersystem crossing (ISC) to highly reducing emissive triplet (−2.61 V vs Fc+/0 MeCN). The low dissipative losses incurred during ISC (∼6% incident light energy) help rationalize ability convert useful chemical energy. Spectroelectrochemical computational data support charge-separated excited-state structure radical-anion character on ligand radical-cation bismuth. Kinetic studies competition experiments afford mechanism iodides; concerted inner-sphere processes from are ruled out, strongly supporting pathway proceeds via outer-sphere dissociative electron transfer.

Language: Английский

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Improved transition metal photosensitizers to drive advances in photocatalysis

Chemical Science, Journal Year: 2023, Volume and Issue: 15(1), P. 77 - 94

Published: Nov. 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.

Language: Английский

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Applications of red light photoredox catalysis in organic synthesis

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(12), P. 2472 - 2485

Published: Jan. 1, 2023

This review summarizes the current progress in red light-mediated and near-infrared-induced reactions organic synthesis.

Language: Английский

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Dual Nickel(II)/Mechanoredox Catalysis: Mechanical‐Force‐Driven Aryl‐Amination Reactions Using Ball Milling and Piezoelectric Materials

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(42)

Published: Aug. 28, 2023

Abstract The combination of a nickel(II) catalyst and mechanoredox under ball‐milling conditions promotes mechanical‐force‐driven C−N cross‐coupling reactions. In this nickel(II)/mechanoredox cocatalyst system, the modulation oxidation state nickel center, induced by piezoelectricity, is used to facilitate highly efficient aryl‐amination reaction, which characterized broad substrate scope, an inexpensive catalysts (NiBr 2 BaTiO 3 ), short reaction times, almost negligible quantity solvents. Moreover, can be readily up‐scaled multi‐gram scale, all synthetic operations carried out atmospheric without need for complicated setups. Furthermore, force‐induced system suitable excitation‐energy‐accepting molecules poorly soluble polyaromatic substrates that are incompatible with solution‐based nickel(II)/photoredox cocatalysts.

Language: Английский

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Oxidative Addition of Aryl Electrophiles into a Red-Light-Active Bismuthinidene

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(34), P. 18742 - 18747

Published: Aug. 21, 2023

The oxidative addition of aryl electrophiles is a fundamental organometallic reaction widely applied in the field transition metal chemistry and catalysis. However, analogous version based on main group elements still remains largely underexplored. Here, we report ability well-defined organobismuth(I) complex to undergo formal with wide range electrophiles. process facilitated by reactivity both ground excited states N,C,N-bismuthinidenes upon absorption low-energy red light.

Language: Английский

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Low-energy photoredox catalysis

Nature Reviews Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 11, 2024

Language: Английский

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