Photochemical formation of hydride using transition metal complexes and its application to photocatalytic reduction of the coenzyme NAD(P ) plus and its model compounds

The photochemical formation of metal hydride complexes or organic hydride compounds plays an impor-tant role in the conversion of light energy into the formation of chemical bonds in various photocatalytic reactions and has been an important subject of research from the viewpoint of energy transformation chemistry. Because one-photon excitation of a substrate principally induces only a one-electron transfer process, in photocatalytic reactions involving redox reactions, the key is the conversion of multiple elec-trons produced by photochemical one-electron transfer processes to the form of a hydride, which accu-mulates two electrons with a proton. In photosynthesis as the best example, sunlight is utilized to form an organic hydride compound, NADPH, which is the reduced form of the redox coenzyme in photosystem I where the hydride reduction of the oxidized form, NADP+ is involved. This paper reviews the research conducted over the past 30 years on light-induced hydride formation mediated by transition metal com-plexes and their applications: (1) photochemical formation mechanisms of metal hydrido complexes and metal complexes with hydride-donating moieties, and (2) applications of these systems for photocat-alytic and electrocatalytic hydride reductions of the redox coenzyme NAD(P)+ and its model compounds.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

The formation of metal hydride complexes or organic hydride compounds through photochemical reactions is crucial in converting light energy into chemical bonds during various photocatalytic reactions. This paper reviews the research conducted over the past 30 years on light-induced hydride formation mediated by transition metal complexes and their applications. The key aspect of photocatalytic reactions involving redox reactions lies in the conversion of multiple electrons produced by photochemical one-electron transfer processes to form a hydride.