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

• Published in: Coordination chemistry reviews Vol. 477; p. 214955
• Main Authors: Matsubara, Yasuo, Ishitani, Osamu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2023
• Subjects: Artificial photosynthesis; Hydricity; Metal hydrido complex; Organic hydride; Photocatalytic reaction; Metal hydrido complex; Organic hydride; Photocatalytic reaction; Hydricity; Artificial photosynthesis
• ISSN: 0010-8545; 1873-3840
• DOI: 10.1016/j.ccr.2022.214955

•Mechanisms for photochemical formation of metal hydrido complexes.•Photocatalytic hydride reduction of the redox coenzyme NAD(P)+ and its model compounds.•Role of potential inversion on the formation of metal and organic hydrides. The photochemical formation of metal hydride complexes or organic hydride compounds plays an important 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 electrons produced by photochemical one-electron transfer processes to the form of a hydride, which accumulates 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 complexes 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 photocatalytic and electrocatalytic hydride reductions of the redox coenzyme NAD(P)+ and its model compounds.