Photo-hydrogen-evolving molecular devices driving visible-light-induced water reduction into molecular hydrogen: Structure–activity relationship and reaction mechanism

This article summarizes the ongoing studies on the photo-hydrogen-evolving molecular devices (PHEMDs) made up of polypyridyl Ru(II) photosensitizers and Pt(II)-based molecular catalysts, carried out in the authors’ group in the last two decades. The H₂-evolving activities of Pt(II)-based molecular catalysts demonstrated by various experimental evidences are first described. Then the structure–activity relationship, some important factors required for the higher catalytic activity, and several important insights into the mechanism of photochemical H₂ evolution catalyzed by the Ru(II)Pt(II)-based PHEMDs will be discussed in detail.