Application of the five-membered ring products of cyclometalation reactions for hydrogen production

2-Phenylpyridine cyclometalated iridium compounds and their derivatives are primarily used as photosensitizers. The other cyclometalated iridium compounds and cyclometalated compounds using other metal, such as palladium, gold, ruthenium and platinum, are also used as photosensitizers. These photosensitizers, together with catalysts as cobalt, ruthenium and rhodium chelate compounds and such sacrificial electron donors as triethylamine (TEA) and triethanolamine (TEOA), were used for hydrogen production in this study. Furthermore, 1-(4-benzoic acid)phenyl iridium compounds and 2-phenylpyrazoline iridium compounds were used to prepare catalysts for the generation of hydrogen from water or formic acid. (C) 2017 Elsevier B.V. All rights reserved.