可視光を吸収する多核ヒドリド錯体の設計と光反応性

Abstract

Dinuclear iridium polyhydride complexes bearing diphosphine ligands were synthesized and characterized for visible-light sensitive photocatlysis, such as CO_2 hydrogenation and hydrogen production. These complexes can be synthesized in high yields in two steps from a mononuclear cationic iridium complex, [Ir(cod)_2]BF_4, as a precursor. The structures of the complexes were unambiguously determined on the basis of single-crystal X-ray diffraction studies. One of the complexes showed favorable catalytic activity for CO_2 hydrogenation under low pressure conditions compared with the existing mononuclear catalysts. The catalytic activity was significantly higher under photoirradiation (λ = 395 nm), suggesting acceleration of the reaction by light. DFT calculations were conducted to elucidate the effect of light toward these polyhydride complexes.