Photocatalytic CO<sub>2</sub> Reduction under Visible‐Light Irradiation by Ruthenium CNC Pincer Complexes
Yasuhiro Arikawa, Itoe Tabata, Yukari Miura, Hiroki Tajiri, Yudai Seto, Shinnosuke Horiuchi, Eri Sakuda, Keisuke Umakoshi
Abstract
Abstract Photocatalytic CO 2 reduction using a ruthenium photosensitizer, a sacrificial reagent 1,3‐dimethyl‐2‐( o ‐hydroxyphenyl)‐2,3‐dihydro‐1 H ‐benzo[ d ]imidazole (BI(OH)H), and a ruthenium catalyst were carried out. The catalysts contain a pincer ligand, 2,6‐bis(alkylimidazol‐2‐ylidene)pyridine (CNC) and a bipyridine (bpy). The photocatalytic reaction system resulted in HCOOH as a main product (selectivity 70–80 %), with a small amount of CO, and H 2 . Comparative experiments (a coordinated ligand (NCMe vs. CO) and substituents ( t Bu vs. Me) of the CNC ligand in the catalyst) were performed. The turnover number (TON HCOOH ) of carbonyl‐ligated catalysts are higher than those of acetonitrile‐ligated catalysts, and the carbonyl catalyst with the smaller substituents (Me) reached TON HCOOH =5634 (24 h), which is the best performance among the experiments.