Photoinduced Catalytic Organic‐Hydride Transfer to CO2 Mediated with Ruthenium Complexes as NAD+/NADH Redox Couple Models

The catalytic organic‐hydride transfer to CO2 was first achieved through the photoinduced two‐electron reduction of the [Ru(bpy)2(pbn)]2+/[Ru(bpy)2(pbnHH)]2+ (bpy=2,2’‐bipyridine, pbn=2‐(pyridin‐2‐yl)benzo[b]‐1,5‐naphthyridine, and pbnHH=2‐(pyridin‐2‐yl)‐5,10‐dihydrobenzo[b]‐1,5‐naphthyridine) redox couple in the presence of 1,3‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐benzo[d]imidazole (BIH). The active species for the catalytic hydride transfer to carbon dioxide giving formate is [Ru(bpy)(bpy⋅−)(pbnHH)]+ formed by one‐electron reduction of [Ru(bpy)2(pbnHH)]2+ with BI⋅. The first catalytic organic‐hydride transfer to CO2 is achieved through the photoinduced two‐electron reduction of [Ru(bpy)2(pbn)]2+ and the subsequent one‐electron reduction of the resultant [Ru(bpy)2(pbnHH)]2+ with generation of [Ru(bpy)(bpy⋅−)(pbnHH)]+ as the active catalyst in the presence of BIH in H2O/CH3CN.