A nature inspired molecular Ni-catalyst for efficient photocatalytic CO₂ reduction to CO under visible light

Development of efficient molecular catalysts for photocatalytic CO₂ reduction is desirable but challenging. At present, the majority of reported molecular catalysts consist of the transition metal centers coordinated by N-containing ligands. Inspired by the sulfur-containing active site found in carbon monoxide dehydrogenases, we here report a novel Ni-based molecular catalyst bearing 2,6-bis([(2-pyridinylmethyl)thio]methyl) pyridine) as the pentadentate ligand. The product is assessed for photocatalytic CO₂ reduction in acetonitrile/water solution using Ru(bpy)₃Cl₂ as the photosensitizer and triethanolamine as the electron donor. Under the optimal condition, a total of ca. 25 μmol CO is produced after 7 h visible light irradiation with a large turnover number of 63 and high selectivity of 91%.