Carbon Dioxide Reduction Catalyzed by Dinuclear Ruthenium Polypyridyl Complexes

Ono, T.; Planas, N.; Miró, P.; Ertem, M. Z.; Escudero-Adán, E. C.; Benet-Buchholz, J.; Gagliardi, L.; Cramer, C. J.; Llobet, A.
ChemCatChem 2013, 5, 3897 (doi:10.1002/cctc.201300372).

Dinuclear ruthenium complexes with formula [(Ru(bid))₂(μ-bpp)(μ-OAc)] and [(Ru(trpy))₂(μ-bpp)(μ-X)]²⁺ (X = Cl^–, OAc^– and OCHO^–) (bid^– is (1Z,3Z)-1,3-bis(pyridin-2-ylmethylene)isoindolin-2-ide; trpy is 2,2':6',2"-terpyridine) were tested as catalysts for hydrogenative reduction of CO₂ in 2,2,2-trifluoroethanol (TFE) as solvent in the presence of excess amine (NEt₃). Significant amounts of formic acid were produced by these catalysts and a kinetic analysis based on initial rate constants was carried out. These catalytic systems were investigated by means of density functional theory calculations (DFT) to elucidate the hydrogenative reduction mechanism. Results are compared to those obtained with previously reported mononuclear catalyst counterparts.