Artificial Photosynthesis

Rapid Transfer of Hydride Ion from a Ruthenium Complex to C1 Species in Water

Water is recognized as a desirable solvent for catalysis and as a promising raw material for solar generation of fuels; however, relatively few kinetics and mechanism studies of C1 reduction reactions in aqueous media have been reported. We found that solvent water (Gutmann acceptor number, AN = 55) accelerates the rate of reaction of [Ru(terpy)(bpy)H]⁺ with CO₂ by more than 4 orders of magnitude compared to acetonitrile (AN = 18.9) (as reported in Inorg. Chim. Acta 2000, 299, 155). Water also promotes the related reductions of carbon monoxide to formaldehyde and of formaldehyde to methanol by the ruthenium(II) hydride complex.

Inorg. Chem. 2010, 49, 9809-9822.