Visible-Light Photocatalytic Reduction of CO to Formic Acid with a Ru Catalyst Supported by N,N'-Bis(diphenylphosphino)-2,6-diaminopyridine Ligands.

Visible-light photocatalytic CO reduction is carried out by using a Ru complex supported by N,N'-bis(diphenylphosphino)-2,6-diaminopyridine ("PNP") ligands, an unprecedented molecular architecture for this reaction that breaks the longstanding domination of α-diimine ligands. These competent catalysts transform CO into formic acid with high selectivity and turnover number. A proposed mechanism, with combined electron transfer and catalytic cycles, models the experimental rate of formic acid production.