Synthesis and photochemical properties of ruthenium-cobalt and ruthenium-nickel dinuclear complexes

Three dinuclear colmplexes, two Ru(II)-Co(III) and one Ru(II)-Ni(II) polypyridyl complexes, were prepared by the use of ethylene- and pentamethylene-linked bisphenanthroline as the bridging ligands. Their photochemical and electrochemical properties were examined. Each metal complex component was shown to be electronically insulated. Since the roles of the Ru(II) as a photosensitizer and the Co(III) or Ni(II) moiety as an electron acceptor were expected, a photocatalytic CO2 reduction experiment was carried out. The catalytic ability of the Ru(II)-Co(III) system was shown to be almost the same as the corresponding intermolecular systems with the improved CO/H-2 selectivity, showing that the co(III) polypyridyl complex was as effecticve as the Co(II) species for a catalytic center.