Photophysical and photochemical properties of ruthenium and osmium complexes with substituted terpyridines

Ruthenium(II) and osmium(II) complexes with 2,2′:6′,2″-terpyridine (terpy), 4′-(p-tolyl)-2,2′:6′,2″-terpyridine (tterpy) and 4,4′,4″-triphenyl-2,2′:6′,2″-terpyridine (tterpy) have been prepared and characterized. Their electrochemical, photophysical and photochemical properties (room temperature) have been studied. Metal-to-ligand charge-transfer excited-state quenching measurements using various redox active species clearly show that [Ru(tpterpy)2]2+ is a good electron-transfer agent under light irradiation.