Synthesis, spectroscopic characterization, photochemical and photophysical properties of mono- and tetranuclear Ru(II) and Mn(I) complexes with 4,4′-bipyridine ligand

The synthesis, characterization and the photoinduced electron transfer reactions of the tetranuclear complex cis,fac-[(phen)2Ru(4,4′-bpy)2Mn(CO)3(ImH)]2+6 (III) and the mononuclear moieties cis-[Ru(phen)2(4,4′-bpy)2]2+ (II) and fac-[Mn(CO)3(4,4′-bpy)2(ImH)]+ (I) in the presence of MV2+ are reported. The intramolecular energy/electron transfer process that occurs between the Ru(II) and the Mn(I) upon MLCT (Ru → phen) light excitation is evaluated by time-resolved absorption experiments. Complex II was not able to reduce MV2+, even in the ns scale. Otherwise, complex III showed an ability to generate MV+radical dot when exposed to flash photolysis irradiation.