TRANSIENT ABSORPTIONS DUE TO MIXED-VALENCE SPECIES IN THE EXCITED-STATE ABSORPTION-SPECTRA OF CYANOBRIDGED TRINUCLEAR POLYPYRIDYL COMPLEXES OF RU(II)

Singly oxidized forms of two cyano-bridged trinuclear complexes [(CN)(bpy)2RuII-CN-RuII(dcbpy)2-NC-RuII(bpy)2(CN)] (1) and [(H2O)(bpy)2RuII-NC-RuII(dcbpy)2-CN-RuII(bpy)2(H2O)] (2) show intervalence transition bands in the infrared region typical of mixed valence systems. The 532-nm laser photolysis studies of the parent/nonoxidized complexes show transient absorptions in the near-infrared region (600-1200 nm) with lifetime comparable to that of the luminescence from the lowest-energy CT excited state. The near-IR absorption is attributed to the mixed valence species present during the lifetime of the CT excited state.