SPECTROELECTROCHEMICAL STUDIES OF RUTHENIUM(II) DIIMINE COMPLEXES WITH POLYPYRIDYL BRIDGING LIGANDS

Ruthenium(II) complexes with polypyridyl bridging ligands 2,3-di(2-pyr idyl)pyrazine (dpp) and 6,7-dimethyl-2,3-di(2-pyridyl)quinoxaline (dpq m) have been prepared. The electronic and resonance Raman spectra of t he parent complexes and their reduced and oxidized products have been measured. These results indicate that for both complexes the first oxi dation is metal based and the first reduction bridging ligand based. R aman marker bands for the metal oxidation have been identified. The re sonance Raman spectra of the reduced species suggest electron localiza tion of the LUMO to be spread across the pyridine and pyrazine/quinoxa line sections of the bridging ligands.