Luminescent metal complexes. Part 3. Electrochemical potentials of ground and excited states of ring-substituted 2,2′-bipyridyl and 1,10-phenanthroline tris-complexes of ruthenium

Abstract

E _½ values for 21 tris-complexes of substituted 2,2′-bipyridyls and 1,10-phenanthrolines with Ru^II–Ru^III in acetonitrile have been measured using cyclic voltammetry. A linear correlation exists between E_½ and the Hammett σ constant for data obtained from complexes of 4,4′-and 5,5′-disubstituted 2,2′-bipyridyls. The reduction potential for the couple Ru(ligand)₃³⁺–*Ru(ligand)₃²⁺, where * refers to the excited state, have been calculated from the E_½ values and a combination of data collected from luminescence and magnetic circular dichroism measurements.