EXCITED-STATE REDOX POTENTIALS OF RUTHENIUM DIIMINE COMPLEXES - CORRELATIONS WITH GROUND-STATE REDOX POTENTIALS AND LIGAND PARAMETERS

The relationship between charge transfer emission energies and redox p otentials has been investigated for a large and diverse set of rutheni um diimine complexes. An alternative derivation of excited state redox potentials is developed, which relates them directly to the correspon ding (observable) ground state potentials and allows them to be estima ted when the 0-0' emission energy is unknown. The difference between t he excited state and corresponding ground state potentials, D, is show n to be approximately constant for complexes in which the emission and reduction processes involve ''bipyridine-like'' ligands, provided the re are no strong specific solvent-solute interactions. Excited state r edox potentials may also be obtained directly by using ligand electroc hemical parameters, E(L)(L). E(L)(L(-)) values are calculated here for a number of reduced ligands.