Investigations of charge-separation processes in metal complexes

Abstract

The major thrust of the research has been the quantification of the excited states of inorganic complexes that display potential for mediating charge-separation processes. Investigations of copper(1) mixed-ligand complexes have been completed. Non-equilibrated emitting states have been assigned. Chemical tuning of the emission energy by modifying the basicity of the donor ligand on the metal has been achieved. Structure-property relationships have been defined for crystalline complexes of zinc containing both diimine and monothiol ligands. Correlation of the spectral shifts with the rotations of the thiol phenyl rings in different crystal phases has been shown by comparing with extended Huckel calculations and x-ray structures. Complexes of zinc containing diimine and dithiol ligands are shown to be polynuclear species. A trinuclear species can be forced to assume a binuclear structure by incorporating other non-coordinating ligands into the lattice. The transformation is accompanied by substantial photophysical changes. Syntheses and x-ray structure determinations of platinum(2) complexes containing diimine ligands only, both diimine and dithiol ligands, and dithiol ligands only have been completed. An unusual platinum(3) bis(dithiol) species has been obtained and its structure determined. Investigations of the emission spectra of bis(bipyridine)platinum(2) have revealed the existence of multiple emitting states with both ligand-localized and charge- transfer characteristics.