Valence tautomerism in metal complexes: Stimulated and reversible intramolecular electron transfer between metal centers and organic ligands

Abstract

The defining characteristic of a valence tautomeric (VT) transition in a metal complex with a redox-active organic ligand is a stimulated intramolecular electron transfer between metal and ligand. Reversible VT behavior is well established for octahedral cobalt complexes with o-dioxolene ligands, with other combinations of metal centers and organic ligands also capable of exhibiting the phenomenon. Although the thermodynamic basis of VT transitions in cobalt-dioxolene systems has been understood for some time, it has not necessarily been elucidated for the less common systems. In general a number of factors additional to the redox-active metal-ligand unit influence the manifestation of the V..