Redox reactions of metal ions—III: Electronic rearrangements in the precursor bridged complex of the chromium(III)-chromium(II) exchange reactions

Abstract

A correlation is found between the energy of the first d− d bands of a number of Cr(III) complexes and the rate of the electron exchange reactions of the complex with chromous ions. The correlation reflects the ease of electronic rearrangement at the Cr(III)-site in the activated sate for the electron transfer reaction. The greater tetragonal distortion at the Cr(III) site, caused by some ligands attached to Cr(III), is connected with a lower reorganization energy of the precursor complex and this tetragonal distortion was evaluated from an analysis of the electronic spectrum of the Cr(III) complex taking part in the reaction. Thus electronic spectra of one of the reactants may be used to predict reaction rates of electron exchange between Cr(III) and Cr(II).