Comparative study on He(I) photoelectron spectroscopy and voltammetry of ferrocene derivatives

Abstract

The gas-phase ionization energies of 11 ferrocene derivatives have been measured by He(I) photoelectron spectroscopy and compared with the electrode oxidation potentials in aprotic solvents. The first four ionization energies and the oxidation potentials of these compounds change linearly with the Hammett substitution constants. Linear correlations with slopes ca. 0.7 have been obtained between the first adiabatic ionization energies and the oxidation potentials in several aprotic solvents. This result indicates that the solvent effect on Fc/Fc⁺ couples changes proportionally with the gas-phase ionization energies.