Computational electrochemistry: aqueous two-electron reduction potentials for substituted quinones

The electrode potentials of some quinone derivatives in aqueous solution have been calculated. The calculations are carried out at the Hartree-Fock and B3LYP levels with the inclusion of entropic and thermochemical corrections to yield free energies of redox reactions. The Polarisable Continuum Model (PCM) is used to describe the solvent. The average error of calculation of electrode potentials is less than 0.03 V and is decreased compared to the average error of methods presented previously. The role of relaxation energies and frequency calculations in improving the results has been investigated. (C) 2004 Elsevier B.V. All rights reserved.