Redox Potentials of Ligands and Complexes – a DFT Approach

  • KG von Eschwege
  • J Conradie
Keywords: Oxidation, reduction, predict, electron affinity, electrophilicity index, electronegativity, LUMO energy, HOMO energy

Abstract

A review of the limited literature concerned with theoretical ways to predict experimentally measured redox potentials of ligands and complexes is presented. Electrochemical and related DFT studies involving series of para-substituted nitrobenzenes and β-diketone bidentate ligands are discussed. New studies involving ferrocenes and bimetallic complexes (containing both rhodium and iron) are additionally reported. Correlations of redox potentials with calculated descriptors; electron affinity (EA), group electronegativity (χR), electrophilicity index (ω), LUMO energy (ELUMO) and HOMO energy (EHOMO) – obtained from calculated electronic energies of neutral, anionic and cationic molecules, are compared. Observed E0’, Epa or Epc gave excellent correlations in the linear relationships between Epc and ELUMO (R2 > 0.99), and Epa and EHOMO (R2 > 0.92). Close correlation with the HOMO-1 energy was also found with the ferrocene-based second oxidation in the Rh complex.

Keywords: Oxidation, reduction, predict, electron affinity, electrophilicity index, electronegativity, LUMO energy, HOMO energy

Published
2015-10-13
Section
Articles

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eISSN: 0379-4350