Theoretical calculation of electrode potentials: Electron‐withdrawing compounds

Simon G. Lister, Christopher A. Reynolds, W. Graham Richards

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

The electrode potential of 2,3‐dicyanobenzoquinone in aqueous solution has been calculated relative to parabenzoquinone using a thermodynamic cycle approach that includes accurate gasphase ab initio calculations and calculation of differences in free energies of hydration using the free‐energy perturbation method. The discrepancy between the calculated and experimental electrode potential is disappointingly large (99 mV) compared to previous studies using this approach. This, along with the experimental evidence, suggests that the experimental value itself is too large and that theoretical approaches may indeed be as reliable as experimental ones for determining redox properties of molecules such as 2,3‐dicyanobenzoquinone. In the light of this discrepancy we have examined the variation of the results with the basis set, inclusion of electron correlation and changes in the parameters used in the molecular dynamics free‐energy simulations. The results are shown to be dependent upon the torsional parameters and especially dependent upon the basis set or semiempirical method used to obtain the electrostatic potential‐derived charges. The best charge set was determined using the ab initio criteria of completeness—as far as it can be applied to large molecules—and also by studying the effect of hydration on these charges. This was done by allowing the solvent to perturb the wave function prior to the electrostatic potential determination. Thus, 3‐21G and 6‐31G* basis sets were found to give satisfactory results. Similar results were obtained using semiempirical and ab initio geometries.

Original languageEnglish
Pages (from-to)293-310
Number of pages18
JournalInternational Journal of Quantum Chemistry
Volume41
Issue number2
DOIs
Publication statusPublished - 20 Jan 1992
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'Theoretical calculation of electrode potentials: Electron‐withdrawing compounds'. Together they form a unique fingerprint.

  • Cite this