DFT Study on the Standard Electrode Potentials of Imidazole, Tetrathiafulvalene, and Tetrathiafulvalene-Imidazole

Tugsuz T.

JOURNAL OF PHYSICAL CHEMISTRY B, vol.114, no.51, pp.17092-17101, 2010 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 114 Issue: 51
  • Publication Date: 2010
  • Doi Number: 10.1021/jp106705d
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.17092-17101
  • Hacettepe University Affiliated: Yes


Extensive DFT calculations on the standard electrode potentials of imidazole (Im), tetrathiafulvalene (TTF), and 2-, 4-, and 5-TTF-Im were carried out. Geometries and Gibbs free energies of H-bonded dimer, anion, protonated cation, and neutral structures of Im, mono- and dication, and neutral structures of TTF in gas and acetonitrile solvent were computed by using 10 hybrid density functionals (B3LYP, TPSSH, PBEH1PBE, M06, M062X, X3LYP, BMK, B1B95, M05, M052X) combined with the TZVP basis set. CPCM and SMD solvation models were applied to predict the Gibbs free energies of molecules in acetonitrile solvent. Frequency calculations were carried out for all structures, and none of them has been found to exhibit any imaginary frequency. Finally, the BMK hybrid functional was selected for computation of the standard electrode potential of TTF-Im, because it gives the most accurate values in both Im and TTF, differing by 0.05 V from the experimental ones. Moreover, frequencies from the BMK functional are reasonably close to the experimental ones. The standard electrode potentials of 2-, 4-, and 5-TTF-Im predicted for two-electron oxidation are 0.946, 0.870, and 0.839 V in CPCM and 0.927, 0.866, and 0.824 V in SMD. For one-electron oxidation these are 0.491, 0.421, and 0.400 V in CPCM and 0.476, 0.377, and 0.360 V in SMD, respectively.