Theoretical Predictions of Redox Potentials of Fischer-Type Chromium Aminocarbene Complexes

Redox potentials of series of chromium aminocarbene complexes with general formulas [(CO)5CrC(R)N(CH3)2] and [(CO)4CrC(R)N(CH2CHCH2)2] were calculated using DFT methods for both metal-localized oxidation and ligand-localized reduction processes. The electrostatic contribution of solvation was approximated by the polarizable continuum model (PCM); specific interactions of the complexes with counterions of supporting electrolyte were considered by explicitly including these ions in the model. The theoretical redox potentials were correlated with experimental values, and the qualities of the results of the approaches used were compared. It was shown that both sets of calculated redox potentials reproduce the experimental data well. The mean average error of the calculated redox potentials was 0.088 V with the counterions and 0.111 V without the counterions. The best results were obtained for oxidation processes, where the mean average error decreased from 0.110 to 0.059 V due to the inclusion of the counterions.