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.