Using theoretical calculations to predict the redox potential of mononuclear manganese complexes

Abstract

The rational design of biomimetic complexes of metalloenzymes involved in redox processes is of great interest in bioinorganic chemistry. Its purpose is to utilize the redox properties of mimics and use them as redox-active catalysts. To obtain efficient artificial catalysts, it is necessary to model structurally and electronically the active site of the enzymes. In particular, for redox catalysis, it is necessary that the biomimetic complexes achieve a certain redox potential so their prediction is a valuable tool to improve the rational design of catalysts with specific properties. In this work we set out to predict the one electron redox potential for a series of mononuclear Mn models of Mn superoxide dismutase enzymes using density functional calculations of low computational cost. We obtained an excellent linear correlation between calculated and experimental redox potentials referenced against the ferrocene/ferrocenium (Fc/Fc⁺) couple, when solvation effects were included. Additionally, we validated the strategy predicting the redox potentials of two complexes synthesized in our laboratory.