A conceptual DFT approach for the evaluation and interpretation of redox potentials

Conceptual DFT aims at describing the properties of molecules in interactions by using chemical reactivity descriptors. Herein, the redox behaviour of a given species, as quantified by the redox potential, is linked to DFT-based descriptors. We made use of a hierarchical decomposition of the corresponding half-reactions into one-electron reduction, protonation, dissociation and water-forming or dissociation reactions. Most of these reactions can be readily described through reactivity descriptors, such as the electrophilicity, nucleofugality and electrofugality, as defined in conceptual DFT. The final expression linking the corresponding free energy changes to the redox potential seems to give correct predictions for the redox potentials of bromo, chloro and nitro oxo acids in the gas phase, as in a polarised continuum model.