Effect of Apical Ligands, Substituents and Oxidation States on the Electronic Structure of Co(III) Corrolates

Abstract

Cobalt(III) corroles are the most commonly studied types of metallocorroles, yet the details of their electronic structure, ground spin states and place of redox events are not always straightforward. Corroles are redox active, potentially non-innocent ligands, and it has been found through various experimental and computational techniques, that the innocent or non-innocent behavior is modulated by the apical ligands bound to the cobalt center. In this work, we aim to analyze the effect of corrole substituents and number and type of apical ligands on the electronic structure of cobalt corroles through density functional and wavefunction theories, and to determine the relative energies between closed- and open-shell states. We further perform preliminary analyses on the place of electron abstraction upon oxidation and on the effect of the corrole and apical ligands on the cobalt ligand field splittings. We find that both ligand field and electron-donating or withdrawing effects determine the relative energies of open-shell and closed shell singlet states.