Hydrogen evolution activity of cobalt corroles

Abstract

An electrochemical study of a series of bis-pyridine ligated A2B type cobalt corroles has been carried out. The impact of substituting with electron withdrawing or donating groups on the overall oxidation or reduction potential was assessed through the use of cyclic voltametric (CV) experiments. DFT methods have also been used to assess the influence of meso-substituents and to structurally optimize the geometries of the complexes to help our understanding of the sometimes-subtle structural characteristics found in the macromolecular systems. A novel penta-coordinated triphenylphosphine ligated corrole i.e., [10-(2,6-difluorophenyl)-5,15-bis(4-nitrophenyl)corrolato]cobalt(III) was also synthesised and characterized using different spectroscopic techniques and X-ray diffraction methods. The hydrogen evolution reaction (HER) capability of the two complexes herein were assessed through CV. The complexes do not show activity toward the HER; rather they supply ligands for the process. The meso-substituents have significant effect on the overall activity of Co macrocycles.