Oxo(corrolato)vanadium(iv) catalyzed epoxidation: oxo(peroxo)(corrolato)vanadium(v) is the true catalytic species

Abstract

de Visser et al. demonstrated theoretically that although vanadium(IV)-oxo complexes are slow oxidants, in the presence of H₂O₂ they generated a side-on vanadium-peroxo complex, which is an efficient oxidizer. The catalytic activities of vanadium(IV)-oxo complexes are extensively reported in the literature in different ligand backbones, including porphyrin-based ligands. However, similar reports in corrole based ligand systems have not been explored to date. We have reported the synthesis and characterization of two new oxo(corrolato)vanadium(IV) complexes. Interestingly, we have observed an anionic complex, [V^IVO (Corr)³⁻]⁻. This data is contrary to what was observed earlier by Licoccia et al. We have observed that these newly synthesized oxo(corrolato)vanadium(IV) complexes are highly efficient oxidizers in the presence of H₂O₂ and KHCO₃. The catalytic reaction mixture was thoroughly analyzed, and it was established that an oxo(peroxo)(corrolato)vanadium(V) complex is the true catalytic intermediate. This is the first report on oxo(corrolato)vanadium(IV) complexes bearing meso-substitution. In addition to this, these oxo(corrolato)vanadium(IV) complexes have never been previously investigated from a catalysis point of view.