title: Visible light-induced formation of corrole-manganese(V)-oxo complexes: Observation of multiple oxidation pathways.
abstract: Two manganese(V)-oxo corroles [MnV(Cor)O] that differ in their electronic environments were produced by visible light irradiation of highly photo-labile corrole-manganese(IV) bromates. The corrole ligands under study include 5,10,15-tris(pentafluorophenyl)corrole (TPFC), and 5,10,15-triphenylcorrole (TPC). The kinetics of oxygen transfer atom (OAT) reactions with various organic reductants by these photo-generated MnV(Cor)O were also studied in CH3CN and CH2Cl2solutions. MnV(Cor)O exhibits remarkable solvent and ligand effect on its reactivity and spectral behavior. In the more electron-deficient TPFC system and in the polar solvent CH3CN, MnV(Cor)O returned MnIIIcorrole in the end of oxidation reactions. However, in the less polar solvent CH2Cl2or in the less electron-deficient TPC system, MnIVproduct was formed instead of MnIII. Furthermore, with the same substrates and in the same solvent, the order of reactivity of MnV(Cor)O was TPC>TPFC, which is inverted from that expected based on the electron-demand of corrole ligands. Our spectral and kinetic results in this study provide compelling evidence in favor of multiple oxidation pathways, where MnV(Cor)O may serve as direct two-electron oxidant or undergo a disproportionation reaction to form a manganese(VI)-oxo corrole as the true oxidant. The choice of pathways is strongly dependent on the nature of the solvent and the corrole ligand.
authors: Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101-1079, USA.
authors: Wai Kwong
authors: WK
authors: Ka
authors: Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101-1079, USA.
authors: Fung Lee
authors: FL
authors: Ngo
authors: Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101-1079, USA.
authors: Davis
authors: D
authors: Ranburger
authors: Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101-1079, USA.
authors: Jonathan
authors: J
authors: Malone
authors: Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101-1079, USA. Electronic address: rui.zhang@wku.edu.
authors: Rui
authors: R
authors: Zhang
mesh_terms: D008345:Manganese / Q000737:chemistry*; D010084:Oxidation-Reduction; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D011166:Porphyrins; C431863:corrole; D008345:Manganese
keywords: Corroles; Kinetics; Manganese(V)-oxo; Oxidation; Visible light