Deoxygenation of Nitroxyl Radicals by Oxorhenium(V) Complexes with Redox-Active Ligands

Five-coordinate oxorhenium(V) anions with redox-active catecholate ligands deoxygenate stable nitroxyl radicals, including TEMPO•, to afford dioxorhenium(VII) complexes and aminyl radical-derived products. A structural homologue with redox-inert oxalate ligands does not react with TEMPO•. Redox-active ligands are proposed to lower the kinetic barrier to TEMPO• deoxygenation by giving access to 1e− redox steps that are crucial for the formation and stabilization of intermediate species.