Oxygen-Atom Transfer by a Naked Manganese(V)-Oxo-Porphyrin Complex Reveals Axial Ligand Effect

A ligand-free Manganese(V)-oxo-porphyrin complex generating a naked species in the gas phase and performing efficient oxygen-atom-transfer (OAT) to an array of sampled olefins was obtained. The naked Manganese(V)-oxo-porphyrin cation is obtained in the gas phase by electrospray ionization (ESI) of a solution prepared by controlled treatment of the porphynatomanganese(III) chloride with iodosylbenzene in methanol at -20°C. A high-resolution mass spectrum shows the isotropic peak cluster centered at 1043.0116, as expected for the neat addition of an oxygen atom to the reagent ion at 1027.0148. The overall ion population at 1043 is depleted of the reactive fraction by admitting β-pinene into the ion path leading to the cell.