Some novel manganese(III) porphyrins with catalytic properties

A series of manganese(III) porphyrins with 4-methylimidazole have been prepared. These are high-spin complexes having general formula [Mn^III(THMPP)X(4-MeIm)], where THMP = 5,10,15,20-tetra(4-hydroxy-3-methoxyphenyl)porphine ligand, X = Cl⁻, Br⁻, NCS⁻, or N₃⁻ and 4-MeIm = 4-methylimidazole. All the complexes have been characterized by UV-visible, FT-IR, ESI-MS spectra, elemental analyses and magnetic susceptibility measurements. These manganese(III) porphyrins oxidize aromatic alcohols to aldehydes. The oxidation reactions have been carried out at room temperature in the presence of oxidants such as NaIO₄, H₂O₂, and NaOCl. The comparative studies proved that NaIO₄ behaves as the most efficient oxidant in these oxidative transformation reactions.