Synthesis and superoxide dismutase-like activity of new manganese(III) complexes based on tridentate N2O ligands derived from histamine

We have obtained two new manganese(III) complexes based on tridentate ligands bearing imidazole and phenol moieties. The structure of the chosen ligands favored the Mn(III) oxidation state due to the compatibility of the geometry of the complexes with a Jahn–Teller tetragonal distortion, as was shown by X-ray diffraction for one of the complexes. This induced a lowering of the oxidation potential for the Mn(III)/Mn(II) couple, which can be correlated to the superoxide dismutase-like (SOD-like) activity of the complexes, compared with a previously published Mn(III) complex.

This paper describes preparation, structural data, electrochemical investigations and SOD-like activity for two new Mn(III) complexes. The chosen tridentate N2O ligands were derived from histamine and include a phenol moiety. The electrochemical properties and the SOD-like activity were compared with a previously published Mn(III) complex based on a chemically similar ligand which was less compatible with the Jahn–Teller distortion associated to the Mn(III) state.Figure optionsDownload as PowerPoint slide