Synthesis, crystal structure and superoxide dismutase activity of a five-co-ordinated manganese(II) complex

A five-co-ordinate manganese(II) complex [Mn(ntb)(Hsal)][ClO4], where ntb is tris(benzimidazol-2-ylmethyl)-amine and Hsal(-) is the anion of salicyclic acid (H(2)sal), has been prepared and characterized by X-ray crystallography. The manganese adopts a distorted trigonal-bipyramidal co-ordination geometry with a N4O ligand donor set and bears structural similarities to the active site of manganese superoxide dismutase. The electrochemical properties of the complex were studied in MeCN by cyclic voltammetry. The complex can catalyse the dismutation of superoxide (O-2(-)) effectively in the riboflavin-methionine-nitro blue tetrazolium assay.