A new pentadentate ligand forms both a Di- and a mononuclear MnII complex:: Electrochemical, spectroscopic and superoxide dismutase activity studies

The X-ray crystal structure of the dinuclear complex [1(PF6)(2)] derived from a new ligand bearing both imidazole and phenolato moieties, namely N-(2-hydroxybenzyl)-N,N'-bis [2- (N-methylimidazolyl)methyl] ethane -1,2-diamine (LH), is described and its properties in organic solvent (CH3CN) investigated (EPR, electrochemistry). [1(PF6)(2)] is shown to be a mononuclear Mn-II species in aqueous solution and displays an efficient SOD-like activity, as measured by the McCord-Fridovich assay performed both in conventional phosphate buffer and in a noncoordinating buffer (PIPES). ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).