SYNTHESIS, CHARACTERIZATION AND DEMONSTRATION OF SUPEROXIDE DISMUTASE-LIKE ACTIVITY OF COPPER(II) CHLORIDE, BROMIDE, NITRATE, THIOCYANATE, SULFATE, AND PERCHLORATE COMPLEXES WITH 2-METHYL-AMINO PYRIDINE

A number of copper(II) complexes containing 2-methyl amino pyridine an d various anions (Cl-, Br-, NO3-, SCN-, ClO4-, or SO42-) have been syn thesized and characterized by elemental analysis, X-ray powder diffrac tion, IR, and electronic spectra. Molar conductivity and magnetic mome nt measurements were also employed. A square-pyramidal structure is pr oposed for the complexes in which chloride, bromide, nitrate, thiocyan ate, or sulphate is attached to the metal ion in 1:2 (metal:ligand) st oichiometry. In the case of perchlorate complex, the molar conductivit y and spectral data together suggest a square planar environment aroun d the copper(II) ion. The catalytic activity of the prepared copper(II ) complexes towards the superoxide anion O-2(-) dismutation were assay ed by their ability to inhibit the reduction of nitroblue tetrazolium (NET). The catalytic efficiency of O-2(-) scavenging by complexes depe nds on the particular acidic anion radical bound to the Cu(II) ion in complex and follows the order SO4 > SCN > NO3 > ClO4 > Br greater than or equal to Cl. The kinetic investigations reveal that the rate of O- 2(-) dismutation has a first-order dependence with respect to O-2(-) a nd catalyst concentration. In addition, the rate constant of the catal ytic dismutation of O-2(-) varied between 2.8 x 10(5) and 5.9 x 10(6) mol(-1). S-1, depending on the nature of complex.