Synthesis, spectra and biomimetic properties of copper(II)-copper(II) and copper(II)-zinc(II) binuclear complexes with CuN5 chromophores

X-band electron spin resonance (ESR) and UV-vis spectra of a homobinuclear [(BiPY)(2)Cu-E-Im-Cu(Bipy)(2)](BF4)(3) and a heterobinuclear [(BiPY)(2)Cu-E-Im-Zn(Bipy)(2)](BF4)(3) complexes, E-Im = 2-ethylimidazolate ion have been described as possible models for superoxide dismutase (SOD). Magnetic moment and ESR spectral measurements of the homobinuclear complex have shown an antiferromagnetic exchange interaction. From pH-dependent ESR and UV-vis spectral measurements studies, these complexes have been found to be stable over 8.5-10.5 pH range. These complexes catalyze the dismutation of superoxide (O-2(-)) at biological pH. All the observations indicate that these complexes act as good possible models for superoxide dismutase. (c) 2004 Elsevier B.V. All rights reserved.