Characterisation of a coordinated imidazole as a structural model for superoxide dismutase

The copper complex [Cu(HL)](ClO4)(2).2H(2)O, where HL is N-[2-(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)ethyl]-N-(benzimidazol-2-yl)methanimine, has been prepared and characterised by X-ray crystallography and solution absorption spectroscopy. Deprotonation of the benzimidazole moiety in this complex has been investigated by electronic spectroscopy. The results show a definite shift in lambda(max) for [Cu(HL)](2+), at 632-818 nm for the deprotonated [CuL](+), in acetonitrile. This complex has been synthesised as a structural homologue to half of the enzyme Cu-Zn superoxide dismutase (SOD) which contains a bridged imidazolate moiety between the two Cu and Zn metal ions. (C) 2002 Elsevier Science B.V. All rights reserved.