Bisbenzimidazole diamide copper(II) complexes and their reactivity towards superoxide

Department of Chemistry, University of Delhi, Delhi-110 007, India
E-mail : pavanmat@yahoo.co.in
Manuscript received 6 June 2005

A benzimidazole-based diamide ligand N,N' -bis(2-benzimidazolylmethyl)propane diamide (GBMA) and N,N' -bis(N-ethyl-2-benzimidazolylmethyl)hexane diamide (E-GBHA) have been synthesized and utilized to prepare copper(II) complexes of general composition [Cu(L)X]X, where X = Cl^-, NO^-₃, SCN^- and L = GBMA, E-GBHA. The EPR spectra reveal the presence of distorted tetragonal copper site in the complexes with g_‖ > g_ꓕ > 2. The complexs display a quasireversible redox wave due to the Cu^II/Cu^I redox couple with E_½ varying in the order Cl^- < NO^-₃ = SCN^-. The copper(ll) complexes react by quenching of superoxide radical generated electrochemically.