Mixed-ligand copper(II) complexes with diethylenetriamine and histidine- or methioninehydroxamic acids in water solution

Abstract

Stability of the mixed-ligand complexes of Cu 2+ ion with diethylenetriamine [bis(2-aminoethyl)amine, dien] as a primary ligand and histidinehydroxamic acid [2-amino-3-(4′-imidazolyl)propanehydroxamic acid, Hisha] or methioninehydroxamic acid [2-amino-4-(methylthio)butanehydroxamic acid, Metha] as a secondary ligand L and their absorption and EPR spectra at various pH values are reported. The visible spectra exhibit a characteristic red shift and a shoulder at lower energies indicating a five-co-ordinate structure of the formed complexes. The EPR spectral parameters support formation of mixed-ligand complexes which geometry is slightly deviated from square pyramidal.