Equilibrium studies on mixed-ligand mixed-metal complexes of copper(II), nickel(II) and zinc(II) with glycylvaline and imidazole

361-367Imidazolate bridged homo/hetero binuclear complexes of copper(II), nickel(II) and zinc(II) formed with glycylvalinate have been studied by pH-metry, EPR and visible absorption spectrometry in aqueous medium at 25 ± 1o and I= 0.1 M NaClO4 . The experimental data have been obtained for the following species (A-= glycylvalinate and B=imidazole):M2+,AH2+ , AH, A-, BH+, B , M(OH)+, M(OH)2, M(A)+, M(A)(OH), M(B)2+,M(A)(B)+, M2(A)2B2+, M2(A)2(B -H)+ M1M2(A)(B)2+ and M1M2(A)2(B-H)+. The anion (B-H)- provides (N1-, N3) bridging bidentate co-ordination in M2(A)2(B -H)+and M1M2(A)2(B-H)+ complexes