Formation Constants of Mixed Ligand Complexes of Cu (Ii), Ni(Ii), Zn(Ii) and Cd(Ii) With 2,2'-Bipyridine    

M. Alamgir Kabir* and M. Rafique Ullah

Department of Chemistry, Bangladesh University of Engineering and Technology Dhaka- 1000 (Bangladesh)

The formation constants (log KM ) of the mixed ligand complexes of the type [MAL], where M= Cu(II), Ni(II), Zn(II) and Cd(II); A = 2,2-bipyridine (bipy) and L = oxalic acid (ox), ethylenediamine (en), glycine (gly), a-aniline (a-ala), phenylalanine (ph-ala) and tyrosine (tyr) have been determined in aqueous medium at μ = 0.2 mol dm-3 (NaClO4) and 25°±1°C by using a computer program. The value of Dlog K (log KM - logKM - log KM ) is small negative or positive showing an astatistical increase in the values of mixed ligand formation constants. The cyclic voltammetry (CV) and UV-visible spectral studies have been employed to confirm the formation of mixed ligand complexes as well as trend in stability constants of mixed ligand complexes. The relative order of stability of mixed ligand complexes is as follows- [Cd(bipy)(L)]>[Zn(bipy)(L)]>[Ni(bipy)(L)]>[Cu(bipy)(L)]

Lanthanides (III) metal ion complexes; Thiosemicarbazone derivatives