POTENTIOMETRIC AND SPECTROSCOPIC STUDIES OF NICKEL(II), COPPER(II) AND ZINC(II) COMPLEXES WITH SALICILIDEN 2-AMINOTHIAZOLE

Metal complexes of the divalent ions Ni, Cu and Zn with a Schiff base obtained through condensation of salicylaldehyde with 2-aminothiazole has been investigated potentiomerically and spectrophotometrivally. The stoichiometric formula of the obtained complexes are: Ni(SAT)2, Cu(SAT)2 and Zn(SAT) where: SAT = saliciliden 2-aminothiazole. The formation constants of proton-ligand and metal-ligand complexes have been determined at 25 oC and 0.1 M (NaClO4) ionic strength in 50% (V/V) ethanol - water solution. The formation constants values obtained from spectrophotometric studies are found to be consistent with those obtained from potentiometric studies. The complexation reaction in the systems investigated were demonstrated and characterized using graphical logarithmic analysis of the absorbance versus pH graph. The binary systems obeyed beer's law up to 0.21, 0.19 and 0.24 µg/ml and the molar absorptivity ɛ = 3.12 x 103, 2.16 x 103 3.80 x 103 l mol-1 cm-1 for Ni2+, Cu2+ and Zn2+ respectively.