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Abstract
Proton ligand association constants of 1 benzoyl(1,2,4 triazol 3 yl) thiourea (BTTU) and its complex formation constants with some metal ions diorganotin(IV), Ni (II), Co (II), Mn(II), Zn (II) and Cu(II) have been determined potentiometrically in 50% EtOH - H O and 0.1 M NaNO. In solutions the 2 3 complexes formed are of stoichiometry 1 : 1 and 1 : 2 [M: L], where M represents the metal ion, while L represents the ligand BTTU. The corresponding thermodynamic parameters are derived and discussed. The complexes are stabilized by enthalpy changes and the results suggested that the complexation is an enthalpy-driven process. The effect of metal ion, ionic radius, electronegativity and ionization potential on the formation constants is discussed. The formation constants of the complexes with 3d transition metals follow the order: Mn2 + < Co2 + < Ni2 + < Cu2 + > Zn2 +. The metal complexes have been synthesized and characterized by elemental analyses, conductance, IR, 1H NMR and magnetic measurements. The concentration distribution diagrams of the complexes are evaluated. The ligand and its metal complexes have been screened in vitro against some bacteria and fungi