Conductometric Study of Complex Formation Between Cu (II) Ion and 2-hydroxyimino-3-(2'-hydazonopyridyl)-butane (HL)

Abstract

<b> </b>The association constant ,formation constants and Gibbs free energies are calculated from the conductometric titration curves of CuCl<SUB>2</SUB> with 2-hydroxyimino-3-(2’-hydazonopyridyl)-butane (HL) in absolute ethanol at different temperatures( 293.15 K , 298.15 K , 303.15 K and 308.15 k). On drawing the relation between molar conductance and the ratio of metal to ligand concentrations, different lines are obtained indicating the formation of 1:2 , 1:1 and 2:1 (M:L) stoichiometric complexes. The formation constants of different complexes in absolute ethanol follow the order: K<SUB>f</SUB> (2:1) > K<SUB>f </SUB>(1:1) > K<SUB>f</SUB> (1:2) for (M: L). As the temperature increases, the formation constants and association constants of different complexes increase. The enthalpy and entropy of formation and association of CuCl<SUB>2</SUB> with HL were also estimated and their values were also discussed. The solvation free energies (∆G<SUB>s</SUB>) ,Enthalpy changes of solvation (∆H<SUB>s</SUB>)and the entropy of salvation (∆S<SUB>s</SUB>) were also calculated from solubility measurements for 2-hydroxyimino-3-(2- hydrazonopyridyl)-butane (HL) at different temperatures (293.15 K,298.15 K,303.15 K and 308.15 K).