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

The association constant ,formation constants and Gibbs free energies are calculated from the conductometric titration curves of CuCl2 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: Kf (2:1) > Kf (1:1) > Kf (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 CuCl2 with HL were also estimated and their values were also discussed. The solvation free energies ( Gs) ,Enthalpy changes of solvation ( Hs)and the entropy of salvation ( Ss) 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).