The Association and Formation Constants for CuCl2 Stoichiometric Complexes with (E)-3-(2-Benzylidene Hydrazinyl)-3-oxo-N-(thiazol-2-yl)Propanamide in Absolute Ethanol Solution at 294.15 K

The association constants and Gibbs free energies for CuCl2 with (E)-3-(2-benzylidene hydrazinyl)-3-oxo-N-(thiazol-2-yl)propanamide (H2BH) had been calculated by using the conductometric titration curves in absolute ethanol at 294.15 K. New equation was applied to determine the association constant for 1:2 asymmetric salts. Different stoichiometric complexes were obtained on drawing the relation between (/\m) and (M:L). The association free energies that were evaluated for CuCl2-ligand complexes were small and spontaneous indicating electrostatic attraction force. The formation constants and Gibbs free energies of different complexes follow that order: Kf (2:1) Kf (1:1) Kf (1:2) for (M:L), and ΔGf (2:1) ΔGf (1:1) ΔGf (1:2) for (M:L).