Conductometric study of complex formation between Cu(II) ion and 4-amino-3-ethyl-1,2,4-triazol-5-thione in binary ethanol / water mixtures

Abstract

The stability constant, Kf, for the complexation of copper(II) ion with 4-amino-3-ethyl-1,2,4-triazol-5-thione (AETT ) in 0, 20, 40, 60 and 80 (v/v) % ethanol-water mixtures were determined conductometrically at different tempratures. Stability constant of resulting 1:1 complexes were being larger by increasing of temprature and ethanol percent. Stability constants of complexes vary inversly with dielectric constant of solvents. The enthalpy and entropy of complexation were determined from the temprature dependence of the formation constant. In all cases, the complexation were found to be enthalpy unstablized but entropy stablized. ΔG0 of the studied complexes were evaluated at 250C using thermodynamic relations, the negative values of ΔG0 means that the complexation process is spantaneously.