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E-Journal of Chemistry
Volume 5 (2008), Issue 3, Pages 551-556
http://dx.doi.org/10.1155/2008/364510

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

Mohammad Hakimi,1 Azizollah Nezhadali,1 and Asghar Naemi2

1Department of Chemistry, Payame Noor University (PNU), Fariman, Iran
2Department of Chemistry, Payame Noor University (PNU), Mashhad, Iran

Received 1 October 2007; Revised 9 January 2008; Accepted 5 March 2008

Copyright © 2008 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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. ࢞G0 of the studied complexes were evaluated at 25°C using thermodynamic relations, the negative values of ࢞G0 means that the complexation process is spantaneously.