Thermodynamics of the complexation between salicylaldehyde thiosemicarbazone with Cu(II) ions in methanol-1,4-dioxane binary solutions

Abstract

The complexation reaction between salicylaldehyde thiosemicarbazone, abbreviated as STSC, with Cu(II) ion was studied in binary mixtures of methanol-1,4-dioxane using UV-Vis spectrophotometric and conductometric methods at different temperatures. The formation constants (Kf) for the 1:1 complex, Cu(II)-STSC, were calculated from computer fitting of the absorbance and molar conductance data against various concentrations ratios (cM:cL or cL:cM) in different binary solvent mixtures. A non-linear correlation was observed for the variation of log Kf for the complex against the solvent compositions. Various thermodynamic parameters (?H, ?S and ?G) for the formation of the Cu(II)-STSC complex were also determined from the temperature dependence of the formation constants (Kf). The results showed that the complexation reaction is affected by the nature and composition of the mixed solvents. © 2014 SCS. All rights reserved.