Calorimetric determination of the thermodynamic properties involved in the complex formation of silver(I) with some sulphur-containing pyridines

Abstract

The enthalpy changes involved in the complex formation of Ag + with several sulphur-containing pyridines of general formula ▪ where R = Ch 3, C 2H 5 and CH 2CH 2OH and x=1,2 have been determined by direct calorimetric measurements at 25°C in 0.5 M KNO 3 solution. From the Δ H values obtained and from the free energy changes reported in an earlier publication, the corresponding entropy changes Δ S have been calculated. Changes in Δ H and Δ S are discussed in terms of inductive and steric effects. It is shown that enthalpy values are linearly correlated with the Taft σ * parameters of the substituents on the ligand.