Complexation Study of N-Phenylaza-15-Crown-5 with Cd2+ Cation in Binary Mixed Non-aqueous Solvents

Abstract

The complexation reaction of N-phenylaza-15-crown-5 (PhA15C5) with Cd²⁺ cation was studied in acetonitrile-methanol, acetonitrile-butanol, acetonitrile-ethylacetate, acetonitrile-nitromethane and methanol-propylencarbonate binary solvent solutions, at different temperatures by conductometric method. The stability constant of the resulting 1:1 complex at each temperature was determined using a computer fitting conductance-mole ratio data. A non-linear relationship was observed for changes of log K_f of (PhA15C5.Cd)²⁺ complex versus the composition of the binary mixed solvents. The corresponding standard thermodynamic parameters (DHº_c, DSº_c) were obtained from temperature dependence of the stability constant. The results show that the complexation reaction is enthalpy destabilized but entropy stabilized.