Thermodynamic study of the binding of hexathia-18-crown-6-tetraone with some transition and heavy metal ions in dimethyl sulfoxide solution

Abstract

A conductance study of the interaction between CO2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+ and Hg2+ ions with hexathia-18-crown-6-tetraone in dimethyl sulfoxide solution has been carried out at various temperatures. Formation constants of the resulting 1:1 complexes were determined from the molar conductance–mole ratio data and found to vary in the order Hg2+>Pb2+>Cd2+>Cu2+>Ni2+>Co2+>Zn2+. The enthalpy and entropy of complexation were determined from the temperature dependence of the formation constants. All complexes formed were enthalpy stabilized but entropy destabilized.