Conductance Study of the Thermodynamics of Dibenzo-21-crown-7 Complexes with Na~+,K~+,Rb~+and Cs~+Ions in Acetonitrile Solution

摘要

A conductance study of the interaction between Na~+,K~+,Rb~+and Cs~+ions and dibenzo-21-crown-7 in acetonitrile solution has been carried out at various temperatures.The formation constants of the resulting 1:1 complexes were determined from the molar conductance-mole ratio data and,in the entire temperature range,found to vary in the order Rb~+> K~+> Cs~+> Na~+.The enthalpy and entropy of complexation reactions were determined from the temperature dependence of the formation constants.In all cases,the resulting complexes were found to be both enthalpy and entropy stabilized.