The complexation reactions between Tl+ ion and dibenzo-30-crown-10 (DB30C10), dibenzo-24-crown-8 (DB24C8),dibenzo-21-crown-7 (DB21C7), and aza-18-crown-6 (A18C6) were studied in different dimethylformamide-acetonitrile mixtures at various temperatures. The formation constants of the resulting 1 : 1 complexes were determined from the molar conductance-mole ratio data and found to vary in the order A18C6 > DB30C10 > DB21C7 > DB24C8. The enthalpy and entropy of complexation were determined from the temperature dependence of the formation constants
