Thermodynamics and selectivity of complexation of lithium and sodium thiocyanates with phosphorus-containing podands and compounds modeling the terminal groups of these podands

A series of model compounds and heptadentate neutral phosphorus-containing podands that differ in the conformational rigidity of the terminal groups and in the coordination properties of the phosphoryl groups were synthesized. The thermodynamic parameters of complexation and the cationic selectivity of organophosphorus compounds and podands with respect to LiNCS and NaNCS were studied by calorimetric titration in acetonitrile at 298 K. The reasons for the high selectivity of certain phosphorus-containing podands to the Li⁺ cation are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1581–1587, September, 1994.This work was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-08848) and the International Science Foundation (Grant No. MTH000).