Study of the competitive binding of mixed alkali and alkaline earth metal ions with dibenzo-30-crown-10

Selectivity towards Na+, K+, Ca2+ and Mg2+ from their equimolar mixture and also from bittern with DB30C10 and the extraction equilibrium constant for K+ with the same ligand has been estimated by a two-phase extraction method. Results have been rationalized on the basis of the crystal structure of [K-DB30C10][picrate] and molecular mechanics calculations.