Selective Complexation of Hg2+ by Biscalix[4]arene Nitriles

Ionophoric biscalix[4]arenyl nitriles in which the lower rims are linked via a single site on each calixarene were synthesized. Their complexing abilities were studied by the liquid-liquid extraction of alkali (Li+, Na+, K+, and Cs+) and selected transition metal (Cu2+, Co2+,Cd2+, Ni2+, and Hg2+) cations. We found a novel selectivity of these compounds toward Hg+2 cations through examination of the extraction.