Calix[4]arene-dithiacrown ethers: synthesis and potentiometric membrane sensing of Hg2+

A series of calix[4]arene-dithiacrown-5 and -dithiacrown-6 compounds in cone and 1,3-alternate conformations has been synthesized. Responses of these ionophores to Hg2+ and competing metal ions were determined in solvent polymeric membrane electrodes. High potentiometric selectivity for Hg2+ over Na+ and a variety of transition and heavy metal ions was obtained.