Voltammetric studies for cation recognition with thiacalix[4]crown-6s

Binding properties of p-tert-butylthiacalix[4]crown-6 (TCC-6), p-tert-butylthiacalix[4]monoquinonecrown-6 (TmQC-6) and p-tert-butylcalix[4]crown-6 (CC-6) with alkali metal and alkaline earth metal ions were investigated by voltammetry. Their behavior is closely related to the complex formation by entrapping individual metal ion into the cavity of host molecules. All three calix[4]crown-6s showed better binding ability towards alkaline earth metal ions than towards alkali metal ions. Introduction of metal ions causes a significant ion–dipole interaction of two phenolic groups of calix[4]crown-6s, and induces changes in voltammetric peaks.