Calix[4]arenes Containing Ferrocene Amide as Carboxylate Anion Receptors and Sensors

Calix[4]arene derivatives containing amide ferrocene units at the wide rim and ethyl ester groups at the narrow rim, L1-L3, were synthesized and their anion binding and sensing properties were investigated. It was found from (1)H NMR titrations that L1-L3 were able to bind selectively with carboxylate anions. Moreover, cyclic voltammetry and square wave voltammetry showed that L1-L3 were able to act as electrochemical sensors for carboxylate anions. [structure: see text]