Bis(imidazolium) salts derived from amino acids as receptors and transport agents for chloride anions

The binding properties of bis(imidazolium) hosts 1a-c derived from amino acids towards different anions have been studied by H-1 NMR titration experiments in 95 : 05 CD3CN : H2O at 303 K, ESI-MS and theoretical calculations. Among this family, the salt 1c showed a strong and high selectivity for chloride anions. Transmembrane chloride transport activity has also been studied for the three bis(imidazolium) based transporters in POPC liposome models, and compound 1a was identified as an active chloride/nitrate exchanger.