One-step synthesis of a singly bridged biscalix[6]arene and evaluation of its alkali metal recognition properties

This article describes one-step synthesis of a singly bridged biscalix[6]arene ( 2 ) and evaluation of its recognition properties towards alkali metal ions for the first time. Synthesis of 2 was accomplished through coupling of two 4-tert-butylcalix[6]arene units with one molecule of diethyleneglycol ditosylate. Both base and linker were found to play a role in the outcome of coupling reaction for the simple and efficient synthesis of 2 . Complexation ability of 2 was studied by liquid-liquid extraction using alkali metal (Na +, K +, Cs +) picrates. Carrier activity of 2 towards the facilitated transport of alkali metal ions across a bulk liquid membrane was also studied and the transport behaviour was mechanistically explained. The predominant role of an ion exchange action mechanism in the transport process was observed.