1,3-Alternate calixarene crown-5 (1) and corresponding biscrown-5 (2) were synthesized and the complexation behavior with alkali metal ions examined. For both 1 and 2, potassium ion was selectively extracted from aqueous phase into organic phase over other alkali metal ions based on two phase extraction experiment. The complexation ratio between calixarene biscrown-5 (2), in which two crown cavities connect to the calixarene framework by 1,3-alternate fashion and potassium metal ion is found to 1:1 by proton NMR spectroscopy and extraction equilibria. Association constants (log Ka) for 1 and 2 were determined to give 2.51 and 3.49, respectively.
ASJC Scopus subject areas
- Analytical Chemistry