1,3-Dialkoxycalixarene dibenzocrown ethers (6-9) were successfully synthesized in the fixed 1,3-alternate conformation, with greater than 90% yields by reaction of the corresponding 1,3-dialkoxycalixarenes 2-5 with dibenzodimesylate 13 in acetonitrile as a solvent in the presence of cesium carbonate as a base. In view of the cyclization yield, dimesylate is better than dibenzoditosylate. Because of an unusual AB pattern in the 1H NMR spectrum for compound 9, it is suggested that the conformational structure of 1,3-diallyloxy calixarene dibenzocrown ether is less flexible than that of usual 1,3-alternate calixcrown ether, probably due to steric effects of two allyl groups. Complexation of the corresponding calixarene ethers 6-9 to alkali metal ions using the single-flux method through a bulk liquid membrane system was found to give high cesium selectivity.
ASJC Scopus subject areas
- Analytical Chemistry