Calixarene bis(dibenzocrown) ethers 3 and 4 were successfully synthesized in the fixed 1,3-alternate conformation in over 70% yield via the reaction of calixarene with dibenzo dimesylates 6 and 7, respectively, in acetonitrile in the presence of caesium carbonate as base. Exhibiting typical 1H NMR spectrum patterns, 3 and 4 are in the 1,3-alternate conformation, which is confirmed by X-ray analysis. Among four synthetic compounds tested, 3 shows the best selectivity and efficiency for a caesium ion complexation over other alkali metal ions using the single flux method through a bulk liquid membrane system. Enhancement of the complexation ability is attributable to the flatness and lipophilicity of the ethereal linkages caused by introducing the dibenzo groups on the calixarene moiety. Two phase extraction experiments using calixarene bis(crown) ethers with caesium ions are found to give a 1:1 ligand-metal complexation ratio.
|Number of pages||5|
|Journal||Journal of the Chemical Society - Perkin Transactions 1|
|Publication status||Published - 1998 Aug 7|
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