Synthesis and metal ion complexation studies of proton-ionizable calix[4]azacrown ethers in the 1,3-alternate conformation

Jong Seung Kim, Ok Jae Shon, Jong Won Ko, Moon Hwan Cho, Ill Yong Yu, Jacques Vicens

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A series of novel N-chromogenic calix[4]arene azacrown ethers were synthesized as selective extractants of potassium ion. 1,3-Alternate calix[4]arene azacrown ethers were prepared by reacting 25,27-dipropyloxy- 26,28-bis(5-chloro-3-oxapentyloxy) calix[4]arenes with p-toluenesulfonamide in the presence of potassium carbonate. The coupling reaction of calix[4]arene azacrown ether with 2-hydroxy-5-nitrobenzyl bromide in the presence of triethylamine in THF gave the chromogenic calix[4]arene azacrown ether in moderate yield. These compounds show high potassium selectivity over other metal ions as shown by two-phase extraction, bulk liquid membrane, and 1H NMR studies on a ligand-metal complex. It is assumed that the OH of the chromogenic group attached on nitrogen can assist the complexation by encapsulation of the metal.

Original languageEnglish
Pages (from-to)2386-2392
Number of pages7
JournalJournal of Organic Chemistry
Issue number8
Publication statusPublished - 2000 Apr 21
Externally publishedYes


ASJC Scopus subject areas

  • Organic Chemistry

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