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Thiacalix[4]arene Derivatives Bearing Imidazole Units: A Ditopic Hard/Soft Receptor for Na + and K + /Ag + with an Allosteric Effect and a Reusable Extractant for Dichromate Anions
Author(s) -
Zhao JiangLin,
Wu Chong,
Zeng Xi,
Rahman Shofiur,
Georghiou Paris E.,
Elsegood Mark R. J.,
Warwick Mr. Thomas G.,
Redshaw Carl,
Teat Simon J.,
Yamato Takehiko
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600245
Subject(s) - imidazole , chemistry , titration , proton nmr , aqueous solution , stereochemistry , medicinal chemistry , allosteric regulation , metal ions in aqueous solution , tetra , ion , crystallography , receptor , organic chemistry , biochemistry
Abstract Two novel receptors 5,11,17,23‐tetra‐tert‐butyl‐25,27‐bis[(ethoxycarbonyl)methoxy]‐26,28‐bis‐[1‐methyl‐(imidazole)meth‐oxy]‐2,8,14,20‐tetra‐thiacalix[4]arene ( L1 ) and 5,11,17,23‐tetra‐tert‐butyl‐25,27‐bis‐[(benzyl)methoxy]‐26,28‐bis‐[1‐methyl‐(imidazole)‐methoxy]‐2,8,14,20‐tetrathiacalix[4]arene ( L2 ) possessing imidazole moieties based on thiacalix[4]arene in the 1,3‐ alternate conformation have been synthesized and characterized. The crystal structures of L1 and L2 have been determined. The binding behaviour towards Li + , Na + , K + and Ag + ions has been examined by 1 H NMR titration experiments in (CDCl 3 /CD 3 CN; 10:1, v/v) solution. The exclusive formation of mononuclear complexes of L1 with metal cations is of particular interest revealing a negative allosteric effect in the thiacalix[4]arene family. Liquid‐liquid extraction experiments indicate that synthesized L2 can be utilized as an efficient reusable extractant for dichromate anion by controlling the pH of the aqueous solution.