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 1H NMR titration experiments in (CDCl3/CD3CN; 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.
Two novel receptors possessing imidazole moieties based on thiacalix[4]arene in the 1,3‐alternate conformation have been synthesized and characterized. The exclusive formation of mononuclear complexes of di‐topic hard/soft receptor L1 with metal cations is of particular interest revealing a negative allosteric effect. Liquid‐liquid extraction experiments indicate that synthesized mono‐topic receptor L2 can be utilized as an efficient reusable extractant for dichromate anion by controlling the pH of the aqueous solution.