1,3‐Alternate Tetraamido‐Azacalix[4]arenes as Selective Anion Receptors |
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| Authors: | Dr Gabriel Canard Judicaelle Andeme Edzang Zhongrui Chen Matthieu Chessé Dr Mourad Elhabiri Dr Michel Giorgi Dr Olivier Siri |
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| Institution: | 1. Centre Interdisciplinaire de Nanosciences de Marseille (CINaM), Aix Marseille Université, CNRS UMR 7325, Marseille, France), Fax;2. Laboratoire de Chimie Bioorganique et Médicinale, UMR 7509 CNRS-, Université de Strasbourg, ECPM, 25 rue Becquerel, Strasbourg Cedex, France;3. Fédération des Sciences Chimiques de Marseille-Spectropole FR 1739, Aix Marseille Université, Marseille, France;4. +33)?491418916 |
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| Abstract: | Six tetraaza1.1.1.1]cyclophane derivatives bearing peripheral amide groups were prepared according to two distinct synthetic strategies that depend on the connection pattern between the aryl units. NMR experiments combined with the X‐ray structures of two tetraamide derivatives 4 b and 10 show that these cavitands adopt a 1,3‐alternate conformation both in solution and in the solid state. Consequently, the four amide groups of the aza1.1.1.1]‐m,m,m,m‐cyclophane isomer 10 can contribute to the same recognition process towards neutral water molecules or anion guests. NMR experiments, mass spectrometry analyses and single‐crystal X‐ray structures confirm the anion‐binding ability of this receptor. Absorption spectrophotometric titrations in nonpolar solvents provided evidence for the selectivity of 10 to chloride anions in the halide series, with a corresponding association constant Ka reaching 2.5×106 m ?1. |
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| Keywords: | anions calixarenes conformation analysis host– guest systems macrocycles |
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