Naphthocrown‐Strapped Calix[4]pyrroles: Formation of Self‐Assembled Structures by Ion‐Pair Recognition |
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Authors: | Dr Sung Kuk Kim Hong Gyu Lee Dr Gabriela I Vargas‐Zúñiga Dr Vincent M Lynch Prof Dr Cheal Kim Prof Dr Jonathan L Sessler |
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Institution: | 1. Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street‐Stop A5300, Austin, Texas 78712‐1224 (USA);2. Department of Fine Chemistry, Eco‐Product and Materials Education Center, Seoul National University of Technology, Seoul 139‐743 (Korea) |
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Abstract: | A new approach to the construction of self‐assembled structures is reported that is based on ion‐pair recognition. Towards this end, the calix4]pyrrole naphthocrown‐4 hybrid structures 2 and 3 were prepared. These multitopic receptors contain recognition sites for both anions and cations. On the basis of solution‐phase 1H NMR spectroscopic analysis and solid‐state single‐crystal X‐ray diffraction structural studies, it was established that receptors 2 and 3 are able to bind specific ion pairs with high selectivity via different binding modes. In the case of CsF and CsCl, the ion‐pair complexes formed from receptors 2 and 3 were found to self‐assemble to produce either linear supramolecular polymeric crystalline solids or nanotube‐like cyclic hexamers depending on the specific choice of ion pairs and crystallization solvents. Proton NMR studies provided evidence for solution‐phase self‐association in organic media. |
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Keywords: | calix[4]pyrrole cyclic hexamers ion‐pair receptors self‐assembly supramolecular polymers |
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