title: Naphthocrown-strapped calix[4]pyrroles: formation of self-assembled structures by ion-pair recognition.
abstract: A new approach to the construction of self-assembled structures is reported that is based on ion-pair recognition. Towards this end, the calix[4]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 (1) H 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.
authors: Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street-Stop A5300, Austin, Texas 78712-1224 (USA).
authors: Sung Kuk
authors: SK
authors: Kim
authors: Hong Gyu
authors: HG
authors: Lee
authors: Gabriela I
authors: GI
authors: Vargas-Zúñiga
authors: Vincent M
authors: VM
authors: Lynch
authors: Cheal
authors: C
authors: Kim
authors: Jonathan L
authors: JL
authors: Sessler
keywords: calix[4]pyrrole; cyclic hexamers; ion-pair receptors; self-assembly; supramolecular polymers