Acid−Base Controllable Molecular Shuttles
| Autor: | Marcos Gómez-López, Margherita Venturi, J. Fraser Stoddart, M. Victoria Martínez-Díaz, Roberto Ballardini, Neil Spencer, David J. Williams, Maria Teresa Gandolfi, Matthew C. T. Fyfe, and Andrew J. P. White, Arianna Piersanti, Ian Baxter, Peter R. Ashton, Alberto Credi, Vincenzo Balzani |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Journal of the American Chemical Society. 120:11932-11942 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja982167m |
| Popis: | Two novel [2]rotaxanes, comprised of a dibenzo[24]crown-8 (DB24C8) macroring bound mechanically to a chemical “dumbbell” possessing two different recognition sitesviz., secondary dialkylammonium (NH2+) and 4,4‘-bipyridinium (Bpym2+) unitshave been synthesized by using the supramolecular assistance to synthesis provided by, inter alia, hydrogen bonding interactions. One of these rotaxanes bears a fluorescent and redox-active anthracene (Anth) stopper unit. NMR spectroscopy and X-ray crystallography have demonstrated that the DB24C8 macroring exhibits complete selectivity for the NH2+ recognition sites, i.e., that the [2]rotaxanes exist as only one of two possible translational isomers. Deprotonation of the rotaxanes' NH2+ centers effects a quantitative displacement of the DB24C8 macroring to the Bpym2+ recognition site, an outcome that can be reversed by acid treatment. The switching processes have been investigated by 1H NMR spectroscopy and, for the Anth-bearing rotaxane, by electrochemical and photophys... |
| Databáze: | OpenAIRE |
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