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- Publisher Website: 10.1021/ja012654t
- Scopus: eid_2-s2.0-0037165719
- PMID: 11960422
- WOS: WOS:000175088600003
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Article: Reversing a rotaxane recognition motif: Threading oligoethylene glycol derivatives through a dicationic cyclophane
Title | Reversing a rotaxane recognition motif: Threading oligoethylene glycol derivatives through a dicationic cyclophane |
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Authors | |
Issue Date | 2002 |
Citation | Journal of the American Chemical Society, 2002, v. 124, n. 16, p. 4174-4175 How to Cite? |
Abstract | An already well-established recognition motif-namely one in which the NH2+ centers in the rod sections of the dumbbell components of rotaxanes are encircled by macrocyclic polyether components-has been turned simultaneously outside-in and inside-out, a fact that has been proved beyond any doubt by the stoppering of both ends of a [2]pseudorotaxane to give a stable [2]rotaxane. The [2]pseudorotaxane is formed in nitromethane when a benzylic dibromide, obtained after reacting an excess of 1,4-bis(bromomethyl)benzene with hexaethylene glycol, is added to an equimolar amount of a dicationic cyclophane in which two -CH2OCH2- chains link a pair of dibenzylammonium ions through the para positions on their phenyl rings. When the [2]pseudorotaxane is reacted in nitromethane with triphenylphosphine, a [2]rotaxane and the corresponding free dumbbell compound are isolated in 58 and 31% yields, respectively. The structure of the [2]rotaxane is established by using mass spectrometry (FABMS and ESMS) and NMR (1H and 13C) spectroscopy in nitromethane-d3. The [2]rotaxane exhibits quite dramatic changes in the 1H chemical shifts of the signals for its CH2N+ and CH2O protons compared with those in the free dumbbell compound. The 1H NMR spectrum of the [2]pseudorotaxane shows many similar features. Titration experiments with three of the six different CH2O probes give an average Ka value of 2900 ± 750 M-1 in nitromethane-d3. The new recognition motif for the template-directed synthesis of rotaxanes can now be exploited at both the molecular and macromolecular levels of structure with numerous potential applications in sight. Copyright © 2002 American Chemical Society. |
Persistent Identifier | http://hdl.handle.net/10722/332522 |
ISSN | 2021 Impact Factor: 16.383 2020 SCImago Journal Rankings: 7.115 |
ISI Accession Number ID |
DC Field | Value | Language |
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dc.contributor.author | Chiu, Sheng Hsien | - |
dc.contributor.author | Stoddart, J. Fraser | - |
dc.date.accessioned | 2023-10-06T05:12:10Z | - |
dc.date.available | 2023-10-06T05:12:10Z | - |
dc.date.issued | 2002 | - |
dc.identifier.citation | Journal of the American Chemical Society, 2002, v. 124, n. 16, p. 4174-4175 | - |
dc.identifier.issn | 0002-7863 | - |
dc.identifier.uri | http://hdl.handle.net/10722/332522 | - |
dc.description.abstract | An already well-established recognition motif-namely one in which the NH2+ centers in the rod sections of the dumbbell components of rotaxanes are encircled by macrocyclic polyether components-has been turned simultaneously outside-in and inside-out, a fact that has been proved beyond any doubt by the stoppering of both ends of a [2]pseudorotaxane to give a stable [2]rotaxane. The [2]pseudorotaxane is formed in nitromethane when a benzylic dibromide, obtained after reacting an excess of 1,4-bis(bromomethyl)benzene with hexaethylene glycol, is added to an equimolar amount of a dicationic cyclophane in which two -CH2OCH2- chains link a pair of dibenzylammonium ions through the para positions on their phenyl rings. When the [2]pseudorotaxane is reacted in nitromethane with triphenylphosphine, a [2]rotaxane and the corresponding free dumbbell compound are isolated in 58 and 31% yields, respectively. The structure of the [2]rotaxane is established by using mass spectrometry (FABMS and ESMS) and NMR (1H and 13C) spectroscopy in nitromethane-d3. The [2]rotaxane exhibits quite dramatic changes in the 1H chemical shifts of the signals for its CH2N+ and CH2O protons compared with those in the free dumbbell compound. The 1H NMR spectrum of the [2]pseudorotaxane shows many similar features. Titration experiments with three of the six different CH2O probes give an average Ka value of 2900 ± 750 M-1 in nitromethane-d3. The new recognition motif for the template-directed synthesis of rotaxanes can now be exploited at both the molecular and macromolecular levels of structure with numerous potential applications in sight. Copyright © 2002 American Chemical Society. | - |
dc.language | eng | - |
dc.relation.ispartof | Journal of the American Chemical Society | - |
dc.title | Reversing a rotaxane recognition motif: Threading oligoethylene glycol derivatives through a dicationic cyclophane | - |
dc.type | Article | - |
dc.description.nature | link_to_subscribed_fulltext | - |
dc.identifier.doi | 10.1021/ja012654t | - |
dc.identifier.pmid | 11960422 | - |
dc.identifier.scopus | eid_2-s2.0-0037165719 | - |
dc.identifier.volume | 124 | - |
dc.identifier.issue | 16 | - |
dc.identifier.spage | 4174 | - |
dc.identifier.epage | 4175 | - |
dc.identifier.isi | WOS:000175088600003 | - |