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- Publisher Website: 10.1002/(SICI)1099-0690(199904)1999:4<899::AID-EJOC899>3.0.CO;2-C
- Scopus: eid_2-s2.0-0032839117
- WOS: WOS:000079499800022
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Article: Molecular meccano, 48 [(+)] - Probing co-conformational changes in chiral [2]rotaxanes by 1H-NMR spectroscopy
Title | Molecular meccano, 48 [(+)] - Probing co-conformational changes in chiral [2]rotaxanes by 1H-NMR spectroscopy |
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Authors | |
Keywords | Co-conformation Molecular recognition Planar chirality Rotaxanes Template-directed synthesis |
Issue Date | 1999 |
Citation | European Journal of Organic Chemistry, 1999, n. 4, p. 899-908 How to Cite? |
Abstract | The template-directed syntheses of three [2]rotaxanes possessing either chiral centers or elements of planar chirality, in one of their two mechanically interlocked components, have been realized and their solid-state structures have been analyzed by X-ray crystallography. In one instance, an enantiomerically pure dumbbell-shaped component incorporating a 1,5- dioxynaphthalene recognition site and two (1R,2S,5R)-menthyl stoppers was employed to template the formation of the achiral tetracationic cyclophane, cyclobis(paraquat-p-phenylene). The resulting enantiomerically pure [2]rotaxane was isolated in a yield of 55%. In the other two instances, an achiral 1,5-dioxynaphthalene-based dumbbell-shaped component was employed to template the formation of bipyridinium-based cyclophanes possessing either one or two elements of planar chirality. The resulting [2]rotaxane, possessing one element of planar chirality, was isolated as a racemate in a yield of 24%. The related [2]rotaxane, possessing two elements of planar chirality, was isolated as a mixture of a meso form and an enantiomeric pair in an overall yield of 28%. The 1H-NMR-spectroscopic analysis of this mixture revealed a diastereoisomeric ratio of 4:1. A degenerate coconformational change was identified by variable-temperature 1H-NMR spectroscopy in all [2]rotaxanes. The symmetry loss arising from the introduction of one or two elements of planar chirality enabled the elucidation of the mechanism of this dynamic process in two instances. |
Persistent Identifier | http://hdl.handle.net/10722/333588 |
ISSN | 2023 Impact Factor: 2.5 2023 SCImago Journal Rankings: 0.584 |
ISI Accession Number ID |
DC Field | Value | Language |
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dc.contributor.author | Ashton, Peter R. | - |
dc.contributor.author | Bravo, José A. | - |
dc.contributor.author | Raymo, Françisco M. | - |
dc.contributor.author | Stoddart, J. Fraser | - |
dc.contributor.author | White, Andrew J.P. | - |
dc.contributor.author | Williams, David J. | - |
dc.date.accessioned | 2023-10-06T05:20:49Z | - |
dc.date.available | 2023-10-06T05:20:49Z | - |
dc.date.issued | 1999 | - |
dc.identifier.citation | European Journal of Organic Chemistry, 1999, n. 4, p. 899-908 | - |
dc.identifier.issn | 1434-193X | - |
dc.identifier.uri | http://hdl.handle.net/10722/333588 | - |
dc.description.abstract | The template-directed syntheses of three [2]rotaxanes possessing either chiral centers or elements of planar chirality, in one of their two mechanically interlocked components, have been realized and their solid-state structures have been analyzed by X-ray crystallography. In one instance, an enantiomerically pure dumbbell-shaped component incorporating a 1,5- dioxynaphthalene recognition site and two (1R,2S,5R)-menthyl stoppers was employed to template the formation of the achiral tetracationic cyclophane, cyclobis(paraquat-p-phenylene). The resulting enantiomerically pure [2]rotaxane was isolated in a yield of 55%. In the other two instances, an achiral 1,5-dioxynaphthalene-based dumbbell-shaped component was employed to template the formation of bipyridinium-based cyclophanes possessing either one or two elements of planar chirality. The resulting [2]rotaxane, possessing one element of planar chirality, was isolated as a racemate in a yield of 24%. The related [2]rotaxane, possessing two elements of planar chirality, was isolated as a mixture of a meso form and an enantiomeric pair in an overall yield of 28%. The 1H-NMR-spectroscopic analysis of this mixture revealed a diastereoisomeric ratio of 4:1. A degenerate coconformational change was identified by variable-temperature 1H-NMR spectroscopy in all [2]rotaxanes. The symmetry loss arising from the introduction of one or two elements of planar chirality enabled the elucidation of the mechanism of this dynamic process in two instances. | - |
dc.language | eng | - |
dc.relation.ispartof | European Journal of Organic Chemistry | - |
dc.subject | Co-conformation | - |
dc.subject | Molecular recognition | - |
dc.subject | Planar chirality | - |
dc.subject | Rotaxanes | - |
dc.subject | Template-directed synthesis | - |
dc.title | Molecular meccano, 48 [(+)] - Probing co-conformational changes in chiral [2]rotaxanes by 1H-NMR spectroscopy | - |
dc.type | Article | - |
dc.description.nature | link_to_subscribed_fulltext | - |
dc.identifier.doi | 10.1002/(SICI)1099-0690(199904)1999:4<899::AID-EJOC899>3.0.CO;2-C | - |
dc.identifier.scopus | eid_2-s2.0-0032839117 | - |
dc.identifier.issue | 4 | - |
dc.identifier.spage | 899 | - |
dc.identifier.epage | 908 | - |
dc.identifier.isi | WOS:000079499800022 | - |