Source:http://linkedlifedata.com/resource/pubmed/id/15609933
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
26
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| pubmed:dateCreated |
2004-12-21
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| pubmed:abstractText |
A combination of electronic, structural, and energetic analyses shows that a somewhat larger intrinsic donor ability of the C-H bonds compared to that of C-C bonds can be overshadowed by cooperative hyperconjugative interactions with participation of remote substituents (double hyperconjugation or through-bond interaction). The importance of double hyperconjugation was investigated computationally using two independent criteria: (a) relative total energies and geometries of two conformers ("hyperconjomers") of delta-substituted cyclohexyl cations (b) and natural bond orbital (NBO) analysis of electronic structure and orbital interactions in these molecules. Both criteria clearly show that the apparent donor ability of C-C bonds can vary over a wide range, and the relative order of donor ability of C-H and C-C bonds can be easily inverted depending on molecular connectivity and environment. In general, relative donor abilities of sigma bonds can be changed by their through-bond communication with remote substituents and by greater polarizability of C-X bonds toward heavier elements. These computational results can be confirmed by experimental studies of conformational equilibrium of delta-substituted cyclohexyl cations.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Dec
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| pubmed:issn |
0022-3263
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
24
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| pubmed:volume |
69
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
9011-24
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| pubmed:year |
2004
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| pubmed:articleTitle |
Effect of double-hyperconjugation on the apparent donor ability of sigma-bonds: insights from the relative stability of delta-substituted cyclohexyl cations.
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| pubmed:affiliation |
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA. alabugin@chem.fsu.edu
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| pubmed:publicationType |
Journal Article
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