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231223s2008 xx |||||o 00| ||eng c |
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|a 10.1002/jcc.20910
|2 doi
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|a pubmed24n0592.xml
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|a (DE-627)NLM177581255
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|a (NLM)18270959
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|a DE-627
|b ger
|c DE-627
|e rakwb
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|a eng
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|a Chandra, Asit K
|e verfasserin
|4 aut
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|a Blue shifts of the C-H stretching vibrations in hydrogen-bonded and protonated trimethylamine. Effect of hyperconjugation on bond properties
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|c 2008
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|a Text
|b txt
|2 rdacontent
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|a ƒaComputermedien
|b c
|2 rdamedia
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|a ƒa Online-Ressource
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|2 rdacarrier
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|a Date Completed 15.07.2008
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|a Date Revised 15.11.2012
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|a published: Print
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|a Citation Status MEDLINE
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|a (c) 2008 Wiley Periodicals, Inc.
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|a The optimized geometry of isolated trimethylamine (TMA), its hydrogen bond complexes with phenol derivatives and protonated TMA is calculated at the B3LYP/6-31++G(d,p) level. A natural bond orbital (NBO) analysis on these systems is carried out at the same level of theory. In isolated TMA, one of the C-H bond in each of the three CH(3) groups is more elongated than the two other ones. As revealed by the NBO data, this results from a hyperconjugative interaction from the N lone pair to the sigma*(C-H) orbitals of the C-H bonds being in a transoid position with respect to the N lone pair. The formation of an intermolecular OH...N hydrogen bond with phenols results in a decrease of the lone pair effect. A linear correlation is found between the decrease in occupation of the sigma*(C-H) orbitals and the decrease in the hyperconjugative interaction energy in the complexes and isolated TMA. Complex formation with phenols results in a blue shift of 55-74 cm(-1) of the C-H stretching vibrations involved in the lone pair effect. Smaller blue shifts between 14 and 23 cm(-1) are predicted for the other C-H bonds. In these complexes, a linear correlation is found between the frequency shifts and the elongation of the C-H bonds. Protonation of TMA results in a nearly equalization of all the C-H distances and a blue shift of 180 cm(-1) of the C-H bonds involved in hyperconjugation with the N lone pair
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|a Journal Article
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|a Research Support, Non-U.S. Gov't
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|a Methylamines
|2 NLM
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|a Phenols
|2 NLM
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|a Protons
|2 NLM
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|a trimethylamine
|2 NLM
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|a LHH7G8O305
|2 NLM
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|a Parveen, Salma
|e verfasserin
|4 aut
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|a Das, Subojit
|e verfasserin
|4 aut
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|a Zeegers-Huyskens, Thérèse
|e verfasserin
|4 aut
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|i Enthalten in
|t Journal of computational chemistry
|d 1984
|g 29(2008), 9 vom: 15. Juli, Seite 1490-6
|w (DE-627)NLM098138448
|x 1096-987X
|7 nnns
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| 773 |
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|g volume:29
|g year:2008
|g number:9
|g day:15
|g month:07
|g pages:1490-6
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|u http://dx.doi.org/10.1002/jcc.20910
|3 Volltext
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