C-H- - -O Hydrogen Bonds in -Sheetlike Networks: Combined X-ray Crystallography and High-Pressure Infrared Study
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- 作者：Kwang Ming Lee ; Hai-Chou Chang ; Jyh-Chiang Jiang ; Jack C. C. Chen ; Hsiang-En Kao ; Sheng Hsien Lin ; and Ivan J. B. Lin
- 刊名：Journal of the American Chemical Society
- 出版年：2003
- 出版时间：October 8, 2003
- 年：2003
- 卷：125
- 期：40
- 页码：12358 - 12364
- 全文大小：215K
- 年卷期：v.125,no.40(October 8, 2003)
- ISSN：1520-5126
文摘
Close interactions of the C
-H- - -O type have been analyzed via X-ray crystallography andhigh-pressure infrared spectroscopy. The results demonstrate that the C-H- - -O interactions can offeran additional stability to the 
-sheet formation. X-ray structural data suggest that while 1-acetamido-3-(2-pyrimidinyl)-imidazolium bromide exhibits a bilayer stacking, the PF6- salt reveals a -sheetlike pattern.The appearance of the free-NH infrared absorption indicates that the conventional N-H- - -O or N-H- - -Nhydrogen bonds do not fully dominate the packing for the PF6- salt. The high-pressure infrared studysuggests that the C-H- - -O hydrogen bonds are the important determinants for the stability of the PF6-salt. This study also verifies that the imidazolium C-H stretching frequency shifts to a longer wavelengthupon the formation of the C-H- - -O hydrogen bonds.
-H- - -O type have been analyzed via X-ray crystallography andhigh-pressure infrared spectroscopy. The results demonstrate that the C-H- - -O interactions can offeran additional stability to the -sheet formation. X-ray structural data suggest that while 1-acetamido-3-(2-pyrimidinyl)-imidazolium bromide exhibits a bilayer stacking, the PF6- salt reveals a -sheetlike pattern.The appearance of the free-NH infrared absorption indicates that the conventional N-H- - -O or N-H- - -Nhydrogen bonds do not fully dominate the packing for the PF6- salt. The high-pressure infrared studysuggests that the C-H- - -O hydrogen bonds are the important determinants for the stability of the PF6-salt. This study also verifies that the imidazolium C-H stretching frequency shifts to a longer wavelengthupon the formation of the C-H- - -O hydrogen bonds.