C[bond]H- - -O hydrogen bonds in beta-sheetlike networks: combined X-ray crystallography and high-pressure infrared study

Kwang Ming Lee; Hai-Chou Chang; Jyh-Chiang Jiang; Jack C C Chen; Hsiang-En Kao; Sheng Hsien Lin; Ivan J B Lin

doi:10.1021/ja036719z

C[bond]H- - -O hydrogen bonds in beta-sheetlike networks: combined X-ray crystallography and high-pressure infrared study

J Am Chem Soc. 2003 Oct 8;125(40):12358-64. doi: 10.1021/ja036719z.

Authors

Kwang Ming Lee¹, Hai-Chou Chang, Jyh-Chiang Jiang, Jack C C Chen, Hsiang-En Kao, Sheng Hsien Lin, Ivan J B Lin

Affiliation

¹ Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan.

PMID: 14519022
DOI: 10.1021/ja036719z

Abstract

Close interactions of the C(alpha)[bond]H- - -O type have been analyzed via X-ray crystallography and high-pressure infrared spectroscopy. The results demonstrate that the C(alpha)[bond]H- - -O interactions can offer an additional stability to the beta-sheet formation. X-ray structural data suggest that while 1-acetamido-3-(2-pyrimidinyl)-imidazolium bromide exhibits a bilayer stacking, the PF(6)(-) salt reveals a beta-sheetlike pattern. The appearance of the free-NH infrared absorption indicates that the conventional N[bond]H- - -O or N[bond]H- - -N hydrogen bonds do not fully dominate the packing for the PF(6)(-) salt. The high-pressure infrared study suggests that the C(alpha)[bond]H- - -O hydrogen bonds are the important determinants for the stability of the PF(6)(-) salt. This study also verifies that the imidazolium C[bond]H stretching frequency shifts to a longer wavelength upon the formation of the C[bond]H- - -O hydrogen bonds.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acetamides / chemistry*
Crystallography, X-Ray
Hydrogen Bonding
Imidazoles / chemistry*
Models, Molecular
Pyrimidines / chemistry*
Spectrophotometry, Infrared

Substances

Acetamides
Imidazoles
Pyrimidines