High-pressure Raman studies on aqueous protonated thiazole: presence of charge-enhanced C-H…O hydrogen
| Autor: | Guan-Ciao Chen, 陳冠橋 |
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| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 Close interactions of the charge-enhanced C-H…O type have been analyzed both experimentally and computationally in the protonated thiazole-water system. The formation of a weak hydrogen bond was directly evidenced by a low-frequency shift of the hydrogen-bonded aromatic C-H stretch in the protonated thiazole moiety. For pure thiazole, the pressure dependence of the C-H bands yielded blue frequency shifts. The peak frequency of the aromatic C-H stretch band of protonated thiazole in a dilute D2O solution possesses an unusual nonmonotonic pressure dependence, which indicates enhanced C-H…O hydrogen-bond formation at high pressure. We performed density functional theory calculations to predict the frequency shift of the C-H stretching vibrations. The reorganization of the hydrogen-bonded network may be one of the factors to induce the blue frequency shift to the red frequency shift. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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