Molecules | |
1H-NMR as a Structural and Analytical Tool of Intra- and Intermolecular Hydrogen Bonds of Phenol-Containing Natural Products and Model Compounds | |
Pantelis Charisiadis1  Vassiliki G. Kontogianni1  Constantinos G. Tsiafoulis2  Andreas G. Tzakos1  Michael Siskos1  | |
[1] Section of Organic Chemistry & Biochemistry, Department of Chemistry, University of Ioannina, Ioannina GR-45110, Greece; E-Mails:;NMR Center, University of Ioannina, Ioannina GR-45110, Greece; E-Mail: | |
关键词: chemical shifts; hydrogen bonding; 1H-NMR; 1H-13C HMBC; phenol OH; natural products; | |
DOI : 10.3390/molecules190913643 | |
来源: mdpi | |
【 摘 要 】
Experimental parameters that influence the resolution of 1H-NMR phenol OH signals are critically evaluated with emphasis on the effects of pH, temperature and nature of the solvents. Extremely sharp peaks (Δν1/2 ≤ 2 Hz) can be obtained under optimized experimental conditions which allow the application of 1H-13C HMBC-NMR experiments to reveal long range coupling constants of hydroxyl protons and, thus, to provide unequivocal assignment of the OH signals even in cases of complex polyphenol natural products. Intramolecular and intermolecular hydrogen bonds have a very significant effect on 1H OH chemical shifts which cover a region from 4.5 up to 19 ppm. Solvent effects on –OH proton chemical shifts, temperature coefficients (Δ
【 授权许可】
CC BY
© 2014 by the authors; licensee MDPI, Basel, Switzerland.
【 预 览 】
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RO202003190022314ZK.pdf | 7867KB | download |