期刊
JOURNAL OF INORGANIC BIOCHEMISTRY
卷 110, 期 -, 页码 27-35出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.jinorgbio.2012.02.007
关键词
Quercetin; Al(III) complexation; Solid-state NMR; MAS NMR; DFT GIAO calculations
资金
- Interdisciplinary Centre for Mathematical and Computational Modelling of Warsaw University [G14-6]
Quercetin (Q) as a pentahydroxy flavonoid, has three possible chelating sites competing in complexation processes. H-1 and C-13 MAS NMR spectra were recorded for solid quercetin and its Al(III) complex (AlQ). H-1 MAS spectrum of quercetin shows a broad resonance at ca. 12 ppm that confirms the existence of intramolecular C5 - OH ... O=C4 hydrogen bond. Such a signal is absent in the spectrum of AlQ which is in accordance with other spectroscopic data and the suggested model for the solid-state structure of the complex. OFT CIAO calculations were used to verify the experimental C-13 CPMAS NMR data and to suggest the best model structure for the complex AlQ The calculated shielding constants for different conformers of isolated quercetin molecules, quercetin trimer as taken from the X-ray data, and different model structures for possible Al(III) complexes were compared with the C-13 CPMAS NMR experimental values. The results demonstrate the importance of intermolecular interactions when dealing with structures in solid state and the successful application of the combined DFT CIAO and C-13 CPMAS NMR approach. All data confirm that the chelating site of Q in the solid complex AlQ involves the deprotonated C5 - OH and the C4=O groups at ring C, in contrast to the available studies performed in solution. (C) 2012 Elsevier Inc. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据