Structure of 2,3-dicarboxy-1-methylpyridinium monohydrate studied by X-ray diffraction, DFT calculations, FTIR, Raman and NMR spectra

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• 作者：P. Barczyń ; ski ; M. Ratajczak-Sitarz ; Ł ; . Nowaczyk ; A. Katrusiak ; Z. Dega-Szafran ; M. Szafran ; ^{szafran@amu.edu.pl}
• 关键词：2 ; 3-Dicarboxy-1-methylpyridinium inner salt ; Hydrogen bond ; X-ray diffraction ; B3LYP calculations ; FTIR ; Raman and NMR spectra
• 刊名：Journal of Molecular Structure
• 出版年：2012
• 期刊代码：62_00222860
• 类别：ch
• 出版时间：11 April, 2012
• 卷：1013
• 期：Complete
• 页码：1-10
• 文件大小：826 K

摘要

The structure of 2,3-dicarboxy-1-methylpyridinium monohydrate (1) has been studied by X-ray diffraction, DFT calculations and on the basis of FTIR, Raman and NMR spectra. The crystals are monoclinic, space group P2₁/n. The water molecule is linked by three intermolecular and asymmetric OH鈰疧 hydrogen bonds of 2.554(1), 2.715(1) and 2.753(2) 脜 between 3-carboxyl and 2-carboxylate groups of neighboring molecules of 2,3-dicarboxy-1-methylpyridinium inner salt. The different conformations of monohydrate molecules (1a, 2, 3), anhydrous molecules (4-6) in the gas phase and in water solutions (7, 8) have been optimized by the B3LYP/6-311++G(d,p) approach and the results have been compared with the X-ray data of 1. The correlations between the experimental ¹H and ¹³C NMR chemical shifts (未_exp) of 1 in D₂O and the magnetic isotropic shielding constants (蟽_calc) calculated by the GIAO/B3LYP/6-311G++(d,p) approach, using the screening solvation model (COSMO), 未_exp = a + b 蟽_calc, for optimized molecules 7 and 8 in water solutions are linear and correctly reproduce the experimental chemical shifts. The assignments of water vibrations in FTIR spectrum are consistent with those for other monohydrate crystals.