P. Barczyński, A. Komasa, A. Katrusiak
Apr 30, 2007
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0
Influential Citations
3
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract The effect of hydrogen bonding, inter- and intramolecular electrostatic interactions on the structure of 3-hydroxy-pyridine betaine hydrochloride monohydrate (1-carboxymethyl-3-hydroxypyridinium chloride monohydrate), 3-HO-PBH·Cl·H 2 O, has been studied by X-ray diffraction, 1 H and 13 C NMR and FTIR spectroscopies, and by the B3LYP/6-31G(d,p) calculations. In the crystal, the Cl − anion is connected with protonated betaine via the hydrogen bond, O C O H⋯Cl − = 2.993(2) A and with neighboring H 2 O molecules via the 3.111(1) and 3.578(1) A bonds, while the 3-OH group interacts with water molecule by the hydrogen bond of 2.566(2) A, forming an aggregate along the [b] direction. The water molecule additionally forms hydrogen bonds of 2.888(3) A to the C O bond of O C OH group. On recrystallization the 1:1 complex slowly converts into the 2:1 complex, bis(3-hydroxy-pyridine betaine) hydrochloride, [bis(1-carboxymethyl-3-hydroxypyridinium) chloride], [(3-HO-PB) 2 H·Cl]. The geometries of 3-HO-PBH·Cl·H 2 O in the gas phase (vacuum), DMSO and water solutions have been optimized by the B3LYP/6-31G(d,p) level of theory using the COSMO model. Good linear correlations between 13 C and 1 H experimental chemical shifts and GIAO/ B3LYP/6-31G(d,p) calculated magnetic isotropic shielding tensors ( σ ) have been obtained. The FTIR spectrum of the 1:1 complex shows a broad and intense absorption in the 3100–2500 cm −1 region due to the stretching vibration of hydrogen bonds between the Cl − anion and COOH, OH substituents and H 2 O molecules, and the νC O band at 1739 cm −1 . The spectrum of the 2:1 complex shows an additional broad absorption in the 1900–800 cm −1 region due to the O H·O hydrogen bonds between COO groups.