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Structural and IR-spectroscopic characterization of pyridinium acesulfamate, a monoclinic twin

Baran, Enrique J., Piro, Oscar E., Echeverría, Gustavo A., Parajón-Costa, Beatriz S.
Zeitschrift für Naturforschung 2018 v.73 no.11 pp. 753-758
Fourier transform infrared spectroscopy, X-ray diffraction, cations, crystal structure, crystallization, electrostatic interactions, hydrogen bonding, salts
The crystal structure of pyridinium 6-methyl-1,2,3,-oxathiazine-4(3H)-one-2,2-dioxide [(C₅NH₆)(C₄H₄NO₄S)], for short, pyH(ace), was determined by X-ray diffraction methods. It crystallizes as a twin in the monoclinic space group P2₁/c with a=6.9878(9), b=7.2211(7), c=21.740(2) Å, β=91.67(1)° and Z=4 molecules per unit cell. The structure was determined employing 1599 reflections with I>2 σ(I) from one of the twin domains and refined employing 2092 reflections from both crystal domains to an agreement R1 factor of 0.0466. Besides electrostatic attractions, intermolecular pyH···O=C(ace) hydrogen bonds stabilize the acesulfamate anion and the pyridinium cation into planar discrete units parallel to the (100) crystal plane. The units form stacks of alternating ace⁻ and pyH⁺ ions along the a axis that favors inter-ring π–π interactions. The Fourier transform-infrared (FT-IR) spectrum of the compound was recorded and is briefly discussed. Some comparisons with related pyridinium saccharinate salts are also made.