کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1405863 1501760 2013 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Molecular structures of N-ethylpiperidine betaine hydrate and its 1:1 complex with squaric acid
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Molecular structures of N-ethylpiperidine betaine hydrate and its 1:1 complex with squaric acid
چکیده انگلیسی


• X-ray and DFT structures of the centrosymmetric dimer of N-ethylpiperidine betaine hydrate.
• Hydrogen bonds in the complex of squaric acid with N-ethylpiperidine betaine.
• Preference of the carboxymethyl substituent to a hydrogen-bond formation.
• 2D NMR spectra determine the chemical shifts of methylene groups in betaine unit.

N-ethylpiperidine betaine, (N-carboxymethyl-N-ethylpiperidinium inner salt, EtPB) crystallizes as a hydrate. EtPB and water molecules are bonded by intermolecular OH⋯O hydrogen bonds of 2.817(1) and 2.863(1) Å, into a centrosymmetric dimer, in which only one carboxylate oxygen atom is involved in H-bonds formation. In the complex of EtPB with squaric acid (3,4-dihydroxy-3-cyclobutene-1,2-dione, H2SQ) both carboxylate oxygen atoms are engaged in the hydrogen bonds which links molecules through two short, non-symmetric OH⋯O hydrogen bonds of 2.489(1) and 2.500(1) Å. The preferences of the conformation of the EtPB unit in the hydrogen bond formation have been studied by X-ray diffraction, FTIR and NMR spectroscopy and the results are supported by DFT calculations. EtPB, in hydrate and in the complex, has a chair conformation with the CH3CH2 group in the axial position and the CH2COO substituent in the equatorial position.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure - Volumes 1054–1055, 24 December 2013, Pages 170–178
نویسندگان
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