X-ray diffraction,spectroscopic (IR,Raman) and DSC studies of bis(betainium) p-toluenesulfonate monohydrate crystal |
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Institution: | 1. School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China;2. Hefei National Laboratory for Physical Sciences at the Microscale, Hefei, Anhui 230027, China;3. Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China;1. Ludwig Maximilian University Munich, Faculty of Biology, Department of Biology I, Anthropology and Human Genomics, Grosshaderner Str. 2, 82152 Planegg-Martinsried, Germany;2. Friedrich Alexander University Erlangen-Nuremberg, Institute of Geography, Wetterkreuz 15, 91058 Erlangen, Germany;3. Ludwig Maximilian University Munich, Faculty of Geosciences, Department of Earth and Environmental Studies, Richard-Wagner-Str. 10, 80333 Munich, Germany;4. Ludwig Maximilian University Munich, GeoBio-Center, Richard-Wagner-Str. 10, 80333 Munich, Germany |
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Abstract: | Bis(betainium) p-toluenesulfonate monohydrate (abbreviated as BBTSH) was studied at various temperatures by X-ray diffraction, differential scanning calorimetry and vibrational spectroscopy methods. DSC curves of BBTSH show a peak at about 349 K which corresponds to water escape from the crystal, and reveal the “cold crystallization” phenomenon. BBTSH crystallizes in the P21/c space group of monoclinic system. After heating above 349 K the compound dehydrates, the crystal system changes to triclinic, the monocrystalline samples become non-merohedral twins. The BBTSH crystal comprises p-toluenesulfonic anions, monoprotonated betaine dimers and water molecules. Three kinds of hydrogen bonds are present in the crystal: strong, asymmetric and almost linear O H?O hydrogen bond (R(O?O) = 2.463(2) Å), weak Ow H?O hydrogen bonds (R(Ow?O) = 2.820(2) ? 2.822(2) Å) and weak C H?O hydrogen bonds (R(C?O) = 3.295(2) ? 3.416(2) Å). The νaOHO vibration of the strongest hydrogen bond in the crystal gives rise to an intense broad absorption with numbers of transmission windows in the low wavenumber region of the infrared spectra. Coupling between νC O stretching vibrations of two COO groups of the betaine dimer was detected. The process corresponding to the loss of water is accompanied by the breakage of strong O H?O hydrogen bonds in betaine dimers and rearrangement inside half of the betaine dimers. This rearrangement results in formation of the new betaine dimers with O H???O hydrogen bond of similar strength as corresponding bond in the hydrated form (BBTSH). |
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Keywords: | Hydrogen bonds Infrared spectra Single crystal Raman spectra Betaine dimer Twinned structure Dehydration process |
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