Complementary optical and neutron vibrational spectroscopy study of bromanilic acid: 2,3,5,6-tetramethylpyrazine (1:1) cocrystal |
| |
Affiliation: | 1. School of Pharmacy and Department of Chemistry, University of Wisconsin‐Madison, Madison, Wisconsin 53705;2. School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK;1. Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China;2. Department of Epidemiology and Health Statistics, School of Public Health, Capital Medical University, Beijing, China;3. Beijing Municipal Key Laboratory of Clinical Epidemiology, Capital Medical University, Beijing, China;4. Department of Cardiology, Kailuan Hospital, Hebei United University, Tangshan, China |
| |
Abstract: | Complementary structural and vibrational spectroscopy study of bromanilic acid:2,3,5,6-tetramethylpyrazine (BrA:TMP) 1:1 cocrystal is reported. The crystallographic structure was determined by means of single-crystal X-ray diffraction and can be described as a stacked net of hydrogen-bonded TMPH+⋯BrA−⋯BrA−⋯TMPH+ moieties. The structural analysis was supported by 13CP/MAS NMR study. The complementary vibrational analysis was performed by combining optical (infrared, Raman, terahertz) and inelastic neutron scattering spectroscopy with the state-of-the-art solid–state density functional theory (DFT) computations, which have proven to be superior to the hybrid cluster modeling approach. An excellent agreement between theoretical and experimental data was observed over the entire spectral range, allowing for deep understanding of the vibrational properties. While the primary hydrogen-bonding interactions are limited to the above quoted structural units, the system revealed very little dispersion of the phonon branches, manifested mainly in the intermolecular vibrations range. Moreover, the studied phase does not exhibit any mechanical instability, which could suggest a displacive structural transformation tendency. |
| |
Keywords: | Molecular crystals Infrared and Raman spectroscopy Time-domain terahertz spectroscopy Inelastic neutron scattering Plane-wave DFT |
本文献已被 ScienceDirect 等数据库收录! |
|