title: Experimental (X-ray, (13)C CP/MAS NMR, IR, RS, INS, THz) and Solid-State DFT Study on (1:1) Co-Crystal of Bromanilic Acid and 2,6-Dimethylpyrazine.
abstract: A combined structural, vibrational spectroscopy, and solid-state DFT study of the hydrogen-bonded complex of bromanilic acid with 2,6-dimethylpyrazine is reported. The crystallographic structure was determined by means of low-temperature single-crystal X-ray diffraction, which reveals the molecular units in their native protonation states, forming one-dimensional infinite nets of moderate-strength O···H-N hydrogen bonds. The nature of the crystallographic forces, stabilizing the studied structure, has been drawn by employing the noncovalent interactions analysis. It was found that, in addition to the hydrogen bonding, the intermolecular forces are dominated by stacking interactions and C-H···O contacts. The thermal and calorimetric analysis was employed to probe stability of the crystal phase. The structural analysis was further supported by a computationally assisted (13)C CP/MAS NMR study, providing a complete assignment of the recorded resonances. The vibrational dynamics was explored by combining the optical (IR, Raman, TDs-THz) and inelastic neutron scattering (INS) spectroscopy techniques with the state-of-the-art solid-state density functional theory (DFT) computations. Despite the quasi-harmonic approximation assumed throughout the study, an excellent agreement between the theoretical and experimental data was achieved over the entire spectral range, allowing for a deep and possibly thorough understanding of the vibrational characteristics of the system. Particularly, the significant influence of the long-range dipole coupling on the IR spectrum has been revealed. On the basis of a wealth of information gathered, the recent implementation of a dispersion-corrected linear-response scheme has been extensively examined.
authors.affiliation: †Institute of Nuclear Chemistry and Technology, 16 Dorodna Street, 03-195, Warsaw, Poland.|‡Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russian Federation.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Łuczyńska
authors.affiliation: ‡Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russian Federation.|§Department of Radiospectroscopy, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614, Poznan, Poland.
authors.forename: Kacper
authors.initials: K
authors.lastname: Drużbicki
authors.affiliation: †Institute of Nuclear Chemistry and Technology, 16 Dorodna Street, 03-195, Warsaw, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Lyczko
authors.affiliation: †Institute of Nuclear Chemistry and Technology, 16 Dorodna Street, 03-195, Warsaw, Poland.|∥National Medicines Institute, 30/34 Chełmska Street, 00-725 Warsaw, Poland.
authors.forename: Jan Cz
authors.initials: JC
authors.lastname: Dobrowolski
mesh_terms: D016227:Benzoquinones / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004355:Drug Stability; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D033363:Neutron Diffraction; D011719:Pyrazines / Q000737:chemistry*; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D055068:Terahertz Spectroscopy
chemical_list: D016227:Benzoquinones; D011719:Pyrazines; C075524:2,5-dimethylpyrazine