IR and X-ray Study of Polymorphism in 1-Alkyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imides

• Published in: The journal of physical chemistry. B Vol. 113; no. 28; pp. 9538 - 9546
• Main Authors: Paulechka, Y. U, Kabo, G. J, Blokhin, A. V, Shaplov, A. S, Lozinskaya, E. I, Golovanov, D. G, Lyssenko, K. A, Korlyukov, A. A, Vygodskii, Ya. S
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 16.07.2009
• Subjects: B: Statistical Mechanics, Thermodynamics, Medium Effects
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp903702c

The crystal structure of [C n mim]NTf2 (n = 2, 4, 6) was studied for the first time simultaneously by X-ray diffraction method and IR spectroscopy. The temperature-dependent IR spectrum for crystalline [C4mim]NTf2 was demonstrated to correlate with both the X-ray data and the calorimetric results obtained earlier. Therefore, it was found that IR spectroscopy is able to establish the correspondence between the X-ray and the calorimetric data in this case. The joint use of X-ray diffraction, IR spectroscopy, and quantum-chemical calculations allowed us to determine the structure of all [C2mim]NTf2 crystalline modifications obtained earlier by adiabatic calorimetry measurements. Thus, a new approach for the future identification of ionic liquid crystal structure by use of temperature-dependent infrared spectroscopy is suggested and justified.