Vibrational Optical Activity of Intermolecular, Overtone, and Combination Bands: 2-Chloropropionitrile and alpha-Pinene

0503714 - ÚOCHB 2020 RIV US eng J - Journal Article
Michal, P. - Čelechovský, R. - Dudka, M. - Kapitán, J. - Vůjtek, M. - Berešová, Marie - Šebestík, Jaroslav - Thangavel, Karthick - Bouř, Petr
Vibrational Optical Activity of Intermolecular, Overtone, and Combination Bands: 2-Chloropropionitrile and alpha-Pinene.
Journal of Physical Chemistry B. Roč. 123, č. 9 (2019), s. 2147-2156. ISSN 1520-6106. E-ISSN 1520-5207
R&D Projects: GA ČR(CZ) GA17-00121S; GA ČR(CZ) GA18-05770S; GA MŠMT(CZ) LTC17012
Institutional support: RVO:61388963
Keywords : normal mode optimization * circular dichroism * molecular dynamics
OECD category: Physical chemistry
Impact factor: 2.857, year: 2019
Method of publishing: Limited access
https://pubs.acs.org/doi/10.1021/acs.jpcb.9b00403

Spectroscopy of vibrational optical activity has been established as a powerful tool to study molecular structures and interactions. In most cases, only fundamental molecular transitions are analyzed. In the present study, we analyze a broader range of vibrational frequencies (40-4000 cm(-1)), which could be measured on a new Raman optical activity (ROA) instrument. An unexpectedly strong vibrational Raman optical activity of 2-chloropropionitrile has been observed within the low-frequency region (40-150 cm(-1)). On the basis of combined molecular dynamics and density functional theory simulations, it could be assigned to intermolecular vibrations. A detailed analysis also revealed connection between spectral shapes and molecular structure and flexibility, such as bending of the CCN group. At the other edge of the scale, within similar to 1500-4000 cm(-1), for the first time, many combination and overtone ROA bands have been observed for 2-chloropropionitrile and alpha-pinene. These were also partially assigned, using quantum-chemical computations. The band assignment was confirmed by a comparison with Raman, absorption, and vibrational circular dichroism spectra. The measurement in the broader vibrational range thus significantly extends the information that can be obtained by optical spectroscopy, including intermolecular interactions of chiral molecules and liquids.
Permanent Link: http://hdl.handle.net/11104/0296685