Study of the Experimental and Simulated Vibrational Spectra Together with Conformational Analysis of Thioether Cyanobiphenyl-Based Liquid Crystal Dimers
Abstract
:1. Introduction
2. Results
2.1. Molecular Structures
Dihedral Angle Distributions and Conformations
2.2. Molecular Vibrations
2.3. Vibrational Spectra and Their Assignments
- 500–600 cm−1 and 700–900 cm−1 ranges, which cover the deformational vibrations of the carbon atoms (C-C) and hydrogen atoms (C-H) out of the benzene plane;
- 900–1650 cm−1 range, which includes both the characteristic deformation vibrations in the benzene plane as well as the deformation vibrations of the methylene groups of the alkyl chain of the linker in a dimer;
- 2100–2400 cm−1 range, which includes the stretching vibrations of the cyan group (C≡N) that were observed as a sharp and very intense peak in the experimental spectrum;
- 2800–2950 cm−1 range, which includes the C-H stretching vibrations of the methylene groups. In this range, the vibrations were not well reproduced by the theoretical spectra because the calculations did not take into account the anharmonic effect;
- 2900–3100 cm−1 range, which represents the stretching vibrations of the hydrogen atoms (C-H) in the aromatic ring. These vibrations were also not well reproduced by the theoretical frequencies. The bands in this range corresponded to the mixed vibrations, which were strongly overlapping, and the vibrations stretching the C-H hydrogen atoms, significantly disturbed by the Fermi resonance effect.
2.3.1. The CBSC7SCB Dimer
2.3.2. The CBSC7OCB Dimer
3. Discussion
4. Materials and Methods
4.1. Materials
4.2. Infrared Spectroscopy
4.3. Density Functional Theory Calculations
5. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Sample | Conf. | Potential Energy RMS (kJ/mol) | Torsion Angles, φt (°) | Opening Angle (°) | |||
---|---|---|---|---|---|---|---|
φ1 | φ2 | φ3 | φ4 | ||||
CBC9CB | Upright (U) | −3,843,952.076 0.014 | 92.3 | 86.2 | −38.7 | −38.5 | 112 |
CBSC7SCB | Upright (U) | −5,521,962.5193 0.0035 | −92.9 | −92.8 | −39.0 | −39.0 | 94 |
Flat (F) | −5,521,963.9252 0.0024 | 5.8 | 5.8 | −37.2 | −37.2 | 108 | |
CBSC7OCB | Mixed (M) | −4,673,985.9556 0.0077 | −96.1 | −179.1 | −38.8 | −37.2 | 120 |
Flat (F) | −4,673,986.6314 0.0037 | −176.3 | −180.0 | −37.4 | −37.6 | 126 | |
CBOC7OCB | Flat (F) | −3,826,009.436 0.020 | −179.3 | −179.2 | −37.3 | −37.3 | 144 |
CBC9CB | CBSC7SCB | CBSC7OCB | CBOC7OCB | Assignments | ||||
---|---|---|---|---|---|---|---|---|
Ir | Ir | Ir | Ir | |||||
520 | vvw | 522 | m | 523 | w | -- | -- | γCC op CB + δCS |
-- | -- | -- | -- | 532 | w | 532 | w/m | γCC op CB + δCO |
554 | w | 562 | w | 562 | w | 562 | w | γCC op CB + δCN |
816 | vs | 811 | vs | 813 | vs | -- | γCH op CB | |
-- | -- | -- | -- | 821 | s, sh | 821 | vs | νsCOC + γCH op CB |
836 850 | w | 852 | w | 850 | w | 850 | w | γCH op CB + νCCC sk + δasCH2 rocking |
1007 | w | 999 | w | 999 | w | 1000 | w | βCC ip CB, breathable |
1026 | vw | 1020 | vw | 1013 | vw | 1013 | vw | νCCC sk + βCH ip CB |
-- | -- | -- | -- | 1029 1051 | w | 1032 | w | νasCAlO + βCH ip CB |
-- | -- | 1097 | m | 1095 | m | -- | -- | νasCArS + βCH ip CB |
1112 | vw | -- | -- | -- | -- | 1120 | w | βCH ip CB |
1185 | m | 1185 | s | 1180 | s | 1178 | s | βCH ip CB |
-- | -- | -- | -- | 1249 1266 | vs m, sh | 1249 1266 | vs m,sh | νasCArO + βCH ip CB |
1284 1315 1360 | vw | 1279 1315 | vw | 1290 1311 | vw | 1290 1313 | vw | γsCH2 wagging γsCH2 twisting |
1397 | w | 1395 | w | 1392 | w | 1390 | w | βCH ip CB |
1460 | w | 1437 1462 | w | 1435 1472 | w | 1472 | w | βsCH2 scissoring |
-- 1493 | s | 1484 -- | vs | 1485 1494 | vs | -- 1493 | vs | νCC br |
-- | -- | -- | -- | 1522 1577 | m vw | 1523 1580 | m w | νCC br + βsCH2 + νasCArO |
-- 1605 | s | 1594 1604 | vs | -- 1603 | vs | -- 1602 | vs | νCC br |
2224 | vs | 2223 | vs | 2223 | vs | 2223 | vs | νCN |
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Kocot, A.; Loska, B.; Arakawa, Y.; Mehl, G.H.; Merkel, K. Study of the Experimental and Simulated Vibrational Spectra Together with Conformational Analysis of Thioether Cyanobiphenyl-Based Liquid Crystal Dimers. Int. J. Mol. Sci. 2022, 23, 8005. https://doi.org/10.3390/ijms23148005
Kocot A, Loska B, Arakawa Y, Mehl GH, Merkel K. Study of the Experimental and Simulated Vibrational Spectra Together with Conformational Analysis of Thioether Cyanobiphenyl-Based Liquid Crystal Dimers. International Journal of Molecular Sciences. 2022; 23(14):8005. https://doi.org/10.3390/ijms23148005
Chicago/Turabian StyleKocot, Antoni, Barbara Loska, Yuki Arakawa, Georg H. Mehl, and Katarzyna Merkel. 2022. "Study of the Experimental and Simulated Vibrational Spectra Together with Conformational Analysis of Thioether Cyanobiphenyl-Based Liquid Crystal Dimers" International Journal of Molecular Sciences 23, no. 14: 8005. https://doi.org/10.3390/ijms23148005