Study of the Experimental and Simulated Vibrational Spectra Together with Conformational Analysis of Thioether Cyanobiphenyl-Based Liquid Crystal Dimers

Kocot, A.; Loska, Barbara; Arakawa, Yuki; Mehl, Georg H.; Merkel, Katarzyna

doi:10.3390/ijms23148005

Cited by 3 publications

(7 citation statements)

References 79 publications

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“…A detailed analysis of the infrared spectra compared to those simulated for different conformers, along with the exact assignments of vibrations, is presented in a separate paper [ 76 ]. Several vibrational bands that belonged to the longitudinal and transverse transition dipole that showed significant dichroism of the band were selected to be analyzed.…”

Section: Resultsmentioning

confidence: 99%

“…For the longitudinal transition dipole moment, the phenyl stretching band (νCC) at 1600 cm −1 and the C-H deformation vibration in the benzene plane at 1100 cm −1 (βCH) were selected. The band at 1100 cm −1 was a vibration that involved a sulfide group, so it may be a good indicator of the dimer’s conformational change [ 76 ]. Figure 1 shows the temperature dependencies of the average absorbances, A 0 , for the bands corresponding to the longitudinal transition dipole.…”

Section: Resultsmentioning

confidence: 99%

“…The latter result can be analyzed considering the rotation barrier between the cyanobiphenyl group’s bond and the alkyl linker. This barrier is much higher for the oxygen group than for the sulfur one [ 12 , 76 ], so it can be assumed that the oxygen bridge remains in planar conformation. However, the sulfur bridge has conformational freedom and can escape from the phenyl plane [ 76 ].…”

Section: Resultsmentioning

confidence: 99%

“…This barrier is much higher for the oxygen group than for the sulfur one [ 12 , 76 ], so it can be assumed that the oxygen bridge remains in planar conformation. However, the sulfur bridge has conformational freedom and can escape from the phenyl plane [ 76 ]. It is reasonable to conclude that the origin of the absorbance increase is due to transversal order rearrangement and emergence phase biaxiality.…”

Section: Resultsmentioning

confidence: 99%

“…The potentially stable conformers were determined based on calculating the energy barriers for the internal rotation of the cyanobiphenyl group (CB) and the rotation around the dihedral angle between the CB and the linker. All the technical details were described and discussed in a previous paper [ 76 ].…”

Section: Resultsmentioning

confidence: 99%

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How Do Intermolecular Interactions Evolve at the Nematic to Twist–Bent Phase Transition?

Merkel

Loska

Arakawa

et al. 2022

IJMS

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Polarized beam infrared (IR) spectroscopy provides valuable information on changes in the orientation of samples in nematic phases, especially on the role of intermolecular interactions in forming the periodically modulated twist–bent phase. Infrared absorbance measurements and quantum chemistry calculations based on the density functional theory (DFT) were performed to investigate the structure and how the molecules interact in the nematic (N) and twist–bend (NTB) phases of thioether dimers. The nematic twist–bend phase observed significant changes in the mean IR absorbance. On cooling, the transition from the N phase to the NTB phase was found to be accompanied by a marked decrease in absorbance for longitudinal dipoles. Then, with further cooling, the absorbance of the transverse dipoles increased, indicating that transverse dipoles became correlated in parallel. To investigate the influence of the closest neighbors, DFT calculations were performed. As a result of the optimization of the molecular cores system, we observed changes in the square of the transition dipoles, which well corresponds to absorbance changes observed in the IR spectra. Interactions of molecules dominated by pairing were observed, as well as the axial shift of the core to each other.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

How Do Intermolecular Interactions Evolve at the Nematic to Twist–Bent Phase Transition?

Merkel

Loska

Arakawa

et al. 2022

IJMS

Self Cite

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Selenium-linked cyanobiphenyl-based liquid crystal dimers: the effects of chalcogen linkage and spacer length on the twist-bend nematic phase

Arakawa,

Shiba,

Igawa

2024

Liquid Crystals

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Density Functional Theory Calculations for Interpretation of Infra-Red Spectra of Liquid Crystalline Chiral Compound

Deptuch,

Górska,

Murzyniec

et al. 2024

Crystals

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The experimental IR spectra of (S)-4′-(1-methylheptyloxycarbonyl) biphenyl-4-yl 4-[2-(2,2,3,3,4,4,4-heptafluorobutoxy) ethyl-1-oxy]-2-fluorobenzoate in the crystal phase are analyzed with the help of dispersion-corrected density functional theory (DFT+D3) calculations for isolated molecular monomer and dimer models, and a periodic model computed at the extended density functional tight-binding (xTB) level of theory. It is found that the frequency scaling coefficients obtained with the results of the molecular calculations are good matches for the crystal phase, being close to 1. The molecular and periodic models both confirm that varied intra- and intermolecular interactions are crucial in order to reproduce the broadened shape of the experimental band related to C=O stretching; the key factors are the conjugation of the ester groups with the aromatic rings and the varied intermolecular chemical environments, wherein the C=O group that bridges the biphenyl and F-substituted phenyl groups seems particularly sensitive. The C=O stretching vibrations are investigated as a function of temperature, covering the range of the crystal, smectic CA*, smectic C* and isotropic liquid phases. The structure changes are followed based on the X-ray diffraction patterns collected in the same temperatures as the IR spectra. The experimental and computational results taken together indicate that the amount of weak C=O…H-C hydrogen bonds between the molecules in the smectic layers decreases with increasing temperature.

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Study of the Experimental and Simulated Vibrational Spectra Together with Conformational Analysis of Thioether Cyanobiphenyl-Based Liquid Crystal Dimers

Cited by 3 publications

References 79 publications

How Do Intermolecular Interactions Evolve at the Nematic to Twist–Bent Phase Transition?

How Do Intermolecular Interactions Evolve at the Nematic to Twist–Bent Phase Transition?

Selenium-linked cyanobiphenyl-based liquid crystal dimers: the effects of chalcogen linkage and spacer length on the twist-bend nematic phase

Density Functional Theory Calculations for Interpretation of Infra-Red Spectra of Liquid Crystalline Chiral Compound

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