Vibrational spectroscopic characterization of cyclic and acyclic molecular rotors with 1,4-diethynylphenylene-d4 rotators

Runka, Tomasz; Olszewska, Karolina; Fertsch, Piotr; Łapiński, Andrzej; Jastrzębska, Izabella; Santillán, Rosa; Farfán, Norberto

doi:10.1016/j.saa.2017.11.052

Cited by 2 publications

(8 citation statements)

References 15 publications

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“…Primarily, they must contain free space around moving components in order to facilitate the movement of the rotator. This can be achieved by numerous means, for example, by introducing massive, steroid-based stators and additional bridging chains connecting them. , Second, they must contain a volume conserving rotator, which translates into a requirement of high rotational symmetry. Third, the motion of rotators must be correlated.…”

Section: Introductionmentioning

confidence: 99%

Steroidal Molecular Rotors with 1,4-Diethynylphenylene Rotators: Experimental and Theoretical Investigations Toward Seeking Efficient Properties

et al. 2020

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Properly designed molecular rotors with sizable stators and a fast-moving rotator could provide efficient building blocks for amphidynamic crystals. Herein, we report the synthesis of steroidal compounds 1 , 2 , and 3 and their deuterated analogues 1D , 2D , and 3D envisioned to work as molecular rotors. The obtained compounds were characterized by attenuated total reflection-infrared, Raman, and circular dichroism (CD) spectroscopy measurements. The interpretation of spectra was supported by theoretical calculations using density functional theory methods. The analysis of the most characteristic bands confirmed different molecular dynamics of the rotors investigated. Angle-dependent polarized Raman spectra showed the crystallinity of some samples. Electronic CD (ECD) spectra of compounds 1–3 and their relevant deuterated analogues 1D–3D are identical. The increase of the band intensity with lowering the temperature shows that the equilibrium is shifted to the thermodynamically most stable conformer. ECD spectra simulated at the TDFFT level of theory for compound 3 were compared with experimental results. It was proved that conformer 3a , with a torsion angle of +50°, exhibits the best agreement with the experimental results. Simulated vibrational CD and IR spectra for conformer 3a and its deuterated analogue 3Da also display good agreement with experimental results. In light of our comprehensive investigations, we evidenced that steroidal compounds 1 , 2 , and 3 can work as molecular rotors.

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Section: Introductionmentioning

confidence: 99%

Steroidal Molecular Rotors with 1,4-Diethynylphenylene Rotators: Experimental and Theoretical Investigations Toward Seeking Efficient Properties

et al. 2020

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“…The spectroscopic properties of rotors 3 – 5 were investigated using experimental and theoretical methods. Compounds 4 and 5 differ from previously investigated deuterated compounds [23,24] in that they have a rotating moiety composed of a dipolar fluorine‐substituted phenyl group. Compound 4 has one fluorine atom, while compound 5 has two, positioned on the same side of the aromatic ring.…”

Section: Resultsmentioning

confidence: 82%

“…We also considered two different conformations of the rotor molecule in terms of stator orientation, namely “A” and “B” (see Figure 2). We were unable to incorporate the rotational movement of the rotator in the rotor molecule in theoretical calculations, which is an unrealistic circumstance given that many articles demonstrate the rotational movement of the rotator [19–24,28] . It is evident that the rotation of the rotor should influence molecular dynamics, especially in the rotator and axles of rotation.…”

Section: Resultsmentioning

confidence: 99%

“…The change in the intensity ratio can be related to the rotator‘s symmetry, caused by replacing hydrogen with a fluorine atom(s) and/or the orientation of crystallites in the sample. The latter aspect was discussed in detail for other rotors in our previous papers [23,24] . Considering the lack of direct influence of fluorine substitution on triple CC bonds in the axle of rotation of the rotator, we can assume that the intensity of the Raman band assigned to triple CC bonds vibration can be treated as a reference band for the band attributed to C=C aromatic bonds vibration.…”

Section: Resultsmentioning

confidence: 99%

“…The topic was further investigated for compounds with steroidal stators created from two mestranol molecules, [21,22] with the focus of identifying different conformation and packing arrangements in solid state, depending on different rotator substitution, type of solvent, and crystallization temperature. In this paper, we concentrate on exploring molecular dynamics of molecular gyroscopes with 1,4‐diethynylphenylene based rotators and steroidal stators, extending our research into the topic of molecular rotors with deuterated rotators and steroidal stators [23,24] . Using vibrational spectroscopy, electronic circular dichroism (ECD), and impedance spectroscopy methods, we endeavour to show how different substitution with fluorine of the phenyl group of the rotator influences the molecular dynamics of the rotors investigated.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Dynamics of Steroidal Rotors Probed by Theoretical, Spectroscopic and Dielectric Methods

Olszewska,

Mizera,

Ławniczak

et al. 2024

Chemistry A European J

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Our study focuses on molecular rotors with fast‐moving rotators and their potential applications in the development of new amphidynamic crystals. Steroidal molecular rotors with a dipolar fluorine‐substituted phenyl group as the rotator were synthesized and characterized. Three different rotors were investigated with varying numbers of fluorine atoms. A comprehensive analysis was performed using vibrational spectroscopy (Raman, FT‐IR), electronic circular dichroism (ECD), and dielectric response to understand the behavior of the investigated model rotors. The results were supported by theoretical calculations using Density Functional Theory (DFT) methods. The angle‐dependent polarized Raman spectra confirmed the crystallinity of the samples. Nearly frequency and temperature‐independent permittivity suggest low‐frequency librational motion of stators. An in‐depth analysis of ECD spectra revealed high conformational flexibility in solution, resulting in low ECD effects, while in the solid‐state with restricted rotation, significant ECD effects were observed. These findings shed light on the conformational behavior and potential applications of the studied steroidal molecular rotors.

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Vibrational spectroscopic characterization of cyclic and acyclic molecular rotors with 1,4-diethynylphenylene-d4 rotators

Cited by 2 publications

References 15 publications

Steroidal Molecular Rotors with 1,4-Diethynylphenylene Rotators: Experimental and Theoretical Investigations Toward Seeking Efficient Properties

Steroidal Molecular Rotors with 1,4-Diethynylphenylene Rotators: Experimental and Theoretical Investigations Toward Seeking Efficient Properties

Molecular Dynamics of Steroidal Rotors Probed by Theoretical, Spectroscopic and Dielectric Methods

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