Chemical and physical aspects of recent bent-shaped liquid crystals exhibiting chiral and achiral mesophases

Kaur, Supreet; Punjani, Vidhika; Yadav, Neelam; Barthakur, Abinash; Baghla, Anshika; Dhara, Surajit; Pal, Santanu Kumar

doi:10.1080/02678292.2022.2028313

Cited by 6 publications

(3 citation statements)

References 242 publications

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“…[47,48] Eventually, several research groups described the observation of ferroelectric response in other bent-core molecular architectures with distinct structural organizations and inter-and intramolecular interactions. [25][26][27]49,50] Thus, in continuation of our interest in investigating cybotactic clustering in the nematic phase, herein we report the synthesis and material characterization of newly designed polar bent-core molecules n/Y (Figure 1). The new materials derived from 3-amino-2-methylbenzoic acid as the central core, are tethered to À CN or À NO 2 terminus with an ester linker on one side and an H-bonded imine and an ester linker with flexible alkyl chains (n = 6 and 8) at the other end.…”

Section: Introductionmentioning

confidence: 99%

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Nematic Phase of Polar Unsymmetrical Bent‐Core Molecules

et al. 2023

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In liquid crystalline systems, the presence of polar groups at lateral or terminal positions is fundamentally and technologically important. Bent-core nematics composed of polar molecules with short rigid cores usually exhibit highly disordered mesomorphism with some ordered clusters that favourably nucleate within. Herein, we have systematically designed and synthesized two new series of highly polar bent-core compounds comprised of two unsymmetrical wings, highly electronegative À CN and À NO 2 groups at one end, and flexible alkyl chains at the other end. All the compounds showed a wide range of nematic phases composed of cybotactic clusters of smectic-type (N cyb ). The birefringent microscopic textures of the nematic phase were accompanied by dark regions. Further, the cybotactic clustering in the nematic phase was characterized via temperature-dependent XRD studies and dielectric spectroscopy. Besides, the birefringence measurements demonstrated the ordering of the molecules in the cybotactic clusters upon lowering the temperature. DFT calculations illustrated the favourable antiparallel arrangement of these polar bent-core molecules as it minimizes the large net dipole moment of the system.

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Section: Introductionmentioning

confidence: 99%

“…However, the biaxial ordering of BCNs is yet to be proved unequivocally [47,48] . Eventually, several research groups described the observation of ferroelectric response in other bent‐core molecular architectures with distinct structural organizations and inter‐ and intramolecular interactions [25–27,49,50] …”

Section: Introductionmentioning

confidence: 99%

Nematic Phase of Polar Unsymmetrical Bent‐Core Molecules

et al. 2023

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“…Through the doping of the bent-shaped molecules with photoisomeric functional groups, the BPLC can also exhibit excellent light-induced color variance or photoinduced phase transition performances [29,30]. After years of innovative research, it has been proven that the molecular structures and functional groups of the bent-shaped molecules play a decisive role in the performance of the BP mixtures [31][32][33]. To date, different compounds with 2,5-disubstituted furan, 2,5-disubstituted pyrrole, 2,5-disubstituted oxadiazole, or 1,3-disubstituted benzene ring as the core structure have been successfully synthesized and used to stabilize the blue-phase temperature range [9,[34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Thiophene-Based Derivatives and the Effects of Their Molecular Structure on the Mesomorphic Behavior and Temperature Range of Liquid-Crystalline Blue Phases

Wang,

Song,

et al. 2023

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The development of blue-phase liquid crystal (BPLC) materials with a wide temperature range is of great significance for practical applications in the optoelectronic field. In the study, bent-core derivatives with a 3-hexyl-2,5-disubstituted thiophene central ring in the λ-shaped molecular structure were designed and synthesized. Their mesomorphic behavior and effect on the blue-phase (BP) temperature range were investigated. Interestingly, a BP was achieved both during the heating and cooling processes by doping with a proper concentration of chiral compound into the thiophene bent-shaped molecule with high rigidity, while derivatives with fluorine atom substitution only exhibited cholesteric phase no matter how many chiral compounds were added. This result proved that BP is highly sensitive to the molecular structures of bent-shaped molecules. Moreover, the BP temperature range was broadened when adding these molecules into a BPLC host, which thus improved the BP temperature range from the initial value, no more than 4 °C, to as much as 24 °C. The experimental phenomena were reasonably explained through molecular simulation calculations. The study may provide some experimental basis and theoretical guidance for the design of novel bent-shaped molecules and BPLC material with a wide temperature range.

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