On the balance between nematic and smectic phases in 2′,3′-difluoro-4,4″-dialkyl-p-terphenyls

Wąchała, Agata; Pytlarczyk, Marta; Kula, Przemysław

doi:10.1080/02678292.2019.1590656

Cited by 14 publications

(6 citation statements)

References 19 publications

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“…For 1T0, T m = 129 C and ÁH m = 97 J g À1 , while for 1T1, T m = 180 C and ÁH m = 134 J g À1 . In contrast, 1T2 is a mesogenic compound (Wą chała et al, 2019). The DSC analysis, shown in Fig.…”

Section: Figurementioning

confidence: 99%

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Phase behaviour and crystal structures of 2′,3′-difluorinated p-terphenyl derivatives

et al. 2021

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The crystal structures of difluorine derivatives of p-terphenyls (nTm) have been determined by single-crystal X-ray diffraction. For the unsymmetrical substituted compounds 2′,3′-difluoro-4-methyl-p-terphenyl (1T0, C19H14F2) and 4-ethyl-2′,3′-difluoro-4′′-methyl-p-terphenyl (1T2, C21H18F2), the crystal structure is disordered, with molecules statistically entering the crystal in up and down orientations, with full superposition of all the atoms, except for those of the terminal groups (H/methyl for 1T0 and methyl/ethyl for 1T2). For triclinic 2′,3′-difluoro-4,4′′-dimethyl-p-terphenyl (1T1, C20H16F2), with the space group P\overline{1}, the two crystallographically independent molecules have the same conformation, which is different from monoclinic 1T0 (space group C2) and 1T2 (space group C2/c). A common feature of the conformation of the three compounds is the noncoplanar twisted arrangement of the three rings of the p-terphenyl moiety. Two-dimensional (2D) Hirshfeld fingerprint plots are consistent with H...H and C...H contacts in the crystal packing. For the three compounds, the phase behaviour has been investigated by POM (Petra/Osiris/Molinspiration) and differential scanning calorimetry (DSC) analysis. 1T2 is mesogenic, with enantiotropic nematic behaviour.

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Section: Figurementioning

confidence: 99%

“…The synthesis of 1T0, 1T1 and 1T2 was performed according to the procedure already reported by Wą chała et al (2019). Prismatic colourless crystals of the three compounds suitable for X-ray analysis were obtained by slow evaporation at 296 K from a 50:50 (v/v) acetone-ethanol solution.…”

Section: Synthesis and Crystallizationmentioning

confidence: 99%

Phase behaviour and crystal structures of 2′,3′-difluorinated p-terphenyl derivatives

et al. 2021

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“…The fluorinated terphenyls are promising components of ferroelectric mixtures because of low viscosity, low conductivity, and high chemical and thermal stability. 18,19 Appropriately functionalised terphenyls exhibit the following properties: nematics with negative dielectric anisotropy, 20 medium birefringence nematics, 21 smectics, 22 cholesterics, 23 ferroelectrics, 24 antiferroelectrics 15 and twist-bend nematics. 25 Our main aim is to check how the linking bridge type ('X' = -CH 2 O-or -COO-) connected to the alkyl chain of various lengths ('(CH 2 ) n ', n = 3 or 6) affects the self-assembly behaviour and the crystallization kinetics of the CH2O.3 and COO.6 compounds.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of the linking bridge type on the self-assembly behaviour of 2′,3′-difluoroterphenyl derivatives

Drzewicz,

Jasiurkowska-Delaporte,

Kula

et al. 2024

Phys. Chem. Chem. Phys.

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“…It assumes that in order for a compound to exhibit liquid crystal properties, it must consist of a rigid core and appropriate substituents in the terminal and lateral positions. The most commonly used cores include derivatives of oligophenyls (e.g., terphenyl [ 40 , 41 ] and quaterphenyl [ 42 ]) and tolanes (e.g., phenyltolane [ 43 , 44 , 45 , 46 ] and bistolane [ 47 ]), which may also have other linking groups, e.g., ester and ether [ 48 ]. To obtain a suitable shape anisotropy, aliphatic chain(s) and/or strong dipole moment generating groups, such as cyano (CN) [ 49 ] and isothiocyanate (NCS) [ 50 , 51 ], are used as terminal substituents.…”

Section: Introductionmentioning

confidence: 99%

New-Generation Liquid Crystal Materials for Application in Infrared Region

Harmata

Herman

2021

Materials

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This study presents 13 new organic compounds with self-assembling behavior, which can be divided into two groups. The first synthesized group includes compounds based on 4′-(trifluoromethoxy)-[1,1′-biphenyl]-4-yl-4-(trifluoromethoxy) benzoate core, and the second includes compounds based on 4-((4-(trifluoromethoxy)phenyl)ethynyl)phenyl-4-(trifluoromethoxy) benzoate core. They differ in the number and location of the fluorine atom in the lateral position. Mesomorphic properties, phase transition enthalpies, refractive indices, birefringence, and MWIR (mid-wavelength infrared) spectral properties of the compounds were investigated, and the results were compared with currently used materials. The influence of the length of the core as well as type and position of substituents in the molecular core was analyzed. The lack of aliphatic protons in the molecular structure generated unique infrared properties.

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On the balance between nematic and smectic phases in 2′,3′-difluoro-4,4″-dialkyl-p-terphenyls

Cited by 14 publications

References 19 publications

Phase behaviour and crystal structures of 2′,3′-difluorinated p-terphenyl derivatives

Phase behaviour and crystal structures of 2′,3′-difluorinated p-terphenyl derivatives

Effect of the linking bridge type on the self-assembly behaviour of 2′,3′-difluoroterphenyl derivatives

New-Generation Liquid Crystal Materials for Application in Infrared Region

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