Synthesis and mesomorphic properties of fluoro and isothiocyanato biphenyl tolane liquid crystals

Liao, Yung Ming; Janarthanan, N.; Hsu, Chain‐Shu; Gauza, Sebastian; Wu, Shin Tson

doi:10.1080/02678290601008497

Cited by 11 publications

(6 citation statements)

References 39 publications

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“…As a result, they are useful for formulating eutectic mixtures with a wide nematic range. The Dn values of 5d and 5e are estimated to be around 0.4 in the visible spectral region according to our previous reports [12,13].…”

Section: Effect Of Lateral Methyl Groupmentioning

confidence: 99%

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Synthesis of laterally substituted α‐methylstilbene‐tolane liquid crystals

et al. 2008

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Three series of a-methylstilbene-tolane liquid crystals, 4-[2-(4-alkylphenyl)-1-ethynyl]-49-fluoro-a-methylstilbene (3a-3e), 4-[2-(4-alkylphenyl)-1-ethynyl]-29-methyl-49-fluoro-amethylstilbene (4a-4e) and 4-[2-(4-alkylphenyl)-1-ethynyl]-39-methyl-49-fluoro-a-methylstilbene (5a-5e), were synthesized and their phase transition temperatures characterized. All the a-methylstilbene-tolane liquid crystals exhibit an enantiotropic nematic phase. Compounds 5a-5e, which contain a lateral methyl group at the 3 position of the middle phenyl ring, display low melting points, a wide nematic range and a small enthalpy of fusion. Their potential applications for displays and laser-beam steering are noted.

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Section: Effect Of Lateral Methyl Groupmentioning

confidence: 99%

“…Several molecular structures with high Dn values, e.g. diphenyldiacetylene [10][11][12], biphenyltolane [13], bistolane [14,15], naphthalene tolanes [16], naphthylbistolanes [17] and thiophenylacetylene [18,19] have be widely studied. However, a general problem for these highly conjugated molecules is their high melting points.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of laterally substituted α‐methylstilbene‐tolane liquid crystals

et al. 2008

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“…Previous studies have shown that the mesomorphic properties of laterally substituted liquid crystals are dependent on the type and size of the substituents as well as other factors such as polarizability and=or polarity [8,9]. Mesogens with relatively large lateral substituents such as the CH 3 or OCH 3 groups exhibit lower phase transition temperatures and lower-ordered mesophases as the result of reduced lateral intermolecular attraction [10,11].…”

Section: Introductionmentioning

confidence: 99%

Laterally Brominated Symmetric Liquid Crystal Trimers with (S)-(-)-2-Methylbutyl-4′-(4″-phenyl)benzoate Exhibiting N* and Blue Phases

Yeap

Hng

Ito

et al. 2009

Molecular Crystals and Liquid Crystals

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The series of eight symmetric trimers, 4,4 0 -bis{x-[2-methylbutyl-4 0 -(4 00 -phenyl) benzoateoxy]-3-bromo-4-alkyloxybenzylidene}-1,4-phenylenediamines has been synthesized and characterized. Except pentyl and undecyl homologues, the seven-ring chiral trimers exhibit the enantiotropic N Ã phase. In addition to the N Ã phase, the odd trimers with heptyl and nonyl spacers also exhibit the blue phase with platelet texture. The nematogenic properties of the trimers are attributed to the presence of two lateral bulky bromine atoms in the central mesogenic core. The suppression of mesophase thermal stability is largely due to the increase in molecular breadth at positions the bromine atoms are attached, which results in weaker overall lateral intermolecular attraction. The thermal properties of the trimers are also compared to those of the earlier reported analogous trimers that do not possess any lateral substituents in the mesogenic cores.

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“…Lots of these compounds have been synthesised and used in modern display technology. [24] Polar phenyl-tolane-type liquid crystals with terminal fluorine (1a', 1b', 1d' in Figure 4) were firstly synthesised by Takatsu et al, [25] and their properties were investigated by Wu et al [26] The Δn was found to be 0.37 and the melting points of above 150°C, which make them nearly insoluble in the common liquid crystal mixtures. In this work, more lateral fluorine atoms were introduced into different region of the terminal-fluorinated phenyl-tolane molecule core.…”

Section: Introductionmentioning

confidence: 99%

The effect of lateral fluorination on the properties of phenyl-tolane liquid crystals

Li¹,

Yang²,

Gan³

et al. 2015

Liquid Crystals

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Multifluorinated phenyl-tolane liquid crystals were synthesised by two steps cross-coupling reactions, and their structures were confirmed by nuclear magnetic resonance (NMR), mass spectra (MS) and infrared spectrometry (IR). All of these compounds show only nematic phase, and their melting points decrease dramatically with the introduction of lateral fluorine atom. The physical properties of the compounds were also evaluated. The extrapolated birefringence of the compounds are at the range of 0.32-0.37 at 589 nm, and the dielectric anisotropies exist between 3.1 and 20.6, and the rotational viscosities are as low as 63.7-130.7 mPa·s. With the increase of lateral fluorine substituents in the benzene ring, the Δε value increases tremendously while the clearing points, birefringence and rotational viscosity decrease. These compounds show good solubilities and are favourable to form eutectic mixtures. The effect of lateral fluorine atoms at different region of the core on the dielectric anisotropy and mesophase is also discussed.

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Synthesis and mesomorphic properties of fluoro and isothiocyanato biphenyl tolane liquid crystals

Cited by 11 publications

References 39 publications

Synthesis of laterally substituted α‐methylstilbene‐tolane liquid crystals

Synthesis of laterally substituted α‐methylstilbene‐tolane liquid crystals

Laterally Brominated Symmetric Liquid Crystal Trimers with (S)-(-)-2-Methylbutyl-4′-(4″-phenyl)benzoate Exhibiting N* and Blue Phases

The effect of lateral fluorination on the properties of phenyl-tolane liquid crystals

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