Liquid crystalline banana‐shaped monomers derived from 2,7‐naphthalene: synthesis and properties

Rahman, Lutfor; Asik, Jahimin; Kumar, Sandeep; Tschierske, Carsten

doi:10.1080/02678290802513808

Cited by 43 publications

(20 citation statements)

References 35 publications

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“…The products were TLC pure and give transition temperatures as given in the literature. [24] 2.2.3. Preparation of 4-n-alkoxy phenylazo benzoic acids (An)…”

Section: Preparation Of Ethyl 4-n-alkoxy Phenylazo Benzoates (Bn)mentioning

confidence: 98%

“…[24] Ethyl-4-hydroxyphenylazo benzoate (0.001 mol) in alcoholic KOH (0.02 mol) to which the appropriate amount of 1-bromo-n-alkane (0.0012 mol) was added drop-wise while stirring. Stirring was continued at room temperature for 2 days.…”

Section: Preparation Of Ethyl 4-n-alkoxy Phenylazo Benzoates (Bn)mentioning

confidence: 99%

“…[21] Therefore, the azo-ester mesogens were chosen because of their remarkable thermal stability; in addition, they are attractive with regard to their photo-induced effect. [21][22][23][24][25][26][27] The present work aims to prepare some three-ring azo/ester compounds, In a-h , possessing two unsymmetrical wing groups. The first wing, attached to the phenyl azo moiety, is an alkoxy group with chain length that varies between 6 and 12 carbons.…”

Section: Introductionmentioning

confidence: 99%

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Polarity and steric effect of the lateral substituent on the mesophase behaviour of some newly prepared liquid crystals

et al. 2015

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Eight homologous series of 2-(or 3-) substituted phenyl 4ʹ-(4ʺ-alkoxy phenylazo) benzoates (In a-h ) were prepared in which, within each homologous series, the length of the terminal alkoxy group varies between 6, 8, 10 and 12 carbons, while the other substituent, X, is a laterally attached polar group that alternatively changed from CH 3 , H, F, Br and CN. Compounds prepared were characterised by infrared and 1 H-NMR spectroscopy, and their mesophase behaviour investigated by differential scanning calorimetry and identified by polarised light microscopy. The results were discussed in terms of polarity and steric effects. The stability of the mesophase was correlated once with the dipolar anisotropy of the whole molecule and another with the dipolar anisotropy of the substituent, X. A comparative study was made between the investigated compounds and their previously prepared linear 4-substituted isomers, namely 4-substituted phenyl 4ʹ-(4ʺ-alkoxy phenylazo) benzoates (In i-k ).

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“…The products were TLC pure and give transition temperatures as given in the literature. [24] 2.2.3. Preparation of 4-n-alkoxy phenylazo benzoic acids (An)…”

Section: Preparation Of Ethyl 4-n-alkoxy Phenylazo Benzoates (Bn)mentioning

confidence: 98%

Section: Preparation Of Ethyl 4-n-alkoxy Phenylazo Benzoates (Bn)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polarity and steric effect of the lateral substituent on the mesophase behaviour of some newly prepared liquid crystals

et al. 2015

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“…The combination of molecular tilt and layer polarization makes each smectic layer structurally chiral 2. Research in the field of bent‐core mesogens has been concentrated mainly on low‐molecular‐weight bent‐core mesogens of various chemical structures 3–9. Generally, liquid‐crystalline polymers are of interest due to their special material properties, combining the typical features of polymers (elasticity, mechanical stability) with LC properties (ferroelectric or anti‐ferroelectric switching under an applied external field accompanied by optical effects10).…”

Section: Introductionmentioning

confidence: 99%

A Liquid‐Crystalline Co‐Polysiloxane with Asymmetric Bent Side Chains

Bubnov¹,

Novotná²,

Pociecha³

et al. 2010

Macro Chemistry & Physics

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A co‐polysiloxane has been prepared with an asymmetric bent side group based on a liquid‐crystalline monomer showing a B2 (SmCP) phase. In order to dilute the side chain mesogens along the polymer backbone, octyl side chains were also incorporated. X‐ray studies confirmed that the resulting co‐polysiloxane exhibits a liquid‐crystalline layered phase, the siloxane polymer chains being microphase segregated from the incompatible side chain mesogens. The mesophase of polymer exhibits a homeotropic structure that can be successfully aligned by unidirectional shear. This phase does not exhibit polar switching under an applied electric field unlike the bent‐core monomer used as the side chains of this polymer. This can be caused by the homeotropic alignment of the polymer samples. magnified image

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“…16 Since then, some other bent shaped molecules containing azobenzene moieties have been synthesized, the majority of these molecules presenting interesting liquid crystalline properties. [16][17][18][19][20][21][22][23][24] The goal of the paper is to extent the classes of bent shaped molecules containing the azo photoisomerisable group. The paper presents the synthesis of some bent-core liquid crystals based on a 1,3-dihydroxy-benzene core with two symmetric wings containing each three benzene rings connected via esteric, azomethinic and azo groups.…”

Section: Introductionmentioning

confidence: 99%

Symmetric Bent-core Liquid Crystals of Some Schiff Bases Containing Azo Linkage

Ciobanu¹,

Carlescu²,

Lisă³

et al. 2014

Croat. Chem. Acta

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Abstract. The paper presents the synthesis and liquid crystalline properties of some new symmetric bentcore liquid crystals containing a 1,3-dihydroxybenzene central core disubstituted with mesogenic units consisting of three aromatic rings connected through esteric, azomethinic and azo groups. The wings are ended with terminal acyloxy or alkyloxy chains containing 6 to 10 carbon atoms. Compounds were obtained by the condensation reactions between some 4-((4-alcanoyloxyphenyl)azo)benzaldehydes or 4-((4-alkyloxyphenyl)azo)benzaldehydes with the 1,3-phenylene bis(4-aminobenzoate) core. The new synthesized compounds were characterized from structural point of view ( 1 H NMR, 13 C NMR, MS spectroscopy) and liquid crystalline properties (polarizing optical microscopy and differential scanning calorimetry). All the banana shaped compounds presented enantiotropic liquid crystalline properties, with a wideranging stability of mesophases both on heating and cooling cycles. The synthesized compounds presented a good thermal stability in the existence range of the mesophases as evidenced by thermogravimetric studies. (doi: 10.5562/cca2150)

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Liquid crystalline banana‐shaped monomers derived from 2,7‐naphthalene: synthesis and properties

Cited by 43 publications

References 35 publications

Polarity and steric effect of the lateral substituent on the mesophase behaviour of some newly prepared liquid crystals

Polarity and steric effect of the lateral substituent on the mesophase behaviour of some newly prepared liquid crystals

A Liquid‐Crystalline Co‐Polysiloxane with Asymmetric Bent Side Chains

Symmetric Bent-core Liquid Crystals of Some Schiff Bases Containing Azo Linkage

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