The isomerization kinetics of a liquid crystalline azobenzene dimer, comprising cyanoazobenzene and naphthalene (NAZ6), were investigated at the air–water interface.

A novel approach to designing liquid crystal dimers with high chirality is described. The synthesis, and properties of several new optically active unsymmetrical fluorescent belonging four homologous series are presented. These oligomesogens possess pro-mesogenic cholesterol as a chiral moiety covalently linked bent aromatic (chalcone) core through trimethylene (4-oxybutanoyl)/tetramethylene (5-oxypentanoyl)/pentamethylene (6-oxyhexanoyl)/heptamethylene (8-oxyoctanoyl) central spacer giving...

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This research presents the synthesis and analysis of a novel series mesogenic dimers comprising cyanobiphenyl azonaphthyl units. Structural validation was performed using FT-IR, 1H-NMR, 13C-NMR, mass spectrometry, and...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTLiquid Crystal Abrikosov Flux Phase: The Exclusive Wide Thermal Range Enantiotropic OccurrenceChannabasaveshwar V. Yelamaggad, Ammathnadu S. Achalkumar, Nilesh L. Bonde, and Ashish K. PrajapatiView Author Information Centre for Liquid Research, Jalahalli, Bangalore 560 103, India, Applied Chemistry Department, Faculty of Technology Engineering, Kalabhavan, M. University Baroda, P.O. Box No. 51, Vadodara, India 390 002 Cite this: Chem. Mater....

We measured the splay (K11) and bend (K33) elastic constants in nematic phase of a liquid crystal with T-shaped molecules. find that ratio, K33/K11 ≃1 entire range except very close to Sm-A (SN) transition. Both K33 K11 show pretransitional divergence as SN transition is approached from higher temperature. The suggests length (L) effective width (D) ratio (i.e., L/D ) significantly smaller due presence long flexible lateral group, compared rigid rodlike It argued apart extra contribution...

Abstract The conventional H-shaped symmetrical dimeric liquid crystalline compounds were synthesised and their thermotropic properties studied by hot-stage of a polarising microscope. These consist azoester–ether mesogenic unit with different polar-terminal substituents (–NO2 –Cl) for series I II, interconnected through flexible spacer (n = 4) via ether linking to itself at the lateral hydroxyl position azoesters. All these characterised combination elemental analysis standard spectroscopic...

In the current study, one new series of symmetrical liquid crystalline homologous dimers with a rigid aromatic core azo and azomethine group were synthesized using an ether-linking group. Several spectroscopic methods, including FT-IR, 1H-NMR, 13C-NMR elemental analysis, used to describe synthesised dimers. The differential scanning calorimetry (DSC) polarised optical microscopy (POM) assess their mesomorphic properties. results showed that number methylene spacers significantly affected...

Abstract Two mesogenic homologous series of H-shaped symmetrical dimers were synthesised and their thermotropic properties studied by differential scanning calorimetry on a hot-stage polarising microscope. These compounds consisted two units azoester interconnected through tetramethylene flexible spacers (n = 4) ether linkage resulting in the structure 'H-shaped' dimeric compounds. The difference between was terminal substituents (–CH3 for I –OCH3 II) attached mesogens at one terminus. All...

Two new mesogenic homologous series containing 6-nitrobenzothiazole moiety at the terminus of molecule, viz 2-(4′-n-alkoxyphenylazo)-6-nitrobenzothiazoles and 2-[4′-(4"-n alkoxybenzoyloxy) phenylazo]-6-nitrobenzothiazoles were synthesized. The molecular structures these compounds both have been characterized by elemental analysis, FTIR, NMR spectral studies. mesomorphic behavior has studied using mainly polarized microscopy in some cases differential scanning calorimetry as well. All nine I...

The mesomorphism of three series compounds has been studied. Compounds in Series I [4-nitrobenzoic acid N′-(4′-n-alkoxybenzoyl)hydrazides] were synthesised by the Schotten–Baumann reaction 4-nitrobenzhydrazide with 4-n-alkoxybenzoyl chloride dry pyridine. resulting cyclised using phosphoryl to give bent-shaped mesogenic 2-(4′-nitrophenyl)-5-(4″-n-alkoxyphenyl)-1,3,4-oxadiazoles (Series II) or, phosphorus pentasulphide, 2-(4′-nitrophenyl)-5-(4″-n-alkoxyphenyl)-1,3,4-thiadiazoles III). These...

New unconventional T-shaped non-symmetrical dimeric liquid crystalline compounds have been synthesised and their thermotropic properties studied on the hot-stage of a polarising microscope. These consist an azo-ester mesogenic unit with range terminal substituents (–CH3, –OCH3, –NO2 or –Cl) at one end, interconnected by flexible spacer (n = 4, 5 10) via ether ester linking units to biphenyl moiety lateral hydroxyl position azo-ester. All were characterised using combination elemental...

Abstract Two extensive homologous series of H-shaped symmetrical dimers were synthesized and their thermotropic properties studied by differential scanning calorimetry on a hot-stage polarizing microscope. These compounds consist two mesogenic units azoester interconnected through flexible spacers (n = 4) resulting in the structure ‘H-shaped’ dimeric compounds. The difference between is terminal substituents (–CH3 for I –OCH3 II) attached mesogens at one terminus. All these found to be...

Abstract Four mesogenic homologous series have been synthesized by fixing a rigid 4-substituted phenylazo group to resorcinol moiety. In I and II, one phenolic -OH is esterified 4-n-alkoxybenzoyl groups; in III IV both the groups are groups. All homologues of exhibit low melting smectic C phases. Monoesters having free lateral hydroxy with strong hydrogen bonding, high temperature nematic The effect different substituents on mesomorphic properties discussed. One homologue was doped chiral...

We have synthesized a novel mesogenic azobenzene molecule and studied its monolayer film properties at air-water interface (Langmuir film) air-solid (Langmuir-Blodgett film). The material, H-shaped dimer bis[5-(4'-n-dodecyloxy benzoyloxy)-2-(4''-methylphenylazo)phenyl] adipate (12D1H) exhibits smectic C phase between 51 48 degrees on cooling. Surface manometry studies showed the formation of stable interface. Brewster angle microscopy (BAM) that liquid domains coexisting with gas region...