Synthesis and mesomorphic study of new phenylthiophene liquid crystals

Ahmed, Hoda A.; Aboelnaga, Asmaa

doi:10.1080/02678292.2021.2008032

Cited by 14 publications

(12 citation statements)

References 44 publications

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“…The magnitude of any system’s thermodynamic dynamic parameters, as well as its energy, is proportional to its length. This conclusion is supported by Table 2 , which shows that the values of all estimated parameters increased as the length of the terminal alkyl chain increased [ 38 , 39 , 40 , 41 , 42 , 43 , 44 ].…”

Section: Resultsmentioning

confidence: 53%

New Advanced Liquid Crystalline Materials Bearing Bis-Azomethine as Central Spacer

et al. 2022

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In this study, a homologous series of novel liquid crystalline compounds bearing the bis-azomethine central linkage (–CH=N-N=CH–), namely ((1E,1′E)-hydrazine-1,2-diylidenebis(methanylylidene))bis(4,1-phenylene) dialkanoate (In), was synthesized, and the mesophase and thermal properties were investigated theoretically and experimentally. The molecular structures of the prepared compounds were determined using elemental analysis, NMR, and FT-IR spectroscopy. The mesophase transitions were detected by differential scanning calorimetry (DSC), and the mesophases were identified using polarized optical microscopy (POM). The results indicated that the derivative with the shortest length (I5) was purely nematogenic, while the other homologues (I9 and I15) possessed SmC mesophases. The optimal geometrical structures of the investigated group were derived theoretically. The estimated results demonstrated that all homologues were mesomorphic, and their type depended on the length of the terminal chains. Computations based on density functional theory (DFT) were used to explain the experimental data. The calculated dipole moment, polarizability, thermal energy, and molecular electrostatic potential all showed that it was possible to predict the mesophase type and stability, which varied according to the size of the molecule.

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Section: Resultsmentioning

confidence: 53%

New Advanced Liquid Crystalline Materials Bearing Bis-Azomethine as Central Spacer

et al. 2022

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“…According to earlier reports [24,32], the type of the phase and its stability are mostly determined by the dipole moment of the mesogenic component of the molecule, which varies depending on the polar groups present and its steric impact, which subsequently varies based on the volume and location of the substituent. Moreover, adding terminals to an LC material has two opposing effects: first, a decrease in phase stability due to the steric influence of the terminal substituent [33,34], and second, an increase or decrease in molecular anisotropy depending on the polarizing effect of the substituent. The position and polarity of the coupled lateral and terminal groups determine the dipole moment of the entire compound.…”

Section: Thermal and Mesomorphic Propertiesmentioning

confidence: 99%

Mesomorphic, Computational Investigations and Dyeing Applications of Laterally Substituted Dyes

et al. 2022

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Two groups of laterally substituted non-mesomorphic and liquid crystalline materials bearing monoazo group were prepared and investigated via experimental and theoretical techniques. The molecular structures of the designed dyes were evaluated by FT-IR and NMR spectroscopic analyses. Mesomorphic examinations for all synthesized dyes were investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). Results revealed that, the thermal and optical properties of investigated compounds are mainly dependent on their molecular geometry. The optimized geometries of the azo derivatives and their electronic absorption of the dyes were carried out using the B3LYP/6-311G level of the DFT method. The azo dyes were measured for their dyeing performance on polyester fabrics. The dyed fabrics have excellent fastness properties with a color strength of 1.49–3.43 and an exhaustion rate of 82–64%. The chemical descriptor parameters of disperse azo dyes in gas phase were calculated and correlated with dyeing parameters.

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“…Numerous rod-like LC materials have been generated from Schiff bases and extensively examined [ 26 , 27 , 28 , 29 , 30 , 31 ]. Different impacts, including the orientation of the ester group within the rigid core, the position of the Schiff base unit with regard to the ester group, the lateral substitution [ 32 ], and the length of the terminal chain [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], have been studied.…”

Section: Introductionmentioning

confidence: 99%

Design of Liquid Crystal Materials Based on Palmitate, Oleate, and Linoleate Derivatives for Optoelectronic Applications

et al. 2023

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Herein, liquid crystalline derivatives based on palmitate, oleate, and linoleate moieties with azomethine cores were synthesized, and their physical, chemical, optical, and photophysical properties were investigated in detail. The mesomorphic activity of these materials was examined through polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The observed results revealed that the stability of the thermal mesophase depends on the terminal polar as well as on the fatty long-chain substituents. Purely smectogenic phases were detected in all three terminal side chains. A eutectic composition with a low melting temperature and a broad smectic A range was found by constructing a binary phase diagram and addressing it in terms of the mesomorphic temperature range. The energy bandgap of the palmitate-based derivative (Ia) was determined as 3.95 eV and slightly increased to 4.01 eV and 4.05 eV for the oleate (Ib) and linoleate (Ic) derivatives, respectively. The optical constants (n, κ, εr, and εi) were extracted from the fitting of measured spectroscopic ellipsometer data. The steady-state spectra of these samples exhibited a broad emission in the range 400–580 nm, which was found to be blue shifted to 462 nm for both Ib and Ic derivatives. The average fluorescence decay lifetime of the Ia derivative was found to be 598 ps, which became faster for the Ib and Ic derivatives and slower for the sample with a chloride end polar group.

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Synthesis and mesomorphic study of new phenylthiophene liquid crystals

Cited by 14 publications

References 44 publications

New Advanced Liquid Crystalline Materials Bearing Bis-Azomethine as Central Spacer

New Advanced Liquid Crystalline Materials Bearing Bis-Azomethine as Central Spacer

Mesomorphic, Computational Investigations and Dyeing Applications of Laterally Substituted Dyes

Design of Liquid Crystal Materials Based on Palmitate, Oleate, and Linoleate Derivatives for Optoelectronic Applications

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