New Liquid Crystals Based on Terminal Fatty Chains and Polymorphic Phase Formation from Their Mixtures

Alamro, Fowzia S.; Ahmed, Hoda A.; Bedowr, Noha S.; Naoum, Magdi M.; Mostafa, Ayman M.; Al-Kadhi, Nada S.

doi:10.3390/cryst12030350

Cited by 10 publications

(12 citation statements)

References 27 publications

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“…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. A terminal fatty acid substituent may stimulate and lower the melting temperature [ 43 , 44 , 45 ]. The resulting mesomorphic characteristics clearly illustrate this.…”

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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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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“…The basic symmetrical and nonsymmetrical configurations of the designed molecule are affected by the number of aromatic units, the length of terminal chains, the alteration of polar spacers in elongating wings, and the mesomeric character of the central molecular core [ 32 ]. There have also been reports on the materials with two and three rings, as well as non-symmetrical molecular shapes and a core unit with one or two different linkages [ 33 , 34 ]. We recently looked into the thermal stability of symmetrical materials having the azomethine linkage as the central connecting group, 4-alkoxybenzoyloxy 4’-phenylmethineazophenyloxy 4”-alkoxybenzoate, in the mesophase [ 35 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Theoretical Investigations of Three-Ring Ester/Azomethine Materials

et al. 2022

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New three-ring ester/azomethine homologues series, (E)-4-((4-hydroxybenzylidene)amino)phenyl 4-(alkoxy)benzoate In, were prepared and their properties were investigated experimentally and theoretically. FT-IR, NMR, and elemental analyses were used to confirm the chemical structures of the synthesized compounds. The mesomorphic activities of the planned homologues were evaluated using differential scanning calorimetry (DSC) and polarized optical microscopy. All of the homologous examined were found to have non-mesomorphic properties. Theoretical calculations using the density functional theory (DFT) were used to validate the experimental data and determine the most stable conformation of the synthesized compounds. All calculated conformers’ thermal properties, dipole moments, and polarizability were discussed. The results show that the terminal alkoxy chain length affects the thermal parameters of the conformers. The correlations between these parameters’ values and the conformer type were demonstrated. The base component was expected to be in two conformers according to the orientation of the N atom of imine-linkage. DFT calculations revealed the more probable of the two possible conformers, and the incorporation of the alkoxy terminal chain in one position affect its geometrical and mesomerphic characteristics.

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“…Different azomethine/ester homologous series of liquid crystals (LCs) have been thoroughly researched to appreciate the relation between chemical structure and mesomorphic attributes because of their unique mesomorphic properties [ 37 , 38 , 39 , 40 , 41 ]. An organic molecule’s molecular shape generally affects the mesophase stability and temperature ranges it can withstand; even a little alteration in molecular geometry can have a significant impact on mesomorphic behavior [ 42 ].Moreover, the Schiff base (azomethine group) serves as a connecting group within the molecule’s rigid core.…”

Section: Introductionmentioning

confidence: 99%

Novel Imidazole Liquid Crystals; Experimental and Computational Approaches

et al. 2022

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The liquid crystalline materials named (E)-4-(2-(4-oxo-5,5-diphenyl-4,5-dihydro-1H-imidazol-2-yl)hydrazineylidene)methyl)phenyl and 4-(alkoxy)benzoate, In, were synthesized and their mesomorphic behaviors were examined. The chemical structures of the produced compounds were confirmed by Fourier-transform infrared spectroscopy (FT-IR), NMR, and elemental analysis. Differential scanning calorimetry (DSC) and polarized optical microscopy were used to investigate the mesomorphic properties of designed heterocyclic derivatives. All the compounds tested had suitable thermal stability and enantiotropic behavior of smectogenic temperature ranges. Furthermore, the enantiotropic smectic C phases were observed to cover all the homologues. Moreover, computational investigations corroborated the experimental findings of the mesomorphic behavior. The reactivity parameters were computed for the derivatives and linked with the experimental data. Theoretical calculations revealed that the polarizability of the studied series increases with the chain length, whereas the HOMO–LUMO energy gap or other reactivity descriptors were less sensitive to the size of the system. On the other hand, the predicted thermodynamic parameters revealed the size dependence of thermal stability of the compounds.

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New Liquid Crystals Based on Terminal Fatty Chains and Polymorphic Phase Formation from Their Mixtures

Cited by 10 publications

References 27 publications

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

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

Experimental and Theoretical Investigations of Three-Ring Ester/Azomethine Materials

Novel Imidazole Liquid Crystals; Experimental and Computational Approaches

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