- Synthesis and mesomorphic properties of new columnar liquid crystal containing 1,3,5-triiminebenzene with pendant 1,3,4-thiadiazole Group
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A novel discotic liquid crystal series based on 1,3,5-benzenetrisazomethine derivatives with three pendant 2-amino-5-(4′-n-alkoxy)phenyl-1,3,4- thiadiazole has been synthesized, which is the first columnar molecules containing 1,3,4-thiadiazole moiety exhibiting a discotic liquid crystal. The molecular structure of compounds was confirmed by FT-IR, 1H-NMR, and mass spectroscopy and elemental analysis. The electron excitation properties of these compounds were investigated by UV-vis absorption spectroscopy. Their liquid crystalline properties were studied by polarizing optical microscopy and differential scanning calorimetry. The formation of a columnar mesophase was found to be dependent on the number of methylene unit in alkoxy side chains.
- Al-Malki, Mustafa K.S.,Hameed, Ayad S.,Al-Dujaili, Ammar H.
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- Synthesis and properties of Schiff's bases derived from 1,3,4-thiadiazole as a mesogenic unit
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Some new liquid crystalline 2,5-disubstituted 1,3,4-thiadiazole derivatives incorporating a central group (-CH=N-) have been synthesized by treating 2-amino-5-(4-alkoxyphenyl)-1,3,4-thiadiazole with corresponding p-alkoxybenzaldehyde. Their structures have been characterized with Elementary Analysis, IR, 1HNMR and MS, and their properties were determined by using DSC and Texture. All 12 compounds are enantiotropic liquid crystals, and most of them exhibit nematic mesomorphism and broad smectic C mesomorphic ranges. Several compounds show only the smectic C mesophase. By introducing an -OH group into the phenyl ring the thermal stability of the mesophases increases due to the formation of a hydrogen bond.
- Xu,Lu,Tai
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p. 151 - 159
(2007/10/03)
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