81005-00-7Relevant articles and documents
Synthesis of aromatic liquid crystals with asymmetric diester based on rod-like multi-ring system by two-step esterification method
Zheng, Min-Yan,Wei, Yong-Sheng,Geng, Wei,Gu, Yuan-Zi
, p. 19 - 27 (2016/07/14)
A novel method of two-step esterifications was developed to synthesize compounds with asymmetric double ester groups. By using this method, six rod-like double ester compounds were prepared with p-hydroxy benzaldehyde, p-hydroxy benzoic acid bicyclohexyl carboxylic acid, cyclohexyl benzoic acid and biphenyl carboxylic acid substituted by n-propyl and n-pentyl as main reactants. The structures and properties of target compounds were confirmed by IR, MS, 1H NMR, elemental analysis, differential scanning calorimetry (DSC) and hot stage polarizing optical microscope (HS-POM). Typical yields of the target molecules were more than 70%. All the molecules have mesophases with the textures of nematic type, indicating a rod-like molecule with a longer rigid skeleton can keep its mesophases. There was no clearing point observed for any of the derivatives before they decomposed so that the temperature ranges of the mesophases could not be determined. The energy differences between frontier molecular orbitals (HOMO-LUMO) (Eg) of the compounds were calculated by cyclic voltammetry (CV). The terminal ring system has an obvious influence on the energy levels and the energy gaps (Eg).
Synthesis of multiring azo-benzoic acid liquid crystalline molecules and their special photosensitive property
Zheng, Min-Yan,Wei, Yong-Sheng,Geng, Wei,Guo, Nai-Ni,Zhang, Ping
, p. 1 - 13 (2015/03/18)
10 new rod-like azo benzoic acid liquid crystals belonged to three series have been prepared, in which trans-cyclohexyl benzene, biphenyl or bi-trans-cyclohexyl carboxylic acid mesogenic cores with ethyl, n-propyl, n-butyl or n-pentyl substituents were connected with azo benzoic acid. Meantime, a simple method was developed in synthesizing compounds bearing both ester and carboxyl groups in one-step reaction. All these compounds have been characterized on the basis of their spectral data, differential scanning calorimeter (DSC) and hot stage polarizing optical microscope (HS-POM). All these compounds have higher thermo-stability. 8 of these compounds have liquid crystalline properties. Their temperature ranges of mesophase have not been obtained, resulting from all the compounds decomposed before their clearing points. Although these compounds are photosensitive in solution under illumination of UV light (365nm), they can't do trans-cis isomerization in their mesophses, indicating the super stabilities of the trans isomer in mesophase.
SYNTHESIS AND LIQUID CRYSTAL PROPERTIES OF SUBSTITUTED 5-(ARYLCARBONYLOXY)-2-(p-CYANOPHENYL)PYRIMIDINES
Mikhaleva, M. A.,Igonina, G. A.,Savel'ev, V. A.
, p. 320 - 325 (2007/10/03)
Liquid crystal p-substituted benzoates, biphenylcarboxylates, and benzoyloxybenzoates were obtained on the basis of 5-hydroxy-2-(p-cyanophenyl)pyrimidine.The development of nematogenicity by the esters due to the p-cyanophenyl grouping was noted, and the appearance of the smectic mesophase by the variation of the ring framework of the acid fragment of the molecule was investigated.
