Synthesis and mesomorphic properties of non-symmetric liquid crystal dimers stabilized by benzothiazole and substituted aromatic imines
Al-Taifi, E., Yeap, G., Ibrahim, O., Marae, I., Al-Waleedy, S., Bakhite, E. (2023). Synthesis and mesomorphic properties of non-symmetric liquid crystal dimers stabilized by benzothiazole and substituted aromatic imines. EKB Journal Management System, 66(1), 419-429. doi: 10.21608/ejchem.2022.122190.5478
Elham A. Al-Taifi; Guan-Yeow Yeap; Omaima F. Ibrahim; Islam S. Marae; Safiyyah A. H. Al-Waleedy; Etify Bakhite. "Synthesis and mesomorphic properties of non-symmetric liquid crystal dimers stabilized by benzothiazole and substituted aromatic imines". EKB Journal Management System, 66, 1, 2023, 419-429. doi: 10.21608/ejchem.2022.122190.5478
Al-Taifi, E., Yeap, G., Ibrahim, O., Marae, I., Al-Waleedy, S., Bakhite, E. (2023). 'Synthesis and mesomorphic properties of non-symmetric liquid crystal dimers stabilized by benzothiazole and substituted aromatic imines', EKB Journal Management System, 66(1), pp. 419-429. doi: 10.21608/ejchem.2022.122190.5478
Al-Taifi, E., Yeap, G., Ibrahim, O., Marae, I., Al-Waleedy, S., Bakhite, E. Synthesis and mesomorphic properties of non-symmetric liquid crystal dimers stabilized by benzothiazole and substituted aromatic imines. EKB Journal Management System, 2023; 66(1): 419-429. doi: 10.21608/ejchem.2022.122190.5478

Synthesis and mesomorphic properties of non-symmetric liquid crystal dimers stabilized by benzothiazole and substituted aromatic imines

Egyptian Journal of Chemistry
Volume 66, Issue 1, January 2023, Page 419-429  XML PDF (1.05 MB)
Document Type: Original Article
DOI: 10.21608/ejchem.2022.122190.5478
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Authors
Elham A. Al-Taifi1; Guan-Yeow Yeap2; Omaima F. Ibrahim3; Islam S. Marae4; Safiyyah A. H. Al-Waleedy5; Etify Bakhite email 6
1Chemistry Department, Faculty of Science, Sana’a University, Sana’a, Yemen
2Liquid Crystal Research Laboratory, School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
33Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt
4Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt
5Chemistry Department, Faculty of Science, Taiz University, Taiz, Yemen
6Chemistry department, Faculty of Science, Assiut University
Abstract
Two new homologous series of non-symmetric liquid crystal dimers N-(4-(n-(4- (benzothiazol-2-yl)phenoxy)alkyloxy)benzylidene)-4-bromoanilines and N-(4-(n-(4- (benzothiazol-2-yl)phenoxy)alkyloxy)benzylidene)-4-methoxyanilines in which the methylene spacer of CnH2n with even parity of n ranging from 4 to 12 and the substituents of bromo and methoxy attached to respective aniline fragments have successfully been synthesized and characterized. The salient feature of these series can be attributed to the conversion of non-mesogenic units of benzothiazole and aromatic imine units to mesogens through the formation of dimers. All the title compounds exhibit enantiotropic nematic phases. The smectogenic properties also prevail among the series containing Br entity wherein the spacers are C8H16, C10H20 and C12H24. In general, the isotropization temperatures for both series were seen to descend with the increase in the spacer length. Comparison among the compounds possessing Br and OCH3 substituents shows that the anisotropic properties are governed partially by the presence of substituent residing in the aniline unit.
Keywords
non-symmetric dimers; benzothiazole; aromatic imine; enantiotropic nematic; smectic
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