Synthesis and thermal properties of liquid crystalline compounds containing carbazolyl group

Citation
K. Matsumoto et N. Koide, Synthesis and thermal properties of liquid crystalline compounds containing carbazolyl group, MOLEC CRYST, 365, 2001, pp. 1037-1045
Citations number
9
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Volume
365
Year of publication
2001
Pages
1037 - 1045
Database
ISI
SICI code
Abstract
New liquid crystalline compounds containing carbazolyl moiety as part of th e mesogenic group were synthesized. 2-(9-Methylcarbazolyl)-4-alkoxybenzoate and 2-(9-methylcarbazolyl)-4-trifluoromethylbenzoate did not show any text ures by polarizing optical microscopy (POM) measurement. However, 2-(9-meth ylcarbazolyl)-4-cyanobenzoate and 2-(9-metylcarbazolyl)-4-alkanecarboxybenz oate ate show schlieren texture. 2-(9-methylcarbazolyl)-4-cyanobenzoate has two phase transition temperatures on both heating and cooling process. By X-ray diffraction Measurement of this compound, only one weak broad peak wa s detected at the mesomorphic temperature in the wide-angle region. Therefo re, the LC phase of the compound wag assigned to a nematic. 2-(9-Methylcarb azolyl)-4-pentynylcarboxybenzoate shows only one phase transition on heatin g process. However, the compound shows two phase transition temperatures on cooling processes. By X-ray diffraction measurement, the compound indicate s two broad peaks at around 4.5 and 19.0 degree. These LC phases would be a ssigned to a cybotactic nematic phase based on the shorten molecular length of the calculated value and the optical texture.