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Liquid Crystals with Large Negative Dielectric Anisotropy. Part V
Author(s) -
Osman Maged A.
Publication year - 1985
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19850680311
Subject(s) - chemistry , substituent , moiety , alkyl , liquid crystal , group (periodic table) , ethylene , crystallography , dielectric , core (optical fiber) , stereochemistry , organic chemistry , condensed matter physics , optics , physics , catalysis , optoelectronics
Liquid crystals with negative Δϵ can be obtained by incorporating a cyano group in the terminal alkyl substituent or in an ethylene bridge between the cyclic units of the rigid core. The clearing points of such compounds are higher than those of the corresponding derivatives where the cyano group is laterally attached to a phenyl moiety. In compounds where both cyclic units of the rigid core are cyclohexyl, this type of substitution leads to an optimal contribution to ϵ⟂ in contrast to the cyanophenyl derivatives.