16571-39-4Relevant academic research and scientific papers
Effects of Polysubstitution on Mesomorphic Properties: Chloro Derivatives of 4-Methoxyphenyl 4-(Phenyliminomethyl)benzoate and Related Compounds
Matsunaga, Y.,Yasuhara, K.
, p. 239 - 249 (2007/10/02)
The effects of mono-, di-, and trichloro substitution of one of the end phenyl rings upon the nematic-isotropic transition temperature have been studied employing seven three-ring systems with a terminal methoxyl group, in which the linkage groups are -CO-O- and -CH=N-.The transition temperatures in these compounds were mostly in this order: 4-Cl > 2,4-Cl2 > 2,3,4-Cl3 > 3,4-Cl2 > unsubstituted > 2,3-Cl2 > 2-Cl or 3-Cl.Both the substituents on the 2- and 3-positions drastically lowered the transition temperature of the parent compound and the extent of depression by the former substituent varied by a factor of more than two when the -CH=N- group nearby was inverted.The condition that the thermal stabilities of mesophases and the temperature ranges over which the mesophases exist must be considerable in a parent compound was not necessarily required for the appearance of an enantiotropic nematic-isotropic transition in laterally substituted derivatives.Keywords: Liquid crystals; nematic; smectic; lateral substituent
