128895-75-0Relevant articles and documents
Controlling Mirror Symmetry Breaking and Network Formation in Liquid Crystalline Cubic, Isotropic Liquid and Crystalline Phases of Benzil-Based Polycatenars
Reppe, Tino,Poppe, Silvio,Tschierske, Carsten
supporting information, p. 16066 - 16079 (2020/11/02)
Spontaneous development of chirality in systems composed of achiral molecules is important for new routes to asymmetric synthesis, chiral superstructures and materials, as well as for the understanding of the mechanisms of emergence of prebiotic chirality. Herein, it is shown that the 4,4′-diphenylbenzil unit is a universal transiently chiral bent building block for the design of multi-chained (polycatenar) rod-like molecules capable of forming a wide variety of helically twisted network structures in the liquid, the liquid crystalline (LC) and the crystalline state. Single polar substituents at the apex of tricatenar molecules support the formation of the achiral (racemic) cubic double network phase with Ia (Formula presented.) d symmetry and relatively small twist along the networks. The combination of an alkyl chain with fluorine substitution leads to the homogeneously chiral triple network phase with I23 space group, and in addition, provides a mirror symmetry broken liquid. Replacing F by Cl or Br further increases the twist, leading to a short pitch double gyroid Ia (Formula presented.) d phase, which is achiral again. The effects of the structural variations on the network structures, either leading to achiral phases or chiral conglomerates are analyzed.
The Synthesis and Liquid Crystal Properties of Some Laterally Fluorinated trans-Cyclohexane-1-carboxylate and Benzoate Esters
Gray, G. W.,Hogg, C.,Lacey, D.
, p. 1 - 24 (2007/10/02)
A large number of laterally fluorinated 4-n-alkyl- and -alkoxy-phenyl 4'-n-alkyl- and -alkoxy-bezoates and 4-n-alkylphenyl trans-4'-n-alkyl- and -alkoxy-cyclohexane-1-carboxylates were synthesised.In these compounds, the lateral fluoro-substituent was situated in either the phenol or the carboxylic acid moiety of the molecules for the benzoate esters, but only in the phenol moiety for the trans-cyclohexane-1-carboxylate esters.The nematic thermal stabilities for the fluorophenyl bezoate and trans-cyclohexane-1-carboxylate esters and the fluorobenzoate esters were compared with those for the corresponding non-fluorinated analogues.A nematic thermal efficiency order was derived for the 4-n-alkyl-fluorophenyl 4-n-alkylbezoate and trans-4-n-alkylcyclohexane-1-carboxylate esters, but only in the case of the latter esters, which were extensively examined, was the smectic tendency of the system investigated.Explanations are given for the observed nematic and smectic thermal stabilities of the titled esters, and some of their physical properties are discussed.
