Preparation and Liquid Crystalline Behaviour of a Series of Semifluorinated Allylic Monomers

Abstract

A series of smectic liquid-crystalline 4,4 0 -biphenyl derivatives incorporating a perfluorinated segment and an allylic part have been prepared and their mesomorphic properties investigated. The preparation of these compounds has been done from 2-F-butylethyl iodide, the 2-F-hexylethyl iodide or the 2-F-octylpropanoic acid. The physical properties of these novel fluorinated materials are commented and illustrated in comparison with four homologous allylic series previously described. The choice of the molecular design of these monomers allows us to obtain dimorphism and high mesomorphic range determined from differential thermal analysis and the light microscopy.

Dimesogenic compounds consisting of cholesterol and fluorinated azobenzene moieties: dependence of liquid crystal properties on spacer length and fluorination of the terminal tail

“…26 Boden et al 27 showed that monofluorination of hexahexyloxy triphenylene resulted in the formation of the columnar LC phase, most probably the D h phase. De Givenchy et al 28 recently reported that inclusion of perfluorinated tails in a series of 4,49-biphenyl derivatives bearing the allylic group formed smectic phases of high order, the S E and S F phases. More recently, it was demonstrated by Bilgin-Eran et al 29 that they could prepare a series of LC chloro-bridged dinuclear Pd organyls carrying fluorinated alkyl chains.…”