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An inversion in the cholesteric phase has been found to occur with change in temperature. Additionally, the material under investigation was found to exhibit unusual ferroelectric properties on cooling from the chiral nematic phase. We report the synthesis and physical properties, including pitch and polarization data, for (S)-4-noctyloxy-2,3-difluorobiphenyl-4'-yl 3-difluorobiphenyl-4'-yl 3-fluoro-4-(2-fluorooctanoyloxy)benzoate.

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The preparation of a series of 1-substituted ferrocene derivatives is described. The structure of the substituent was varied systematically in order to determine the structural limits within which mesogenic behaviour is retained. The compounds are particularly useful for stabilizing the nematic phase, the range of which was increased substantially by extending the aromatic core of the substituent. Selective lateral fluorination was successfully used to lower the nematic temperatures as well as to suppress any smectic phases. Derivatives with no more than two rings in the core only display the crystal smectic B phase. The significance of substituents on the cyclopentadienyl rings is discussed with reference to their electronic properties and their effect on the stability of the compounds.

Research in the late 1940s in academic institutions, most notably the University of Hull in the UK, led to the development of liquid crystal display technology in the 1970s, which has subsequently had a large impact throughout the world. The liquid crystal technology is based on simple organic molecules. Since the late 1980s, some liquid crystal scientists have turned their attention to investigating the effect of introducing a metal atom into the systems. This review focuses on the major developments in the field of ferrocenyl-containing liquid crystals in which the organometallic group is situated in a terminal position with respect to the core of the molecule. Metallomesogens with terminal metal atoms are not very common, since it can be deduced from the theory of organic liquid crystals that bulky terminal groups would not be conducive to the stabilization of liquid crystal phases. Nevertheless, a terminal ferrocenyl group can stabilize a nematic liquid crystal phase and examples of this will be discussed in this review.