Effect of the pentafluorophenyloxy group on liquid crystalline behaviour

Abstract

A new series of liquid crystalline compounds, the α‐(4‐cyanobiphenyl‐4′‐yloxy)‐ω‐(pentafluorophenyloxy)alkanes, were synthesized. The nematic–isotropic transition temperatures of the compounds showed a remarkable odd–even effect on increasing the length of the alkyl chain. In order to establish the effect of the pentafluorophenyloxy group, the α‐(4‐cyanobiphenyl‐4′‐yloxy)‐ω‐(4‐fluorophenyloxy)alkanes and the α‐(4‐cyanobiphenyl‐4′‐yloxy)‐ω‐(3,4,5‐trifluorophenyloxy)alkanes were also prepared. The comparison of the properties of these three series revealed interesting effects of the pentafluorophenyloxy group on the liquid crystalline properties.

Acknowledgements

The author would like to express his thanks to Professor C. T. Imrie for valuable advice, and to Professor I. Saito and Dr A. Okamoto (Kyoto University, Faculty of Engineering) for mass spectrometric analyses.