Mesogenic cinnamates with a substituted ethyl terminal chain*

*. This paper was presented at the 12^th National Conference on Liquid Crystals held at Department of Chemistry, Assam University, Silchar, Assam, India during 19–21 December 2005.

Abstract

Two new mesogenic homologous series of liquid crystalline cinnamates with substituted ethyl tails, β‐methoxyethyl [4‐(4′‐n‐alkoxycinnamoyloxy)benzoates (I) and β‐chloroethyl [4‐(4′‐n‐alkoxycinnamoyloxy)benzoates (II), have been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. In series I, lower‐chain members exhibit nematic mesophase, middle members exhibit enantiotropic nematic as well as smectic A (SmA) mesophases, whereas higher members exhibit only an enantiotropic SmA mesophase. In series II, methoxy to n‐butyloxy derivatives exhibit a monotropic nematic mesophase. The SmA mesophase commences from n‐propyloxy derivative as monotropic and persists up to the last member synthesized. The mesomorphic properties of present series were compared with each other and with a structurally related mesogenic homologous series to evaluate the effects of substituted ethyl tail and cinnamoyloxy central linkage on mesomorphism.

*. This paper was presented at the 12^th National Conference on Liquid Crystals held at Department of Chemistry, Assam University, Silchar, Assam, India during 19–21 December 2005.

Acknowledgements

The authors thank the Dean, Faculty of Technology and Engineering, and Head, Department of Applied Chemistry, for providing research facilities. One of the authors (HNP) is also thankful to the Principal, Smt. D.J. Shah Parivar Science College, for providing research facilities.

Notes

*. This paper was presented at the 12^th National Conference on Liquid Crystals held at Department of Chemistry, Assam University, Silchar, Assam, India during 19–21 December 2005.