Mesogenic homologous series with a butoxyethyl terminal chain

ABSTRACT

Two new mesogenic homologous series with butoxyethyl terminal chain, viz., 2-butoxyethyl-4-((E)-3-(4-n-alkoxyphenyl) acryloyloxy) benzoates (In) and 2-butoxyethyl4-(4-n-alkoxy benzoyloxy) benzoates (IIn), where n varies between 1 and 18 carbons, have been synthesised and characterised by standard spectroscopic methods. All the compounds prepared were screened under polarising optical microscope for liquid crystalline properties, and thermograms of all mesogenic compounds were studied using differential scanning calorimetry to get phase transition temperatures, enthalpy and entropy. In series In, the first two homologues are non-mesogenic. The homologue I3 exhibits only enantiotropic nematic mesophase, whereas the rest of the series exhibit only the SmA phase, enantiotropically. Homologues of series IIn are purely smectogenic. The SmA mesophase commences from n = 4 as monotropic and persists up to the last homologue synthesised. The mesomorphic behaviour of the present two series is compared with each other and with three structurally related compounds to evaluate the effect of cinnamoyloxy central linkage and the terminal butyloxyethyl chain on their mesophase behaviour.

Graphical abstract

KEYWORDS:

• Butyloxyethyl tail
• cinnamates
• homologous series
• thermotropic liquid crystals

Acknowledgements

The authors specially thank the principal Dr (Prof.) Keyur Shah of Shri M. M. Patel Institute of Sciences and Research, Department of Chemistry (KSV), Gandhinagar, and Prof. A. U. Patel, The Head, Department of Chemistry, Faculty of Science, The M. S. University of Baroda, Vadodara, for providing research facilities.

Disclosure statement

The Authors declare that there is no conflict of interest.