Room temperature nematic liquid crystals: Synthesis and characterisation of pentabromophenol and cyanobiphenyl derived rod-shaped molecules

ABSTRACT

Calamitic molecules consisting of pentabromophenol tethered to cyanobiphenyl via a flexible alkyl chain were synthesised and characterised for their mesomorphic properties. New chemical structures differing in the length of the spacer (6a–f) were confirmed by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopies, and by elemental analysis. Compounds having six, eight, nine and ten methylene units in the spacer show room-temperature nematic liquid crystalline phases and the other derivatives are soft solids. The mesomorphic behaviour and thermal stability of all compounds have been investigated by polarised optical microscopy, differential scanning calorimetry and thermal gravimetric analysis, respectively.

GRAPHICAL ABSTRACT

General chemical structure and Nematic phase of compound 6c at room temperature.

KEYWORDS:

• Liquid crystals
• cyanobiphenyl
• pentabromophenol
• calamitics
• fluorobenzoic acid
• alkyl chain

Acknowledgments

The authors thank K. N. Vasudha for the help in DSC and X-ray experiments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.