Influence of polar substituents on the mesomorphism of non-symmetrical achiral four-ring bent-core compounds: synthesis and characterisation

Abstract

The synthesis and characterisation of stable achiral asymmetrical four-ring banana-shaped molecules are presented. These consist of a laterally fluoro-substituted 3,4ʹ-disubstituted biphenyl unit with an ester linkage between the phenyl rings as the central unit in 4-(N-4ʹ-n-alkyloxysalicylidene)aminophenyl [2-fluoro-5-(N-4ʹ-n-alkyloxy-salicylidene) amino-benzoate]. These compounds are thermally and hydrolytically stable due to inter- or intramolecular hydrogen bonding and exhibit columnar (B1) phases. The phases have been characterised by thermal microscopy and differential scanning calorimetry. A representative example has also been characterised by X-ray diffraction.

Keywords:

• banana mesomorphism
• four-ring systems
• B1 columnar

Acknowledgements

This research was supported by Department of Atomic Energy (DAE), Department of Science and Technology (DST), Defence Research and Development Organization (DRDO), Naval Research Board and Development (NRBD) and University Grants Commission (UGC), India.

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