Heterocyclic benzothiazole-based liquid crystals: Synthesis and mesomorphic properties

Sie Tiong Ha, Teck Ming Koh, Hong Cheu Lin, Guan Yeow Yeap, Yip Foo Win, Siew Teng Ong, Yasodha Sivasothy, Lay Khoon Ong

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50 Citations (Scopus)


Two homologous series of 2-(4-alkanoyloxybenzylidenamino)benzothiazoles and 2-(2-hydroxy-4-alkanoyloxy-benzylidenamino)benzothiazoles were synthesised and characterised. Their molecular structures differed wherein the latter comprised a lateral hydroxyl group, unlike the former. Spectroscopic techniques such as FT-IR, 1H & 13C NMR and mass spectrometry together with elemental analysis were employed to elucidate the molecular structures. The transition temperatures and their mesophases were determined by differential scanning calorimetry, optical polarising microscopy and X-ray diffraction techniques. Members with decanoyloxy till hexadecanoloxy chain in the series without the lateral hydroxyl group each exhibited a smectic A phase, while those in the series with the lateral hydroxyl group were non-mesogenic. The mesomorphic properties of the present series were compared with other structurally related series to establish the chemical structure-mesomorphic properties relationship.

Original languageEnglish
Pages (from-to)917-925
Number of pages9
JournalLiquid Crystals
Issue number9
Publication statusPublished - Sept 2009
Externally publishedYes


  • Schiff base
  • Smectic A
  • Structure-property relationship

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