[2]Benzothiophene bent-shaped liquid crystals

Abstract

New liquid crystalline (LC) compounds containing the [2]benzothiophene chromophore unit have been synthesised and their mesomorphic properties studied. Mesomorphic and fluorescent properties have been modified by various chemical moieties. Among others, terminal fluoroalkyl and/or chiral chains were introduced to stabilise mesophases and support the formation of polar phases. In spite of the bent shape due to the central 1,3-diphenylbenzo[c]thiophene unit, all compounds exhibit phases typical for the rod-like LC: nematic, smectic A and smectic C or their chiral analogues using the chiral  (S)-C₂H₅CH(CH₃)(CH₂)₆CO or (S)-C₁₀H₂₁OCH(CH₃)CO chain. The orientational order in the nematic phase was studied by polarised infrared measurements. The fluorescent properties of the studied compounds have been measured and their parameters established.

Keywords:

• [2]benzothiophene
• liquid crystals
• mesomorphic properties
• fluorescence
• polarised infrared measurements

Acknowledgements

This work was supported by grant No. 202/09/0047 (Czech Science Foundation), project IAA100100911 (Grant Agency of AS of the Czech Republic) and project OC 176 (Ministry of Education, Youth and Sports of the Czech Republic). The research for this paper was in part supported by the EU through the European Social Fund, contract number UDA-POKL.04.01.01-00-072/09-00.