The functionalised hexa-peri-hexabenzocoronenes by Sonogashira coupling method to modify the columnar mesophase behaviour

Abstract

In this paper, we present a series of different thermotropic discotic columnar liquid crystalline forms of mono-substituted functionalised hexabenzocoronene (HBC) carrying five alkyl chains. Using the Sonogashira coupling reaction, 1-ethynyl-4-alkylbenzene, 1-ethynyl-4-alkoxybenzene, and alkyl-4-ethynyl benzoate groups were introduced into mono-bromohexabenzocoronenes to obtain compounds 5–7. These compounds obtained were characterised by ¹H and ¹³C-NMR, UV-Vis, and MALDI-MS spectrometry. The thermotropic liquid crystalline (LC) properties of the compounds were investigated by polarising optical microscopy (POM), differential scanning calorimetry (DSC), and powder X-ray diffractometry (XRD).

Keywords:

• columnar liquid crystalline
• Sonogashira coupling reaction
• hexabenzocoronene

Acknowledgement

We acknowledge the support and encouragement of Prof. C.-C. Liao at Chung Yuan Christian University.

Additional information

Funding

This work was supported by the Ministry of Science and Technology [MOST 103-2113-M-017-004 –MY2].