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

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 H-1 and C-13-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).