Design and mesomorphism of a triskelion shape-persistent HBC-TP hybrid: 2,8,14-tris(triphenylen-2-yl)hexabenzocoronene

Abstract

A triskelion-shaped mesogen has been synthesized by combining in a single structure, two iconic discotic polycyclic aromatic hydrocarbons (PAHs), namely hexabenzocoronene (HBC), serving as the central core, and three radial mesomorphic triphenylene (TP) subunits sigma-bonded to HBC. The resulting mixed, π-extended oligomer displays a broad temperature range columnar mesophase, characterized by self-sorted columnar stacks of HBC radially fused with three TP-based columns, respectively, evenly distributed within a rectangular 2D lattice (Col_rec-p2mg). The photophysical properties reveal a wide absorption band that encompasses the combined absorption features of both components, while the emission is predominantly centred on the HBC moiety. Furthermore, the compound demonstrates ambipolar charge transport behaviour, with a pronounced electron-dominant transport.