Direct Synthesis of Fluorinated Polycyclic Aromatic Dioxanes: Mesomorphism, Luminescence, and Charge Transport

We report a straightforward synthesis of new Janus-fluorinated dioxa-bridged tetracene and pentacene liquid crystals. These materials self-assemble into stable columnar mesophases driven by noncovalent perfluoroarene-arene interactions that promote effective intermolecular π-stacking. The degree of fluorination on the aromatic core plays a pivotal role in the induction of mesomorphism: substitution with two fluorine atoms is insufficient to induce mesomorphism, whereas homologous derivatives bearing four or six fluorine atoms readily self-organize into mesophases. They display luminescence with an absolute quantum yield of 4% in the thin film. These molecules also exhibit an electron mobility rate in the 10^-2-10^-3 cm² V^-1 s^-1 range, well within the values needed for molecular-based devices. The synthetic strategy described here presents great potential for the construction of novel fluorine-containing molecular materials of interest for applications in organic electronics.