4‘-Bromo-2‘,3‘,5‘,6‘-tetrafluorostilbazole: Donor and Acceptor Site for Halogen Bonding and π-Stacking in One Rigid-Rod-Type Molecule

The title compound, a new fluorinated stilbazole-based chromophore combines hydrocarbon (HC) donor and perfluorocarbon (PFC) acceptor sites in one rigid-rod-type conjugated molecule. The bifunctional stilbazole derivative combines several possibilities of weak, medium, and strong intermolecular interactions leading to an attractive crystal packing. The chromophore shows strong π−π stacking behavior in solution, while its crystal structure consists of an infinite unimolecular network involving both interchain π−π stacking and N···Br halogen bonding. The latter Lewis acid−base interactions do not play a dominant role in controlling the solution optical properties. In the solid state, the molecules are aligned in one-dimensional infinite head-to-tail chains as a result of attractive halogen bonding. Adjacent chains are oriented in opposite directions.