Propeller-Shaped Aluminum Complexes with an Azaperylene Core in the Ligands

Tris(8-hydroxyquinoline) aluminum(III) (Alq₃) and its derivatives, characterized by a propeller-shaped three-dimensionally π-conjugated structure, have been intensively studied in the few past decades on account of their potential utility in optoelectronic applications. Reported herein are the synthesis and properties of π-extended Alq₃ complexes that contain an azaperylene core in each ligand. Intramolecular palladium-catalyzed direct C–H arylations or base-promoted arylations were employed to prepare these large Alq₃ analogues. A single-crystal X-ray diffraction analysis of one of the obtained Al complexes revealed a unique three-dimensional packing structure within the crystal, i.e., a honeycomb packing along the ab-plane and columnar π-stacks along the c-axis. An Alq₃ analogue with azaperylene-dicarboximide ligands exhibited deep blue color in solution with an intense absorption band that extended to 780 nm (λ_max = 634 nm; ε = 58,000 M⁻¹ cm⁻¹). View Full-Text