Triazacoronene Derivatives with Three peri-Benzopyrano Extensions: Synthesis, Structure, and Properties

New -extended triazacoronene derivatives containing three peri-benzopyrano extensions were successfully synthesized through tandem triflic acid catalyzed threefold Pictet-Spengler cyclization and K2CO3-catalyzed ipso-aromatic substitution in one pot. The structure was verified by X-ray diffraction analysis and was found to form a sandwich-type trimer in the crystalline state. The -extended triazacoronenes showed reasonable solubility, high thermal stability, and remarkably repeatable electroluminescent emissions.