Tetraazacoronenes and Their Dimers, Trimers and Tetramers

Tetraazacoronenes were synthesized from bay‐functionalized tetraazaperylenes by Zr‐mediated cyclization and four‐fold Suzuki–Miyaura cross coupling. In the Zr‐mediated approach, an η4‐cyclobutadiene‐zirconium(IV) complex was isolated as an intermediate to cyclobutene‐annulated derivatives. Using bis(pinacolatoboryl)vinyltrimethylsilane as a C2 building block gave the tetraazacoronene target compound along with the condensed azacoronene dimer as well as higher oligomers. The series of extended azacoronenes show highly resolved UV/Vis absorption bands with increased extinction coefficients for the extended aromatic cores and fluorescence quantum yields of up to 80 % at 659 nm. Tetraazacoronenes were synthesized from bay‐functionalized tetraazaperylenes by Zr‐mediated cyclization and four‐fold Suzuki–Miyaura cross coupling. The latter not only gives the tetraazacoronene target compound but also the condensed azacoronene dimer and higher oligomers.