Synthesis of a Benzotrisazulene via Trioxobenzotrisazulene.

Polycyclic aromatic hydrocarbons (PAHs) containing odd-membered rings (such as pentagons or heptagons) are fascinating synthetic targets. A special case is the introduction of five- and seven-membered rings in form of an azulene unit. Azulene itself is an aromatic compounds known for its deep blue color, which is a result of its internal dipole moment. When azulene is embedded into PAHs it can change the optoelectronic properties of the PAH significantly. Herein, the synthesis and characterization of a PAH containing three azulene units is reported via reduction and elimination of its trioxo derivative.