Heptacyclic aromatic hydrocarbon isomers with two azulene units fused.

Azulene, known for its unique electronic properties and structural asymmetry, serves as a promising building block for the design of novel non-benzenoid polycyclic aromatic hydrocarbons (PAHs). Herein, we present the synthesis, characterization, and physical properties of three diazulene-fused heptacyclic aromatic hydrocarbons, 8,17-dioctyldiazuleno[2,1-:2',1'-]anthracene ( configuration), 16,18-dioctyldiazuleno[2,1-:1',2'-]anthracene ( configuration) and 3,18-dioctyldiazuleno[2,1-:1',2'-]phenanthrene ( configuration). Three compounds are configurational isomers with different fusing patterns of aromatic rings.