Abstract: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 con… Show more
Chiral nanographenes are an intriguing class of polycyclic aromatic hydrocarbon structures, where combining the unique properties of inherently chiral molecules with the optical, electronic, and even magnetic properties of nanographenes...
Chiral nanographenes are an intriguing class of polycyclic aromatic hydrocarbon structures, where combining the unique properties of inherently chiral molecules with the optical, electronic, and even magnetic properties of nanographenes...
We disclose π‐expanded pyracylenes and their cationic species comprising 7‐membered rings. The compounds were synthesized by stepwise oxidative cyclodehydrogenation to monitor the effect of successive cyclization on the structural and optoelectronic properties. As shown by X‐ray crystallography the complete cyclization leads to a boat‐shaped scaffold featuring negative curvature provided by the 7‐membered ring. The embedded tropone unit enabled the convenient generation of a stabilized tropylium cation, showing bathochromically shifted absorption bands reaching into the near‐infrared region beyond 1000 nm. The altered structural features supported by theoretical calculations point towards aromatic character of the positively charged 7‐membered ring.
We disclose π‐expanded pyracylenes and their cationic species comprising 7‐membered rings. The compounds were synthesized by stepwise oxidative cyclodehydrogenation to monitor the effect of successive cyclization on the structural and optoelectronic properties. As shown by X‐ray crystallography the complete cyclization leads to a boat‐shaped scaffold featuring negative curvature provided by the 7‐membered ring. The embedded tropone unit enabled the convenient generation of a stabilized tropylium cation, showing bathochromically shifted absorption bands reaching into the near‐infrared region beyond 1000 nm. The altered structural features supported by theoretical calculations point towards aromatic character of the positively charged 7‐membered ring.
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