Question

Azulene is antiaromatic.

Answer 1

Azulene is a non-benzenoid aromatic compound which has large resonance energy and a large dipole moment. It is a 10 pi electron system. It is common to suggest that azulene is made up of the “fusion” of two aromatic ions, both with 6 π electrons, cycloheptatrienyl (tropylium) cation and cyclopentadienyl anion. It exhibits aromatic properties: (i) the peripheral bonds have similar lengths and (ii) it undergoes Friedel-Crafts-like substitutions.