Question

Among the following, the number of anti-aromatic compound(s) is/are:

Answer 1

Structure (i) : Planar, has resonance and has $4\pi e^{-}$ or $4n\pi e^{-}$ thus making it anti-aromatic.
Structure (ii) : Planar, has resonance and has $8\pi e^{-}$ or $4n\pi e^{-}$ thus making it anti-aromatic.
Structure (iii) : Non-planar, since $s{p}^3$ hybridised carbon is there. So, non aromatic.
Structure (iv) : Planar, has resonance and has $4\pi e^{-}$ or $4n\pi e^{-}$ thus making it anti-aromatic.
Structure (v) : Planar , has resonance and has $6\pi e^{-}$ or $(4n+2)\pi e^{-}$, i.e. it follows huckel rule, thus making it aromatic.
Structure (vi) : Planar , has resonance and has $6\pi e^{-}$ or $(4n+2)\pi e^{-}$, i.e. it follows huckel rule, thus making it aromatic.
Total number of anti aromatic compounds are 3.