Explain why the following systems are not aromatic?

Question

Philoid · Accepted Answer

For the given compound, the number of π-electrons is 4.

By Huckel’s rule,

⇒ 4n + 2 = 4

⇒ 4n = 2

⇒ n = 1/2

For a compound to be aromatic, the value of n must be an integer (n = 0, 1, 2…).

This is not true for the given compound as it is a fraction. Hence, it is not aromatic in nature.