Explain why the following systems are not aromatic?

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.


12