Question

What is Arenium ion mechanism?

Answer 1

Answer:

An arenium ion in organic chemistry is a cyclohexadienyl cation that appears as a reactive intermediate in electrophilic aromatic substitution. For historic reasons this complex is also called a Wheland intermediate, after American chemist George Willard Wheland (1907–1976). They are also called sigma complexes.

Explanation:

The attacking electrophile may be a positive ion dipole. The aremium ion is stabilised by resonance but due to the loss of aromaticity its resonance energy is much less than that of the parent aromatic system. Thus, the arenium ion loses proton and reverts to the more stable aromatic state.