In the detailed multi-step mechanistic view of electrophilic aromatic substitution, an electrophile — Aromatic Hydrocarbons Chemistry Question
Question
In the detailed multi-step mechanistic view of electrophilic aromatic substitution, an electrophile ($E^+$) interacts with benzene to form various complexes. Which of the following statements correctly describe these initial interactions and complexes?
💡 Solution & Explanation
A $\pi$ -complex forms via a weak interaction between the electrophile and the $\pi$ -cloud. In the $\sigma$ -complex, a distinct covalent bond forms, breaking aromaticity and creating an $sp^3$ carbon. The $\sigma$ -complex sits in an energy valley (a true intermediate). Aromaticity is lost, not restored, when moving from the $\pi$ -complex to the $\sigma$ -complex.