Chapter 12.20, Problem 24P

Interpretation Introduction

Interpretation:

Whether the cycloheptatrienyl radical is aromatic or antiaromatic is to be identified

Concept introduction:

An aromatic molecule must obey Hückel’s rule of $\text{(4n+2)π}$ electrons where $\text{n}$ is an integer.

Aromatic molecules are cyclic and planar and have cyclic conjugation.

Antiaromatic molecules are cyclic and planar and have cyclic conjugation like aromatic molecules, but they have $\text{(4n)π}$ electrons instead $\text{(4n+2)π}$ electrons.

A carbon radical contributes single $\text{π}$ electron.