Unusual Effect of Methylation of a Benzene Ring on the Strength of Phenyl–Phenyl Interaction

Gas-chromatographic studies have shown that the strength of the weak interaction between a phenyl group in a stationary liquid and a benzene molecule in a sample alters most greatly when, among various substituents examined (e.g., Me, Et, Cl, and OMe), a methyl group—a “simple” nonpolar group—is introduced into a benzene ring in the sample.