Reaction Pathways for the He, Li, and Li⁺ Penetrations of the Benzene Ring

Abstract

The He, Li, and Li⁺ penetrations of the benzene ring are discussed from density functional theory (DFT) computations and intrinsic reaction coordinate (IRC) analyses. The high activation energy of more than 200 kcal/mol for the He penetration appears to derive mainly from the electrostatic repulsion between the benzene ring and the He atom. The activation energies decrease in the sequence of He > Li > Li⁺. The activation barrier for the Li⁺ penetration (160 kcal/mol) may be overcome under high-temperature and high-pressure conditions. If it occurs in preparing lithium intercalation graphite, we must change our concept of “staging” in graphite intercalation compounds.