8. Computational Studies of Li@C₆₀

Molecular dynamics simulations have been carried out to understand the mechanism of encapsulating the Li atom into the C₆₀ cage. The results suggest that when Li⁺ collides at the center of the 6-membered rings of \({{\text{C}}_{60}}^{ - }\), the Li⁺ ion passes through the 6-membered rings and becomes trapped in the C₆₀ cage. From the early period of endohedral metallofullerenes research, structural optimization of Li@C₆₀ was performed and its electronic structures were investigated. In these theoretical studies, various calculation conditions such as a kind of inner ion were changed to understand this material further. Theoretical calculations predicted some properties of Li⁺@C₆₀, such as an upfield chemical shift in ⁷Li NMR and absorption in the terahertz region due to the motion of the inner Li⁺. The interactions of Li⁺@C₆₀ with nucleobases, corannulene, and [10]cycloparaphenylene were examined in computational studies to estimate the binding characteristics in these complexes. The Diels–Alder reaction of Li⁺@C₆₀ with cyclopentadiene was studied by density functional theory calculations, suggesting roles of various inner ions and counter anions.