Understanding the Reactivity of Ion-Encapsulated Fullerenes

摘要

The influence of the encapsulation of an ion inside the C_(60) fullerene cage on its exohedral reactivity was explored by means of DFT calculations. To this end, the Diels-Alder reaction between 1,3-cyclohexadiene and M-C_(60) (M=Li+, Na~+, K~+, Be~(2+), Mg~(2+), Al~(3+), and Cl-) was studied and compared to the analogous process involving the parent C_(60) fullerene. A significant enhancement of the Diels-Alder reactivity is found for systems having an endohedral cation, whereas a clear decrease in reactivity is observed when an anion is encapsulated in the C_(60) cage. The origins of this reactivity trend were quantitatively analyzed in detail by using the activation strain model of reactivity in combination with energy decomposition analysis.