CO₂ Activation Within a Superalkali-Doped Fullerene

With the aim of finding a suitable synthesizable superalkali species, using the B3LYP/6-31G* density functional level of theory we provide results for the interaction between the buckminsterfullerene C₆₀ and the superalkali Li₃F₂. We show that this endofullerene is stable and provides a closed environment in which the superalkali can exist and interact with CO₂. It is worthwhile to mention that the optimized Li₃F₂ structure inside C₆₀ is not the most stable C_2v isomer found for the "free" superalkali but the D_3h geometry. The binding energy at 0 K between C₆₀ and Li₃F₂ (D_3h) is computed to be 119 kJ mol^-1. Once CO₂ is introduced in the endofullerene, it is activated, and the $$ angle is bent to 132^°. This activation does not follow the previously studied CO₂ reduction by an electron transfer process from the superalkali, but it is rather an actual reaction where a F (from Li₃F₂) atom is bonded to the CO₂. From a thermodynamic analysis, both CO₂ and the encapsulated [Li₃F₂⋅CO₂] are destabilized in C₆₀ with solvation energies at 0 K of 147 and < -965 kJ mol^-1, respectively.