Consecutive Trifluoromethylation of C ₈₈ (7) Fullerene: A Theoretical Study

Abstract The trifluoromethylation of C 88 (7) fullerene has been systematically studied using an energy‐controlled consecutive CF 3 addition approach. The thermodynamically favored C 88 (7)(CF 3 ) 2 n isomers with 2 n = 2–20 were predicted at the DFT B3LYP‐D3BJ/6–311G* level of theory for the first time, in harmony with the two experimentally characterized isomers C 88 (7)(CF 3 ) 12/16 . It was found that these stable isomers are formed mainly by 1,4‐additions of CF 3 groups, and meanwhile, there are a few stable isomers with isolated CF 3 groups for 2 n ≤ 12, with ortho addition for 2 n > 12, and with triple‐hexagon‐junction addition for the highest degree of trifluoromethylation (2 n ≥ 18). The addition patterns of CF 3 groups were discussed in terms of the local structural motif of the pristine cage and the formation of stabilizing substructures of local aromaticity. The possible trifluoromethylation pathways of C 88 (7) were proposed on the basis of the relative Gibbs free energies. The results show that almost all the intermediate isomers for the thermodynamically most stable isomers of C 88 (7)(CF 3 ) 2 n possess low relative Gibbs free energies (below 14 kJ·mol −1 ). Moreover, the hardness, chemical potential, electrophilicity index, electron affinity, HOMO and LUMO energies, and HOMO–LUMO gaps of the thermodynamically most stable C 88 (7)(CF 3 ) 2 n isomers were also calculated.