Trifluoromethyl derivatives of pentagon-fused C: C(CF) (n = 10, 12, 14, 16).

The carbon cage of buckminsterfullerene I-C, obeying the Isolated-Pentagon Rule (IPR), can be transformed to the non-IPR C-C cage by a single Stone-Wales rearrangement (SWR) in the course of high-temperature chlorination of C with SbCl. The following high-temperature trifluoromethylation of the chlorination products with CFI afforded non-IPR CF derivatives, C(CF). X-ray diffraction studies of C(CF) (n = 10, 12, 14, 16) revealed that the sites of pentagon-pentagon fusions on the carbon cage are preferentially occupied by CF groups. The addition patterns of C(CF) and related CCl are compared, demonstrating a prevailing role of pentagon-pentagon fusions in the stability and structural chemistry of these compounds. Further SWR skeletal transformations of C are discussed and compared with the experimental data available.