Two Isolated-Pentagon-Rule Isomers C₉₈(110) and C₉₈(111) Isolated as Trifluoromethylfullerenes C₉₈(CF₃)₂₂

The fullerene C₉₈ has 259 topologically possible isomers that obey the isolated-pentagon rule (IPR). In this work, a family of experimentally confirmed IPR isomers of C₉₈ fullerene is extended by the high-performance liquid chromatography isolation and X-ray structural characterization of two trifluoromethyl derivatives, C₁-C₉₈(110)­(CF₃)₂₂ and C₁-C₉₈(111)­(CF₃)₂₂. The carbon cages of isomers C_s-C₉₈(110) and C_s-C₉₈(111) differ by a Stone–Wales rotation of only one C–C bond, which results in very similar addition patterns of 22 CF₃ groups in the C₉₈(CF₃)₂₂ molecules. The stabilizing substructures in both C₉₈(CF₃)₂₂ molecules include six benzenoid rings and four isolated CC bonds. Both C_s-C₉₈(110) and C_s-C₉₈(111) belong to the isomers of moderate relative stability among altogether seven IPR isomers of C₉₈ fullerene with experimentally confirmed cage structures.