Two Isolated-Pentagon-Rule Isomers C 98 (110) and C 98 (111) Isolated as Trifluoromethylfullerenes C 98 (CF 3 ) 22

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