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  Vysochanskaya, O.N.; Brotsman, V.A.; Goryunkov, A.A.; Feiler, C.G.; Troyanov, S.I.: Fused-Pentagon Isomers of C₆₀ Fullerene Isolated as Chloro and Trifluoromethyl Derivatives. Chemistry - A European Journal 26 (2020), p. 2338-2341

10.1002/chem.201905229

Abstract:
The carbon cage of buckminsterfullerene Ih-C60, which obeys the Isolated-Pentagon Rule (IPR), can be transformed to non-IPR cages in the course of high-temperature chlorination of C60 or C60Cl30 with SbCl5. The non-IPR chloro derivatives were isolated chromatographically (HPLC) and characterized crystallographically as 1809C60Cl16, 1810C60Cl24, and 1805C60Cl24, which contain, respectively two, four, and four pairs of fused pentagons in the carbon cage. High-temperature trifluoromethylation of the chlorination products with CF3I afforded a non-IPR CF3 derivative, 1807C60(CF3)12, which contains four pairs of fused pentagons in the carbon cage. Addition patterns of non-IPR chloro and CF3 derivatives were compared and discussed in terms of the formation of stabilizing local substructures on fullerene cages. A detailed scheme of the experimentally confirmed non-IPR C60 isomers obtained by Stone–Wales cage transformations is presented.