Synthesis and structures of trifluoromethyl derivatives of fullerenes C84(16) and C84(18)

Trifluoromethyl derivatives of fullerene C84 minor cage isomers C s -C84(16) and C 2v -C84(18) of general formulas C84(16)(CF3)2m (2m = 8, 10, 12, 14, 18) and C84(18)(CF3)2m (2m = 10, 12) were isolated by a multi-step HPLC from the products of high-temperature trifluoromethylation of a mixture of higher fullerenes. Molecular structures of these compounds were determined by single crystal X-ray diffraction using synchrotron radiation. The experimentally obtained structural data and the results of quantum chemical calculations were discussed in terms of general regularities of trifluoromethylation of C84 isomers in a wide range of compositions. The addition patterns of CF3 groups in C84(16/18)(CF3)2m molecules were found to depend on particular structural features of isomeric C84 cages.