Synthesis, isolation, and X-ray structural characterization of trifluoromethylated C78 fullerenes: C78(2)(CF3)10/12 and C78(3)(CF3)12/14

Abstract

Four CF 3 derivatives of C 78 , C 78 (2)(CF 3 ) 10/12 and C 78 (3)(CF 3 ) 12/14 , have been isolated via HPLC from the products of high-temperature trifluoromethylation of a C 76 -C 96 fullerene mixture or a C 78 fraction. Their molecular structures were determined by single crystal X-ray crystallography using synchrotron radiation. The addition patterns of the new compounds are compared with each other and with the previously known C 78 (2)(CF 3 ) 10 and C 78 (3)(CF 3 ) 12 .

Chlorination‐promoted Transformation of Isolated Pentagon Rule C78 into Fused‐pentagons‐ and Heptagons‐containing Fullerenes

“…The involvement of all pentagons into fullerene derivatization was observed in most derivatives with 12 or more addends. However, some exceptions are known for chloro and CF 3 derivatives as a consequence of an enhanced stability of specific substructures formed on a fullerene cage . For instance, two pentagons are free from additions in the structure of C 88 (7)Cl 24 …”

Synthesis, Isolation and Structure of Trifluoromethylated Fullerene D3‐C78, C78(1)(CF3)10−18

“…Chloro and bromo derivatives are known for C 78 (1)Cl 30 , C 78 (2,3)Br 18 , C 78 (2,3,5)Cl 18 ,, and C 78 (2)Cl 30 . For the same four IPR isomers, perfluoroalkyl derivatives were isolated and structurally characterized by either X‐ray crystallography or 19 F NMR spectroscopy for C 78 (1)(CF 3 ) 10 , C 78 (2)(CF 3 ) 10,12 , C 78 (2)(C 2 F 5 ) 10 , C 78 (3)(CF 3 ) 8,12,14 , and C 78 (5)(CF 3 ) 12 . Therefore, among others, CF 3 derivatives of isomer C 78 (1) belong to the less investigated and structurally characterized compounds.…”

“…An X‐ray diffraction study with the use of synchrotron radiation revealed the known structure of C 78 (1)(CF 3 ) 10 (toluene solvate) and fourteen new structures of C 78 (1)(CF 3 ) 10−18 (see Table S1 in the Supporting Information). The structures of the isolated CF 3 derivatives of isomers C 78 (2) and C 78 (3) have been presented in a separate publication …”

“…2, 3, and 5, the distribution of cage pentagons on C 78 carbon cages does not prevent the formation of longer ribbons of edge‐sharing para C 6 (CF 3 ) 2 hexagons. In the known isomers of C 78 (2)(CF 3 ) 12 and C 78 (5)(CF 3 ) 12, all twelve CF 3 groups are involved in a single ribbon or a single loop. The dependence of the average trifluoromethylation enthalpy on n was reported for C 70 (CF 3 ) 2−18 with a maximum at n =8, because the formation of a contiguous ribbon of seven para C 6 (CF 3 ) 2 hexagons is possible on the C 70 carbon cage …”