Trifluoromethylation of a higher fullerene mixture with CF3I was performed in ampoules at 550 °C. HPLC separation followed by crystal growth and X-ray diffraction study resulted in the structure elucidation of nine CF3 derivatives of D2d-C84 (isomer 23). The molecular structures of C84(23)(CF3)4, C84(23)(CF3)8, C84(23)(CF3)10, C84(23)(CF3)12, two isomers of C84(23)(CF3)14, two isomers of C84(23)(CF3)16, and C84(23)(CF3)18 were discussed in terms of their addition patterns and the relative formation energies. Extensive theoretical DFT calculations were performed to identify the most stable molecular structures. It was found that the addition of CF3 groups to the C84(23) fullerene is governed by two main rules: no additions in positions of triple hexagon junctions and predominantly para additions in C6(CF3)2 hexagons on the fullerene cage. The only exception with an isolated CF3 group in C84(23)(CF3)12 is discussed in more detail.

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Trifluoromethyl derivatives of fullerene C 84 minor cage isomers C s C 84 (16) and C 2v C 84 (18) of general formulas C 84 (16)(CF 3 ) 2m (2m = 8, 10, 12, 14, 18) and C 84 (18)(CF 3 ) 2m (2m = 10, 12) were isolated by a multi step HPLC from the products of high temperature trifluoromethyla tion of a mixture of higher fullerenes. Molecular structures of these compounds were deter mined by single crystal X ray diffraction using synchrotron radiation. The experimentally ob tained structural data and the results of quantum chemical calculations were discussed in terms of general regularities of trifluoromethylation of C 84 isomers in a wide range of compositions. The addition patterns of CF 3 groups in C 84 (16/18)(CF 3 ) 2m molecules were found to depend on particular structural features of isomeric C 84 cages.To date, the most studied is the chemistry of fullerenes C 60 and C 70 , which is primarily due to a predominance of these compounds in the fullerene soot. 1 A third predo minant (and the first among higher fullerenes) is fullerene C 84 . It is known 2 that the synthesis of fullerenes leads only to those of them which obey an empirical isolated penta gon rule (IPR), i.e. do not have adjacent five membered rings in the cage. The absence of the fused five membered rings decreases steric strain of the carbon cage of fullerenes, which leads to greater thermodynamic stability and chem ical inertness of such fullerenes, resulting in their accu mulation in the course of the synthesis.Unlike fullerenes C 60 and C 70 , each of which is repre sented by the only IPR isomer, fullerene C 84 can exist as 24 IPR isomers. 2 By now, the presence in the fullerene soot of ten different C 84 isomers is experimentally con firmed, with the D 2 C 84 (22) and D 2d C 84 (23) cage iso mers (a consecutive number of isomer according to the spiral algorithm 2 is given in parentheses) being the major representatives in accordance with their higher thermo dynamic stability. 3,4 The remaining (minor) C 84 isomers are present in much smaller amounts. 5 Fullerenes are commonly separated by HPLC, where as 13 C NMR spectroscopy is a conventional method for their identification. These means were used 6 to confirm the existence of minor isomers No. 4 (D 2d ), No. 5 (D 2 ), No. 11 (C 2 ), No. 14 (C s ), No. 16 (C s ), 5 No. 19 (D 3d ), and No. 24 (D 6h ) for fullerene C 84 . However, the 13 C NMR data showed that in this case the assignment of chromato graphic peaks of C s C 84 (14) and C s C 84 (16) isomers was not unambiguous because of the same symmetry. 5 After wards, the use of X ray diffraction method for the deter mination of the cage structures of fullerenes (only for C s C 84 (14) 7 ) or their derivatives confirmed the existence of all the indicated isomers except C 84 (19) and C 84 (24). The presence in the mixtures of C 2v C 84 (18) isomer was confirmed 8 by the crystal and molecular structures of its C 84 (18)(C 2 F 5 ) 12 derivative.Like fullerenes, their derivatives can be subjected to HPLC separation and in this case it can be more ...

C84 is the most abundant higher fullerene which is present in the arc‐discharge fullerene soot. Among 24 topologically possible Isolated‐Pentagon Rule isomers of C84, two major isomers, C84(22) and C84(23), and several minor ones have been identified experimentally. We report the synthesis, HPLC isolation, and synchrotron X‐ray structure elucidation of trifluoromethyl derivatives of the most abundant minor isomer of C84, C84(11)(CF3)10,12,14. The experimentally determined addition patterns are discussed in terms of the attachments in ribbons of edge‐sharing para C6(CF3)2 hexagons and the uniform distribution of CF3 groups on the C2‐C84(11) carbon cage. A general scheme of C84(11) trifluoromethylation pathways was proposed on the basis of theoretical DFT calculations of formation energies. Thus, trifluoromethylation pathways are now discussed in details for five different isomers of C84.