Synthesis and Structure of a Highly Chlorinated C₇₈: C₇₈(2)Cl₃₀ 

Abstract

A Highly chlorinated C 78 fullerene, C 78 (2)Cl 30 , has been obtained by the reaction of the isomer C 78 (2) with SbCl 5 in ampoules at 330-340 °C. Single crystal structure determination revealed that the C 2v -C 78 IntroductionFullerene halides were among the first structurally investigated fullerene derivatives [1]. On the one hand, they can serve as intermediates for further derivatization of fullerenes. On the other hand, they sometimes facilitate characterization of the connectivity patterns of higher fullerenes. Chlorides of a given fullerene comprise a range of compositions, which lies between those of bromides and fluorides. For example, the known chlorides of C 60 contain 6 to 30 attached Cl atoms [2][3][4][5], whereas extreme compositions for bromide are C 60 Br 6 [1] and C 60 Br 24 [6], and those reported for fluorides are C 60 F 2 and C 60 F 48 [7]. Interestingly, lower chlorides of C 60 and C 70 , C 60 Cl 6 [2] and C 70 Cl 10 [8], differ significantly in their properties such as solubility, stability and reactivity from the corresponding higher chlorides, C 60 Cl 30 [4, 5] and C 70 Cl 28 [9].In the last years, remarkable progress has been achieved in synthesis and investigation of chlorides of higher fullerenes. Using the reaction of fullerenes with a mixture of TiCl 4 and bromine, higher fullerenes D 2 -C 76 (1), three isomers of C 78 (C 2v (2), C 2v (3), and D 3h (5)), and D 2 -C 80 (2) have been selectively chlorinated, respectively, to C 76 Cl 18 [10], C 78 Cl 18 [11, 12], and C 80 Cl 12 [13] in crystalline form thus enabling structural investigation of the connectivity pattern in pristine fullerenes. The chlorinating power of TiCl 4 and Br 2 mixtures depends on the bromine concentration [14, 15], however, on average, it results in the formation of chlorides with lower to middle chlorine content. Higher chlorides can be produced by using stronger chlorinating agents such as Cl 2 or some inorganic chlorides (ICl, SbCl 5 etc.) at higher temperature [16]. For instance, recently chlorination of the mixture of higher fullerenes with SbCl 5 resulted in isolation and structural characterization of C 90 Cl 32 [17]. In this paper, we report the synthesis and single crystal X-ray study of C 78 Cl 30 which seems to be the highest chloride of C 78 fullerene. Experimental SectionC 78 fullerene was separated from toluene extraction of the fullerene soot by a two-step HPLC using a Cosmosil Buckyprep column (10 mm i.d. x 250 mm, Nacalai Tesque Inc.) and toluene as the eluent (5.0 mL min -1 flow rate, 320 nm). Briefly, in the firststep HPLC a mixed fraction comprised of C 76 and two isomers of C 78 was collected, which was subjected to the second-step recycling HPLC separation. After two cycles, the major isomer of C 78 was successfully obtained with the identification and purity confirmed by MALDI-TOF MS analysis. UV-Vis spectrum of the isolated C 78 fullerene dissolved in toluene was recorded on a UVVis-NIR 3600 spectrometer (Shimadzu, Japan).Approximately 0.3 mg of C 78 (2) was placed into a glass ampo...

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

“…HPLC separation of the toluene fraction eluted at 6.8 min was performed in a toluene/hexane (v/v = 1/1) eluent and a subfraction eluted at 23.1 min afforded a compositionally pure C 78 (CF 3 ) 12 compound. Slow evaporation of solvent gave small crystals which were studied by X-ray crystallography revealing the molecular structure of C 78 (2)(CF 3 ) 12 .…”

“…The chemical reactivity of C 78 fullerene was studied in cyclopropanation, halogenations, trifluoromethylation, and other reactions [6][7][8][9][10][11][12][13][14]. Structural characterization of the derivatives was carried out by 1 H, 13 C, and 19 F spectroscopy as well as by X-ray crystallography.…”

“…Structural characterization of the derivatives was carried out by 1 H, 13 C, and 19 F spectroscopy as well as by X-ray crystallography. Among the most structurally investigated compounds are the bromides, C 78 (2,3)Br 18 [8], chlorides, C 78 (2,3,5)Cl 18 [9][10][11] and C 78 (1,2)Cl 30 [12,13], and several trifluoromethylated derivatives, C 78 (CF 3 ) 2n [14]. For the latter group, structural data obtained by 19 F NMR spectroscopy and/or X-ray studies are available for compositions C 78 (3)(CF 3 ) 8 , C 78 (1,2)(CF 3 ) 10 , and C 78 (3,5)(CF 3 ) 12 .…”

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

“…1, 2, 3, and 5, have been studied as pristine fullerenes or derivatives thereof . 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 .…”

In Situ Synthesis of Chlorinated Fullerenes by the High‐Frequency Furnace Method

“…[6][7][8][9][10] However, no higher, in situ synthesized chlorinated fullerene species have been reported so far and all chlorinated derivatives of IPR higher fullerenes have been synthesized by the chlorination of stable IPR fullerenes. [11][12][13][14][15][16] Very recently Ioffe and coworkers reported on the possibility of chlorine stabilization of non-classical higher fullerene cages obtained by the rearrangement of the IPR carbon network during chlorination. [17,18] The high-frequency furnace (HF furnace) method developed by our group presents an attractive alternative method for effective fullerene as well as endohedral fullerene production.…”