Isolation and Structural Characterization of the Most Stable, Highly Symmetric Isomer of C60(CF3)18

Samokhvalova, Nadezhda A.; Khavrel, Pavel A.; Markov, Vitaliy Yu.; Samokhvalov, Pavel; Goruynkov, Alexey A.; Kemnitz, Erhard; Sidorov, Lev N.; Troyanov, Sergey I.

doi:10.1002/ejoc.200900168

Cited by 18 publications

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References 17 publications

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“… 54 The isomer with this addition pattern, 60-18-2 , has been isolated and characterized by single-crystal X-ray diffraction. 82 It is followed by four isomers with SPP moieties (Δ E = 9–28 kJ·mol −1 ). Note that these isomers span a larger range of relative energies than TMFs with 8, 10, 14, and 16 CF 3 groups.…”

Section: Pfaf Addition Patternsmentioning

confidence: 99%

Perfluoroalkylfullerenes

et al. 2015

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Section: Pfaf Addition Patternsmentioning

confidence: 99%

Perfluoroalkylfullerenes

et al. 2015

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“…71 Synthesis, partial isolation and X-ray structure determination of C 3v -C 60 (CF 3 ) 18 , the most stable and symmetric isomer of this composition, have been reported. 72 DFT was used to analyse the evolution of the structure and electronic properties of the fullerene derivatives C 60 (CF 3 ) n (n = 2, 4, 6, 10). It was found that the C 60 (CF 3 ) 6 is the most stable structure.…”

Section: Production Separation and Properties Of Fullerenesmentioning

confidence: 99%

Fullerenes

Darwish¹

2010

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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“…Because of the higher steric demand of bulkier CF 3 groups, the C 94 (CF 3 ) 20 molecule can be regarded as overcrowded. For comparison, all other structurally characterized CF 3 derivatives of fullerenes (C 60 ,13 C 70 ,14 C 86 7c), or C 88 9) contain at most 18 attached groups. It should be noted that the average C‐C‐CF 3 angle at THJ positions (109.8°) is significantly smaller than at PHH junctions (112.5°) owing to the difference in cage curvature.…”

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confidence: 99%

Crystal Structures of C₉₄(CF₃)₂₀ and C₉₆(C₂F₅)₁₂ Reveal the Cage Connectivities in C₉₄ (61) and C₉₆ (145) Fullerenes

et al. 2009

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Investigation of higher fullerenes and their derivatives is hampered not only by the small quantities of materials available but also because for each fullerene two or more cage isomers can exist that obey the Isolated Pentagon Rule (IPR).[1] Typically higher fullerenes and their mixtures are characterized by 13 C NMR spectroscopy of HPLC fractions which yields information on molecular symmetry but not always on definitive isomer cages. [2,3] Theoretical calculations provide information concerning the relative stability or the expected line distribution in the NMR spectra, thus assisting the cage assignment. [4][5][6] Derivatization can help in characterizing higher fullerenes because their derivatives are easier to separate. In this way, metalation and chlorination of higher fullerenes contributed to the determination of cage connectivities in C 76 -C 80 , C 84 , and C 90 . Perfluoroalkylation followed by HPLC separation and X-ray structure determination of perfluoroalkyl (R F ) derivatives confirmed the cage connectivities in isomers of C 76 -C 78 , [7] C 84 -C 88 , [8,9] and C 92 . [9] Experimental observations of even higher fullerenes, C 94 and C 96 , have been limited to 13 C NMR and UV/Vis spectra of the HPLC fractions containing isomer mixtures. [2,3,10] Here we report the synthesis, separation, and X-ray structure determination of R F derivatives C 94 (CF 3 ) 20 and C 96 (C 2 F 5 ) 12 . The results provide direct proof of the cage connectivities of the highest fullerenes investigated so far, C 94 and C 96 , for which respectively 134 and 187 IPR isomers are possible.[1]A mixture of higher fullerenes C 76 -C 96 (30 mg) also containing small amounts of C 60 and C 70 was allowed to react with excess CF 3 I (98 %) in a glass ampoule at 400-420 8C and a pressure of roughly 6 bar for 3 days. The orange-colored sublimate that deposited in the colder part of the ampoule contained a complex mixture of CF 3 derivatives of C 60 , C 70 , and C 76 -C 96 according to MALDI MS analysis. The number of attached CF 3 groups ranged from 12 to 20. The mixture was partially dissolved in hexane and subjected to HPLC separation using a Cosmosil Buckyprep column (10 mm i.d., 25 cm length), hexane as the eluent (4.6 mL min À1 ), monitored at the wavelength of 290 nm. Several fractions containing C 94 (CF 3 ) n compounds were eluted between 4 and 38 min. The fraction eluting at 4.64 min contained C 94 (CF 3 ) 20 as the main component. After an additional HPLC separation and recrystallization from a toluene/hexane mixture, small orange crystals were obtained which were investigated by X-ray diffraction with the use of synchrotron radiation.[11] The same reaction batch provided some other CF 3 compounds which were isolated and characterized by X-ray diffraction: C 84 -(CF 3 ) 12 [9] and C 92 (CF 3 ) 16 .[9]The same mixture of higher fullerenes (15 mg) was allowed to react with excess C 2 F 5 I (98 %, Apollo) in a glass ampoule at 250 8C under a pressure of about 20 bar for 5 days. After the ampoule had been opened, the excess C...

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Isolation and Structural Characterization of the Most Stable, Highly Symmetric Isomer of C₆₀(CF₃)₁₈

Cited by 18 publications

References 17 publications

Perfluoroalkylfullerenes

Perfluoroalkylfullerenes

Fullerenes

Crystal Structures of C₉₄(CF₃)₂₀ and C₉₆(C₂F₅)₁₂ Reveal the Cage Connectivities in C₉₄ (61) and C₉₆ (145) Fullerenes

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Isolation and Structural Characterization of the Most Stable, Highly Symmetric Isomer of C60(CF3)18

Cited by 18 publications

References 17 publications

Perfluoroalkylfullerenes

Perfluoroalkylfullerenes

Fullerenes

Crystal Structures of C94(CF3)20 and C96(C2F5)12 Reveal the Cage Connectivities in C94 (61) and C96 (145) Fullerenes

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Isolation and Structural Characterization of the Most Stable, Highly Symmetric Isomer of C₆₀(CF₃)₁₈

Crystal Structures of C₉₄(CF₃)₂₀ and C₉₆(C₂F₅)₁₂ Reveal the Cage Connectivities in C₉₄ (61) and C₉₆ (145) Fullerenes