High‐temperature chlorination of C90‐containing fullerene fraction resulted in the isolation and X‐ray structural characterization of C90(1)Cl10/12, the first derivatives of a relatively unstable isomer D5h‐C90(1) with a nanotubular shape. In the crystal structure, three isomers of both C90(1)Cl10 and C90(1)Cl12 with similar chlorination patterns co‐crystallize in the same crystallographic site. Thus, in contrast to the previous reports, D5h‐C90(1) is present, though with a low abundance, in the fullerene soot produced by arc‐discharge method with undoped graphite rods. 相似文献
Chlorination of a mixture of C86 isomers no. 16 (Cs) and no. 17 (C2) with VCl4 or a (TiCl4+Br2) mixture afforded crystalline chlorides with 16 to 22 Cl atoms per fullerene cage. Single crystal X‐ray diffraction with the use of synchrotron radiation enabled us to determine the chlorination patterns of C86(16)Cl16, C86(17)Cl18, C86(17)Cl20, and C86(17)Cl22. At these degrees of chlorination, addition patterns of C86(16) and C86(17) chlorides have some features in common, owing to the close similarity in the cage structures of both isomers. The average energy of C?Cl bonds decreases with increasing number of attached Cl atoms. 相似文献
High‐temperature chlorination of pristine C98 fullerene isomers separated by HPLC from the fullerene soot afforded crystals of C98Cl22 and C98Cl20. An X‐ray structure elucidation revealed, respectively, the presence of carbon cages of the most stable C2‐C98(248) and rather unstable C1‐C98(116), which represent the first isolated pentagon rule (IPR) isomers of fullerene C98 confirmed experimentally. The chlorination patterns of the chlorides are discussed in terms of the formation of isolated C=C bonds and aromatic substructures on the fullerene cages. 相似文献
Isolation and characterization of very large fullerenes is hampered by a drastic decrease of their content in fullerene soot with increasing fullerene size and a simultaneous increase of the number of possible IPR (Isolated Pentagon Rule) isomers. In the present work, fractions containing mixtures of C102 and C104 were isolated in very small quantities (several dozens of micrograms) by multi‐step recycling HPLC from an arc‐discharge fullerene soot. Two such fractions were used for chlorination with a VCl4/SbCl5 mixture in glass ampoules at 350–360 °C. The resulting chlorides were investigated by single‐crystal X‐ray diffraction using synchrotron radiation. By this means, two IPR isomers of C104, numbers 258 and 812 (of 823 topologically possible isomers), have been confirmed for the first time as chlorides, C1‐C104(258)Cl16 and D2‐C104(812)Cl24, respectively, while an admixture of C2‐C104(811)Cl24 was assumed to be present in the latter chloride. DFT calculations showed that pristine C104(812) belongs to rather stable C104 cages, whereas C104(258) is much less stable. 相似文献
Chlorination of various HPLC fractions of C96 with a mixture of VCl4 and SbCl5 at 340–360 °C and single‐crystal X‐ray diffraction study of the products led to the identification of three new IPR isomers of C96. The C96(175) isomer forms a stable chloride, C96(175)Cl20, while chlorides of two other new isomers, C96(114) and C96(80), undergo cage shrinkage yielding C94(NC1)Cl28 and C96(NC2)Cl32 with non‐classical (NC) cages. These two NC chlorides contain, respectively, one and two heptagons flanked by pairs of fused pentagons and are stabilized by chlorine attachment to the emerging pentagon–pentagon junctions. Thus, the number of the experimentally confirmed C96 isomers has reached nine, which corroborates the empirical rule that the C6n fullerenes exhibit particularly rich isomerism. 相似文献
Chlorofullerenes C86(16)Cl16 and C86(17)Cl18,20 were prepared by chlorination of Cs-C86(16) and C2-C86(17), respectively, with VCl4 at 320–340 °C. An X-ray crystallo- graphic study with the use of synchrotron radiation revealed the chlorination patterns which show certain similarity due to only small differences between isomeric C86 cages. 相似文献
Chlorination of C100 fullerene with a mixture of VCl4 and SbCl5 afforded C96Cl20 with a strongly unconventional structure. In contrast to the classical fullerenes containing only hexagonal and pentagonal rings, the C96 cage contains three heptagonal rings and, therefore, should be classified as a fullerene with a nonclassical cage (NCC). There are several types of pentagon fusions in the C96 cage including pentagon pairs and pentagon triples. The three‐step pathway from isolated‐pentagon‐rule (IPR) C100 to C96(NCC‐3hp) includes two C2 losses, which create two cage heptagons, and one Stone–Wales rotation under formation of the third heptagon. Structural reconstruction established C100 isomer no. 18 from 450 topologically possible IPR isomers as the starting C100 fullerene. Until now, no pristine C100 isomers have been confirmed based on the experimental results. 相似文献
Two for the price of one : The first halogenated derivative of C90, C90Cl32 (see structure; gray C, green Cl), is obtained by chlorination of a higher fullerene mixture with SbCl5. Its molecular structure, elucidated by single‐crystal X‐ray diffraction, reveals the presence of two isomeric C90 cages that correspond to C2v isomer 46 and Cs isomer 34. The addition of 32 chlorine atoms is the maximum degree of chlorination achieved for fullerenes.
The chlorination of HPLC fractions with pristine giant fullerenes, C102 and C104, followed by X‐ray crystallographic study of chlorides, C102(603)Cl18/20 and C104(234)Cl16–22, confirmed the presence of the most stable IPR (IPR=Isolated Pentagon Rule) isomers, C102(603) and C104(234), in the fullerene soot. The discussion concerns the chlorination patterns of polychlorides and relative stability of pristine isomers of C102 and C104 fullerenes. 相似文献
Chlorofullerenes C84(11)Cl20 and C84(11)Cl22 were prepared by chlorination of C2–C84(11) with VCl4 at 340–360 °C. An X-ray crystallographic study with the use of synchrotron radiation revealed the chlorination patterns featuring only para additions in C6Cl2 hexagons. 相似文献
Direct proof of the cage connectivities of four isomers of C(96) , the highest isolable empty fullerene, has been achieved. C(96) fractions, which were isolated from fullerene soot by recycling HPLC, were chlorinated and the resulting single crystals of C(96) Cl(22) and C(96) Cl(24) were studied by X-ray diffraction using synchrotron radiation. D(2) -C(96) (183)Cl(24) (see structure; gray C, green Cl) was obtained in two crystalline modifications. 相似文献
High‐temperature chlorination of a fullerene C86 with VCl4 afforded non‐classical C84Cl30 and C82Cl30 containing one and two heptagons, respectively, in the carbon cages. Two types of C2 losses, which differ in the final arrangements of separate or fused pentagons, can occur successively in either order, producing rather flat or concave regions on the shrinked carbon cage. In the chlorination‐promoted skeletal transformation of C86 (isomer no. 16) with the loss(es) of C2 units, the structures of the starting, intermediate, and final compounds were all revealed unambiguously by X‐ray single crystal diffraction. 相似文献
High‐temperature trifluoromethylation of fullerene C78 followed by HPLC separation of C78(CF3)n derivatives resulted in the isolation and X‐ray structural characterization of 15 compounds, that is, two C78(1)(CF3)10, three C78(1)(CF3)12, four C78(1)(CF3)14, and five C78(1)(CF3)16 isomers as well as one isomer of C78(1)(CF3)18. The addition patterns of the C78(1)(CF3)n molecules are discussed in terms of trifluoromethylation pathways and relative formation energies. 相似文献
Three C(90) fractions were isolated by multi-step HPLC from fullerene soot obtained from direct current (DC) arc discharge of undoped graphite rods. C(90) of each fraction was chlorinated with VCl(4) or SbCl(5) in ampoules at 290-310 °C, affording a series of C(90)Cl(n) compounds. Single-crystal X-ray crystallography with the use of synchrotron radiation resulted in structure elucidation of seven C(90)Cl(n) compounds containing six different isolated pentagon rule (IPR) C(90) cages (the number of the C(90) isomer is given in the parentheses): C(90)(46)Cl(32) (I), C(90)(34)Cl(32) (II), C(90)(35)Cl(24) (III), and C(90)(35)Cl(28) (IV), C(90)(32)Cl(24) (V as co-crystals with III), co-crystals of C(90)(30)Cl(22) and C(90)(28)Cl(24) (VI), and C(90)(28)Cl(24) (VII). Cage connectivities of C(90) isomers 35 and 28 have been crystallographically confirmed for the first time. The chlorination patterns of the C(90)Cl(n) molecules are discussed in terms of the formation of isolated aromatic systems and isolated C=C double bonds on the fullerene cage. The distribution of six C(90) isomers in three HPLC fractions is compared with data from the literature. 相似文献
High‐temperature chlorination of C100 fullerene followed by X‐ray structure determination of the chloro derivatives enabled the identification of three isomers of C100 from the fullerene soot, specifically numbers 18, 425, and 417, which obey the isolated pentagon rule (IPR). Among them, isomers C1‐C100(425) and C2‐C100(18) afforded C1‐C100(425)Cl22 and C2‐C100(18)Cl28/30 compounds, respectively, which retain their IPR cage connectivities. In contrast, isomer C2v‐C100(417) gives Cs‐C100(417)Cl28 which undergoes a skeletal transformation by the loss of a C2 fragment, resulting in the formation of a nonclassical (NC) C1‐C98(NC)Cl26 with a heptagon in the carbon cage. Most probably, two nonclassical C1‐C100(NC)Cl18/22 chloro derivatives originate from the IPR isomer C1‐C100(382), although both C1‐C100(344) and even nonclassical C1‐C100(NC) can be also considered as the starting isomers. 相似文献
High‐temperature trifluoromethylation of isolated‐pentagon‐rule (IPR) fullerene C92 chlorination products followed by HPLC separation of C92(CF3)n derivatives resulted in the isolation and X‐ray structural characterization of IPR C92(38)(CF3)18 and non‐classical C92(NC)(CF3)22. The formation of C92(38)(CF3)18 as the highest CF3 derivative of the known isomer C92(38) can be expected. The formation of C92(NC)(CF3)22 was interpreted as chlorination‐promoted cage transformation of C92(38) followed by trifluoromethylation of non‐classical C92(NC) chloride. Noticeably, C92(NC)(CF3)22 shows the highest degree of trifluoromethylation among all known CF3 derivatives of fullerenes. The addition patterns of C92(38)(CF3)18 and C92(NC)(CF3)22 are discussed and compared to the chlorination patterns of C92(38)Cln compounds. 相似文献