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• 作者：Hua Yang ; Hongxiao Jin ; Xinqing Wang ; Ziyang Liu ; Meilan Yu ; Fukun Zhao ; Brandon Q. Mercado ; Marilyn M. Olmstead ; Alan L. Balch
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：August 29, 2012
• 年：2012
• 卷：134
• 期：34
• 页码：14127-14136
• 全文大小：629K
• 年卷期：v.134,no.34(August 29, 2012)
• ISSN：1520-5126

文摘

Three isomers of Sm@C₈₂ that are soluble in organic solvents were obtained from the carbon soot produced by vaporization of hollow carbon rods doped with Sm₂O₃/graphite powder in an electric arc. These isomers were numbered as Sm@C₈₂(I), Sm@C₈₂(II), and Sm@C₈₂(III) in order of their elution times from HPLC chromatography on a Buckyprep column with toluene as the eluent. The identities of isomers, Sm@C₈₂(I) as Sm@C_s(6)-C₈₂, Sm@C₈₂(II) as Sm@C_3v(7)-C₈₂, and Sm@C₈₂(III) as Sm@C₂(5)-C₈₂, were determined by single-crystal X-ray diffraction on cocrystals formed with Ni(octaethylporphyrin). For endohedral fullerenes like La@C₈₂, which have three electrons transferred to the cage to produce the M³⁺@(C₈₂)^{3鈥?/sup> electronic distribution, generally only two soluble isomers (e.g., La@C_2v(9)-C₈₂ (major) and La@C_s(6)-C₈₂ (minor)) are observed. In contrast, with samarium, which generates the M2+@(C₈₂)2鈥?/sup> electronic distribution, five soluble isomers of Sm@C₈₂ have been detected, three in this study, the other two in two related prior studies. The structures of the four Sm@C₈₂ isomers that are currently established are Sm@C₂(5)-C₈₂, Sm@C_s(6)-C₈₂, Sm@C_3v(7)-C₈₂, and Sm@C_2v(9)-C₈₂. All of these isomers obey the isolated pentagon rule (IPR) and are sequentially interconvertable through Stone鈥揥ales transformations.}