Large Endohedral Fullerenes Containing Two Metal Ions, Sm2@D2(35)-C88, Sm2@C1(21)-C90, and Sm2@D3

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• 作者：Hua Yang ; Hongxiao Jin ; Bo Hong ; Ziyang Liu ; Christine M. Beavers ; Hongyu Zhen ; Zhimin Wang ; Brandon Q. Mercado ; Marilyn M. Olmstead ; Alan L. Balch
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：October 26, 2011
• 年：2011
• 卷：133
• 期：42
• 页码：16911-16919
• 全文大小：1178K
• 年卷期：v.133,no.42(October 26, 2011)
• ISSN：1520-5126

文摘

The carbon soot obtained by electric arc vaporization of carbon rods doped with Sm₂O₃ contains a series of monometallic endohedral fullerenes, Sm@C_2n, along with smaller quantities of the dimetallic endohedrals Sm₂@C_2n with n = 44, 45, 46, and the previously described Sm₂@D_3d(822)-C₁₀₄. The compounds Sm₂@C_2n with n = 44, 45, 46 were purified by high pressure liquid chromatography on several different columns. For endohedral fullerenes that contain two metal atoms, there are two structural possibilities: a normal dimetallofullerene, M₂@C_2n, or a metal carbide, M₂(渭-C₂)@C_2n鈥?. For structural analysis, the individual Sm₂@C_2n endohedral fullerenes were cocrystallized with Ni(octaethylporphyrin), and the products were examined by single-crystal X-ray diffraction. These data identified the three new endohedrals as normal dimetallofullerenes and not as carbides: Sm₂@D₂(35)-C₈₈, Sm₂@C₁(21)-C₉₀, and Sm₂@D₃(85)-C₉₂. All four of the known Sm₂@C_2n endohedral fullerenes have cages that obey the isolated pentagon rule (IPR). As the cage size expands in this series, so do the distances between the variously disordered samarium atoms. Since the UV/vis/NIR spectra of Sm₂@D₂(35)-C₈₈ and Sm₂@C₁(21)-C₉₀ are very similar to those of Gd₂C₉₀ and Gd₂C₉₂, we conclude that Gd₂C₉₀ and Gd₂C₉₂ are the carbides Gd₂(渭-C₂)@D₂(35)-C₈₈ and Gd₂(渭-C₂)@C₁(21)-C₉₀, respectively.