Fu Wujun, Xu Liaosa, Azurmendi Hugo, Ge Jiechao, Fuhrer Tim, Zuo Tianming, Reid Jonathan, Shu Chunying, Harich Kim, Dorn Harry C
Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, USA.
J Am Chem Soc. 2009 Aug 26;131(33):11762-9. doi: 10.1021/ja902286v.
The members of a new family of yttrium trimetallic nitride-templated (TNT) endohedral metallofullerenes (EMFs), Y(3)N@C(2n) (n = 40-43), have been synthesized and purified. On the basis of experimental and computational (13)C NMR studies, we propose cage structures for Y(3)N@I(h)-C(80) (IPR allowed), Y(3)N@D(5h)-C(80) (IPR allowed), Y(3)N@C(s)-C(82) (non-IPR), Y(3)N@C(s)-C(84) (non-IPR), and Y(3)N@D(3)-C(86) (IPR allowed). A significant result is the limited number of isomers found for each carbon cage. For example, there are 24 isolated pentagon rule (IPR) and 51 568 non-IPR structures possible for the C(84) cage, but only one major isomer of Y(3)N@C(s)-C(84) was found. The current study confirms the unique role of the trimetallic nitride (M(3)N)(6+) cluster template in the Kratschmer-Huffman electric-arc process for fullerene cage size and high symmetry isomer selectivity. This study reports the first (89)Y NMR results for Y(3)N@I(h)-C(80,) Y(3)N@C(s)(51365)-C(84), and Y(3)N@D(3)(19)-C(86), which reveal a progression from isotropic to restricted (Y(3)N)(6+) cluster motional processes. Even more surprising is the sensitivity of the (89)Y NMR chemical shift parameter to subtle changes in the electronic environment at each yttrium nuclide in the (Y(3)N)(6+) cluster (more than 200 ppm for these EMFs). This (89)Y NMR study suggests that (89)Y NMR will evolve as a powerful tool for cluster motional studies of EMFs.
一种新的钇三金属氮化物模板（TNT）内嵌金属富勒烯（EMF）家族成员Y(3)N@C(2n)（n = 40 - 43）已被合成和纯化。基于实验和计算的(13)C NMR研究，我们提出了Y(3)N@I(h)-C(80)（允许孤立五边形规则，IPR）、Y(3)N@D(5h)-C(80)（允许IPR）、Y(3)N@C(s)-C(82)（非IPR）、Y(3)N@C(s)-C(84)（非IPR）和Y(3)N@D(3)-C(86)（允许IPR）的笼状结构。一个重要的结果是每个碳笼中发现的异构体数量有限。例如，对于C(84)笼，有24种孤立五边形规则（IPR）结构和51568种非IPR结构是可能的，但仅发现了一种主要的Y(3)N@C(s)-C(84)异构体。当前的研究证实了三金属氮化物（M(3)N）(6+)簇模板在富勒烯笼尺寸和高对称性异构体选择性的克拉斯奇默 - 哈夫曼电弧法中的独特作用。本研究报告了Y(
