Nanoscale Fullerene Compression of an Yttrium Carbide Cluster

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• 作者：Jianyuan Zhang ; Tim Fuhrer ; Wujun Fu ; Jiechao Ge ; Daniel W. Bearden ; Jerry Dallas ; James Duchamp ; Kenneth Walker ; Hunter Champion ; Hugo Azurmendi ; Kim Harich ; Harry C. Dorn
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：May 23, 2012
• 年：2012
• 卷：134
• 期：20
• 页码：8487-8493
• 全文大小：468K
• 年卷期：v.134,no.20(May 23, 2012)
• ISSN：1520-5126

文摘

The nanoscale parameters of metal clusters and lattices have a crucial influence on the macroscopic properties of materials. Herein, we provide a detailed study on the size and shape of isolated yttrium carbide clusters in different fullerene cages. A family of diyttrium endohedral metallofullerenes with the general formula of Y₂C_2n (n = 40鈥?9) are reported. The high field ¹³C nuclear magnetic resonance (NMR) and density functional theory (DFT) methods are employed to examine this yttrium carbide cluster in certain family members, Y₂C₂@D₅(450)-C₁₀₀, Y₂C₂@D₃(85)-C₉₂, Y₂C₂@C₈₄, Y₂C₂@C_3v(8)-C₈₂, and Y₂C₂@C_s(6)-C₈₂. The results of this study suggest that decreasing the size of a fullerene cage with the same (Y₂C₂)⁴⁺ cluster results in nanoscale fullerene compression (NFC) from a nearly linear stretched geometry to a constrained 鈥渂utterfly鈥?structure. The ¹³C NMR chemical shift and scalar ¹J_YC coupling parameters provide a very sensitive measure of this NFC effect for the (Y₂C₂)⁴⁺ cluster. The crystal structural parameters of a previously reported metal carbide, Y₂C₃ are directly compared to the (Y₂C₂)⁴⁺ cluster in the current metallofullerene study.