Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan.
J Am Chem Soc. 2011 Mar 2;133(8):2382-5. doi: 10.1021/ja1107723. Epub 2011 Feb 3.
Unambiguous X-ray crystallographic results of the carbene adduct of Sc(2)C(82) reveal a new carbide cluster metallofullerene with the unexpected C(2v)(5)-C(80) cage, that is, Sc(2)C(2)@C(2v)(5)-C(80). More interestingly, DFT calculations and NMR results disclose that the dynamic motion of the internal Sc(2)C(2) cluster depends strongly on temperature. At 293 K, the cluster is fixed inside the cage with two nonequivalent Sc atoms on the mirror plane, thereby leading to C(s) symmetry of the whole molecule. However, when the temperature increases to 413 K, the (13)C and (45)Sc NMR spectra show that the cluster rotates rapidly inside the C(2v)(5)-C(80) cage, featuring two equivalent Sc atoms and weaker metal-cage interactions.
钪卡宾加成物的 X 射线晶体学结果明确显示，一种新型的碳化簇金属富勒烯具有出人意料的 C(2v)(5)-C(80)笼，即 Sc(2)C(2)@C(2v)(5)-C(80)。更有趣的是，DFT 计算和 NMR 结果表明，内部 Sc(2)C(2)簇的动态运动强烈依赖于温度。在 293 K 时，簇固定在笼内，两个不等价的 Sc 原子位于镜面平面上，从而导致整个分子具有 C(s)对称性。然而，当温度升高到 413 K 时，(13)C 和 (45)Sc NMR 谱表明，簇在 C(2v)(5)-C(80)笼内快速旋转，呈现出两个等价的 Sc 原子和较弱的金属-笼相互作用。
