Institute for Chemical Research, Kyoto University, Kyoto 611-0011, Japan.
Nat Commun. 2013;4:1554. doi: 10.1038/ncomms2574.
Single crystal X-ray analysis has been used as a powerful method to determine the structure of molecules. However, crystallographic data containing helium has not been reported, owing to the difficulty in embedding helium into crystalline materials. Here we report the X-ray diffraction study of He@C60 and the clear observation of a single helium atom inside C60. In addition, the close packing of a helium atom and a nitrogen atom inside fullerenes is realized using two stepwise insertion techniques, that is, molecular surgery to synthesize the fullerenes encapsulating a helium atom, followed by nitrogen radio-frequency plasma methods to generate the fullerenes encapsulating both helium and nitrogen atoms. Electron spin resonance analysis reveals that the encapsulated helium atom has a small but detectable influence on the electronic properties of the highly reactive nitrogen atom coexisting inside the fullerene, suggesting the potential usage of helium for controlling electronic properties of reactive species.
单晶 X 射线分析已被用作确定分子结构的有力方法。然而，由于将氦嵌入晶体材料非常困难，因此尚未有包含氦的晶体学数据被报道。在这里，我们报告了 He@C60 的 X 射线衍射研究，并清晰地观察到了单个氦原子在 C60 内部。此外，我们还通过两步插入技术实现了氦原子和氮原子在富勒烯内部的紧密堆积，即通过分子手术合成包裹氦原子的富勒烯，然后通过氮射频等离子体方法生成同时包裹氦和氮原子的富勒烯。电子自旋共振分析表明，封装在富勒烯内部的氦原子对共存的高反应性氮原子的电子性质有微小但可检测的影响，这表明氦在控制反应性物质的电子性质方面具有潜在的应用价值。
