Development of Method to Separation and Punfication 0f Novel-Fullerene Corn-pound Materials Using Plasma Chromatography

在用钾富勒烯（K^+_-C^-_<60>）等离子体形成薄膜的实验中，通过控制K^+和C^-_<60>离子流入底物的能量和通量，成功地形成了内质金属富勒烯K@C_<60>。然而，由于K@C_<60>与C_<60>的产率最多为30%，通常为5 ~ 10%或更低，因此很难明确等离子体效应与包封机制之间的关系。从上述观点出发，实验是在钠富勒烯（Na^+_-C^-_<60>）等离子体中进行的，其中Na^+的直径小于K^+的直径。得到了以下结果：通过对在衬底上形成的薄膜的质谱分析，观察到与纳米面体富勒烯对应的质谱峰Na(@)C_<60>。结果表明，Na(@)C_<60>与C_<60>的平均强度比为30 ~ 50%。此外，在衬底的狭窄区域内，Na(@)C_<60>与C_<60>的产率达到200%以上。当衬底偏压改变时，发现Na(@)C_<60>的平均谱峰强度在特定电压下达到最大值。采用高分辨电子显微镜（HREM）直接观察了薄膜的组成和结构。在薄膜图像上，在衬底的狭窄区域观察到大量C_<60>分子，其中心周围有暗影。HREM成像的圆形材料被认为是C_<60>，将Na包裹在笼内，因为Na^+直径几乎与暗影直径相对应。可以说，含有Na@C_<60>的Na-C_<60>复合材料的大量生产，有利于进行成分分析和结构观察，阐明其理化性质。这项工作在建立具有新功能的富勒烯基薄膜的形成方法方面也具有重要意义。

The endohedral metallofullerene K@C_<60> was successfully formed by the energy and flux control of K^+ and C^-_<60> ions flowing into substrates in experiments of the thin-film formation with a potassiumfullerene (K^+_-C^-_<60>) plasma. Since the K@C_<60> production ratio to C_<60> was at most 30% and usually 5〜10% or less, however, it was difficult to clarify the relation between the plasma effect and encapsulation mecharuism. From the abovementioned viewpoint, the experiments were carried out by a sodiumfullerene (Na^+_-C^-_<60>) plasma, where the diameter of Na^+ is srmaller than that of K^+. The following results were obtained.According to the mass analysis of thin films formed on the substrates, the large massspectrum peak (Na(@)C_<60>) corresponding to the Naendohedral fullereoe is observed. The average intensity ratio of Na(@)C_<60> to C_<60> is turned out to be 30〜50%. Moreover, the Na(@)C_<60> production ratio to C_<60> in a narrow region of the substrate attains to 200% or more.When the substrate bias is chansed, the average spectrumpeak intensity of Na(@)C_<60> is found to give the maximum value at a specific voltage.The composition and structure of the thin film are directly investigated by the highresolution electron microscope (HREM) observation. A lot of C_<60> molecules with dark shadows around the centers are observed over the image of the thin film in the narrow region of the substrate. The round material imaged by the HREM is considered to be C_<60> encapsulating Na inside the cage, because the Na^+ diameter almost corresponds to the dark shadow diameter.It can be said that a large amount of production of the Na-C_<60> compound materials containing Na@C_<60> facilitates the constituent analysis and structure observation for the purpose of clarifying their physical and chemical properties. This work is also important in the sence of establishing the method of forming fullerenebased thin films with new functions.