Organic Synthesis of Transition Metal Encapsulated Fullerenes

1. 环碳结构的光谱研究：利用激光解吸质谱法从相应的有机前驱体中生成的环[n]碳（n= 12、16、18、20和24）的分子结构，基于簇阴离子的紫外光电子能谱进行了研究。结果表明，含有4n个碳的环[n]碳具有多聚结构，而含有4n+2个碳的环[n]碳具有累积结构。笼型聚乙烯（C_<60>H_6）的生成及其异构化成富勒烯：为了研究C_<60>H_6脱氢异构化成C_<60>富勒烯的可能性，制备了笼型聚乙烯的前体C_<60>H_6。在前驱体的激光解吸质谱中，我们不仅观察到由消除6个吲哚分子得到的C_<60>H_6，而且还观察到可能由反应性聚乙烯链异构化形成的C_<60>富勒烯。这些结果为富勒烯及其金属包封衍生物在聚烯烃环化的基础上进行全合成提供了可能的途径。笼型氮杂炔（C_<58>N_2H_4）的生成及其异构化成重氮杂烯：由相应的有机前驱体用上述相同的方法生成具有两个吡啶环的C_<58>N_2H_4笼型氮杂炔。在激光解吸质谱中，不仅观察到C_<58>N_2H_4，而且由于重氮富勒烯C_<58 >n_2存在一个小峰。这是关于金属包覆富勒烯合成的一个重要发现，因为它代表了这种新型杂富勒烯的首次观察，它与富勒烯离子是等电子的。

1. Spectroscopic Studies on the Structures of Cyclocarbons : Molecular structures of cyclo[n]carbons (n= 12, 16, 18, 20, and 24), which were generated in the laser-desorption mass spectroscopic method from the corresponding organic precursors, were investigated on the basis of the ultraviolet photoelectron spectra of the cluster anions.It was revealed that the cyclo[n]carbons with 4n carbons possess polyynes structure whereas those with 4n+2 carbons are cumulenic structure.2. Generation of Cage Polyyne (C_<60>H_6) and its Isomerization into Fullerene : A precursor to the cage polyyne C_<60>H_6 was prepared in order to investigate the possibility regarding dehydrogenative isomerization of C_<60>H_6 into C_<60> fullerene.In the laser-desorption mass spectra of the precursor, we observed not only C_<60>H_6 derived from elimination of six indane molecules but also C_<60> fullerene which was formed presumably by the isomerization of the reactive polyyne chain.These results suggest the possible total synthetic pathway of fullerenes and their metal encapsulated derivatives on the basis of polyyne cyclization.3. Generation of Cage Azapolyyne (C_<58>N_2H_4) and its Isomerization into Diazafullerene : The cage polyyne C_<58>N_2H_4 having two pyridine rings was generated from the corresponding organic precursor by the same method as described above.In the laser-desorption mass spectra, we observed not only C_<58>N_2H_4 but also a small peak due to diazafullerene C_<58>N_2.This is an important finding with regard to the synthesis of metal encapsulated fullerenes, because it represents the first observation of this novel heterofullerene which is isoelectronic with fullerene dianion.