PROPERTY DEVELOPMENT OF NOVEL ENDOHEDRAL FULLERENES THROUGH SYNTHETIC RESEARCH

我们已经建立了分子外科方法来产生内源性富勒烯，根据传统的物理程序只能获得微量的富勒烯。本研究的目的是开发这类新型内嵌富勒烯的新性能。采用分子外科方法合成了包封氢和氘的内嵌富勒烯H2@C60和D2@C60。制备了一种掺钾的内嵌富勒烯K3/H2@C60，在Tc=19.2K的临界温度下，该富勒烯成为电超导体。这与在空C60中观察到的温度相同，表明在k掺杂条件下，被封装的氢和富勒烯笼之间没有任何电子相互作用。在顺磁性氮氧化物的存在下，测量了溶解在不同有机溶剂中的H2和H2@C60的质子对自旋晶格弛豫速率的双分子贡献。结果表明，在相同条件下，H2@C60中顺磁体的弛豫效应比H2增强了5倍。考察了C60、H2@C60和D2@C60对单线态分子氧^1O2的猝灭作用，并与溶液中游离H2和D2对单线态分子氧^1O2的猝灭作用进行了比较。结果表明，H2@C60和D2@C60对^1O2的猝灭速率常数大于H2和D2对^1O2的猝灭速率常数。这表明π共轭C60笼的存在对o2淬火起着重要的作用。合成了含He原子和H2分子的开笼富勒烯。连接在笼外的质子的^1H NMR化学位移受到笼内客体物质的影响，从而表明客体物质与开笼富勒烯笼之间存在某种相互作用。新合成了一种开笼富勒烯，在13元环孔的边缘以硒原子代替硫原子。研究了氢分子的包封和释放过程，发现这些过程的激活较小，表明硒原子的引入扩大了孔的尺寸。少

We have established the molecular surgical method for the creation of endohedral fullerenes, which were obtained only in minute amounts according to the conventional physical procedures. The present research aims at the development of new properties in this kind of new endohedral fullerenes.1. Endohedral fullerenes encapsulating hydrogen and also deuterium, H2@C60 and D2@C60, were newly synthesized according to the molecular surgical method.2. An endohedral fullerene doped with potassium, K3/H2@C60, was prepared and it was shown to become an electric superconducter below the critical temperature of Tc=19.2K. This is the same temperature observed for empty C60, indicating the absence of any electronic interaction between encapsulated hydrogen and the fullerene cage under the K-doped conditions.3. The bimolecular contribution to the spin-lattice relaxation rate for the protons of H2 and H2@C60 dissolved in various organic solvents was measured in the presence of paramagnetic nitroxide ra … More dicals. It was found that the relaxation effect of the paramagnets is enhanced five-fold in H2@C60 compared to H2 under the same conditions.4. The quenching of singlet molecular oxygen ^1O2 by C60, H2@C60, and D2@C60 was examined and compared with that by free H2 and D2 in solution. The rate constants for quenching of ^1O2 by H2@C60 and D2@C60 were found to be larger than those for the quenching of ^1O2 by H2 and D2. This indicates that the presence of a pi-conjugated C60 cage plays an important role for the, ^1O2 quenching.5. Open-cage fullerenes incorporating a He atom and a H2 molecule were synthesized. The ^1H NMR chemical shift of a proton attached outside the cage is influenced by the inside guest species, thus indicating the presence of some interaction between the guest species and the open-cage fullerene cage.6. An open-cage fullerene having a selenium atom instead of sulfur at the rim of a 13-membered-ring orifice was newly synthesized. The encapsulation and release of a hydrogen molecule were examined, and it was found that activation of these processes is smaller indicating that the orifice size has been enlarged by introduction of the selenium atom. Less