PROPERTY DEVELOPMENT OF NOVEL ENDOHEDRAL FULLERENES THROUGH SYNTHETIC RESEARCH

我们已经建立了一种分子外科方法来合成内面体富勒烯，按照传统的物理程序只能获得微量的富勒烯。本研究旨在开发这类新型内面体富勒烯的新性质。根据分子外科的方法，新合成了包覆氢和氢的面体内富勒烯，H2@C60和D2@C60。制备了K掺杂的体内富勒烯K_3/H_2@C_(60)，发现其在临界温度T_c=19.2K以下为电性超导体。这与空C60的观察到的温度相同，表明在K掺杂条件下，包裹的氢与富勒烯笼子之间没有任何电子相互作用。在顺磁性氮氧化物ra…存在下，测量了H_2和H_2@C_(60)在不同有机溶剂中的双分子对自旋晶格驰豫速率的贡献更多的骰子。研究发现，在相同条件下，在H2@C60中，顺磁网的驰豫效应是H2的5倍。考察了C60、H2@C60和D2@C60对单线态氧的猝灭作用，并与溶液中游离H2和D2的猝灭作用进行了比较。H_2@C_(60)和D_2@C_(60)对^1O_2的猝灭速率常数大于H_2和D_2对^1O_2的猝灭。这表明pi共轭C60笼的存在对^1O2猝灭起着重要作用。合成了一个He原子和一个H2分子的开笼富勒烯。笼外质子的~1H核磁共振化学位移受内部客体物种的影响，从而表明客体物种与开笼富勒烯笼子之间存在一定的相互作用。新合成了一种开笼富勒烯，在13元环孔的边缘用硒原子代替了硫原子。研究了氢分子的包覆和释放，发现这些过程的激活程度较小，表明硒原子的引入扩大了孔口尺寸。较少

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