Synthesis, Characterization And Chemical Reactivity Of Endohedral Clusterfullerenes

Clusterfullerenes attract increasing attentions and have great potentials on the application in the research fields such as biomedicine, energy, superconducativity etc. due to their unique electronic structures, relative high thermal stability and structural variety. To date, nitride clusterfullerenes, carbide clusterfullerenes, cyanide clusterfullerenes, oxide clusterfullerenes and sulfide clusterfullerenes have been reported. Among them, oxide clusterfullerenes are featured by their exceptional structural versatility, but the reported cage structures of this family have been very limited. It is therefore desiable to explore new oxide clusterfullerenes with variable cage structures. In the study of the chemical reactivity of endohedral fullerenes, the interaction between clusters and cages and the impact of the interaction on the chemical reactivity of EMFs have become the focus in recent research. On the other hand, the synthesis of water-soluble endohedral fullerene derivatives have become an important subject in the recent chemical reactivity studies of endohedral fullerenes. Thus it is necessary to explore the methods for preparing water-soluble endohedral fullerene derivatives and reaction intermediate. The contents of this thesis include the following three aspects:1. The introducing of C2H5 OH, H2 O and CO2 as the oxide sources during arc discharging processes was explored in the synthesis of oxide clusterfullerenes. CO2 has been deterimined as the the optimal oxygen source for this synthesis. Under the optimal oxygen source, we discovered an extensive scandium dioxide clusterfullerenes family with carbon cages ranging from C70 to C82, Sc2O@C2n(n=35-41). A multi-stage-high-performance-liquid chromatography(HPLC) procedure was utilized to isolate and purify fullerene isomers from the reaction mixture and a new scandium dioxide clusterfullerene, Sc2O@C76 was obtained in isomeric purified form. Sc2O@C76 was characterized by mass spectrometry, single-crystal X-ray diffraction, 45 Sc NMR, UV-Vis-NIR absorption spectroscopy, cyclic voltammetry and computational studies. The crystallographic analysis unambiguously assigned the cage structure to Td(19151)-C76, the first tetrahedral fullerene cage characterized by single crystal X-ray diffraction. The combined experimental and computational studies revealed that the Sc-O-Sc angle in the Sc2O@Td(19151)-C76 is considerably smaller than that in Sc2O@Cs(6)-C82 and the dynamics of Sc2 O was more restrained in the Td(19151)-C76 cage compared to that in the Cs(6)-C82 cages, suggesting the significant impact of cage size on the shape and motion of endohedral clusters inside IPR cages.2. By the Diels-Alder reaction between Lu3N@C80 and 6,7 dimethoxyisochroman-3-one, new derivatives of Lu3N@C80 including two Lu3N@C80 mono-adducts(A, B), a monoxide of a Lu3N@C80 mono-adduct(C) and several di-adducts of Lu3N@C80, were obtained. A HPLC procedure was utilized to isolate and purify A, B and C. The purified A, B and C was characterized by mass spectrometry, Vis-NIR absorption spectroscopy, cyclic voltammetry. For comparison, only one [5,6] monoadduct was obtained by the D-A reaction between Sc3N@C80 and 6,7 dimethoxyisochroman-3-one. The results showed that the reactivity of Lu3N@C80 was higher than that of Sc3N@C80 in the reaction and verified the significant impact of cluster size on on the chemical reactivity of clusterfullerenes.3. The synthesis of a monooxide derivative of endohedral fullerene, Lu3N@C80O, was reported. To our best knowledge, Lu3N@C80O is the first monooxide derivative of endohedral fullerene reported so far. The synthesis was carried under both thermal and photochemical conditions and the Lu3N@C80O compound was characterized by mass spectrometry, UV-Vis-NIR spectroscopy, IR spectroscopy and cyclic voltammetry. IR spectrum indicated that the oxygen atom might be bridged on the cage. The UV-Vis-NIR spectroscopy and cyclic voltammetry results suggested that the introduction of oxygen perturbed the absorption spectrum slightly but had a great influence on its electrochemical behavior.