文摘
A new oxide cluster fullerene, Sc<sub>2sub>O@C<sub>2vsub>(5)-C<sub>80sub>, has been isolated and characterized by mass spectrometry, UV鈥搗is鈥揘IR absorption spectroscopy, cyclic voltammetry, <sup>45sup>Sc NMR, DFT calculations, and single crystal X-ray diffraction. The crystallographic analysis unambiguously elucidated that the cage symmetry was assigned to C<sub>2vsub>(5)-C<sub>80sub> and suggests that the Sc<sub>2sub>O cluster is ordered inside the cage. The crystallographic data further reveals that the Sc1鈥揙鈥揝c2 angle is much larger than that found in Sc<sub>2sub>O@T<sub>dsub>(19151)-C<sub>76sub> but almost comparable to that in Sc<sub>2sub>O@C<sub>ssub>(6)-C<sub>82sub>, suggesting that the endohedral Sc<sub>2sub>O unit is flexible and can display large variation in the Sc鈥揙鈥揝c angle, which depends on the size and shape of the cage. Computational studies show that there is a formal transfer of four electrons from the Sc<sub>2sub>O unit to the C<sub>80sub> cage, i.e., (Sc<sub>2sub>O)<sup>4+sup>@(C<sub>80sub>)<sup>4鈥?/sup>, and the HOMO and LUMO are mainly localized on the C<sub>80sub> framework. Moreover, thermal and entropic effects are seen to be relevant in the isomer selection. Comparative studies between the recently reported Sc<sub>2sub>C<sub>2sub>@C<sub>2vsub>(5)-C<sub>80sub> and Sc<sub>2sub>O@C<sub>2vsub>(5)-C<sub>80sub> reveal that, despite their close structural resemblance, subtle differences exist on the crystal structures, and the clusters exert notable impact on their spectroscopic properties as well as interactions between the clusters and corresponding cages.