Synthesis, Isolation, Characterization, and Theoretical Studies of Sc3NC@C78-C2
journal contributionposted on 08.12.2011, 00:00 by Jingyi Wu, Taishan Wang, Yihan Ma, Li Jiang, Chunying Shu, Chunru Wang
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Following the first isolation of Sc3NC@C80, a second member of this family of endohedral metallofullerenes, Sc3NC@C78, was prepared by an arc-discharging method. Experimental and theoretical studies demonstrated that the Sc3NC@C78 has a C78-C2 cage with two pairs of adjacent pentagons, which is different from the IPR-satisfying Sc3N@C78-D3h. It was revealed that the size of C78-D3h is appropriate for the Sc3N cluster, but not large enough for encaging the large planar species Sc3NC. Theoretical calculations were preformed on Sc3NC@C78-C2 and Sc3NC@C78-D3h. The results show that Sc3NC would bear a strong depression inside the C78-D3h fullerene cage due to the limited internal space of C78-D3h; on the contrary, C78-C2 has two pairs of adjacent pentagons that induce a large curvature in these sites to form an oblate ellipsoid structure. Thus, it is more favorable to encapsulate the planar species Sc3NC. Ab initio calculations were also performed to further disclose the electronic and electrochemical properties of Sc3NC@C78-C2. It was revealed that the molecule has an electronic structure of (Sc3+)3(NC)3–@C786–, in which the inner species NC has an unprecedented (NC)3– trianion charging status similar to that in the recently reported Sc3NC@C80-Ih.