Sc₂O@C_3v(8)-C₈₂: A Missing Isomer of Sc₂O@C₈₂

Qiangqiang Tang^†,Laura Abella^‡, Yajuan Hao^§, Xiaohong Li^†, Yingbo Wan^†, Antonio Rodríguez-Fortea^*‡, Josep M. Poblet^*‡, Lai Feng^*§（冯莱）, and Ning Chen^*† （谌宁）

^† Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University,

^‡ Departament de Química Física i Inorgànica, Universitat Rovira i Virgili

^§College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University

Inorg. Chem., 2016, 55 (4), 1926–1933

By introducing CO₂ as the oxygen source during the arcing process, a new isomer of Sc₂O@C₈₂, Sc₂O@C_3v(8)-C₈₂, previously investigated only by computational studies, was discovered and characterized by mass spectrometry, UV–vis–NIR absorption spectroscopy, cyclic voltammetry, ⁴⁵Sc NMR, density functional theory (DFT) calculations, and single-crystal X-ray diffraction. The crystallographic analysis unambiguously elucidated that the cage symmetry was assigned to C_3v(8) and suggests that Sc₂O cluster is disordered inside the cage. The comparative studies of crystallographic data further reveal that the Sc1–O–Sc2 angle is in the range of 131.0–148.9°, much larger than that of the Sc₂S@C_3v(8)-C₈₂, demonstrating a significant flexibility of dimetallic clusters inside the cages. The electrochemical studies show that the electrochemical gap of Sc₂O@C_3v(8)-C₈₂ is 1.71 eV, the largest among those of the oxide cluster fullerenes (OCFs) reported so far, well correlated with its rich abundance in the reaction mixture of OCF synthesis. Moreover, the comparative electrochemical studies suggest that both the dimetallic clusters and the cage structures have major influences on the electronic structures of the cluster fullerenes. Computational studies show that the cluster can rotate and change the Sc–O–Sc angle easily at rather low temperature.

链接：//pubs.acs.org/doi/abs/10.1021/acs.inorgchem.5b02901