摘要
两个金属硫化物富勒烯Sc2S@C82-Cs(6)和Sc2S@C82-C3v(8)的结构已经通过单晶X射线衍射验证,但对于其形成机理却知之甚少.本文通过密度泛函理论方法计算研究了Sc2S@C82的不同异构体的热力学和动力学稳定性.结合封闭网络增长模型,研究了Sc2S@C82的形成机理.计算表明,该金属富勒烯是在Sc2S@C80-D5h(31923)的基础上通过C2增长而来,且增长路径是通过中间体Sc2S@C82-Cs(39704)而不是通常认为的Sc2S@C82-Cs(39663);此外,证实了异构体Sc2S@C82-Cs(6)和Sc2S@C82-C3v(8)的相互转化是一个可逆过程;碳催化的Stone-Wales旋转可以大大降低反应的能垒.这些结果对其他金属富勒烯的形成机理具有参考意义.
The structures of endohedral fullerenes Sc2S@C82-Cs(6) and Sc2S@C82-C3v(8) have been definitely confirmed by Single-crystal X-ray Diffraction recently, however their formation mechanisms are yet unknown. Here extensive DFT calculations are performed to identify and compare the favored isomers of Sc2S@C82. The calculated results are in good agreement with the experimental results that Sc2S@C82-Cs(6) and Sc2S@C82-C3v(8) are the two most favored isomers both on thermodynamics and kinetics. The formation of Sc2S@C82 was studied based on the closed network growth model and the interconversion between different isomers of Sc2S@C82. The calculations demonstrate that two pathways may be occurred from Sc2S@C80-D5h(31923), and the favored pathway is via intermediate Sc2S@C82-Cs(39704) instead of the most well-known Sc2S@C82-Cs(39663). Furthermore, the interconversion between Sc2S@C82-Cs(6) and Sc2S@C82-C3v(8) is proved to be a reversible process by C-catalyzed bond rearrangement. These calculations can rationalize the experimental observations and put insights into the formation of other metallofullerenes.
出处
《中国科学:化学》
CAS
CSCD
北大核心
2015年第1期68-75,共8页
SCIENTIA SINICA Chimica
基金
国家自然科学基金(51272216)
中央高校基本科研业务费项目(XDJK2014B032)资助
关键词
金属硫化物
富勒烯
异构化
密度
泛函理论
能垒
metallic sulfide fullerene
isomerization
density functional theory
barrier