Quantum Chemical Study on the Configurations of Encapsulated Metal Ions and the Molecular Vibration Modes in Endohedral Dimetallofullerene La2@C80
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- 作者：Hidekazu Shimotani ; Takayoshi Ito ; Yoshihiro Iwasa ; Atsushi Taninaka ; Hisanori Shinohara ; Eiji Nishibori ; Masaki Takata ; and Makoto Sakata
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：January 14, 2004
- 年：2004
- 卷：126
- 期：1
- 页码：364 - 369
- 全文大小：486K
- 年卷期：v.126,no.1(January 14, 2004)
- ISSN：1520-5126
文摘
The configuration of La ions of La2@C80 in the [80]fullerene cage was investigated by use ofquantum chemical calculations. We found that the D3d configuration is the global minimum in total energy,being more stable by 1.9 kcal/mol than the D2h configuration, which has been considered to be the moststable. The potential energy surface calculation clarified that La ions travel between 10 equivalent D3dpositions through D2h positions and consequently form pentagonal dodecahedral trajectory, which is ingood agreement with the previous synchrotron radiation structural study. The experimental and theoreticalinvestigation of the Raman spectrum revealed that the symmetry of molecular vibration is dramaticallyreduced simply by encapsulation of two La ions, and resulting vibrational modes were successfully assigned.The Raman peak at 163 cm-1 was interpreted as the in-phase synchronously coupled mode of the[80]fullerene cage elongation and the La-La stretching, rather than a conventional and naive assignmentas a metal-to-cage vibration mode.