ARE THE MOTION OF LA ATOMS INSIDE C_(80) CONTROLLABLE BY EXOHEDRAL ADDITION ?

摘要

Among endohedral metallofullerenes whose structures have been determined,La_2@C_(80) has been most extensively investigated since it has a unique I_h cage structure,as does C_(60).From theoretical calculations [1] and NMR experiments [2],in 1996 we found that two La atoms can circulate inside C_(80) with small barriers.The time-averaged trajectory corresponding to the motion has been recently shown by the electron distribution determined by Maximum Entropy Method (MEM)/Rietvelt analysis of the synchrotron X-ray powder diffraction data [3].It is of considerable interest how the dynamic properties of encapsulated metals are controllable,because molecular rotation within a cage is expected to be of great help in designing functional molecular devices.