Computational Study On The Endohedral Metallofullerene(EMF)

Modern scientific computations, especially those based on the density functional theory (DFT) offer us a powerful tool to explore various aspects of chemistry, materials sciences and condensed matter physics, thanks to the rapid developments of related theories, algorithms as well as computer hardware. To clarify the structures is crucial for fullerene-based Compounds. The symmetry and structure of most endohedral fullerenes have been successfully characterized by X-ray diffraction and NMR spectroscopy. In the case of metallofullerenes for which no X-ray analysis is available, the datas supported by DFT calculations have provided valuable information. In present paper, by means of Gaussian03 package and Materials Studio software, the structure of trimetallic nitride fullerenes (TNFs) encaged lanthanide clusters were clarified.Most of the recent theoretical explanations on the stabilization mechanism of TNFs are dominatingly based on the electron transfer interaction model. Herein, for lanthanide-based TNFs with general formula M3N6+@C2n6-, a systematic theoretical study including both electron transfer interaction and the sizes of the encaged lanthanide clusters as well as the cages was performed.DFT calculations demonstrated that the parent cage of both Lu3N@C88 and Gd3N@C88 is D2 symmetrical C88:81738 and their structures and stability are mainly determined by electron transfer interaction between the encaged cluster and the parent cage. However, for La3N@C88, the parent cage is Cs symmetric C88:81734, La3N cluster are pyramidal in most screened cages, and the structure and stability of La3N@C88 is determined by both electron transfer interaction and size effect. The calculations can rationalize the recent experimental observations and clearly demonstrate that the size of encaged cluster play a substantial role in determining the structures and stability of M3N@C88.