Modulation of structural and electronic properties of fullerene and metallofullerenes by surface chemical modifications.

Many applications of fullerene, metallofullerene, and carbon nanotubes request the chemical modifications. But how the modification influences the stability, structural, and electronic properties that directly relate to the practical functions of the carbon nanomaterials, this issue is discussed in this paper. The outer chemical modifications can sensitively influence the stability of final derivatives of fullerenes, depending on parameters such as the number of the modified groups, the unintended impurity groups on the cage surface, and chemical conditions in synthesizing processes. The outer chemical modification can induce alteration in electronic properties of metallofullerene. Gd@C-82 is taken as a model to show how the electronic properties of the encaged metal atom are modulated by the cage surface modification. There exist sandwich-type electronic interactions along pathway: [outer modification group]-[cage surface]-[inner atom], and their synergistic effects are discussed. Beside the number of the modified groups, whose distribution patterns on the cage surface also play crucial roles in determining how the electronic interactions are modulated. Their synergistic effects dominate the electronic, optical, or magnetic properties of functionalized fullerenic nanomaterials. As the surface of nanotube is chemically more inert as compared to that of fullerene or metallofullerene, to achieve desirable modulations of nanotubes is probably more difficult. The research aimed to explore the changes in their structural or electronic property after the outer chemical functionalization was few, though this is of special significant and needs investigations because the chemical modifications are widely applying to the carbon nanotubes in applications.