Chapter 249 - Metallofullerenes

Abstract

Endohedral metallofullerenes (fullerenes with metal atom(s) encapsulated) are novel forms of fullerene-based materials which have attracted wide interest during the past couple of decades, not only in physics and chemistry but also in such interdisciplinary areas as materials and biological sciences. In this chapter, advances in the production, separation (isolation), and various spectroscopic characterizations of endohedral metallofullerenes are presented in an attempt to clarify their structural, electronic, and solid-state properties. The endohedral metallofullerenes so far produced are centered on group 2 and 3 metallofullerenes such as Sc, Y, La, Ca, Sr, and Ba as well as lanthanide metallofullerenes (Ce–Lu). These metal atoms have been encapsulated in higher fullerenes, especially in C82. One of the most distinct features of such a metallofullerene is superatom character, by which the metallofullerene can be viewed as a positively charged core metal surrounded by a negatively charged carbon cage. Structural and electronic analyses based on X-ray diffraction and UHV-STM measurements indeed provide evidence of such character. Endohedral metallofullerenes will be metal, small-gap semiconductors, or insulators depending upon the fullerene size and the kind and the number of metal atom encapsulated. Finally, some prospective applications of metallofullerenes are presented. Fig. A metallofullerene encap sulating scanium-carbide (Sc2C2) in C84: Sc2C2@C84. Figure options Download full-size image Download as PowerPoint slide