Structures and Properties of Endohedral Metallofullerenes

Endohedral metallofullerenes (EMFs) are a unique class of fullerenes, featuring encapsulation of metal ions or clusters within hollow fullerene cages. Owing to electron transfer from the inner species to the outer fullerene cage, EMFs exhibit unique electronic, physical, and chemical properties. In this chapter, we focus on the structures and properties of EMFs. Determining molecular structures of EMFs has been fulfilled by single-crystal X-ray diffraction crystallography, which can unambiguously tell both the isomeric structures of the outer carbon cages and the geometrical position of the inner species. The electronic properties of EMFs have been extensively investigated by UV-vis-NIR absorption spectroscopy and electrochemistry, revealing the important role of intramolecular electron transfer on the entire EMF molecule. Moreover, magnetic properties especially single molecular magnetisms resulted from the unique coordination interactions within the encapsulated metal clusters are among the most intriguing physical properties of EMFs, which are inaccessible by empty fullerenes, rendering potential applications of EMFs in quantum computing and high-density storage devices.