Isolation and characterization of a new metallofullerene Nd@C82

Nd@C82 has been isolated with a purity of ∼99.9% by an efficient solvent extraction procedure, followed by HPLC separation. UV-VIS-NIR absorption spectra of the metallofullerenes were measured in a wavelength range from 300 to 2100 nm. The spectral features are remarkably similar to those of La@C82 and Ce@C82, a finding which suggests a similar magnitude of charge transfer from the metal atoms to the carbon cage for these species M@C82 (M = rare earth element). A study using X-ray photoelectron spectroscopy (XPS) suggests that the electronic structure of Nd@C82 can be approximately represented by Nd3+@C823−.