In the applications of single-walled carbon nanotubes (SWNTs), it is extremely important to separate semiconducting and metallic SWNTs. Although several methods have been reported for the separation, only low yields have been achieved at great expense. We show a separation method involving a dispersion-centrifugation process in a tetrahydrofuran solution of amine, which makes metallic SWNTs highly concentrated to 87% in a simple way.

The photochemical reaction of La@C82 with 2-adamantane-2,3-[3H]-diazirine affords adduct 2, La@C82(Ad), in a quantitative and highly selective manner. The structure of compound 2 is confirmed by ESR, MS, and UV-vis-NIR spectroscopies, and the first X-ray crystallographic characterization of an endohedral monometallofullerene derivative is reported.