Yttrium-containing endohedral metallofullerenes: Synthesis and extraction

Yttrium-containing endohedral metallofullerenes are synthesized in an RF arc discharge in the helium flow with embedded Y2O3. It is shown that the formation of the metallofullerenes depends on the helium pressure in a chamber; however, this dependence cannot be explained using the model of formation of conventional fullerenes without a guest atom in a molecule. The results of extraction of Y@C82 by pyridine and carbon disulfide are reported. The pressure corresponding to the maximum yttrium-containing endohedral metallofullerene content is shown to be 60 kPa; under this pressure, extraction by carbon disulfide allows obtaining 27.1 wt % of the endohedral metallofullerene, while extraction by pyridine yields its amount of 17.3 wt %.