Retrieving Precursors Toward Endohedral Metallofullerenes

A series of intermediates such as C₆, C₁₀ and C₁₆ have been retrieved by chlorination from the crude soot of carbon arc, affording insight into endofullerene formation. Identified by HPLC-MS and UV/Vis, production of perchlorinated polycyclic aromatic hydrocarbons (PAHs) such as C₆Cl₆, C₁₀C₈, and C₁₆Cl₁₀ from the reaction involving ICl with the crude soot of carbon arc heavily depends on formation of endofullerenes, as exemplified by the arc-discharge synthesis of metallofullerenes encapsulating with lanthanum or dysprosium. The perchlorinated PAHs reduce dramatically in chlorination of the pristine soot in the control trials with arc-discharge of graphite in absence of the typical encapsulated metals, with implication about the polycyclic carbon skeletons (i.e. C₆, C₁₀, C₁₆) originating from the precursors toward endohedral metallofullerens. The work facilitates the understanding of how and what metals encapsulatable in the fullerene cage.