Non-HPLC Rapid Separation of Metallofullerenes and Empty Cages with TiCl4 Lewis Acid

Rapid and efficient separation/purification of pure metallofullerenes M-x@C-n (M = metal; x = 1, 2; n > 70) and carbide metallofullerenes of the type MyC2@Cn-2 (y = 2, 3, 4; n - 2 > 68) has been reported. The present method utilizes rapid and almost perfect preferential formation of TiCl4 (generally known as a Lewis acid)-metallofullerene complexes, which easily decompose to provide pure metallofullerene powders by a simple water treatment. The present method enables one to separate the metallofullerenes up to >99% purity within 10 min without using any type of high-performance liquid chromatography (HPLC). It is found that the oxidation potentials of the metallofullerenes are crucial factors for efficient purification. The current separation/purification technique may open a brand-new era for inducing further applications and commercialization of endohedral metallofullerenes.