Anaerobic Preparation and Solvent-Free Separation of Uranium Endohedral Metallofullerenes

Safe production, handling, and separation of depleted uranium endohedral metallofullernes in an oxygen-free environment is demonstrated. Films of C 60, C 70, and M@C 60 are produced by subliming fullerenes from arc-produced soot onto a mass spectrometry target (with ca. 1% impurities of higher fullerenes). Also, films consisting of higher fullerenes (empty and full) and mostly devoid of C 60 or C 70 are made by subliming at higher temperatures. The temperature of the soot must be uniform and held constant during sublimation in order to produce high-quality films. M@C 60 requires a slightly higher temperature for sublimation than empty C 60, the likely result of stronger interactions between M@C 60 and its surroundings in the soot.