Nonchromatographic "stir and filter approach" (SAFA) for isolating Sc3N@C80 metallofullerenes.

Separation difficulties have led to a paucity of purified metallic nitride fullerenes (MNFs). Fundamental research and application development has been hampered with limited sample availability. Separation techniques designed to remove contaminant empty-cage fullerenes (e.g., C(60), C(70)...C(2)(n)) and classical metallofullerenes (e.g., non-MNFs) traditionally require expensive and tedious chromatographic methods. Our motivation is an alternative purification approach to minimize dependence on HPLC. Herein we report the use of cyclopentadienyl (CPD) and amino functionalized silica to selectively bind contaminant fullerenes. This "Stir and Filter Approach" (SAFA) provides purified MNF samples at ambient and reflux conditions. Under reflux conditions, purified MNFs (80% recovery, 41 h) are obtained using CPD silica. However, at room temperature, there is an equilibrium established between fullerenes and CPD silica, and no purified MNF samples are obtained using SAFA. In contrast, purified MNF samples (99+%) are readily obtained at room temperature using amino, diamino, and triamino silica at recoveries of 93% (11 h), 76% (9 h), and 50% (6 h), respectively.

Synthesis and purification of a metallic nitride fullerene bisadduct: exploring the reactivity of Gd3N@C80.

This research represents initial functionalization of a Gd3N@C80 metallic nitride fullerene (MNF). Results demonstrate that a bisadduct can be prepared in an isolable yield for this MRI precursor MNF. This Gd3N@C80 bisadduct is synthesized and purified, and preliminary characterization is reported. This is a significant finding as, to date, only MNF monoadducts have been purified.