title: Nonchromatographic "stir and filter approach" (SAFA) for isolating Sc3N@C80 metallofullerenes.
abstract: 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.
authors.affiliation: Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Stevenson
authors.forename: Kim
authors.initials: K
authors.lastname: Harich
authors.forename: Hua
authors.initials: H
authors.lastname: Yu
authors.forename: Ryan R
authors.initials: RR
authors.lastname: Stephen
authors.forename: David
authors.initials: D
authors.lastname: Heaps
authors.forename: Curtis
authors.initials: C
authors.lastname: Coumbe
authors.forename: J Paige
authors.initials: JP
authors.lastname: Phillips
mesh_terms: D005374:Filtration; D037741:Fullerenes / Q000737:chemistry / Q000302:isolation & purification*; D005782:Gels / Q000737:chemistry; D006108:Graphite / Q000737:chemistry; D012538:Scandium / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D037741:Fullerenes; D005782:Gels; D012822:Silicon Dioxide; D006108:Graphite; D012538:Scandium