An Alternative Approach for Separating Metallic Nitride Fullerenes (MNFs) from Nanomaterial Mixtures

Metallic nitride fullerenes (MNFs) are of interest to fundamental studies and applications. However, MNF sample availability for these studies has been limited. The lack of samples is related to the currently used chromatographic (HPLC) separation protocol, a tedious approach that is solvent intensive, expensive, and has a limited throughput. To address these drawbacks, we developed an alternative method (non-chromatographic) for removing contaminant C60 and C70 empty-cage fullerenes and other classical metallofullerenes (i.e. non-nitrogen containing endohedrals) from soot extracts. Specifically, we present a purification approach based on differences of cage reactivity of MNFs versus other fullerenes. Results indicate that reactive silica can preferentially bind to contaminant fullerenes and metallofullerenes using our Stir and Filter Approach (SAFA). With this process, fullerene contaminants are immobilized onto reactive silica, while unreacted MNFs remain in the filtrate. In this manner, purified samples of Sc3N@C80 are readily obtained.