Chemical Isolation of Isomerically Purified Sc3n@C68

Abstract

Metallofullerenes with fused pentalenes are rare in arc soot. By far, the majority of endohedral fullerene cages obey the isolated pentagon rule (IPR). In a recent landmark paper (Santiago et al., JACS, 2021, 143, 6037-6042) by the Echegoyen group, they experimentally demonstrated the use of Sc3N@C68 as a new molecular catalyst for Hydrogen Evolution Reactions. Indeed, this fused pentalene metallofullerene (Sc3N@C68) successfully outperformed six other “conventional” (i.e., IPR) endohedrals. Thus, application development for fused pentalene metallofullerenes may open new doors.In this presentation, we discuss our chemical-based purification approach specifically designed for fused pentalene systems such as Sc3N@C68. We find that after two types of selective chemical reaction, we obtain a highly enriched sample of primarily two species, Sc3N@D3(6140)-C68 and Sc3N@Ih(7)-C80. Due to the large retention time difference between C68 and C80 endohedral cages, only a single injection is necessary for a final purification step.