Purification of Uranium-based Endohedral Metallofullerenes (EMFs) by Selective Supramolecular Encapsulation and Release

Abstract

Supramolecular nanocapsule 1⋅(BArF)₈ is able to sequentially and selectively entrap recently discovered U₂ @C₈₀ and unprecedented Sc₂ CU@C₈₀ , simply by soaking crystals of 1⋅(BArF)₈ in a toluene solution of arc-produced soot. These species, selectively and stepwise absorbed by 1⋅(BArF)₈ , are easily released, obtaining highly pure fractions of U₂ @C₈₀ and Sc₂ CU@C₈₀ in one step. Sc₂ CU@C₈₀ represents the first example of a mixed metal actinide-based endohedral metallofullerene (EMF). Remarkably, the host-guest studies revealed that 1⋅(BArF)₈ is able to discriminate EMFs with the same carbon cage but with different encapsulated cluster and computational studies provide support for these observations.

Keywords: endohedral metallofullerenes; separation; supramolecular capsules; uranium.