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

Supramolecular nanocapsule 1(BArF)(8) is able to sequentially and selectively entrap recently discovered U-2@C-80 and unprecedented Sc2CU@C-80, 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 U-2@C-80 and Sc2CU@C-80 in one step. Sc2CU@C-80 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.