Separation and Selective Formation of Fullerene Adducts within an M(II)(8)L(6) Cage

The self-assembly of 4-fold-symmetric porphyrins with Fe^II or Zn^II gave a new cubic M^II₈L₆ cage framework with electron-deficient walls. This cage bound C₆₀-indene or C₆₀-anthracene bisadducts selectively, whereas unfunctionalized fullerenes and monoadducts were not encapsulated. The Fe^II₈L₆ cage also enabled the reaction of C₆₀ and anthracene to yield the bisadducts selectively under conditions where no reaction was observed in the absence of the cage. These findings have relevance in the context of polymer solar cells, where C₆₀ bisadducts have found use as electron acceptors, because these adducts currently require laborious and time-consuming syntheses and purification.