Dual-Tweezer Behavior of an Octapodal Pyrene Porphyrin-Based System as a Host for Fullerenes

The incorporation of eight pyrene units in a single porphyrin core exhibits a great synergistic effect, resulting in high affinity toward C60 and C70. This octapyrene porphyrin is easily accessible by a straightforward two-step synthetic approach that involves an octuple Suzuki reaction. The new supramolecular platform can present single- or double-tweezer fullerene hosting behavior. The switch from double- to single-tweezer behavior is triggered by the simple coordination of Zn2+ to the porphyrin. Both the octapyrene porphyrin 2HPOP and its zinc metalloporphyrin analogue ZnPOP show very high affinity for C60 and C70, while simultaneously allowing the discrimination of C70 over C60 in a C60/C70 mixture. The use of 2HPOP and ZnPOP for the enrichment of real fullerene mixtures is also demonstrated.