Supramolecular assemblies of tripodal porphyrin hosts and C₆₀

The self-assembly of two tripodal porphyrin hosts in the presence of C-60, in the solid state, has been studied using synchrotron X-ray crystallography, and in solution by using H-1 NMR and fluorescence spectroscopies. The binding affinities, stoichiometries and geometries strongly depend on the size of the porphyrin host. Intramolecular and/or intermolecular porphyrin-fullerene interactions are observed in the co-crystallites and in each case, the trimer exhibits a "tweezers-like" structural motif. The solid-state structures of the trimer-fullerene cocrystallites reveal close fullerene-porphyrin and fullerene-fullerene contacts.