Selective C70 Recognition by a Rigid Porphyrin-Carbazole Cavitand.

The development of novel molecular receptors exhibiting strong noncovalent interactions with fullerenes is of significant importance for various applications, particularly in fullerene separation. In this study, two new co-facial porphyrin dimers are presented that demonstrate strong affinities for C70. Notably, both the open and closed conformations of these receptors exhibit similar binding affinities and show selectivity toward the larger fullerene, even in the presence of substantial amounts of C60. Spectroscopic investigations indicate that the binding mechanism is predominantly governed by van der Waals interactions and the structural flexibility of the host in solution, instead of the volume or geometry of the host cavity.