Supramolecular Interaction of Fullerenes with a Curved π‐Surface of a Monomeric Quadruply Ring‐Fused Porphyrin

Abstract

Molecular binding of fullerenes, C₆₀ and C₇₀, with the Zn^II complex of a monomeric ring‐fused porphyrin derivative (2‐py) as a host molecule, which has a concave π‐conjugated surface, has been confirmed spectroscopically. The structures of associated complexes composed of fullerenes and 2‐py were explicitly established by X‐ray diffraction analysis. The fullerenes in the 2:1 complexes, which consist of two 2‐py molecules and one fullerene molecule, are fully covered by the concave surfaces of the two 2‐py molecules in the crystal structure. In contrast, in the crystal structure of the 1:1 complex consisting of one 2‐py molecule and one C₆₀ molecule, the C₆₀ molecule formed a π–π stacked pair with a C₆₀ molecule in the neighboring complex using a partial surface, which was uncovered by the 2‐py molecule. Additionally, the molecular size of fullerene adopted significantly affects the ¹H NMR spectral changes and the redox properties of 2‐py upon the molecular binding.