Tuning the Redox Properties of Fullerene Clusters within a Metal-Organic Capsule.

Abstract

A porphyrin-edged metal-organic tetrahedron was shown to form host-guest complexes containing 1-4 equivalents of fullerene C60, depending on the solvent employed. The molecules of C60 were bound in anti-cooperative fashion within well-defined pockets; an X-ray crystal structure of three fullerenes inside the tet- rahedron was obtained. Electrochemical measurements revealed that the electron-accepting properties of the fullerenes inside the capsules were altered depending on the mode of encapsulation. En- capsulation of a greater number of fullerenes was observed to in- crease the electron affinity of the overall cluster. A non-covalent method of tuning the electronics of fullerenes is thus presented.