A Long‐Lived Azafullerenyl Radical Stabilized by Supramolecular Shielding with a [10]Cycloparaphenylene

Abstract

A major handicap towards exploitation of radicals is their inherently instability. In paramagnetic azafullerenyl radical C59N• the unpaired electron is strongly localized neighbouring the nitrogen and induces dimerization to diamagnetic bisazafullerene (C59N)2. Conventional stabilization employing steric hindrance around the radical is inapplicable due to the concave fullerene geometry. Instead, we develop an innovative radical shielding approach using supramolecular complexation, exploiting the protection offered by a [10]cycloparaphenylene ([10]CPP) nanobelt encircling the C59N•. Photo‐induced radical generation is increased 300 times. The characteristic triplet signal of C59N•⊂[10]CPP is traced even after several weeks, a lifetime increase of >108. The proposed approach can be generalised by tuning the diameter of the employed nanobelts, opening new avenues in the design and exploitation of radical fullerenes.