Fullerenes as Neutral Carbon-Based Lewis Acids^†

Lewis adducts between N-heterocyclic carbenes and fullerenes have been isolated and their structures confirmed by X-ray crystallography. This work shows that simple fullerenes such as C₆₀ or C₇₀ can act as Lewis acids. This result not only opens new perspectives in fullerene chemistry but might also have strong implications in emerging fields such as the metal-free activation of small molecules.