Insertion of Helium and Molecular Hydrogen Through the Orifice of an Open Fullerene.

A "molecular surgery" approach has been used to create an opening within a fullerene cage that is large enough to allow atoms and small molecules to pass through. The thermodynamics for the insertion of He and H into the open fullerene (left and right pictures, respectively) as well as their escape have been studied by NMR spectroscopy and theoretical methods.