H2O@open-cage fullerene C60: control of the encapsulation property and the first mass spectroscopic identification

A novel open-cage C60 derivative (a 19-membered ring orifice), prepared by the sequential cage scission reactions of the ketolactam derivative of C60 with o-phenylenediamine, allows the encapsulation of one water molecule. The resulting endohedral water complexes were confirmed for the first time by mass spectroscopy. The efficiency of the encapsulation was affected by the substituent on the nitrogen atom.