Gas phase abduct of endohedral rare-earth fullerenes Nd@C82 with the ion system of benzene- [Nd @ C82-C6H6] + was observed for the first time by ion-molecular reaction under chemical ionization condition. The possible reaction passageway and molecular structures of this gas phase adduct were discussed and a parallel "reversed umbrella’ π-π interaction complex of the [C6H6]+ ion reacting with the neutral rare-earth fullerenes Nd@C82 was considered to be much reasonable. The experimental result indicated that endohedral rare-earth fullerenes has relatively active relativity and aromatic properties similar towards benzene molecular ion in gas phase.
