Facile Access to Azafullerenyl Cation C₅₉N⁺ and Specific Interaction with Entrapped Molecules

Abstract

The facile preparation of azafullerenyl cation C₅₉N⁺ has been achieved by the assistance of trifluoromethanesulfonic acid. The thus formed C₅₉N⁺ was quite stable in solution over 1 month and can be used as an intermediate for the electrophilic reaction. Applying this method to endohedral azafullerenes, corresponding cations (H₂@C₅₉N⁺ and H₂O@C₅₉N⁺) were prepared and the dynamic behavior of entrapped molecules was studied on the basis of ¹H NMR relaxation time measurements. The results indicated that there is strong intramolecular C₅₉N⁺···O^δ-H₂ interaction in H₂O@C₅₉N⁺, which stands in contrast to isoelectronic H₂O@C₆₀ with no electrostatic interaction. We also demonstrated that the magnetic shielding environment inside the C₅₉N⁺ cage closely resembles that for isoelectronic C₆₀.