Synthesis of Open-Cage Fullerenes Containing a H-Bond between the Encapsulated Water Molecule and the Amide Moiety on the Rim of the Orifice

Further hydrolysis of an open-cage fullerene derivative with an epoxy moiety on the rim of the orifice led to the formation of a new open-cage fullerene with a 17-membered orifice and an amide group directly above the orifice. The water encapsulation ratio in the new open-cage compound reached 100 % as a result of heating with water at 80 degrees C. The amide group above the orifice completely blocks the opening and forms H-bond with the trapped water molecule. Single crystal X-ray structure shows that the bond length between the trapped water oxygen and the amide oxygen is 2.859 angstrom. The H-bond energy is about -3.83 kcal/mol as shown by theoretical calculation.