Orientation of a Water Molecule: Effects on Electronic Nature of the C₅₉N Cage

A hydrogen-bonding network is a key impelling force for an assembly in bulk water. The fullerene cage can incarcerate a water molecule without hydrogen-bonding. Herein, we focused on spin system H₂O@C₅₉N^·. The ¹H NMR relaxation time of entrapped H₂O was significantly reduced by the paramagnetic effect. Interestingly, the electron affinity and ionization energy were suggested to vary depending on the orientation of entrapped H₂O owing to the degree of the partial charge transfer from entrapped H₂O to C₅₉N^·.