The effects of a pyrrolidine functional group on the magnetic properties of N@C60

N@C69H10N2O2 was synthesized and characterized. A permanent zero-field-splitting (ZFS) was observed, and a relaxation mechanism was investigated due to fluctuations of this ZFS in solution. CW-EPR spectra revealed an anisotropic hyperfine interaction, observed for the first time in fullerene derivatives. T1 and T2 showed biexponential decay due to ZFS fluctuations.