Wang, X., et al., Gadolinium based endohedral metallofullerene Gd2@C79N as a relaxation boosting agent for dissolution DNP at high fields. Chem Commun (Camb), 2018. 54(19): p. 2425-2428.
We show increased dynamic nuclear polarization by adding a low dosage of a S = 15/2 Gd based endohedral metallofullerene (EMF) to DNP samples. By adding 60 muM Gd2@C79N, the nuclear polarization of (1)H and (13)C spins from 40 mM 4-oxo-TEMPO increases by approximately 40% and 50%, respectively, at 5 T and 1.2 K. Electron-electron double resonance (ELDOR) measurements show that the high spin EMF shortens the electron relaxation times and increases electron spectral diffusion leading to the increased DNP enhancement.