Dynamic Nuclear Polarization Mechanisms using TEMPOL and trityl OX063 radicals at 1 T and 77 K

1. Data overview All the data shown in the manuscript and the supporting information can be found in the Zenodo repository. 1.1. Figure 2 The NMR data (Bruker Topspin) used for constructing the DNP spectra in Figure 2 are summarized in Table 1 and can be found in the folder ‘UW_DNP’. The frequency range over which was swept is shown in Table 2. Note that for trityl OX063, the 13C DNP spectrum was measured in three stages from 27.99-28.09 GHz (exp 400), 28.09-28.1025 GHz (exp 401) and 28.1025-28.1125 GHz (exp 402) all with steps of 0.0025 GHz. Table 1. Experiment numbers for DNP spectra in the folder ‘UW_DNP’ shown in Figure 2 of the main manuscript. DNP spectrum 1H 13C TEMPOL 100 200 Trityl OX063 300 400-402 Table 2. Total microwave frequency range (GHz) for DNP spectra in Figure 2 of the main manuscript. DNP spectrum 1H 13C Steps TEMPOL 27.8 - 28.44 27.83 - 28.62 0.01 Trityl OX063 27.9 - 28.2975 27.99 - 28.1125 0.0025 1.2. Figure 3 The data for the buildup (µw on) and relaxation (µw off) decay curves for proton magnetization in presence of TEMPOL and trityl OX063 (Figure 3) can be found in the POWER_DNP folder. The experiments used for each microwave power output (watts) are summarized in Table 3. Table 3. Experiment numbers for DNP buildup and spin-lattice relaxation decay curves in Figure 3. Power (W) 0.55 1.32 2.3 3.16 3.8 4.27 4.57 Trityl 11006 11005 11004 11003 11002 11001 11000 TEMPOL 30210 30209 30208 30207 30206 30205 30204 1.3. Figure 4 The electron saturation simulations can be reproduced using the codes available in the ‘CODES’ folder. Electron_depolarization_fixed.mlx is a live script that calculates the influence of the microwave (with fixed frequency) on the depolarization of the unpaired radicals in an amorphous frozen solid. 1.4. Figure 5 The experimental data points in Figure 5 are the same as in Figure 2 (see Table 1 and 2). Electron_depolarization_sweep.mlx is a follow-up livescript that calculates the expected lineshape of the solid effect and cross effect DNP spectrum shown in Figure 5 when the microwave frequency is varied. Guidelines are available in the codes, and the codes needs input of additional functions also present in the folder. 1.5. Figure S1 The Q-band CW-EPR data of TEMPOL in an identical glassy solution as used in at the benchtop polarizer can be found in the folder ‘EPR_TEMPOL’ as ‘50mM_TEMPOL_CW’. The fitting parameters are found in ‘CW_Fitting’ and represent the Lorentzian/Gaussian broadening, the g-anisotropy and the hyperfine coupling interaction with 14N. 1.6. Figure S2 The Q-band pulsed EPR data of TEMPOL in an identical glassy solution as used in at the benchtop polarizer can be found in the folder ‘EPR_TEMPOL’ as ‘50mM_TEMPOL_Pulse’. 1.7. Figure S3 The pulse EPR data for extracting the electron spin-lattice and spin-spin relaxation time constant are available upon request. 1.8. Figure S4 The code for simulating the electron depolarization under microwave perturbation can be found in the ‘CODES’ folder called Electron_depolarization_fixed.mlx. It needs the input of the additional functions also present in the folder. 1.9. Figure S5 The experiment numbers for the NMR data for the 1D hyperpolarized 13C spectra shown in Figure S5d-f are summarized in Table 3 and can be found in the folder ‘UW_DNP’. Table 3. Experiment numbers for hyperpolarized 13C spectra shown in Figure S5. 1D NMR Figure S5d Figure S5e Figure S5f Exp 501 502 500