All the experimental spectra are in black, while the simulated spectra are colored as red, green and blue for 1H1, 1H2, and 1H3, respectively. Simulation parameters for the three β-protons are A(1H1) = [−1.07, −1.07, 13.86] MHz, Euler angle = [0, −36, 0]°; A(1H2) = [−1.70, −1.70, 10.05] MHz, Euler angle = [0, −5, 0]°; A(1H3) = [−0.65, −0.65, 5.84] MHz, Euler angle = [0, −95, 30]°.
Particular spectrometer settings for 1H-ENDOR are 10 K, 34.10 GHz, microwave inversion pulse π = 80 ns, π/2 = 12 ns, τ = 300 ns and RF pulse = 20 μs. Experimental parameters for X-band HYSCORE are as follows: temperature = 10 K, tπ/2 = 16 ns, tπ = 16 ns, and microwave frequency = 9.428 GHz, magnetic field = 348.0 mT, τ = 204 ns for g = 1.935; microwave frequency = 9.326 GHz, magnetic field = 342.1 mT, τ = 200 ns for g = 1.947; microwave frequency = 9.326 GHz, magnetic field = 336.0 mT, τ = 200 ns for g = 1.983; microwave frequency = 9.326 GHz, magnetic field = 334.3 mT, τ = 204 ns for g = 1.993. The time increment in both dimensions was 24 ns with 180 steps.