The spectra were recorded with a sweep range of 475 mT, field modulation of 0.7 mT, microwave power of 10 mW and a field modulation frequency of 100 kHz. Q-band ( 34 GHz) CW EPR 20 spectra were carried out with a Bruker Elexsys E580 EPR X-band spectrometer equipped with a homebuilt Q-band extension capable of delivering 34 GHz microwave radiation. In these cases, a sweep range of 1110 mT, field modulation of 0.7 mT, microwave power of 2.0 mW and field modulation frequency of 100 kHz were employed. Pulse X-band experiments were performed on the same Bruker Elexsys E580 EPR X-band spectrometer. Two-pulse (2p) echo detected field swept (EDFS), three-pulse (3p) electron spin echo envelope modulation (ESEEM) and hyperfine sublevel correlation (HYSCORE) spectra were recorded at 10 K using nonselective pulses of tπ/2 = 20 ns and tπ = 40 ns. The interpulse delay τ was properly chosen to suppress the signal at Larmor frequency of 1 H nuclei in HYSCORE. 200 × 200 data matrix was sampled and the frequency domain spectra was obtained by two-dimensional (2D) Fourier transformation. Cryogenic temperatures (< 90 K) were reached using an Oxford CF935 cryostat. All spectra simulations were done using the Easyspin ESR simulation package 68 .