Analysing low-spin ferric complexes using pulse EPR techniques: a structure determination of bis (4-methylimidazole)(tetraphenylporphyrinato)iron(iii)

摘要: Continuous-wave (CW) EPR has been extensively used as a characterization tool for low-spin ferric complexes. Using the bis(4-methylimidazole) complex of iron(III) tetraphenylporphyrin an example we show how combination CW and pulsed techniques allows detailed structure analysis such Both proton HYSCORE combination-peak experiments indicate that imidazole ligand planes are (nearly) parallel to gx axis (±20°). Simulations porphyrin nitrogen contributions spectra allow determination g-axes frame in molecular frame. Combination these spectral results counter-rotation principle gy axes rotated 5° (±5°) away from Np–Fe–Np counter-rotated over 5° (±5°). The hyperfine nuclear-quadrupole interactions pyrrole nitrogens determined discussed function electronic structure.