Fig. 1. Synthesis, X-ray structure and Mössbauer spectrum of 1.
a, Activation of the pro-ligand using a zirconium reagent with subsequent transmetalation onto iron. MeOH, methanol; RT, room temperature; THF, tetrahydrofuran. Due to the donor strength of the ligand, the FeII complex is oxidized under air to the FeIII complex 1. b, Structure of the cation of 1, as determined by X-ray diffraction. Hydrogen atoms and counter ion are omitted for clarity. c, Mössbauer spectrum of 1 at 80 K showing the characteristic doublet of a low-spin FeIII complex.