Preparation and Characterization of a Microcrystalline Non‐Heme Fe^III(OOH) Complex Powder: EPR Reinvestigation of Fe^III(OOH) Complexes—Improvement of the Perturbation Equations for the g Tensor of Low‐Spin Fe^III

Abstract

The first example of a microcrystalline powder of a synthetic low-spin (LS) mononuclear Fe(III)(OOH) intermediate has been obtained by the precipitation of the [Fe(III)(L(5) (2))(OOH)](2+) complex at low temperature. The high purity of this thermally unstable powder is revealed by magnetic susceptibility measurements. EPR studies on this complex, in the solid state and also in frozen solution, are reported and reveal the coexistence of two related Fe(III)(OOH) species in both states. We also present a theoretical analysis of the g tensor for LS Fe(III) complexes, based on new perturbation equations. These simple equations provide distortion-energy parameters that are in good agreement with those obtained by a full-diagonalization calculation.

Successive light-induced two electron transfers in a Ru–Fe supramolecular assembly: from Ru–Fe(ii)–OH2to Ru–Fe(iv)–oxo

“…4, left, red trace). 21,34–36 Furthermore, these resonances match those observed when 1-OH 2 is chemically oxidized using 2 eq. H 2 O 2 (Fig.…”

Transition Metal Complexes and the Activation of Dioxygen

“…In sum, while some data on non-heme iron(II)-superoxo species have been obtained, full characterization remains an unachieved goal [194]. Many examples of monoiron(III)-hydroperoxo species have been reported, with typical syntheses involving reactions of Fe(III) precursors with H 2 O 2 [145,195,196]. The reactivity of such intermediates prepared in this way has come under particular scrutiny of late [197] due to the discovery of selective catalytic oxidations by iron complexes with H 2 O 2 [198][199][200].…”

An Artificial Enzyme Made by Covalent Grafting of an FeII Complex into β‐Lactoglobulin: Molecular Chemistry, Oxidation Catalysis, and Reaction‐Intermediate Monitoring in a Protein

“…The set of resonances associated with the low‐spin Fe III complex is characteristic of nonheme Fe III (OOH) intermediates 11a, 19. These species are also characterized by a typical hydroperoxo‐to‐Fe III charge transfer at approximately 530 nm,20 which is not observed in the early stage of the reaction (Figure 7).…”