Iron(IV) porphyrins from iron(III) porphyrin cation radicals

Abstract

The preparation and spectroscopic data of FeTMP(C104)2 [(I), TMP = 5,10,15,20-tetramesitylporphyrinato] are reported; the reaction of (1) with NaOMe-MeOH gave a new red species, (2), which is indicated to exist (a) as a symmetrically ligated complex with a vacant dx2-y2 iron orbital (lH n.m.r.1 and (b) in the iron(iv) state (Mossbauer spectroscopy ).

Spectroscopic Characterization of an FeIV Intermediate Generated by Reaction of XO− (X = Cl, Br) with an FeII Complex Bearing a Pentadentate Non‐Porphyrinic Ligand − Hydroxylation and Epoxidation Activity

“…[3] The Mössbauer analysis for the S ϭ 1 porphyrinic dimethoxy complex [Fe IV (TMP)(OCH 3 ) 2 ] gave δ ϭ Ϫ0.025 mm/s and ∆E Q ϭ 2.1 mm/s. [42,43] The Fe IV 2 O 2 diamond-core complex involving two S ϭ 1 metal centers recently characterized by the group of Que yielded corresponding values for δ (0.1 mm/s) and ∆E Q (1.75 mm/s). [18] These comparisons demonstrate that the parameters obtained from Mössbauer analysis are similar for all the Fe IV species with oxygenated ligands and are independent of the nuclearity of the moieties and of the environment(s) of the metal ion(s).…”

High-valent iron in chemical and biological oxidations

“…4) [62][63][64]. Another type of iron(IV) porphyrin isolated at that time was a dimethoxy derivative [65]. These compounds have been extensively studied and well characterized by various spectroscopic techniques, including visible spectroscopy, NMR, EPR (electron paramagnetic resonance), Mö ssbauer and EXAFS [65][66][67][68][69][70][71][72][73].…”

Mechanistic Studies on Peroxide Activation by a Water‐Soluble Iron(III)–Porphyrin: Implications for OO Bond Activation in Aqueous and Nonaqueous Solvents

“…Sawyer et al [42] reported redox interconversions corresponding to shifts between all three sections in Figure 4. www.chemeurj.org Goff et al [40] observed disproportionation of [Fe [28b, 35,43] As mentioned above, the influence of pH on the relative positions of E8' Fe IV /Fe III and E8' PC + /P observed for 1 can be traced to different stabilization of Fe IV by O 2À , HO À , and H 2 O. In this sense, it reflects a more general phenomenon observed for iron-porphyrin complexes: the strong influence of axial ligation on the stabilization of higher oxidation states of Fe (indicated experimentally by numerous electrochemical studies, [32,33,38,41,[43][44][45] and further substantiated by theoretical calculations).…”

“…(assigned on the basis of its UV/Vis spectrum; l = 416 nm (Soret) and 545 nm; [35] Figure S5 b). This experiment can be visualized in the diagram of Figure 5 as a shift from Section II (…”