Resonance Raman evidence for the interconversion between an [FeIII–η1-OOH] 2+ and [FeIII–η2-O2]+ species and mechanistic implications thereof

Ho, Raymond Y. N.; Roelfes, Gérard; Hermant, R.M.; Hage, Ronald; Feringa, Bernard; Que, Lawrence

doi:10.1039/a905535e

Cited by 81 publications

(90 citation statements)

References 18 publications

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“…Examination of the reactivity of 1b toward organic substrates has shown that this form is relatively inert compared to its conjugate acid. 38,71 A similar inertness has been noted for [Fe(EDTA)(η 2 -O 2 )] 3-. 39 A sideon peroxoiron(III) species has been postulated in the mechanism of arene cis-dihydroxylation by the Rieske dioxygenases 4, 74 and recently observed in the crystal structure of a ternary enzyme-substrate-O 2 complex of naphthalene dioxygenase.…”

Section: Summary and Perspectivementioning

confidence: 55%

“…The molecular formulations for 1a and 1b have been established by electrospray mass spectrometry, affording molecular ions at m/z 555 and 455 corresponding to {[Fe-(N4Py)(OOH)]ClO 4 } + and {[Fe(N4Py)(OO)]} + , respectively, with the expected isotope distribution patterns. 23, 38 However, as elaborated below, the conversion from 1a to 1b is not a mere loss of a proton but entails a more significant change in structure and electronic properties (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

“…38 The only other established (η 2 -peroxo)iron complexes prior to these studies are those of Fe III (EDTA) 39 and Fe III (porphyrin). 40 The existence of an acid-base equilibrium affording low-spin Fe III -η 1 -OOH and high-spin Fe III -η 2 -O 2 species in one ligand system provides a unique opportunity to investigate how the change in peroxo binding mode affects the spectroscopic properties of the metal center.…”

Section: -Carboxylic Acid N-[2-(4′-imidazolyl)ethyl]amide;mentioning

confidence: 99%

“…Py5 ) 2,6-bis(methoxy(di(2-pyridyl))methyl)pyridine; pz ) pyrazole; SCE ) saturated calomel electrode; SOR ) superoxide reductase; TACN ) 1,4,7-triazacyclononane; TACNPy2 ) 1-di(2-pyridyl)methyl-4,7-dimethyl-1,4,7-triazacyclononane;tpen )N,N,N′,N′-tetrakis(2-pyridylmethyl)-1,2-diaminoethane; TPP ) meso-tetraphenylporphyrin dianion; Tp 3,5-iPr2 ) hydrotris(3,5-diisopropylpyrazolyl)borate; trispicMeen ) [33][34][35][36][37] Treatment of these low-spin Fe-OOH complexes with base converts them into new high-spin iron(III) species, 20,29-32, 38 and mixed isotope resonance Raman experiments strongly implicate a side-on bound peroxo ligand. 38 The only other established (η 2 -peroxo)iron complexes prior to these studies are those of Fe III (EDTA) 39 and Fe III (porphyrin).…”

Section: -Carboxylic Acid N-[2-(4′-imidazolyl)ethyl]amide;mentioning

confidence: 99%

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End-On and Side-On Peroxo Derivatives of Non-Heme Iron Complexes with Pentadentate Ligands: Models for Putative Intermediates in Biological Iron/Dioxygen Chemistry

et al. 2003

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Mononuclear iron(III) species with end-on and side-on peroxide have been proposed or identified in the catalytic cycles of the antitumor drug bleomycin and a variety of enzymes, such as cytochrome P450 and Rieske dioxygenases. Only recently have biomimetic analogues of such reactive species been generated and characterized at low temperatures. We report the synthesis and characterization of a series of iron(II) complexes with pentadentate N5 ligands that react with H 2 O 2 to generate transient low-spin Fe III −OOH intermediates. These intermediates have low-spin iron(III) centers exhibiting hydroperoxo-to-iron(III) charge-transfer bands in the 500−600-nm region. Their resonance Raman frequencies, ν O-O , near 800 cm -1 are significantly lower than those observed for high-spin counterparts. The hydroperoxo-to-iron(III) charge-transfer transition blue-shifts and the ν O-O of the Fe−OOH unit decreases as the N5 ligand becomes more electron donating. Thus, increasing electron density at the low-spin Mononuclear iron(III) peroxide species are implicated as intermediates in the mechanisms of oxygen activating biomolecules such as cytochrome P450, 1 heme oxygenase, 2 the antitumor drug bleomycin, 3 and Rieske dioxygenases, 4,5 as well as superoxide reductases from anaerobic bacteria. [6][7][8][9] Experimental evidence for some of these intermediates has

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Section: Summary and Perspectivementioning

confidence: 55%

Section: Resultsmentioning

confidence: 99%

Section: -Carboxylic Acid N-[2-(4′-imidazolyl)ethyl]amide;mentioning

confidence: 99%

Section: -Carboxylic Acid N-[2-(4′-imidazolyl)ethyl]amide;mentioning

confidence: 99%

See 2 more Smart Citations

End-On and Side-On Peroxo Derivatives of Non-Heme Iron Complexes with Pentadentate Ligands: Models for Putative Intermediates in Biological Iron/Dioxygen Chemistry

et al. 2003

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“…Two ligand complexes have the ability to transform cyclooctene and cis and trans isomers of hexene to the corresponding cis-dihydrodiols. For one of the complexes, an Fe 3ϩ ( 1 -OOH) intermediate, has been observed, suggesting its participation during catalysis (62,63). Interestingly, these complexes share a similar labile ligand orientation with that of the mononuclear iron of NDO (64).…”

Section: Discussionmentioning

confidence: 89%

Single Turnover Chemistry and Regulation of O2Activation by the Oxygenase Component of Naphthalene 1,2-Dioxygenase

Wolfe¹,

Parales²,

Gibson³

et al. 2001

Journal of Biological Chemistry

173

311

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Naphthalene 1,2-dioxygenase (NDOS) is a three-component enzyme that catalyzes cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene formation from naphthalene, O 2 , and NADH. We have determined the conditions for a single turnover of NDOS for the first time and studied the regulation of catalysis. As isolated, the ␣ 3 ␤ 3 oxygenase component (NDO) has up to three catalytic pairs of metal centers (one mononuclear Fe 2؉ and one diferric Rieske iron-sulfur cluster). This form of NDO is unreactive with O 2 . However, upon reduction of the Rieske cluster and exposure to naphthalene and O 2 , ϳ0.85 cisdiol product per occupied mononuclear iron site rapidly forms. Substrate binding is required for oxygen reactivity. Stopped-flow and chemical quench analyses indicate that the rate constant of the single turnover product-forming reaction significantly exceeds the NDOS turnover number. UV-visible and electron paramagnetic resonance spectroscopies show that during catalysis, one mononuclear iron and one Rieske cluster are oxidized per product formed, satisfying the two-electron reaction stoichiometry. The addition of oxidized or reduced NDOS ferredoxin component (NDF) increases both the product yield and rate of oxidation of formerly unreactive Rieske clusters. The results show that NDO alone catalyzes dioxygenase chemistry, whereas NDF appears to serve only an electron transport role, in this case redistributing electrons to competent active sites.Rieske nonheme iron dioxygenases catalyze a remarkable reaction in which dioxygen is cleaved and both atoms are inserted across a double bond of an unactivated aromatic nucleus to yield a cis-dihydrodiol (1-4). These enzymes initiate the biodegradation of some of the most recalcitrant aromatic compounds that enter the environment from both natural and industrial sources, making their study of great importance for progress in bioremediation practices (5, 6). In addition, the inherent enantio-and regiospecificity of these enzymes make them useful for synthetic applications (7,8). Several of these multicomponent dioxygenases are known that differ in the number of components and the number and type of subunits in the oxygenase component that contains the active site. However, all of the enzyme systems share the common features of a reductase component that can accept and pass on two electrons from reduced pyridine nucleotide, an electron transport system that may be encompassed into the reductase, and an oxygenase that has both Rieske [2Fe-2S] clusters and mononuclear iron centers.One of the most thoroughly studied of the Rieske nonheme iron dioxygenases is naphthalene 1,2-dioxygenase (NDOS) 1 isolated from Pseudomonas sp. NCIB 9816-4, which catalyzes the reaction shown in Scheme 1 to yield (ϩ)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene (9).The complete NDOS consists of three protein components: the 36-kDa reductase protein (NDR) that contains a FAD molecule and a plant-type [2Fe-2S] cluster, the 14-kDa ferredoxin electron transfer protein (NDF) that contains a [2Fe-2S] Rieske cluster, an...

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FeIII-Hydroperoxo and Peroxo Complexes with Aminopyridyl Ligands and the Resonance Raman Spectroscopic Identification of the Fe−O and O−O Stretching Modes

Simaan

Döpner

Banse

et al. 2000

Eur. J. Inorg. Chem.

113

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Resonance Raman evidence for the interconversion between an [FeIII–η1-OOH] 2+ and [FeIII–η2-O2]+ species and mechanistic implications thereof

Cited by 81 publications

References 18 publications

End-On and Side-On Peroxo Derivatives of Non-Heme Iron Complexes with Pentadentate Ligands: Models for Putative Intermediates in Biological Iron/Dioxygen Chemistry

End-On and Side-On Peroxo Derivatives of Non-Heme Iron Complexes with Pentadentate Ligands: Models for Putative Intermediates in Biological Iron/Dioxygen Chemistry

Single Turnover Chemistry and Regulation of O2Activation by the Oxygenase Component of Naphthalene 1,2-Dioxygenase

FeIII-Hydroperoxo and Peroxo Complexes with Aminopyridyl Ligands and the Resonance Raman Spectroscopic Identification of the Fe−O and O−O Stretching Modes

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