Reactivity of the peroxo ligand in metalloporphyrin complexes. Reaction of sulfur dioxide with iron and titanium porphyrin peroxo complexes to give sulfato complexes of sulfate

Miksztal, Andrew R.; Valentine, Joan Selverstone

doi:10.1021/ic00190a023

Cited by 53 publications

(30 citation statements)

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“…The finding that most, if not all, of the sulfoxide oxygen in the 5,5-dioxide product originates from hydrogen peroxide but not from 18 O 2 has been rationalized by the possible participation in this reaction of a peroxoiron catalyst. This view is compatible with the capability of mononuclear peroxo intermediates derived from iron and titanium porphyrin complexes upon treatment with superoxide and H 2 O 2 , respectively, to directly promote sulfoxidation reactions [161].…”

Section: Evidence From Experiments With Genetically Engineered P450 Esupporting

confidence: 63%

Models and mechanisms of O‐O bond activation by cytochrome P450

Hlavica¹

2004

European Journal of Biochemistry

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Cytochrome P450 enzymes promote a number of oxidative biotransformations including the hydroxylation of unactivated hydrocarbons. Whereas the long-standing consensus view of the P450 mechanism implicates a high-valent ironoxene species as the predominant oxidant in the radicalar hydrogen abstraction/oxygen rebound pathway, more recent studies on isotope partitioning, product rearrangements with Ôradical clocksÕ, and the impact of threonine mutagenesis in P450s on hydroxylation rates support the notion of the nucleophilic and/or electrophilic (hydro) peroxo-iron intermediate(s) to be operative in P450 catalysis in addition to the electrophilic oxenoid-iron entity; this may contribute to the remarkable versatility of P450s in substrate modification. Precedent to this mechanistic concept is given by studies with natural and synthetic P450 biomimics. While the concept of an alternative electrophilic oxidant necessitates C-H hydroxylation to be brought about by a cationic insertion process, recent calculations employing density functional theory favour a Ôtwo-state reactivityÕ scenario, implicating the usual ferryl-dependent oxygen rebound pathway to proceed via two spin states (doublet and quartet); state crossing is thought to be associated with either an insertion or a radicalar mechanism. Hence, challenge to future strategies should be to fold the disparate and sometimes contradictory data into a harmonized overall picture.

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Section: Evidence From Experiments With Genetically Engineered P450 Esupporting

confidence: 63%

Models and mechanisms of O‐O bond activation by cytochrome P450

Hlavica¹

2004

European Journal of Biochemistry

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“…Those exemplified by eq. [I ] resemble in stoichiometry those of cytochrome-P450, and here also, Fe(1II)-00H intermediates have been invoked but formed, in this case, via protonation of an Fe(1II)peroxide (1,2,10,11).…”

Section: H+mentioning

confidence: 82%

“…Other groups have reported on formation of Rh-OOH (5,6) and R-OOH complexes (7) via reactivity of the platinum metal monohydride with 02. There is very intense interest generally in selective oxygenations utilizing 0 2 , (1,3,(8)(9)(10). Those exemplified by eq.…”

Section: H+mentioning

confidence: 99%

Hydridoiridium(III) sulfoxide complexes and their reactivity toward dioxygen

James¹,

Morris²,

Kvintovics³

1986

Can. J. Chem.

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, and PAL KVINTOVICS. Can. J. Chem. 64, 897 (1986). Synthetic routes to hydridoiridium(II1) dimethylsulfoxide complexes via oxidative addition of HCl or Hz to precursor in situ iridium(1) species are described. The complexes, tran~,mer-IrHCl~(DMSO)~ (la) and ci~,rner-IrH~Cl(DMSO)~ (2), have been characterized by 'H nrnr and ir, and contain only S-bonded sulphoxide, DMSO. Comparison is made with data for other isomers reported in the literature, and some discrepancies are discussed. The decomposition of l a and 2 in chloroform leads to isomers of IIC~~(DMSO)~, while (2) with HCl generates C~~,C~~-I~HC~~(DMSO)~(DMSO) with the 0-bonded sulfoxide trans to hydride. The reaction of l a in dichloromethane with dioxygen occurs with a 1 : 1 stoichiometry and generates two complexes tentatively formulated as Ir(OH)CIZ(DMS0)2H20 (3) and IrC12(02)(DMS0)2~DMS0 (4); a hydroperoxide intermediate (Ir-OOH) initially formed from l a is considered to react with further l a in the rate-determining step. Oxidation of coordinated DMSO to the sulphone is not observed, implying that such a catalyzed 02-oxidation reported earlier in aqueous 2-propanol proceeds via reaction of IrOOH with free DMSO, or else via free hydrogen peroxide. BRIAN R. JAMES, ROBERT H. MORRIS, et PAL KVINTOVICS. Can. J. hem. 64, 897 (1986).On dtcrit des voies de syntheses de complexes de l'hydroiridium(III) et du dimtthylsulfoxyde qui impliquent l'addition de HCl ou de Hz a des prtcurseurs d'iridium(1) prtpar6s in situ. On a caracttrist les complexes, soit le IrHC12(DMS0)3-trans,mer (la) et le IrHC12(DMS0)3-cis,mer (2), en faisant appel a la rmn du 'H et a la spectroscopic ir et ils ne contiennent que des sulfoxydes lits par le soufre, DMSO. On fait une comparaison avec les donntes publites anttrieurement pour d'autres complexes et on discute des divergences. La dtcomposition des composes l a et 2 dans le chloroforme conduit ?ides isomtres du IrC13(DMS0)3 alors que la rtaction du compost 2 avec du HCl conduit a la formation de IrHC12(DMS0)2(DMS0)-cis,cis dans lequel le sulfoxyde est lit par I'oxygkne en position trans par rapport a l'hydrure. Dans le dichloromtthane, le compos6 l a rtagit avec le dioxygkne avec une sto'ichiomttrie 1:l et conduit 21 deux complexes auxquels on a attribut, ?i titre d'essai, les formules Ir(OH)C12(DMS0)2H20 (3) et IrC12(02)(DMS0)2.DMS0 (4); on a considere qu'un intermtdiaire hydroperoxyde (Ir-OOH) qui se forme initialement ?i partir de l a reagirait 2 1 nouveau avec le compost l a dans I'ttape dtterminante. On n'a pas observt d'oxydation du DMSO coordonnt en sulfone; ce rtsultat implique qu'une telle reaction catalyste d'oxydation par 0 2 , dont on a anttrieurement suggtrt I'existence pour des rtactions dans le propanol-2 aqueux, se produirait soit par une rtaction du W O H avec du DMSO libre soit via du peroxyde d'hydrogkne libre.[Traduit par la revue]

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“…Analogously, addition of sulfur dioxide to [Fe 3+ (P)(0 2 )]-(P = TPP, OEP) yielded sulfate. 217 The nucleophilic character of r| 2 -peroxo porphyrin complexes was demonstrated further by the acylation of manganese and iron-peroxo porphyrins complexes. The acylation of a TMPMn lIl -02~ complex with m-chlorobenzoyl chloride was described.…”

Section: Heme and Pseudo-heme Iron Dioxygen Complexesmentioning

confidence: 99%

Biomimetic Oxygenations Related to Cytochrome P450: Metal-Oxo and Metal-Peroxo Intermediates

McLain

Lee

Groves

2000

Biomimetic Oxidations Catalyzed by Transition Metal Complexes

123

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Oxometalloporphyrin Intermediates in Enzymatic ProcessesMetalloenzymes catalyze a host of biological oxidation reactions that are crucial to life processes. The cytochromes P450, an important family of heme-iron metalloenzymes, are oxidoreductases that activate molecular oxygen (O2) and incorporate one of the oxygen atoms into a wide variety of biological substrates, with concurrent two-electron reduction of the other oxygen atom to H 2 0.' The structure, biochemistry, molecular biology and the chemistry of cytochrome P450 and related model systems was extensively reviewed recently. 1 Cytochrome P450 enzymes have been isolated from numerous mammalian tissues (e.g. liver, kidney, lung, intestine and adrenal cortex), as well as insects, plants, yeast and bacteria, 2 and are known to catalyze hydroxylations, epoxidations, N-, S-and O-dealkylations, N-oxidations, sulfoxidations, and dehalogenations. 1 These oxygenation reactions play a central role in carcinogen activation, drug and xenobiotic detoxification, and steroid and prostaglandin metabolism. Surprisingly, the active site of the enzyme, known in detail from several X-ray crystal structures, is extraordinarily simple, with an iron protoporphyrin IX (3.1; Fig. 3.1) buried deep in a hydrophobic, substrate-binding pocket of 91 Biomimetic Oxidations Catalyzed by Transition Metal Complexes Downloaded from www.worldscientific.com by KAINAN UNIVERSITY on 02/20/15. For personal use only.

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Reactivity of the peroxo ligand in metalloporphyrin complexes. Reaction of sulfur dioxide with iron and titanium porphyrin peroxo complexes to give sulfato complexes of sulfate

Cited by 53 publications

References 1 publication

Models and mechanisms of O‐O bond activation by cytochrome P450

Models and mechanisms of O‐O bond activation by cytochrome P450

Hydridoiridium(III) sulfoxide complexes and their reactivity toward dioxygen

Biomimetic Oxygenations Related to Cytochrome P450: Metal-Oxo and Metal-Peroxo Intermediates

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