Oxygen atom transfer reaction

N—Fe(IV)Por complexes. Oxo iron(IV) porphyrin cation radical complexes, [O—Fe(IV)Por ], are important intermediates in oxygen atom transfer reactions. Compound I of the enzymes catalase and peroxidase have this formulation, as does the active intermediate in the catalytic cycle of cytochrome P Q. Similar intermediates are invoked in the extensively investigated hydroxylations and epoxidations of hydrocarbon substrates cataly2ed by iron porphyrins in the presence of such oxidizing agents as iodosylbenzene, NaOCl, peroxides, and air. 

A further test of whether MeReO(mtp)PAr3 (5) catalyzes other oxygen atom transfer reactions was made through studies of this reaction,... 

A new generation of oxorhenium compounds has now been prepared. They catalyze oxidation reactions of a different type, and appear to function by a different mechanism. They are oxorhenium(V) compounds that form usually metastable dioxorhenium(VII) intermediates. The mechanisms feature Rev(0)-to-ReVII(0)2 interconversions and catalyze oxygen atom transfer reactions. The mechanisms show a certain diversity as to the steps that enter in a kinetic sense. Yet the schemes presented in this review show a great deal of similarity in their overall mode of action. 

Oxygen-atom transfer reactions, 9 370-376 Oxygenators blood, 3 720... 

Oxygen Atom Transfer Reactions at Binuclear Copper Sites... 

Compounds of the composition [ReOCl3(N N)] have also been isolated with pyridine-2-aldi-mine and rr-acidic arylazopyridine and arylazoimidazole ligands." The products (101) are readily reduced by oxygen atom transfer reactions from Re to phosphorus atoms of phosphines which results in the formation of rhenium(III) complexes. Depending on the reaction condition and the phosphines used either mononuclear or binuclear compounds are formed." " Azo splitting reactions with arylazopyridines give access to arylimido and binuclear oxo/imido com-plexes. "" ... 

Oxo-tnolybdenum centers (continued) oxygen atom transfer reactions, 40 49-56 bis(identate) NS-donor ligand complexes, 40 52-53... 

For practical reasons the two-electron oxidations of such prototypical substrates as alkenes, sulfides, amines and phosphines with peroxynitrous acid have been smdied since this type of oxygen atom transfer reaction is similar to the corresponding oxidations with peroxyformic acid, where both experimental and computational data are available The oxidative reactions (equations 3-6) of these key substrates can... 

The facile activation of dioxygen by these simple organometalHc complexes generates high-valent (V(V), Cr(V)) metal 0x0 complexes, which may undergo oxygen atom transfer reaction with organic substrates, and thus serve as catalysts for aerobic oxidations (Sect. 3.3). 

An MoO + unit is likely to be present in the oxidized form of sulfite oxidase and in the desulfo form of xanthine dehydrogenase.20 The reactivity of the MoC>2+ unit has been thoroughly studied, especially with regard to oxygen atom transfer reactions. 

Thermodynamic considerations indicate that the oxygen atom transfer reactions between Mo02(R2dtc)2 and enzyme substrates should be largely irreversible.175 For example, the hypothetical reaction of equation (17) has AH = — 28.5 5.5 kcalmol-1 (= —119 23.0 kJ mol1). The reaction should have a small AS and hence should have a negative AG and proceed spontaneously.175 There are, however, complicating factors. 

Oxidation Catalyzed by Metalloporphyrins. Much attention has been devoted to the metal-catalyzed oxidation of unactivated C—H bonds in the homogeneous phase. The aim of these studies is to elucidate the molecular mechanism of enzyme-catalyzed oxygen atom transfer reactions. Additionally, such studies may eventually allow the development of simple catalytic systems useful in functionalization of organic compounds, especially in the oxidation of hydrocarbons. These methods should display high efficiency and specificity under mild conditions characteristic of enzymatic oxidations. 

Superoxide is also implicated in the conversion of 9.20 to 9.21. The first step of the reaction involves the formation of a nickel(m)-superoxide complex, which then undergoes the intramolecular oxygen atom transfer reaction. In this case, the superoxide is... 

One approach to limit dimer formation in model complexes involves the use of bulky ligands and weakly coordinating solvents. Holm and coworkers [196,198-201] have studied oxygen atom transfer reactions of 2,6-bis(2,2-diphe-nyl-2-thioethyl)pyridinate [2] molybdenum oxo complexes. In contrast to the structurally similar dithiocarbamate molybdenum complexes, the tendency of the 2,6-bis(2,2-dipheny 1-2-thioethy l)pyridinate MoIV monoxo complex to undergo di-... 

Ghiron, A.F. and R.C. Thompson. 1990. Comparative kinetic study of oxygen atom transfer reactions of diperoxo and monoperoxo complexes of oxovanadium(V) in aqueous solution. Inorg. Chem. 29 4457-4461. 

However, these reactions can actually be considered as electron transfer or oxygen atom transfer reactions, as in the case of the ozone reactions with the hydroxyl and hydroperoxide ions or with the nitrite ion, respectively ... 

Among these, a variety of oxygen atom transfer reactions have been described [la,b] and highly stereoselective reactions have been reported [2]. Although the formation of aziridines by the reaction of nitrenes with olefins is well known, the efficiency is moderate, because of the competition between hydrogen abstraction and insertion processes [3]. A typical example is shown (Eq. 2) [3d]. 

Transition-metal oxides are useful oxidizing reagents for organic molecules and often participate in oxygen-atom transfer reactions [21]. A prototypical example is CH3Re03 (MTO), which serves as a versatile reagent for stoi-... 

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