Oxygen migration from

The simplest example of oxygen spillover is found in the adsorption of oxygen on carbon. The spillover oxygen migrates from the basal carbon (donor) to carbon atoms exposed at steps between layers of the graphite surface, where it reacts with the edge carbons (acceptor).71 In this case the donor and acceptor phase consist of the same material with different surface properties. 

Pyrroline-A-oxide (258) is isomerized into y-lactam (259) in the presence of lithium diisopropylamine (LDA) (470) and sodium trityl (471). In these reactions, deprotonation at C3 occurs, leading to carbanion (260). Then oxygen migration from Ni to C2 takes place via intermediate formation of oxaziridine... 

Photochemistry of (2-nitrophenyl)diazomethane 70 has been studied by excitation at 350 nm in argon matrix isolation system54. That shows that at 10 K, 2-nitroso-benzaldehyde is formed by intramolecular oxygen migration from (2-nitrophenyl) carbene... 

Light-catalyzed isomerization of azoxy derivatives to o-hydroxyazo-derivatives by exposure to sunlight, whereby the oxygen migrates from the nitrogen atom to which it is attached to the nucleus which is attached to the other nitrogen atom, seems to proceed via an intramolecular mechanism LXXVII I LXXX.12... 

The mechanical properties of the oxide film, in particular, the formabiUty and state of stress, determine the occurrence of cracks. If the formability of the film is poor, the contact between metal and oxide is lost as long as ion migration of the metal is from the inside to the outside. Oxygen migration from the outside to the metal-oxide interface leads to formation of a new oxide scale, which propagates into the metal. 

The carbon issued from the methane decomposition over the reduced sites will be oxidized by oxygen migrated from the ceria. Adsorbed carbon monoxide, actually under the form of various multibonded, bridged and linear carbonyls will migrate to the support to form formate species as revealed by DRIFT [6]. Figure 4 shows the transient response of the formate formation as predicted by the model. This transient response corresponds quite well with the evolution in time of the assigned formate IR bands as reported in [6]. 

Step 3 Carbon migrates from boron to oxygen displacing hydroxide ion Carbon migrates with the pair of electrons m the carbon-boron bond these become the electrons m the carbon-oxygen bond... 

An alkyl group can also migrate from oxygen to nitrogen or phosphorus [I, 72] (Michaelis-Arbuzov rearrangement) With this methodology, tetrafluoro-pyndine phosphonates and phosphmates can be obtained [75, 74], Chlorine fluoride... 

In the well-known Brook rearrangment, silyl groups migrate from oxygen to carbon, but the following example is less obvious and not necessarily predictable ... 

The alkylboranes obtained by the hydroboration reaction are versatile intermediates for further transformations. The most important transformation is the oxidation to yield alcohols 17 it is usually carried out by treatment with hydroperoxide in alkaline solution. The group R migrates from boron to oxygen with retention of configuration ... 

We recognize redox reactions by noting whether electrons have migrated from one species to another. The loss or gain of electrons is easy to identify for monatomic ions, because we can monitor the charges of the species. Thus, when Br ions are converted into bromine atoms (which go on to form Br2 molecules), we know that each Br ion must have lost an electron and hence that it has been oxidized. When 02 forms oxide ions, 02-, we know that each oxygen atom must have gained two electrons and therefore that it has been reduced. The difficulty arises when the transfer of electrons is accompanied by the transfer of atoms. For example, is chlorine gas, Cl2, oxidized or reduced when it is converted into hypochlorite ions, CIO" ... 

In this reaction, the C atom of C02, the Lewis acid, accepts an electron pair from the O atom of a water molecule, the Lewis base, and a proton migrates from an H20 oxygen atom to a C02 oxygen atom. The product, an H2C03 molecule, is a Bronsted acid. 

The full paper has appeared on the solvolysis of the dibenzyl ester (28) of phosphoenolpyruvic acid and on the related phosphonate ester (29). Reversible phosphoryl migration from the enol oxygen to the carboxy-group occurs readily in (28) and (29) but only to a small extent - and probably not reversibly-in the monoanion (30) and phosphoenolpyruvic acid itself. These observations are readily accounted for in terms of the expected ease of pseudorotation between the various configurations of the... 

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