Nitric oxide trapping

Nitric oxide traps all chain carriers by reaction (5) and suppresses chain sensitization, reaction (4 ). The consistently low Arrhenius parameters reported in the early diethylperoxide studies are thus a result of a minor chain decomposition propagated by reaction (4 ). The main reaction mechanisms postulated for... 

Many studies are directed toward examining the mechanism of the NO interaction with unsaturated organic compounds. It has been reported that 5,6-di(propan-2-ylidene)cyclohexa-l,3-diene (I) reacts with NO to form a persistent AR [18]. Thus, (I) is the real nitric oxide trap ... 

Morkovnik et al. (1989) found experimentally that the addition of an equimolar amount of 4-morpholino- or 4-dimethylaminoaniline to a suspension of nitrosyl perchlorate in 100 % acetic acid, dioxan, or acetonitrile yields a mixture of the diazonium perchlorate and the perchlorate salt of the amine radical cation, with liberation of gaseous nitric oxide. Analogous results in benzene, including evidence for radicals by ESR spectroscopy and by spin trapping experiments, were obtained by Reszka et al. (1990). 

In atmospheric chemistry, reactions between pure nitric oxide and a range of activated alkenes have been examined. However, no addition products were observed." Only in the presence of NO2 was addition to give jS-nitroalkyl radicals, followed by trapping to /3-nitronitroso compounds, observed. These final products can also trap other radicals to give aminoxyl radicals. 

For the photolysis of ferf-butyl nitrite a possible reaction mechanism (Scheme 6) consists of the production of ferf-butoxy radicals (equation 3), followed by their decomposition to give acetone and methyl radicals (equation 4). The latter are trapped by the nitric oxide liberated in the first step (equation 5). However, the absence of ethane production in the actual experiments suggested that an intramolecular formation of nitrosomethane is unlikely ". ... 

Chung, G. Y., et al., Effect of Nitric Oxide Annealing on the Interface Trap Densities Near the Band Edges in the 4H Polytype of Silicon Carbide, Applied Physics Letters, Vol. 76, No. 13, March 27, 2000, p. 1713. 

The reversible dissociation of colorless tetraphenylhydrazine into the green diphenylaminyl (15) at 100°C was discovered by Wieland in 1911 (equation 7), and extended the free radical concept to nitrogen. These radicals are trapped by nitric oxide to give diphenylnitrosoamine (16), and the rate of this reaction was used to show the rate of dissociation of the hydrazine. ... 

Cheletrophic spin trapping of nitric oxide. Ultraviolet light converts the phenolic compound to a biradical, which rapidly reacts with nitric oxide to form a stable nitroxyl radical that is readily observable by electron paramagnetic resonance. 

Nitric oxide has been difficult to detect with conventional spin-trapping agents. However, a new approach has been to use stable biradicals to trap nitric oxide (Fig. 19). The cheletrophic trap has two carbon centered radicals spaced the correct distance to catch nitric oxide and form a new ring (Korth et al.,... 

The trapped nitric oxide becomes a stable nitroxide radical that is the same chemical moiety present in most common spin-trapping reagents. Nitric oxide production from activated macrophages has been directly assayed by this method (Korth et al., 1992). 

Trapping of peroxynitrite from rat alveolar macrophages by superoxide dismutase. Although the fotmation of peroxynitrite is drawn as superoxide reacting with nitric oxide in the extracellular space, the actual reactions may be a combination of the pathways shown in Fig. 40. 

Goretski, j., and Hollocher, T. C. (1988). Trapping of nitric oxide produced during denitrification by extracellular hemoglobin. J. Biol. Chem. 263, 2316-2323. 

Turk and Hollocher (1992) have attempted to trap nitroxyl using the dithiol, dithiothreitol, during the reduction of NO by purified nitric oxide reductase from Pa. denitrificans. Because the dithiol served in this system as both electron donor to the enzyme and trap for nitroxyl, the ratio of thiol groups oxidized to NO consumed would have been 1 if nitroxyl trapping did not occur and 3 if nitroxyl... 

Matrix isolation methods of synthesis have also been used to prepare and study coordination compounds. These involve the vaporization of a metal and a potential ligand, which are then rapidly carried in a stream of inert gas to a very cold surface, where the compound which has been formed is quickly trapped in the solid matrix. It is possible to determine the type of bonding, the structure and the thermodynamic properties of the compounds formed. Only small ligand molecules have been used thus far carbon monoxide, nitric oxide, nitrogen and oxygen, for example, but molecules of great interest have been formed. Some such are [Pd(C2H4)], [Pd(N2)3], [Ni(N2)202], [Ni(N2)4] and [Ni(CO)(N2)3].41... 

The initial pressure was 5 kg per cm2. The carbon monoxide was condensed in a trap cooled with liquid nitrogen, whence it was evaporated into a bomb at a pressure of 1-2 kg per cm2. Air was then admitted from a container bringing the pressure up to 5 kg per cm2. The explosion products were collected in a glass flask in which the nitric oxide content was determined as usual. Control experiments showed that a delay in transferring the explosion products to the flask reduced the yield of nitric oxide in a geometrical progression by 10% per minute. This was apparently due to corrosion and in succeeding experiments the time of transfer did not exceed one minute. 

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