Spin trapping chemistry of 3,3,5,5-tetramethylpyrroline-N-oxide: an improved cyclic spin trap

1981 ◽  
Vol 59 (4) ◽  
pp. 756-758 ◽  
Author(s):  
Edward G. Janzen ◽  
Raghav V. Shetty ◽  
Susan M. Kunanec
Keyword(s):  
Spin Trap ◽  
Esr Spectra ◽  
Spin Trapping

The use of 3,3,5,5-tetramethylpyrroline-N-oxide as a spin trap has been investigated. Spin adducts are found to be more persistent than for 5,5-dimethylpyrroline-N-oxide (DMPO) although the esr spectra are quite similar.

Spin trapping with 9-nitrosotriptycene

1982 ◽  
Vol 60 (12) ◽  
pp. 1594-1596 ◽  
Author(s):  
Harparkash Kaur ◽  
M John Perkins ◽  
André Scheffer ◽  
David C Vendor-Morris
Keyword(s):  
Temperature Dependence ◽  
Organic Solvents ◽  
Rate Constant ◽  
Spin Trap ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Alkyl Radicals ◽  
Restricted Rotation

Nitrosotriptycene is found to be a potentially useful spin trap when used in organic solvents; the esr spectra of its spin adducts are simple, but they may show marked temperature dependence due to restricted rotation. Nitrosotriptycene traps primary alkyl radicals with a rate constant of ca. 2 × 107 L mol−1 s−1 at 40°C in benzene.

scholarly journals Embedding cyclic nitrone in mesoporous silica particles for EPR spin trapping of superoxide and other radicals

The Analyst ◽  
2019 ◽  
Vol 144 (14) ◽  
pp. 4194-4203 ◽  
Author(s):  
Eric Besson ◽  
Stéphane Gastaldi ◽  
Emily Bloch ◽  
Jacek Zielonka ◽  
Monika Zielonka ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Radical Anion ◽  
Superoxide Radical ◽  
Spin Trap ◽  
Aqueous Media ◽  
Spin Trapping ◽  
Silica Particles ◽  
Superoxide Radical Anion ◽  
Wide Range ◽  
Epr Spin Trapping

Mesoporous silica functionalised with a cyclic spin trap enabled the identification of a wide range of radicals in organic and aqueous media, including superoxide radical anion.

scholarly journals The spin trapping of pyrimidine nucleotide free radicals in a Fenton system

1989 ◽  
Vol 261 (3) ◽  
pp. 831-839 ◽  
Author(s):  
W D Flitter ◽  
R P Mason
Keyword(s):  
Free Radicals ◽  
Hydroxyl Radical ◽  
Spin Trap ◽  
Gamma Ray ◽  
Thiobarbituric Acid ◽  
Spin Trapping ◽  
Pyrimidine Nucleotide ◽  
Gamma Ray Irradiation ◽  
Radical Attack ◽  
Fenton System

The reaction of the hydroxyl radical, generated by a Fenton system, with pyrimidine deoxyribonucleotides was investigated by using the e.s.r. technique of spin trapping. The spin trap t-nitrosobutane was employed to trap secondary radicals formed by the reaction of the hydroxyl radical with these nucleotides. The results presented here show that hydroxyl-radical attack on thymidine, 2-deoxycytidine 5-monophosphate and 2-deoxyuridine 5-monophosphate produced nucleotide-derived free radicals. The results indicate that .OH radical attack occurs predominantly at the carbon-carbon double bond of the pyrimidine base. The e.s.r. studies showed a good correlation with previous results obtained by authors who used x- or gamma-ray irradiation to generate the hydroxyl radical. A thiobarbituric acid assay was also used to monitor the damage produced to the nucleotides by the Fenton system. These results showed qualitative agreement with the spin-trapping studies.

scholarly journals Mechanism in the reaction of cytochrome c oxidase with organic hydroperoxides: an ESR spin-trapping investigation

2002 ◽  
Vol 365 (2) ◽  
pp. 461-469 ◽  
Author(s):  
Yeong-Renn CHEN ◽  
Ronald P. MASON
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Spin Trap ◽  
Spin Trapping ◽  
Initial Reaction ◽  
Radical Species ◽  
Alkoxyl Radical ◽  
Tyrosine Residues ◽  
Esr Spin Trapping ◽  
Organic Hydroperoxides

Organic hydroperoxides are of great utility in probing the reaction mechanism and the toxicological consequences of lipid peroxidation. In the present study, ESR spin-trapping was employed to investigate the peroxidation of mitochondrial cytochrome c oxidase (CcO) with t-butyl hydroperoxide (t-BuOOH) and cumene hydroperoxide (CumOOH). The spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) was used to detect the radical species formed from the reaction of CcO with t-BuOOH. The presence of t-BuOOH-derived alkoxyl radical (t-BuO˙) as the primary radical indicates reductive scission of the O—O bond by CcO. The ESR signal of DMPO/˙Ot-Bu can be partially abolished by cyanide, implying that the reductive cleavage involved the haem a3CuB binuclear site of CcO. A nitroso spin trap, 2-methyl-2-nitrosopropane (MNP), was used to detect and identify radical species from the reaction of CcO with CumOOH. In addition to the t-BuOOH-derived methyl, hydroxylmethyl and tertiary carbon-centred radicals, a protein-derived radical was detected. The intensity of the ESR signal from the protein radical increased with the CumOOH concentration at low CumOOH/CcO ratios, with maximal intensity at a ratio of 100mol of CumOOH/mol of CcO. The immobilized protein radical adduct of MNP was stable and persistent after dialysis; it was also resistant to proteolytic digestion, suggesting that it was formed in the transmembrane region, a region that is not accessible to proteases. Its signal was greatly enhanced when CcO cysteine residues were chemically modified by N-ethylmaleimide, when the tryptophan residues in CcO were oxidized by N-bromosuccimide, and when tyrosine residues on the surface of CcO were iodinated, showing that a radical equilibrium was established among the cysteine, tryptophan and tyrosine residues of the protein-centred radical. Pre-treatment of CcO with cyanide prevented detectable MNP adduct formation, confirming that the haem a3-CuB binuclear centre was the initial reaction site. When the CcO was pre-treated with 10mM (100 equivalents) of CumOOH, the enzyme activity decreased by more than 20%. This inhibition was persistent after dialysis, suggesting that the detected protein-centred radical was, in part, involved in the irreversible inactivation by CumOOH. Visible spectroscopic analysis revealed that the haem a of CcO was not affected during the reaction. However, the addition of pyridine to the reaction mixture under alkaline conditions resulted in the destruction of the haem centre of CcO, suggesting that its protein matrix rather than its haem a is the target of oxidative damage by the organic hydroperoxide.

Spin Trapping of Radicals in Gas-Phase Cigarette Smoke

1985 ◽  
Vol 40 (6) ◽  
pp. 850-852 ◽  
Author(s):  
Alexander Halpern ◽  
Josef Knieper
Keyword(s):  
Gas Phase ◽  
Cigarette Smoke ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Alkoxy Radicals

Abstract Spin trapping with N-t-butyl-α-phenyl nitrone (PBN) and 5,5-dimethyl-1-pyrroline-oxide (DMPO) has been utilized to identify the radicals in the gas phase of cigarette smoke. ESR spectra reveal predominantly alkoxy radicals which are continuously formed in smoke, but not directly in the flame.

Electron spin resonance studies of the reactions of sorbate with nitrite in the presence of a spin trap

1982 ◽  
Vol 60 (12) ◽  
pp. 1598-1601 ◽  
Author(s):  
Avinash Joshi ◽  
Dennis M Hinton ◽  
George C Yang
Keyword(s):  
Electron Spin Resonance ◽  
Double Bond ◽  
Sodium Nitrite ◽  
Spin Trap ◽  
Spin Trapping ◽  
Potassium Sorbate ◽  
Radical Product ◽  
Rapid Decomposition ◽  
Esr Spectrum ◽  
Spin Resonance

An esr spectrum was generated when a spin trap, t-nitroso butane (tNB), was added to potassium sorbate solution at pH of 6.4. This spectrum can be explained by the abstraction of allylic hydrogen by NO2, generated by the decomposition of tNB, followed by spin trapping of the radical product. With increasing concentration of NO2, which was accomplished by either the addition of sodium nitrite or by lowering the pH to cause rapid decomposition of tNB, a different esr spectrum was observed. This spectrum can be accounted for by a radical formed by addition of NO2 to the 4,5 double bond of the sorbate and subsequent trapping by tNB.

Spin trapping by use of nitrosodurene and its derivatives

1982 ◽  
Vol 60 (12) ◽  
pp. 1532-1541 ◽  
Author(s):  
Ryusei Konaka ◽  
Shigeru Terabe ◽  
Taiichi Mizuta ◽  
Shigeru Sakata
Keyword(s):  
Hydrogen Peroxide ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Nitroso Compounds ◽  
Spin Adduct ◽  
Spin Traps ◽  
Spectral Pattern ◽  
Alkyl Radicals ◽  
Alkyl Hydroperoxides ◽  
Tert Butyl Hydroperoxide

In spin trapping the N-methyl-N-phenylaminomethyl radical with nitrosodurene, an esr spectmm exhibiting line width alternation was observed despite the normal spectral pattern found with the use of nitroso-tert-butane. Nitrosodurene derivatives, N-duryl nitrone and methyl N-duryl nitrone, have been revealed to be other excellent spin traps for the N-, 0-, and S-centered radicals. Spin adducts of these radicals, which can be independently prepared by spin trapping with nitrosodurene, are stable and can be easily discriminated by large differences in β-hydrogen splittings or characteristic patterns. Methyl N-duryl nitrone reacted with tert-butyl hydroperoxide to give a spin adduct which could be clearly distinguished in the esr spectra from the tert-butoxy adducts prepared independently from other sources. Accordingly, it seems to be the tert-butylperoxy adduct. Similarly, hydrogen peroxide gave a different spectrum from the hydroxy adducts. Alkyl hydroperoxides caused molecule-induced homolysis with the nitroso compounds to produce alkoxy adducts of the respective nitroso compounds. Some phenyl and duryl alkoxy nitroxides undergo decomposition to give alkyl radicals which were trapped by the nitroso compounds.

Utilisation des pièges à radicaux en vue de mettre en évidence des intermédiaires dans la photolyse de complexes contenant une liaison CoIII—C

1982 ◽  
Vol 60 (12) ◽  
pp. 1402-1413 ◽  
Author(s):  
Philippe Maillard ◽  
Charles Giannotti
Keyword(s):  
Free Radicals ◽  
Hydrogen Atom ◽  
Spin Trap ◽  
Spin Trapping ◽  
Spin Adduct ◽  
Efficient Manner ◽  
Solvent Cage ◽  
Selective Deuteration ◽  
Equatorial Ligand ◽  
Spin Trapping Technique

Using the spin trapping technique with 5,5′-dimethyl 1-pyrroline N-oxide (DMPO), phenyl-N-tert-butyl nitrone (PBN), nitrosodurene (ND), and α-4-pyridyl 1-oxide N-tert-butl nitrone (4-POBN), or their mixtures, we have been able to detect two types of radicals, one is a hydrogen atom spin adduct and the other is the corresponding alkyl of the alkylcobaloximes, salens or cobalamines.By the use of selective deuteration and the preparation of the benzyl bis(diphenylglyoximato)-pyridinato cobaloxime, we have shown that the spin trapped hydrogen atom comes from the chelated hydrogen of the dimethylglyoximato anion of the equatorial ligand of CoIII complexes. Using a mixture of two spin traps gives rise to an esr spectrum containing, at the same time, the hydrogen atom and alkyl spin adducts.To explain such an efficient spin trapping reaction while the homolysis is in competition with a β-elimination process, it should be postulated that the photolysis of such compounds proceeds through a solvent cage environment. This hypothesis explains the strong influence of solvents on the nature of the free radicals trapped. Also the spin trap diffuses in the solvent cage, and is able to trap in a very efficient manner any free radicals occurring in the solvent cage. The excited CoIII complexes and the spin trap in the solvent cage behave like an exciplex, which could explain the spin trapping of the hydrogen atom.

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