On the spin trapping of chlorine atoms. Competition from chloride ions

1991 ◽  
Vol 69 (7) ◽  
pp. 1131-1133 ◽  
Author(s):  
Detlef Rehorek ◽  
Edward G. Janzen ◽  
Yashige Kotake
Keyword(s):  
Key Words ◽  
Epr Spectroscopy ◽  
Spin Trapping ◽  
Adduct Formation ◽  
Chloride Ions ◽  
Spin Adduct ◽  
Phenyl Radicals ◽  
Chlorine Atoms ◽  
Tert Butyl ◽  
Epr Spin Trapping

Chlorine atoms generated by photolysis of hexachloroethane add to C-phenyl-N-tert-butyl nitrone (PBN) to form persistent spin adducts that are readily detectable by EPR spectroscopy. The presence of chloride ions reduces spin adduct formation competitively. Chlorine atoms also react with tetraphenylarsenium ions to liberate phenyl radicals by radical replacement. Key words: EPR, spin trapping, C-phenyl-N-tert-butyl nitrone, PBN, photolysis, chlorine atoms, tetraphenylarsenium ion, hexachloroethane.

First Synthesis of C-Phenyl N-tert-Butyl [15N]nitrone (PBN-15N) for the EPR Spin Trapping Methodology

1996 ◽  
Vol 51 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Yong-Kang Zhang
Keyword(s):  
Hyperfine Splitting ◽  
Spin Trap ◽  
Spin Trapping ◽  
Paramagnetic Resonance ◽  
Tert Butyl ◽  
Hyperfine Splitting Constant ◽  
Percent Increase ◽  
Splitting Constant ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic

As compared to normal PBN, about fifty percent increase of electron paramagnetic resonance (EPR) spin trapping sensitivity has been gained by using a new 100% 15N-enriched spin trap, C-phenyl N-tert-butyl[15N]nitrone (PBN-15N). PBN-15N has been prepared by a convenient four-step route using ammonium-15N chloride as the starting material. This synthetic method produces 2-methyl-2-[15N]nitropropane which is useful for the synthesis of many other PBN-15N type spin traps for the purpose of increasing spin trapping sensitivity. EPR spin trapping with PBN-15N in benzene and in phosphate buffer has been investigated. The 15N hyperfine splitting constant (15N-hfsc) is larger than 14N-hfsc by 40%. The larger 15N-hfsc gives more opportunity to identify different radical addends within the same system.

scholarly journals •BMPO-OOH Spin-Adduct as a Model for Study of Decomposition of Organic Hydroperoxides and the Effects of Sulfide/Selenite Derivatives. An EPR Spin-Trapping Approach

Antioxidants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 918
Author(s):  
Anton Misak ◽  
Vlasta Brezova ◽  
Marian Grman ◽  
Lenka Tomasova ◽  
Miroslav Chovanec ◽  
...  
Keyword(s):  
Spin Trapping ◽  
Time Dependent ◽  
Spin Adduct ◽  
Lipid Hydroperoxides ◽  
Paramagnetic Resonance ◽  
Selenium Compounds ◽  
Organic Hydroperoxides ◽  
Exogenous Compounds ◽  
Epr Spin Trapping ◽  
The Impact

Lipid hydroperoxides play an important role in various pathophysiological processes. Therefore, a simple model for organic hydroperoxides could be helpful to monitor the biologic effects of endogenous and exogenous compounds. The electron paramagnetic resonance (EPR) spin-trapping technique is a useful method to study superoxide (O2•−) and hydroxyl radicals. The aim of our work was to use EPR with the spin trap 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO), which, by trapping O2•− produces relatively stable •BMPO-OOH spin-adduct, a valuable model for organic hydroperoxides. We used this experimental setup to investigate the effects of selected sulfur/selenium compounds on •BMPO-OOH and to evaluate the antioxidant potential of these compounds. Second, using the simulation of time-dependent individual BMPO adducts in the experimental EPR spectra, the ratio of •BMPO-OH/•BMPO-OOH—which is proportional to the transformation/decomposition of •BMPO-OOH—was evaluated. The order of potency of the studied compounds to alter •BMPO-OOH concentration estimated from the time-dependent •BMPO-OH/•BMPO-OOH ratio was as follows: Na2S4 > Na2S4/SeO32− > H2S/SeO32− > Na2S2 ~Na2S2/SeO32− ~H2S > SeO32− ~SeO42− ~control. In conclusion, the presented approach of the EPR measurement of the time-dependent ratio of •BMPO-OH/•BMPO-OOH could be useful to study the impact of compounds to influence the transformation of •BMPO-OOH.

Spin trapping azidyl (N3•), cyanatyl (OCN•), cyanyl (•CN) radicals, and chlorine atom (Cl•)

1980 ◽  
Vol 58 (15) ◽  
pp. 1596-1598 ◽  
Author(s):  
Edward G. Janzen ◽  
Henry J. Stronks ◽  
Dale E. Nutter Jr. ◽  
Edward R. Davis ◽  
Henry N. Blount ◽  
...  
Keyword(s):  
Chlorine Atom ◽  
Hydroxyl Radicals ◽  
Spin Trapping ◽  
Chlorine Atoms ◽  
Tert Butyl ◽  
Cn Radicals

Azidyl, cyanatyl, and cyanyl radicals and chlorine atoms have been detected by spin trapping using α-phenyl N-tert-butyl nitrone (PBN) in the monoelectronic electrooxidations of azide, cyanate, cyanide, and chloride. Azidyl and cyanatyl radicals were also detected with PBN in the persulfate oxidations of azide and cyanate. Azidyl radicals could be detected in the reaction of azide with hydroxyl radicals in the presence of PBN.

Photoredox Reactions of Iodo Iron(III) Complexes Containing Tetradentate Ligands

2001 ◽  
Vol 66 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jozef Šima ◽  
Dáša Lauková ◽  
Vlasta Brezová
Keyword(s):  
Schiff Bases ◽  
Spin Trapping ◽  
Molar Ratio ◽  
Oh Radicals ◽  
Solvated Electrons ◽  
Open Chain ◽  
Tetradentate Ligands ◽  
Visible Irradiation ◽  
Epr Spin Trapping ◽  
Spin Trapping Technique

Photoredox reactions occurring in irradiated methanolic solutions of trans-[FeIII(R,R'-salen)(CH3OH)I], where R,R'-salen2- are N,N'-ethylenebis(R,R'-salicylideneiminato), tetradentate open-chain N2O2-Schiff bases with R,R' = H, 5-Cl, 5-Br, 3,5-di-Br, 3,5-di-(CH3), 3-OCH3, 5-OCH3, have been investigated and their mechanism proposed. The complexes are redox-stable in the dark. Ultraviolet and/or visible irradiation of methanolic solution of the complexes induces photoreduction of Fe(III) to Fe(II). Depending on the composition of the irradiated solutions, •CH2OH radicals or solvated electrons were identified by the EPR spin trapping technique. The final product of the photooxidation coupled with the photoreduction of Fe(III) is formaldehyde and the molar ratio of Fe(II) and CH2O is close to 2 : 1. The efficiency of the photoredox process is strongly wavelength-dependent and influenced by the peripheral groups R,R' of the tetradentate ligands.

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