Spin Trapping of the Nitrogen-centered Radicals. Characterization of the DMPO/DEPMPO Spin Adducts

Abstract

To develop the spin trapping utility for the detection of N-centered radicals generated in biological systems, 5,5′-dimethylpyrroline-1-oxide (DMPO) and 5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO), have been applied for the detection of chemically generated N-centered radicals in aqueous solution. Both spin traps yielded N-radical adducts, which were characterized by the EPR parameters.

Electron Spin Resonance Spin Trapping Technique: Application to the Cleavage Process of Photoinitiators

“…For IV and V , the HFS values for the aminoalkyl radicals trapped by DMPO are very scarce in the literature due to the difficulties to directly produce these radicals 24. A nitrogen‐centered radical in IV ( β cleavage) can be ruled out because a third HFS with an additional nitrogen a N should be observed:25 this is not the case. The structure of the aminoalkyl radicals in IV and V strongly affects a N and a H when using DMPO.…”

Polymerization Photoinitiators with Near-Resonance Enhanced Two-Photon Absorption Cross-Section: Towards High-Resolution Photoresists with Improved Sensitivity

“…[82][83] A second signal common to both PIs (aN = 8.1 G) can be attributed to a degradation of PBN, 79 finally a third species is observed with BDEBP exclusively (aN-BDEBP = 14.8 G, aH-BDEBP = 4.6 G): its signature corresponds to a C-centered radical, located on the carbonyl moieties, and is typically encountered with benzophenone derivatives. [84][85] It is therefore absent from V-Shape signature, the latter being devoid of a carbonyl function.…”

“…[82][83] A second signal common to both PIs (aN = 8.1 G) can be attributed to a degradation of PBN, 79 finally a third species is observed with BDEBP exclusively (aN-BDEBP = 14.8 G, aH-BDEBP = 4.6 G): its signature corresponds to a C-centered radical, located on the carbonyl moieties, and is typically encountered with benzophenone derivatives. [84][85] It is therefore absent from V-Shape signature, the latter being devoid of a carbonyl function. By analogy with literature, the first signal observed in DMPO (aN-BDEBP = 14.5 G, aH-BDEBP = 21 G; aN-V-Shape = 14.5 G, aH-V-Shape = 21.5 G) may correspond to adducts of the same species described with a possible superimposition of the two C-centered signals in the case of BDEBP.…”

Redox Conversions of 5-Methyl-6-nitro-7-oxo-4,7-dihydro-1,2,4triazolo[1,5-a]pyrimidinide L-Arginine Monohydrate as a Promising Antiviral Drug

“…As a spin trap, 3,3,5,5-tetramethyl-1-pyrroline N-oxide (TEMPO) (Sigma-Aldrich ® , St. Louis, MI, USA, CAS No. 244007) was used [ 29 , 30 ].…”

“…ESR spectra were recorded with a TEMPO spin trap [ 29 , 30 ] after preliminary generation of Triazid 1a reduction products with a concentration of 0.1 M in DMSO in a conventional electrochemical cell for 15 min in the presence of a spin trap. An aliquot of the resulting solution was taken, and the ESR spectrum was recorded.…”