Derivatives of Dihydropyrazine-1,4-Dioxide, 3-Imidazoline 3-Oxide, and α-Phenyl Nitrones with Functional Groups as New Spin Traps in Solution and in the Gas Phase

Abstract

The title compounds, acyclic phenyl nitrones with functional groups, cyclic dinitrones with conjugated or isolated double bonds, and imidazoline nitrones are studied as spin traps (ST) for short-lived free radicals (R) generated photochemically in solution and in the gas phase. New STs are efficient in trapping OH, hydroxyalkyl, or HO2 radicals. EPR spectra of the spin adducts (SA) of studied dinitrones are triplets of doublets characteristic of the nitroxides with one radical center. Imidazoline ST with amino nitrogen exhibits pH-dependent hyperfine splittings of its SAs. Some spin traps were shown to be efficient in detecting R in the atmospheric experiments.

New Nanoparticle Formation under UV Impact on Acetaldehyde Vapor in Nitrogen and Air Flow

“…The ESR spectra of spin adducts were recorded with a BRUKER ER-200 D-SRC spectrometer as described in detail elsewhere. 11 Since the known spin traps phenyl-tert-butyl nitrone (PBN) and dimethylpyrroline oxide (DMPO) were insufficiently stable in our system, we used new nitrone spin traps: pentamethylimidazoline N-oxide I (PMIO) and conjugated dihydropyrazine dioxides with different substituents II and III. They were chosen among 42 aldonitrone compounds synthesized in cooperation with the Novosibirsk Institute of Organic Chemistry.…”

Semi-Empirical Evaluation of the Probability of Structural Rearrangements in Nitrone Spin Traps

“…In solutions of acyclic spin traps, sometimes EPR signals with the parameters characteristic of cyclic spin adducts appear, and vice versa. Some observations of this kind were described in [9]. The EPR spectra with unexpectedly large a H appeared in the solutions of nitrones 1 and 2 in the presence of oxidizers.…”

“…Short-lived free radicals for spin trapping experiments were generated photolytically [7,8,9]. Photolysis of Chemical Engineering and Science 18 potassium persulphate in water was also used to generate hydroxyl radicals (S 2 O 8 -2  2SO 4 -* , followed by H 2 O + SO 4 -*  OH + HSO 4 -).…”

“…The EPR spectra were recorded with a BRUKER EMX instrument (X band) in a standard flat quartz cell. Microwave power did not exceed 10 mV, modulation amplitude was 0.05 -0.8mT, other parameters were the same as those listed in [9].…”

The Distribution of Relative Humidity in Cirrus Clouds and Its Impact on the Nitric Acid Content of Interstitial Aerosol Particles

“…Radical were detected and identified using spin -trapping technique (Dultseva et al, 1996). Radical were detected and identified using spin -trapping technique (Dultseva et al, 1996).…”