ESR studies of nitroxide radicals formed in the low temperature photolysis ofN-nitrosamines
摘要:
AbstractVarious N‐nitrosamines were photolyzed in toluene solution in the temperature range −100°C to −30°C to yield dialkyl nitroxides. The nitrosamines studied were N‐nitrosodimethylamine, N‐nitrosodiethylamine, N‐nitrosodipropylamine, N‐nitrosodibutylamine and N‐nitrosodicyclohexylamine. Subsequent nitroxide side products were also detected by ESR, and a mechanism for their formation is proposed. Temperature dependent hyperfine couplings of the methylene protons were observed for a few radicals of the type R1CH2NO˙R2.
Aromatic radical anions as possible intermediates in the nucleophilic aromatic substitution (SNAr): an EPR study
作者:Loris Grossi、Samantha Strazzari
DOI:10.1039/a903407b
日期:——
The reactions among halonitrobenzenes or polynitrobenzenes and alkoxides, thiolates or tertiary amines have provided the evidence that in a SNAr reaction type a single electron transfer from the nucleophile to the aromatic substrate, to generate two radical species within the solvent cage, can take place to some extent. The detection of radical intermediates by EPR spectroscopy, in several SNAr reactions
卤代硝基苯或多硝基苯与醇盐,硫醇盐或叔胺之间的反应提供了证据,表明在S N Ar反应类型中,可以发生从亲核体到芳族底物的单电子转移,从而在溶剂笼内产生两个自由基在某种程度上。通过EPR光谱学,在几μs自由基中间体的检测Ñ氩反应报道。
Base-catalyzed autoxidation of trialkylamines. An e.s.r study
作者:Loris Grossi
DOI:10.1016/s0040-4039(00)95520-5
日期:1987.1
When a freshly distilled tertiary alkyl amine is dissolved in water a base-catalyzed oxidative dealkylation process takes place, leading to the formation of secondary nitroxyl radicals, alkenes and carbonyl-containing compounds.
The stable radicals derived from different compounds were detected in process of styrene autopolymerization. The nitroxide radicals are produced from nitrosocompound, hindered hydroxylamine, nitrophenols and nitroanisoles. The phenoxyl radicals are formed from quinine methides, and naphtoxyl radicals are generated from 2-nitro-1-naphtol. The radicals are identified, the kinetics of their formation and follow-up evolution are studied. These radicals can participate in process of living radical polymerization as the mediators and can effect significantly on kinetics of polymerization and structure of the resulting polymer. (c) 2006 Published by Elsevier B.V.
Cholvad, Vlado; Stasko, Andrej; Tkac, Alexander, Collection of Czechoslovak Chemical Communications, 1981, vol. 46, # 4, p. 823 - 832