Electron spin resonance of spin-trapped radicals of amines and polyamines. Hydroxyl radical reactions in aqueous solutions and γ-radiolysis in the solid state

Article abstract of DOI:10.1139/v82-216

The reactions of hydroxyl radicals with methylamine, dimethylamine, trimethylamine, diethylamine, sec-butylamine, ethylenediamine, 1,3-diaminopropane, putrescine, cadaverine, 1,7-diaminoheptane, ornithine, spermidine, spermine, agmatine, and arcaine in aqueous solutions have been investigated by spin-trapping and esr.Hydroxyl radicals were generated by the uv photolysis of H2O2 and 2-methyl-2-nitrosopropane (MNP) was used as the spin-trap.The effects of ionizing radiation on the same polyamines in the polycrystalline state were also investigated.The free radicals produced by γ-radiolysis of these solids at room temperature in the absence of air were identified by dissolution in aqueous solutions of MNP.The predominant reaction of .OH with amines and polyamines below pH 7 was the abstraction of hydrogen atoms from the carbon that is not adjacent to the protonated amino group.For agmatine and arcaine which contain guanidinium groups abstraction occured from from the α-CH.Dimethylamine was oxidized to the dimethylnitroxyl radical by H2O2 in the dark. γ-Radiolysis of polyamines in the polycrystalline state generated radicals due to H-abstraction from either the α-CH or from a carbon atom in the middle of the alkyl chain.The deamination radical was obtained from ornithine.