Electron spin resonance study of γ-irradiated ethyleneimine in the solid state

Abstract

The electron spin resonance (e.s.r.) study of the ethyleneimine in polycrystalline and glassy state shows CH,-XH, that the radical \N/ is formed by y-irradiation at 77 O K . The features of the e.s.r. spectrum of this radical are discussed in terms of the isotropic and anisotropic hyperfine coupling constants of the hydrogen and nitrogen nuclei. The effects of bleaching the y-irradiated sample with visible and ultraviolet light are also reported. -and ultraviolet (u-v.) The field sweep calibration was carried out by a Mn2+ irradiation in the solid state (1-4). The low doped sample of MgO (5). melting points of these compounds make single crystal studies difficult. The published spectra Results have been obtained from irradiated polyciysta~-Anhydrous ethyleneirmne frozen at -196 oC line samples. The anisotropic effects give rise to gives an opaque crystalline matrix which after poorly spectra which are generally y-irradiation shows a weak blue color. The jnterpret Only in a product containing about 20% of water gives a few cases are fairly clear spectra obtained.transparent glass with an intense blue color after In the present investigation the of y-irradiation. The e.s,r. spectrum, recorded at which gives a we' ' -196 OC, is practically the same in both cases and spectrum, is reported.does not change from -196 to about -90 "C. ExperimentalEthyleneimine (Fluka reagent) was purified by distillation and dried with a sodium mirror. Ethyleneimine-dl was prepared by exchange of ethyleneimine with D,O. Its isotopic purity, checked by nuclear magnetic resonance, was better than 95 %. The e.s.r. spectra were recorded at 9.2 GHz using a Hilger and Watts Microspin spectrometer with a TED,, cylindrical cavity.The measurements were performed at -196 "C by keeping the sample tubes in a quartz Dewar filled with liquid nitrogen, or at higher temperatures by using a variable nitrogen flow system. 'This work was supported by Consiglio .Nazionale delle Ricerche.

Electron spin resonance study of dialkylamino free radicals in solution

“…and isolated by sublimation from the residue which remains after evaporation of solvent from the hydrolysate. The nmr spectrum in toluene consists of two triplets in the rato 18 :5.5 at 8.26 (/p_ch> = 4 Hz) and 19.73 (/ -= 14 Hz). The 31P nmr consists of a symmetrical sextet (0.94:5 :10) at +192.1 ppm from external trimethyl phosphite.…”

Electron spin resonance study of radicals produced in irradiated aqueous solutions of amines and amino acids

“…The number of hydrogen atoms displaying the hyperfine constant is given in parentheses. 6 From the second-order pattern this hyperfine constant must have a sign opposite that of a^H. 6.…”

“…6 From the second-order pattern this hyperfine constant must have a sign opposite that of a^H. 6. These changes have been interpreted as arising from the two protonations of H2NCHC02_.…”

“…There is, however, also some evidence from this source22 for reaction lb. ±28.56 (6) °Hyperfine constants are given in gauss and are accurate to ±0.03 G. The g factors are measured relative to the peak from the silica cell and are accurate to about ±0.00005. Second-order corrections have been made [R. W. Fessenden, J. Chem.…”