Electron spin resonance study of dialkylamino free radicals in solution

Danen, Wayne C.; Kensler, Terry T.

doi:10.1021/ja00720a049

Cited by 60 publications

(31 citation statements)

References 3 publications

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“…The first investigation on the neutral compound (CH 3 hN was carried out by Hadly and VoJman [ 13] who concluded that the unpaired electron resides in a sp 3 hybrid orbital, based on the large isotropic hfcc's measured for the nitrogen center ( 32 G). Different results were reported by Danen and Kensler [ 14] who observed a far smaller isotropic hfcc ( 14.78 G) for the nitrogen center. In their interpretation the nitrogen center is sp 2 hybridized and the unpaired electron occupies the nitrogen p-orbital perpendicular to the C-N-C plane.…”

Section: Introductioncontrasting

confidence: 57%

Theoretical study of the dimethylamino radical (CH3)2N and its protonated cation (CH3)2NH+

1994

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In the present work the dimethylamino radical ( ( CH 3 ) 2 N) and its protonated cation ( ( CH 3 hNH +) are investigated by means of ab initio methods. The geometries of various conformations of both compounds are obtained with UMP2/6·31 G** calculations, while the hyperfine structure and its dependence on the geometry is studied using the MRD-Cl/BK method. The two molecules are compared to study the inftuence of the protonation on geometry and hyperfine structure. The effects of the rotational barriers on the hyperfine structures of (CH 3 hN, (CH 3 CH 2 hN and ( (CH 3 hCHhN will be discussed.

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Section: Introductioncontrasting

confidence: 57%

Theoretical study of the dimethylamino radical (CH3)2N and its protonated cation (CH3)2NH+

1994

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“…Free radical formation from aliphatic amines has been investigated previously by a number of methods. For studies of the solid state, electron spin resonance was used to observe radical species produced by X-rays (3) and y-radiolysis (4-6) in single crystals or by uv photolysis (7,8) in frozen glasses. Optical absorption was used to follow the radicals produced by pulse radiolysis (9)(10)(11)(12) in aqueous solutions that were saturated with N 2 0 to convert ePa,.…”

Section: Andh~-(ch~)-~~h~-(ch~)~-~~h~) Etc Asmentioning

confidence: 99%

“…N-centered radicals were also formed by ultraviolet irradiation of glassy samples of mono-, di-, and trialkyl amines at low temperatures (7,8). However, in the reaction of OH radicals with aliphatic amines in aqueous solution (9)(10)(11)(12)(13)(14)17), H-abstraction from the nitrogen as well as from the carbon adjacent to it occurred in alkaline medium.…”

Section: Andh~-(ch~)-~~h~-(ch~)~-~~h~) Etc Asmentioning

confidence: 99%

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

Mossoba¹,

Rosenthal²,

Riesz³

1982

Can. J. Chem.

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MAGDI M. MOSSOBA, IONEL ROSENTHAL, and PETER RIESZ. Can. J. Chem. 60, 1493 (1982). The reactions of hydroxyl radicals with methylamine, dimethylamine, trimethylamine, diethylamine, see-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 H,O, 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 y-radiolysis of these solids at ro0.m 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 a carbon that is not adjacent to the protonated amino group. For agmatine and arcaine which contain guanidinium groups abstraction occurred from the a-CH. Dimethylamine was oxidized to the dimethylnitroxyl radical by H,O, in the dark. y-Radiolysis of polyamines in the polycrystalline state generated radicals due to H-abstraction from either the a-CH or from a carbon atom in the middle of the alkyl chain. The deamination radical was obtained from ornithine. Faisant appel B la rpe et B I'utilisation de piegeurs de spin, on a itudiC la reaction des radicaux hydroxyles avec des solutions aqueuses des amines suivantes: methylamine, dimethylamine, trimethylamine, diethylamine, see-butylamine, Cthylknediamine, I diamino-1,3 propane, putrescine, cadavtrine, diamino-1,7 heptane, ornithine, spermidine, spermine, agmatine et arcaine. Les

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“…This leads to speculation that TMT might be homolytically decomposed to the two aminium radicals in concentrated sulfuric acid as shown in eq. [3]. As the observed products could be rationalized equally satisfactorily with aminium radical or nitrenium ion, mechanisms of TMT decomposition remain an open question.…”

Section: Introductionmentioning

confidence: 98%

“…Thermolysis or photolysis of TMT to generate the dimethylamine radical (eq. [I]) has been proven by the recording of the esr signal of the radical (3,4). TMT decomposition in dilute acidic solution produces equimolar yields of nitrogen, formaldehyde, and methylamine from which TMT-H+ is proposed Can.…”

Section: Introductionmentioning

confidence: 99%

Decomposition of tetramethyl-2-tetrazene under acidic conditions

Madgzinski¹,

Pillay²,

Richard³

et al. 1978

Can. J. Chem.

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Can. J. Chem. 56, 1657Chem. 56, (1978.Decompositions of tetramethyl-2-tetrazene (TMT) under acidic conditions were investigated by product analysis and by nmr and esr spectroscopic monitors. Photolysis in acetonitrile containing trifluoroacetic acid generated the dimethylaminium radical which added efficiently to an olefinic double bond. Some adducts contained a (CH3),NCH2-moiety, the immediate precursor of which could be CH2=N(CH3),+ species. Photolytic addition of TMT to norbornenes generated 2-norbornyl radicals that underwent coupling through the exo or endo side to give the dimers. Thermal decomposition in sulfuric acid in the presence of toluene gave N,N-dimethyltoluidines, N-methylphenethylamine, benzyltoluenes, and a plethora of other minor products in addition to a large amount of formylidene methylamine. The last compound was the major product when thermal decomposition of T M T was carried out in trifluoroacetic acid in the presence of toluene or anisol; amination products of aromatic substrates were low and contained only ortllo and porn isomers. TMT dissolved in these solvents exhibited the esr signal of the stable T M T t (the tetrazene cation radical) which did not react with cyclohexene. In concentrated sulfuric acid, T M T was decomposed in less than 15 min giving formylidene methylamine and dimethylamine as shown by nmr. In trifluoroacetic acid, the esr signal of tetramethylhydrazine cation radical ( T M H t ) emerged after the TMT solution was irradiated ; no dimethylaminium radical signal could be detected. The relationship of TMTf and TMHC with formation of the observed products remains unclear. Chem. 56, 1657Chem. 56, (1978.On a Ctudie, a I'aide de I'analyse des produits et par etudes spectroscopiques rmn et rpe la decomposition de la tetrarnethyltetrazene-2 (TMT) dans des conditions acides. La photolyse dans I'acetonitrile contenant de I'acide trifluoroacetique conduit a la formation de radical dimethylaminium qui s'additionne d'une f a~o n efficace a la double liaison olkfinique. Quelques produits contenaient une portion (CH3),NCH2-dont le prkcurseur immkdiat serait I'espece CH2N(CH3),+. L'addition photolytique du TMT aux norbornenes conduit a des radicaux norbornyl-2 qui subissent des couplages par les faces exo ou erldo pour conduire a des dimeres. La decomposition thermique dans I'acide sulfurique en presence de toluene conduit aux N,N-dimethyltoluidines, a la N-methylphenethylamine, aux benzyltoluenes et a toute une strie d'autres produits mineurs en plus d'une grande quantitt de formylidene methylamine. Ce dernier conrposk est le produit majeur lorsque la dCcomposition therrnique du TMT est effectuee dans I'acide trifluoroacetique en presence du toluene ou d'anisol; les produits d'amination des substrats aromatiques sont faibles et contiennent uniquement les isomeres orflro et pnrn. Lorsque le TMT est dissous dans ces solvants, il presente un signal rpe correspondant a I'entite T M T t (le radical cation tetraztne) qui ne rtagit pas avec le cyclohexene. Dans l'acide sulfurique co...

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Electron spin resonance study of dialkylamino free radicals in solution

Cited by 60 publications

References 3 publications

Theoretical study of the dimethylamino radical (CH3)2N and its protonated cation (CH3)2NH+

Theoretical study of the dimethylamino radical (CH3)2N and its protonated cation (CH3)2NH+

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

Decomposition of tetramethyl-2-tetrazene under acidic conditions

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