ESR spin-trap study of radicals present during the thermolysis of some di-tert-alkyl peroxides

Mekarbane, Pierre G.; Tabner, Brian J.

doi:10.1002/(sici)1097-458x(1998110)36:11<826::aid-omr377>3.0.co;2-1

Cited by 26 publications

(29 citation statements)

References 3 publications

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“…Thermolysis in benzene, between 333 and 353 K, in the presence of DMPO resulted in the spectrum of only one adduct with parameters characteristic of the DMPO adduct of the tert-butoxyl radical (see Table 1 for hyperfine parameters). 12,19 The spectral intensity of this adduct was such that the adducts of radicals 6 and 7, observed during the thermolysis of 2, were not detected.…”

Section: Thermolysis Of Tert-butylperoxy-335-trimethylhexanoate (3)mentioning

confidence: 54%

“…One of these had the characteristic hyperfine parameters of the methyl radical adduct, formed viaˇ-scission of the tertbutoxyl radical. 12,23 The remaining three adducts were the same as those observed in the experiments during the thermolysis of 2. These were the nitroxyl and anilino adducts of a primary carbon-centred (assigned to radical 7) and an anilino adduct of a tertiary carbon-centred radical (again probably formed following abstraction of the methine proton from the parent peroxide).…”

Section: Thermolysis Of Tert-butylperoxy-335-trimethylhexanoate (3)mentioning

confidence: 97%

“…We selected the symmetric bis(3,5,5-trimethylhexanoyl) peroxide (2) in anticipation that thermolysis should initially produce two identical acyloxyl moieties (but no alkoxyl moiety) and the closely related tert-butylperoxy-3,3,5-trimethylhexanoate (3) which (during thermolysis) would be expected to produce the same acyloxyl moiety as 2 and the tertbutoxyl radical whose reactions during the thermolysis of several peroxides have been reported in detail. 6,12 The remaining two peroxides selected were tert-amylperoxy-2-ethylhexanoate (4) and the bifunctional peroxide 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane (5), both of which might be expected to produce the same acyloxyl moiety as one another.…”

Section: Introductionmentioning

confidence: 94%

“…The major adduct was that of the methyl radical, formed viaˇ-scission of the tert-butoxyl radical. 12,22 Two other adducts were those of the tert-butoxyl radical itself and its associated 'unassigned' radical, the latter always being observed (in our experiments) during the thermolysis of any peroxide which releases the tert-butoxyl radical in the presence of PBN or PBN-d 14 . 12,19 The fourth adduct was that of a primary carbon-centred radical (characterized by coupling to two equivalent -protons) which we assign to the PBNd 14 adduct of radical 7.…”

Section: Thermolysis Of Tert-butylperoxy-335-trimethylhexanoate (3)mentioning

confidence: 99%

“…This spin-trap can give both nitroxyl and anilino adducts the latter by attack at the oxygen atom of the nitroso group. 6,12 Unfortunately, although the number of interactingˇ-protons in anilino adducts indicate whether the original radical was a primary, secondary or tertiary C-centred species, it is difficult to obtain information on the exact structure of the original radical within each category because of the broad lines and similarity in the hyperfine parameters associated with their adducts. In addition to their broader hyperfine lines, anilino adducts are characterized by a slightly lower g-factor than that of the corresponding nitroxyl adduct.…”

Section: Introductionmentioning

confidence: 99%

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ESR spin-trap study of the radicals present during the thermolysis of some novel alkyl peroxy esters

Mekarbane

Tabner

2000

Magn. Reson. Chem.

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Section: Thermolysis Of Tert-butylperoxy-335-trimethylhexanoate (3)mentioning

confidence: 54%

Section: Thermolysis Of Tert-butylperoxy-335-trimethylhexanoate (3)mentioning

confidence: 97%

Section: Introductionmentioning

confidence: 94%

Section: Thermolysis Of Tert-butylperoxy-335-trimethylhexanoate (3)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

ESR spin-trap study of the radicals present during the thermolysis of some novel alkyl peroxy esters

Mekarbane

Tabner

2000

Magn. Reson. Chem.

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ESR of newβ-phosphorus nitroxides from aldo- and keto-nitrones

Haire

Janzen

Hrvoic³

1999

Magn. Reson. Chem.

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This investigation deals mainly with the synthesis of new phosphorus–nitroxide free radicals. Nitroxides with a β‐31P group were synthesized from the aldo‐nitrones α‐phenyl‐N‐tert‐butylnitrone and 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO) as well as the keto‐nitrones 2,5,5‐trimethyl‐1‐pyrroline‐N‐oxide (2,5,5‐M3PO) and 2‐phenyl‐5,5‐dimethyl‐1‐pyrroline‐N‐oxide (2‐Ph‐DMPO). Three different routes were explored. The first two routes involved nitronyl spin trapping of phosphorus‐centred radicals generated thermally or photochemically by hydrogen abstraction by tert‐butoxyl radicals from di‐tert‐butyl peroxyoxalate or from photoexcited benzophenone, respectively. The third approach used the addition of phosphorus anions (generated by the strong, hindered base lithium diisopropylamide) to the nitrones and subsequent one‐electron oxidation to the corresponding nitroxides. The most novel feature of the work presented here may be the synthesis of β‐phosphoranyl [P(OR)4] nitroxide spin adducts. For comparison purposes the related β‐phosphityl [P(O)(OR)2] nitroxides were also assembled and characterized by ESR spectroscopy. Copyright © 1999 John Wiley & Sons, Ltd.

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ESR spin-trap study of the radicals present during the thermolysis of some bis(tert-alkylperoxy)alkanes and bis(tert-alkylperoxy)cycloalkanes

Mekarbane

Tabner

2000

Magn. Reson. Chem.

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The thermolysis of three bis(tert‐alkylperoxy)alkanes and two 1,1‐bis(tert‐alkylperoxy)cycloalkanes was undertaken at various temperatures between 333 and 383 K and the radicals generated trapped employing DMPO, DEPMPO, PBN‐d14 and TTBNB. The appropriate tert‐alkoxyl radical was trapped during the thermolysis of all five peroxides and underwent β‐scission to give the appropriate alkyl radical and ketone. Although the appropriate ‘sister’ O‐centred 1‐(tert‐alkylperoxy)alkoxyl radicals (3) were not trapped, adducts of the radicals derived from them via β‐scission were observed. The ethyl radical was trapped during the thermolysis of 2,2‐bis(tert‐butylperoxy)butane (1a) and the ethoxycarbonylmethyl radical during the thermolysis of both ethyl‐3,3‐bis(tert‐butylperoxy)butyrate (1b) and ethyl 3,3‐bis(tert‐amylperoxy)butyrate (1c), thus establishing the thermolysis scheme for these bis(tert‐alkylperoxy)alkanes. In the case of 1,1‐bis(tert‐butylperoxy)cyclohexane (2a) it has been established that the sister O‐centred [1‐(tert‐butylperoxy)cyclohexyl]oxyl radical (6a) undergoes a rapid ring‐opening reaction to give the 5‐(tert‐butylperoxycarbonyl)pentyl radical (7a). Copyright © 2000 John Wiley & Sons, Ltd.

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ESR spin-trap study of radicals present during the thermolysis of some di-tert-alkyl peroxides

Cited by 26 publications

References 3 publications

ESR spin-trap study of the radicals present during the thermolysis of some novel alkyl peroxy esters

ESR spin-trap study of the radicals present during the thermolysis of some novel alkyl peroxy esters

ESR of newβ-phosphorus nitroxides from aldo- and keto-nitrones

ESR spin-trap study of the radicals present during the thermolysis of some bis(tert-alkylperoxy)alkanes and bis(tert-alkylperoxy)cycloalkanes

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