Structure of radicals produced by γ-radiolysis. Part 4. Adamantane matrices doped with various 5-membered heterocyclic molecules

Abstract

D. L. A. CAMPBELL LING. Can. J. Chem. 54, 1971 (1976). The effects of y-radiolysis at room temperature on adamantane and adamantane-dl, matrices doped with 5-membered heterocyclic molecules has been examined by X-band electron spin resonance (esr) spectrometry. Radical structures formed from heterocyclic solute molecules are discussed and tentative assignments made for 2-methyl-, 3-methyl-, and 2,5-dimethylthiophene, 2-methyl-, and 2,5-dimethylfuran. Discussion of possible radical structures derived from furan, tetrahydrofuran, 2-methyl-and 3-methyltetrahydrofuran, 2,5-dihydrofuran, and 4,5-dihydro-2-methylfuran, is included, but unambiguous assignments of structure cannot be made for these compounds from the esr data obtained. Other molecules examined included thiophene, pyrrole, and I-methyl-and 1,2,5-trimethylpyrrole. For these latter molecules, experimentally obtained first derivative X-band esr spectra were too poorly resolved to allow rational discussion of possible structures. It was noted that perdeuterated adamantane matrices provided superior resolution for esr spectra derived from radicals with a delocalized spin center such as ally1 or allenyl species. D. L. WINTERS et A. CAMPBELL LING. Can. J. Chem. 54, 1971Chem. 54, (1976. On a examine par la spectrometrie rpe de la bande X les effets de la radiolyse y, a la temperature de la piece, sur des matrices d'adamantane et d'adamantane-dl, dopees avec des molecules heterocycliques a cinq membres. On discute des structures radicalaires formees a partir des molecules de solutes hetCrocycliques et on fait des attributions non-definitives pour le methyl-2, le methyl-3 et le dimethyl-2,5 thiophtne et le methyl-2 et le dimethyl-2,5 furanne. On inclut aussi une discussion des structures radicalaires possibles pouvant derivees du furanne, du tetrahydrofuranne, des methyl-2 et -3 tetrahydrofuranne, du dihydro-2,5 furanne et du dihydro-4,5 methyl-2 furanne; toutefois on ne peut faire d'attributions non-ambiques pour ces composes a partir des donnees rpe obtenues. Parmi les autres molecules qui ont ete examinees, on note le thiophene, le pyrrole et les methyl-1 et trimethyl-1,2,5 pyrroles. Pour ces dernitres molecules, les premitres derives obtenues expCrimentalement a partir des spectres rpe de la bande X ne sont pas assez bien resolus pour permettre une discussion rationnelle des structures possibles. On a note que les matrices de perdeutiroadamantane fournissent une meilleure resolution pour les spectres rpe derives des radicaux avec un centre de spin delocalise, tels que les esptces allyle et allenyle.[Traduit par le journal]