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  • Author or Editor: V. Belevsky x
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Abstract  

ESR spectra for -irradiated at 77 K solutions /0.02–16%/ of tetramethylurea /TMU/ in CFCl3 and Freon-113 have been studied. TMU+. radical cations radiolytically produced in dilute solutions have been shown to undergo intramolecular hydrogen transfer upon photobleaching resulting in CH2N= type radical. Evidence for intermolecular proton transfer in TMU+. radical cations after annealing to phase transition temperature /110–120 K/ in Freon-113 was obtained. Primary radical cations of TMU+. at their ground state take part in ion-molecular reaction via proton transfer. Molecular cations in their excited states may undergo fragmentation producing Me2N radicals, which were trapped in liquid phase by t-BuNO as a spin trap.

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Abstract  

ESR spectra of -irradiated, at 77 K, acetone and CH3COEt solutions /0.1–22%/ in CFCl3 were studied. The yields of monomer and dimer radical cations of ketones and RCHCOCH3 radicals depend on ketone concentration in CFCl3. When exposed to light the dimeric radical cations are transformed into RCHCOMe, while the monomeric radical cations disappear without further radical production. Different types of solid phase ion-molecular reaction for monomer and dimer radical cations are discussed.

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Abstract  

The radiolysis of some esters /formates and acetates/ has been studied both in liquid and in solid states using a number of different spin traps. Specific deuteration was applied to elucidate the mechanism of radical formation. The radicals were found to result from the reactions of ester radical cations, radical anions and excited molecules. Evidence for intramolecular rearrangement in the radical cations of esters in condensed phase was obtained.

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Abstract  

ESR spectra for -irradiated, at –196 °C, solution of Me2NH, Me3N, and EtNH2 in CFCl3 /0.05÷100% amine/ have been studied. Radical cations Me2NH+., Me3N+. and EtNH 2 +. were trapped in dilute solutions /less than 1% amine in CFCl3/. The yields of radical cations decrease and those of neutral radicals /Me2 N, CH2NMe2, Et NH/ correspondingly increase as the amine concentration increases. Radical cations Me2NH+. are transformed to Me2 N as well as Me3N+. to C H2NMe2 via proton transfer reaction, which is described by the reaction volume model.

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