Showing papers by "Dante Macciantelli published in 1997"
TL;DR: In this article, the radical anions from thiobenzophenone, trimethylsilyl)ethanethial and 3,5-di-tert-butylthiobensoyltriphenylsilane were detected by EPR spectroscopy when these compounds were reacted with a number of Grignard reagents, RMgBr.
Abstract: The radical anions from thiobenzophenone, thiobenzoyltriphenylsilane, and 3,5-di-tert-butylthiobenzoyltriphenylsilane were detected by EPR spectroscopy when these compounds were reacted with a number of Grignard reagents, RMgBr. The radical adducts resulting from addition of R• radicals to the thiones were also detected. The formation of the radical anions indicates unambiguously the occurrence of a SET process which might be the initial stage of these reactions. In the case of tris(trimethylsilyl)ethanethial only the radical adducts were detected. The first reduction potentials of these thiones have also been measured in order to verify the feasibility of the SET process. In agreement with the EPR experiments, the calculated standard free energy changes suggest that electron transfer is possible in the first three cases and disfavored with the thioaldehyde.
19 citations
TL;DR: In this paper, the free radicals formed by the reaction of photochemically generated tert-butoxyl radicals with a range of methyl substituted cyclopentenones and cyclohexenones were characterized using paramagnetic resonance.
Abstract: Electron paramagnetic resonance has been used to characterise free radicals formed by the reaction of photochemically generated tert-butoxyl radicals with a range of methyl substituted cyclopentenones and cyclohexenones. The spectra have been interpreted using computer analysis and simulation and assigned to cyclic allylic and alkyl radicals formed by abstraction of a hydrogen atom. The 1-oxocyclohept-2-en-4-yl radical derived by abstraction of bromine from 4-bromocyclohept-2-enone exhibits a temperature dependent EPR spectrum attributed to ring inversion.
6 citations
TL;DR: In this paper, the synthesis and characterisation of a new phosphorylated nitrone belonging to the spiro[indoline-naphthoxazinic] family are described and the results of spin trapping experiments indicate the ability of this photochromic nitrone to react with carbon-, oxygen- and sulfur-centred radicals are also reported.
Abstract: The synthesis and characterisation of a new phosphorylated nitrone belonging to the spiro[indoline-naphthoxazinic] family are described. The results of spin trapping experiments which indicate the ability of this photochromic nitrone to react with carbon-, oxygen- and sulfur-centred radicals are also reported.
4 citations