Showing papers by "Dante Macciantelli published in 1998"
TL;DR: In this article, five new phosphoryldithioformates bearing different substituents on the phosphoryl group have been synthesised and exploited as spin trapping agents in ESR experiments.
10 citations
TL;DR: In this article, the addition of silyl and germyl radicals to a series of substituted cyclopentenones and cyclohexenones has been investigated using EPR spectroscopy.
Abstract: The addition of silyl and germyl radicals to a series of substituted cyclopentenones and cyclohexenones has been investigated using EPR spectroscopy. At low temperatures the 3-position is the preferred site for addition unless it is substituted or sterically hindered in which case addition occurs at the carbonyl oxygen. The latter process is also favoured at higher temperatures but no evidence has been obtained for either addition at the 2-position or for an intramolecular migration following initial attack at the 3- or 2-position.
5 citations
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.