A series of stable 2,2-disubstituted 3-(phenylimino)indol-1-oxyls, the alkoxyamines 3. were prepared, characterized, and tested as possible candidates in controlled radical polymerization (CRP). The sturctures of 3d and 10 were additionally solved by X-ray diffraction. The lability of the N-O(C) and (N)O-C bonds of compounds 3 were compared, and the possibility of N-O vs. O-C bond cleavage was evaluated by thermal degradation, ESR spin trapping, MS experiments, and DFT calculations. Alkoxyamines with a primary- or secondary-alkyl group bound to the O-atom of the nitroxide function (hexyl and i-Pr) mainly underwent (undesired) N-O bond homolysis. When the O-alkyl radical was a tertiary or a benzyl group (crotonyl or styryl), O-C bond cleavage occurred as the main process, thus suggesting a possible use of these compounds in CRP processes.
Alkoxyamines of Stable Aromatic Nitroxides: N-O vs. C-O Bond Homolysis / D., Gigmes; A., Gaudel Siri; S. R. A., Marque; D., Bertin; P., Tordo; P., Astolfi; L., Greci; Rizzoli, Corrado. - In: HELVETICA CHIMICA ACTA. - ISSN 0018-019X. - 89(2006), pp. 2312-2326. [10.1002/hlca.200690215]
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