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Alkoxyamines of Stable Aromatic Nitroxides: NO vs. CO Bond Homolysis
Author(s) -
Gigmes Didier,
GaudelSiri Anouk,
Marque Sylvain R. A.,
Bertin Denis,
Tordo Paul,
Astolfi Paola,
Greci Lucedio,
Rizzoli Corrado
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690215
Subject(s) - homolysis , chemistry , bond cleavage , alkyl , nitroxide mediated radical polymerization , lability , radical , medicinal chemistry , polymerization , spin trapping , nitroxyl , photochemistry , polymer chemistry , radical polymerization , organic chemistry , polymer , catalysis
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 NO(C) and (N)OC bonds of compounds 3 were compared, and the possibility of NO vs. OC 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) NO bond homolysis. When the O ‐alkyl radical was a tertiary or a benzyl group (crotonyl or styryl), OC bond cleavage occurred as the main process, thus suggesting a possible use of these compounds in CRP processes.