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Alkoxyamines of Stable Aromatic Nitroxides: NO vs. CO Bond Homolysis

2006; Wiley; Volume: 89; Issue: 10 Linguagem: Inglês

10.1002/hlca.200690215

1522-2675

Didier Gigmes, Anouk Gaudel‐Siri, Sylvain R. A. Marque, Denis Bertin, Paul Tordo, Paola Astolfi, Lucedio Greci, Corrado Rizzoli,

Polymer composites and self-healing

Abstract 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.