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Intramolecular hydrogen bond in alkoxyamines. Influence on the C-ON bond homolysis
Paul Brémond1, Teddy Butscher, Valérie Roubaud
1Aix-Marseille Université , CNRS, Institut de Chimie Radicalaire UMR7273, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France.
Abstract:
The C-ON bond homolysis in alkoxyamines can be influenced by the presence of an intramolecular hydrogen bond (IHB) between the alkyl and the nitroxyl fragments, which leads to an 8-fold decrease in the homolysis rate constant k(d). When the IHB is disrupted by the solvent or by substitution of the hydrogen involved in the IHB by a protecting group (OMe, OAc, OBz, OBn, or OTBDMS), a higher homolysis rate constant k(d) is observed, as expected from the correlations developed by Marque (Bertin, D.; Gigmes, D.; Marque, S.; Tordo, P. Macromolecules 2005, 38, 2638-2650). Results were confirmed by DFT calculations at the B3LYP/6-31G(d,p) level.
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