Collect. Czech. Chem. Commun. 2004, 69, 2223-2238

Long-Range Polar Effect on the C-ON Bond Homolysis in (tert-Butyl[1-(diethylphosphonyl)-2,2-dimethylpropyl]aminoxyl) SG1-Based Alkoxyamines

Denis Bertin, Didier Gigmes, Sylvain R. A. Marque*, Stephan Milardo, Jérôme Peri and Paul Tordo

Université de Provence, UMR 6517 case 542, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France


Alkoxyamines and persistent nitroxyl radicals are important regulators of nitroxide-mediated radical polymerization. Because the polymerization times decrease with the increasing rate constant of the homolysis of the C-ON bond between the polymer chain and the nitroxyl moiety, the factors influencing the cleavage rate constant are of considerable interest. Because alkyl acrylate monomers are among the most used in polymerization, we present the measures of the rate constants (kd) of the C-ON bond cleavage for new SG1 based alkoxyamine models containing para-substituted aromatic acrylates (4-XC6H4OC(O)C(Me)H-SG1). It appears that the values of kd increase with the electron-withdrawing properties of the para-substituent groups (4-X) of the ester SG1-based alkoxyamines.

Keywords: Universal electrical effect; SG1-based alkoxyamines; Living/controlled polymerization; Polar molecular state effect; Homolysis rate constants; Radical polymerization.

References: 72 live references.