Intramolecular proton transfer (IPT) in alkoxyamine: a theoretical investigation.

The Intramolecular Proton Transfer (IPT) in alkoxyamines is one of the main factors determining the process of Nitroxide Mediated Polymerization (NMP). Recently, we proposed an experimental approach to study IPT and applied it to a series of alkoxyamines. It was found that IPT dramatically depends on the structure of the alkoxyamine, but it was not clear which factors are significant for IPT (M. V. Edeleva et al., J. Polym. Sci., Part A: Polym. Chem. 2009, 47, 6579-6595). To understand the mechanism and the factors determining the IPT process, in this article we investigate the geometrical parameters and thermokinetics of this reaction using the BMK/6-311++G(3df,3pd)//B3LYP/6-31+G(d,p) method. It was found that the thermokinetics and geometrical parameters of the transition state (TS) for IPT do not depend on the alkoxyamine structure. The only factor which determines the occurrence of IPT is the position of the TS energy level of the C-ON bond homolysis.