Chemically Triggered C-ON Bond Homolysis in Alkoxyamines. Part 2: DFT Investigation and Application of the pH Effect on NMP

Paul Brémond (1) , Mariya Edeleva (2) , Sylvain R.A. Marque (1) , Dmitriy Parkhomenko (3) , Valérie Roubaud (1) , Didier Siri (1) , Elena Bagryanskaya (3)

1 ICR - Institut de Chimie Radicalaire
2 RAS, SB, NN Vorozhtsov Novosibirsk Inst Organ Chem,
3 NSU - Novosibirsk State University

In recent work, a 15-fold increase in the CON bond homolysis rate constant kd of 4-pyridylethyl-SG1-based alkoxyamine was observed upon protonation of the pyridyl moiety in organic solvent. In this report, the pH dependence of kd (pKa = 4.7) is investigated in D2O/CD3OD (v/v 1:1). A 64-fold increase in kd is observed at acidic pH. Calculations show that the increase in kd upon protonation is due to both an increase in the stabilization of the protonated 4-pyridylethyl radical and an increase of the destabilization of the starting materials through an increase in the polarity of the alkyl fragment. This new alkoxyamine is applied to NMP of styrene and sodium styrene sulfonate.

Domains: Theoretical and/or physical chemistry

Paul Brémond, Mariya Edeleva, Sylvain R.A. Marque, Dmitriy Parkhomenko, Valérie Roubaud, et al.. Chemically Triggered C-ON Bond Homolysis in Alkoxyamines. Part 2: DFT Investigation and Application of the pH Effect on NMP. Macromolecular Rapid Communications, 2012, 33 (2), pp.152--157. ⟨10.1002/marc.201100590⟩. ⟨hal-01415191⟩