title: Chemically triggered C-ON bond homolysis in alkoxyamines. Part 2: DFT investigation and application of the pH effect on NMP.
abstract: In recent work, a 15-fold increase in the C-ON 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.
authors.affiliation: International Tomography Center, Institutskaya 3A, 630090 Novosibirsk, Russia.
authors.forename: Elena
authors.initials: E
authors.lastname: Bagryanskaya
authors.affiliation: Aix-Marseille Université, case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille cedex 20, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Brémond
authors.affiliation: International Tomography Center, Institutskaya 3A, 630090 Novosibirsk, Russia.
authors.forename: Mariya
authors.initials: M
authors.lastname: Edeleva
authors.affiliation: Aix-Marseille Université, case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille cedex 20, France. sylvain.marque@univ-provence.fr.
authors.forename: Sylvain R A
authors.initials: SR
authors.lastname: Marque
authors.affiliation: International Tomography Center, Institutskaya 3A, 630090 Novosibirsk, Russia.
authors.forename: Dmitriy
authors.initials: D
authors.lastname: Parkhomenko
authors.affiliation: Aix-Marseille Université, case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille cedex 20, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Roubaud
authors.affiliation: Aix-Marseille Université, case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille cedex 20, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Siri
mesh_terms: D017666:Deuterium Oxide / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008956:Models, Chemical; D011725:Pyridines / Q000737:chemistry*; D020058:Styrene / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D011725:Pyridines; D020058:Styrene; D017666:Deuterium Oxide