title: Enlightening the Mechanism of Copper Mediated PhotoRDRP via High-Resolution Mass Spectrometry.
abstract: The initiation mechanism of photochemically mediated Cu-based reversible-deactivation radical polymerization (photoRDRP) was investigated using pulsed-laser polymerization (PLP) and high-resolution mass spectrometry. The variation of the catalyst composition and ESI-MS analysis of the resulting products provided information on how initiator, ligand, copper species, and monomer are interacting upon irradiation with UV light. A discussion of the results allows for a new postulation of the mechanism of photoRDRP and-for the first time-the unambiguous identification of the initiating species and their interactions within the reaction mixture. One pathway for radical generation proceeds via UV light-induced C-Br bond scission of the initiator, giving rise to propagating radicals. The generation of copper(I) species from copper(II) can occur via several pathways, including, among others, via reduction by free amine ligand in its excited as well as from its ground state via the irradiation with UV light. The amine ligand serves as a strong reducing agent and is likely the main participant in the generation of copper(I) species.
authors.affiliation: †Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 18, 76131 Karlsruhe, Germany.|‡Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Elena
authors.initials: E
authors.lastname: Frick
authors.affiliation: §Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: Athina
authors.initials: A
authors.lastname: Anastasaki
authors.affiliation: §Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: David M
authors.initials: DM
authors.lastname: Haddleton
authors.affiliation: †Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 18, 76131 Karlsruhe, Germany.|‡Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Barner-Kowollik
mesh_terms: D003300:Copper / Q000737:chemistry*; D005609:Free Radicals / Q000138:chemical synthesis / Q000737:chemistry; D007834:Lasers; D013058:Mass Spectrometry; D055668:Photochemical Processes; D058105:Polymerization; D014466:Ultraviolet Rays
chemical_list: D005609:Free Radicals; D003300:Copper