title: Two-in-One: λ-Orthogonal Photochemistry on a Radical Photoinitiating System.
abstract: An alkyne functional radical photoinitiator, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl hex-5-ynoate, and evidence that both reactive moieties - the alkyne and the photoinitiator terminus - can be independently addressed with light of disparate wavelength (λ-orthogonality) are introduced. The alkyne functionality is subjected to a visible light (420 nm) induced copper-catalyzed Huisgen reaction, which is employed for the selective functionalization of the initiator with a poly(ethylene glycol) (PEG) chain. This reaction proceeds completely λ-orthogonal in the presence of the UV-reactive photoinitiating moiety. Conversely, it is demonstrated that the alkyne functionality of the photoinitiator is quantitatively orthogonal to UV irradiation emitted by the pulsing action of an excimer laser (351 nm, pulsed-laser polymerization, PLP) and the generated radical species. In turn, the PEGylated initiator can readily be employed as a macrophotoinitiator during PLP. The introduced λ-orthogonally addressable dual functional initiator can be used in a wide range of applications, including surface lithography and post-synthetic modification of photocured materials.
authors.affiliation: Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76133, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Silvana
authors.initials: S
authors.lastname: Hurrle
authors.affiliation: Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76133, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lauer
authors.affiliation: Institut für Funktionelle Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Gliemann
authors.affiliation: Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76133, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Hatice
authors.initials: H
authors.lastname: Mutlu
authors.affiliation: Institut für Funktionelle Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Wöll
authors.affiliation: Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76133, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.|School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, QLD 4000, Brisbane, Australia.
authors.forename: Anja S
authors.initials: AS
authors.lastname: Goldmann
authors.affiliation: Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76133, Karlsruhe, Germany.|Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.|School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, QLD 4000, Brisbane, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Barner-Kowollik
mesh_terms: D000480:Alkynes / Q000737:chemistry; D002384:Catalysis; D008027:Light; D010777:Photochemistry; D014466:Ultraviolet Rays
chemical_list: D000480:Alkynes
keywords: copper-catalyzed azide-alkyne cycloaddition (CuAAC); functional radical initiator; light induced chemistry; pulsed laser polymerization; λ-orthogonality