title: New core-pyrene π structure organophotocatalysts usable as highly efficient photoinitiators.
abstract: Eleven di- and trifunctional compounds based on a core-pyrene π structure (Co_Py) were synthesized and investigated for the formation of free radicals. The application of two- and three-component photoinitiating systems (different Co_Pys with the addition of iodonium or sulfonium salts, alkyl halide or amine) was investigated in detail for cationic and radical photopolymerization reactions under near-UV-vis light. The proposed compounds can behave as new photocatalysts. Successful results in terms of rates of polymerization and final conversions were obtained. The strong MO coupling between the six different cores and the pyrene moiety was studied by DFT calculations. The different chemical intermediates are characterized by ESR and laser flash photolysis experiments. The mechanisms involved in the initiation step are discussed, and relationships between the core structure, the Co_Py absorption property, and the polymerization ability are tentatively proposed.
authors.affiliation: Institut de Science des Matériaux de Mulhouse IS2M - UMR 7361 - UHA; 15, rue Jean Starcky, F-68057 Mulhouse Cedex, France.
authors.forename: Sofia
authors.initials: S
authors.lastname: Telitel
authors.forename: Frédéric
authors.initials: F
authors.lastname: Dumur
authors.forename: Thomas
authors.initials: T
authors.lastname: Faury
authors.forename: Bernadette
authors.initials: B
authors.lastname: Graff
authors.forename: Mohamad-Ali
authors.initials: MA
authors.lastname: Tehfe
authors.forename: Didier
authors.initials: D
authors.lastname: Gigmes
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Fouassier
authors.forename: Jacques
authors.initials: J
authors.lastname: Lalevée
keywords: cationic photopolymerization; free-radical-promoted cationic photopolymerization; photocatalysts; photoinitiators; radical photopolymerization