title: Emission turn-on and solubility turn-off in conjugated polymers: one- and two-photon-induced removal of fluorescence-quenching solubilizing groups.
abstract: The synthesis of highly efficient two-photon uncaging groups and their potential use in functional conjugated polymers for post-polymerization modification are reported. Careful structural design of the employed nitrophenethyl caging groups allows to efficiently induce bond scission by a two-photon process through a combination of exceptionally high two-photon absorption cross-sections and high reaction quantum yields. Furthermore, π-conjugated polyfluorenes are functionalized with these photocleavable side groups and it is possible to alter their emission properties and solubility behavior by simple light irradiation. Cleavage of side groups leads to a turn-on of the fluorescence while solubility of the π-conjugated materials is drastically reduced.
authors.affiliation: Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120, Heidelberg, Germany.
authors.forename: Korwin M
authors.initials: KM
authors.lastname: Schelkle
authors.forename: Steffy
authors.initials: S
authors.lastname: Becht
authors.forename: Shirin
authors.initials: S
authors.lastname: Faraji
authors.forename: Martin
authors.initials: M
authors.lastname: Petzoldt
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.forename: Tiago
authors.initials: T
authors.lastname: Buckup
authors.forename: Andreas
authors.initials: A
authors.lastname: Dreuw
authors.forename: Marcus
authors.initials: M
authors.lastname: Motzkus
authors.forename: Manuel
authors.initials: M
authors.lastname: Hamburger
mesh_terms: D005449:Fluorenes / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D009578:Nitrobenzenes / Q000737:chemistry; D009596:Nitrophenols / Q000737:chemistry*; D010782:Photolysis; D058105:Polymerization; D011108:Polymers / Q000737:chemistry; D012995:Solubility
chemical_list: D005449:Fluorenes; D005456:Fluorescent Dyes; D009578:Nitrobenzenes; D009596:Nitrophenols; D011108:Polymers
keywords: conjugated polymers; fluorene; fluorescence quenching; photon-induced cleavage