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Metallo-supramolecular photocleavable gels based on ruthenium complexes / eingereicht von DI Sabrina Theis
AutorInnenTheis, Sabrina
Beurteiler / BeurteilerinMonkowius, Uwe ; Hild, Sabine
Betreuer / BetreuerinMonkowius, Uwe
ErschienenLinz, 2017
Umfangviii, 99 Blätter : Illustrationen
HochschulschriftUniversität Linz, Dissertation, 2017
Bibl. ReferenzOeBB
Schlagwörter (GND)Polymere / Supramolekül / Gel / Fotochemie / Abspalten / Rutheniumkomplexe
URNurn:nbn:at:at-ubl:1-19713 Persistent Identifier (URN)
 Das Werk ist gemäß den "Hinweisen für BenützerInnen" verfügbar
Metallo-supramolecular photocleavable gels based on ruthenium complexes [14.58 mb]
Zusammenfassung (Englisch)

The spatiotemporal controlled cleavage of molecules has become of enormous interest in the recent years. In particular, the photochemical manipulation of supramolecular polymers offers a broad field of applications, ranging from drug delivery to photolithography. The two most common ways to link the photoresponsive units to the polymers are the following: the attachment of the photolabile group as pendant group and the incorporation of the photolabile group into the main-chain of the polymer. Within this work, photoactive ruthenium-based complexes and additionally their linkage to polymer chains are presented. [Ru(bpy)2(4AMP)2](PF6)2, with 4-(aminomethyl)pyridine (4AMP) as photocleavable ligand, was incorporated into polymers to obtain supramolecular urea-organo- and hydrogels. Upon irradiation with visible and near infrared irradiation degelation occurs due to the cleavage of the pyridine-ruthenium bond. Since the metallogels are stable in the dark, the gels can be spatiotemporal micropatterned with a photomask. Ruthenium containing poly(4-vinylpyridine) (P4VP) gels show a similar behavior. Herein, the ruthenium complex acts as photoresponsive crosslinker and again the cleavage of the pyridine-ruthenium bond leads to degelation. In the dark the urea gels show a comparative long-term stability. However, the ruthenium containing P4VP gels additionally present a self-healing behavior. The gel becomes liquid upon irradiation with visible light. By heating the reaction mixture at 80 C the gel is obtained again. These gelation/degelation cycles can be repeated up to 10 times. Another concept for photocleavable polymers is the attachment of photosensitive coumarin moieties to polyphosphazenes. The cleavage of the coumarin units upon irradiation with visible light leads to the degradation of the polyphosphazene into small molecules due to better access of water to the hydrolytically labile polymer backbone.

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