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Author: Dietzek, Benjamin × End date: 2022 × Start date: 2022 × End date: 2024 × Start date: 2020 × DDC: 540 × DDC: 660 ×

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    Quinoline Photobasicity: Investigation within Water-Soluble Light-Responsive Copolymers
    (Weinheim : Wiley-VCH, 2021) Sittig, Maria; Tom, Jessica C.; Elter, Johanna K.; Schacher, Felix H.; Dietzek, Benjamin
    Quinoline photobases exhibit a distinctly higher pKa in their electronically excited state than in the ground state, thereby enabling light-controlled proton transfer reactions, for example, in molecular catalysis. The absorption of UV light translates to a pKa jump of approximately 10 units, as established for small-molecule photobases. This contribution presents the first synthesis of quinoline-based polymeric photobases prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization. The integration of quinolines as photobase chromophores within copolymers offers new possibilities for light-triggered proton transfer in nanostructured materials, that is, in nanoparticles, at surfaces, membranes and interfaces. To exploit the light-triggered reactivity of photobases within such materials, we first investigated how the ground- and excited-state properties of the quinoline unit changes upon polymer integration. To address this matter, we combined absorption and emission spectroscopy with time-resolved transient-absorption studies to reveal photoinduced proton-transfer dynamics in various solvents. The results yield important insights into the thermodynamic and kinetic properties of these polymeric quinoline photobases. © 2020 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH
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    1,7,9,10-Tetrasubstituted PMIs Accessible through Decarboxylative Bromination: Synthesis, Characterization, Photophysical Studies, and Hydrogen Evolution Catalysis
    (Weinheim : Wiley-VCH, 2020) Costabel, Daniel; Skabeev, Artem; Nabiyan, Afshin; Luo, Yusen; Max, Johannes B.; Rajagopal, Ashwene; Kowalczyk, Daniel; Dietzek, Benjamin; Wächtler, Maria; Görls, Helmar; Ziegenbalg, Dirk; Zagranyarski, Yulian; Streb, Carsten; Schacher, Felix H.; Peneva, Kalina
    In this work, we present a new synthetic strategy for fourfold-substituted perylene monoimides via tetrabrominated perylene monoanhydrides. X-ray diffraction analysis unveiled the intramolecular stacking orientation between the substituents and semicircular packing behavior. We observed the remarkable influence of the substituent on the longevity and nature of the excited state upon visible light excitation. In the presence of poly(dehydroalanine)-graft-poly(ethylene glycol) graft copolymers as solubilizing template, the chromophores are capable of sensitizing [Mo3S13]2− clusters in aqueous solution for stable visible light driven hydrogen evolution over three days. © 2020 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH
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    Covalent Linkage of BODIPY-Photosensitizers to Anderson-Type Polyoxometalates Using CLICK Chemistry
    (Weinheim : Wiley-VCH, 2021) Cetindere, Seda; Clausing, Simon T.; Anjass, Montaha; Luo, Yusen; Kupfer, Stephan; Dietzek, Benjamin; Streb, Carsten
    The covalent attachment of molecular photosensitizers (PS) to polyoxometalates (POMs) opens new pathways to PS-POM dyads for light-driven charge-transfer and charge-storage. Here, we report a synthetic route for the covalent linkage of BODIPY-dyes to Anderson-type polyoxomolybdates by using CLICK chemistry (i. e. copper-catalyzed azide-alkyne cycloaddition, CuAAC). Photophysical properties of the dyad were investigated by combined experimental and theoretical methods and highlight the role of both sub-components for the charge-separation properties. The study demonstrates how CLICK chemistry can be used for the versatile linkage of organic functional units to molecular metal oxide clusters. © 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH