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Author: Gräfe, Stefanie × Author: Kupfer, Stephan × DDC: 540 × Type: Text × WGL Institute: IPHT ×

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    Light-responsive paper strips as CO-releasing material with a colourimetric response
    (Cambridge : RSC Publishing, 2017) Reddy G., Upendar; Liu, Jingjing; Hoffmann, Patrick; Steinmetzer, Johannes; Görls, Helmar; Kupfer, Stephan; Askes, Sven H. C.; Neugebauer, Ute; Gräfe, Stefanie; Schiller, Alexander
    Carbon monoxide (CO) is known for its multifaceted role in human physiology, and molecules that release CO in a controlled way have been proposed as therapeutic drugs. In this work, a light-responsive CO-releasing molecule (CORM-Dabsyl) showed a strong colourimetric response upon photochemical CO-release, owing to the tight conjugation of a Mn(i) tricarbonyl centre to a dabsyl chromophoric ligand (L). Whereas the complex was very stable in the dark in nitrogen-purged aqueous media, CO-release was effectively triggered using 405 nm irradiation. CORM-Dabsyl, L and the inactive product iCORM-Dabsyl have been investigated by DFT and TD-DFT calculations. Only mild toxicity of CORM-Dabsyl was observed against LX-2 and HepaRG® human cell lines (IC50 ∼ 30 μM). Finally, to develop a CO storage and release material that is readily applicable to therapeutic situations, CORM-Dabsyl was loaded on low-cost and easily disposable paper strips, from which the light triggered CO-release was conveniently visible with the naked eye.
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    An artificial photosynthetic system for photoaccumulation of two electrons on a fused dipyridophenazine (dppz)-pyridoquinolinone ligand
    (Cambridge : RSC Publishing, 2018) Lefebvre, Jean-François; Schindler, Julian; Traber, Philipp; Zhang, Ying; Kupfer, Stephan; Gräfe, Stefanie; Baussanne, Isabelle; Demeunynck, Martine; Mouesca, Jean-Marie; Gambarelli, Serge; Artero, Vincent; Dietzek, Benjamin; Chavarot-Kerlidou, Murielle
    Increasing the efficiency of molecular artificial photosynthetic systems is mandatory for the construction of functional devices for solar fuel production. Decoupling the light-induced charge separation steps from the catalytic process is a promising strategy, which can be achieved thanks to the introduction of suitable electron relay units performing charge accumulation. We report here on a novel ruthenium tris-diimine complex able to temporarily store two electrons on a fused dipyridophenazine-pyridoquinolinone π-extended ligand upon visible-light irradiation in the presence of a sacrificial electron donor. Full characterization of this compound and of its singly and doubly reduced derivatives thanks to resonance Raman, EPR and (TD)DFT studies allowed us to localize the two electron-storage sites and to relate charge photoaccumulation with proton-coupled electron transfer processes.