Light controlled reactivity of copper(I) and copper(II) complexes: Unique opportunities for photoredox catalysis via inner sphere mechanisms
Final Report Abstract
Photoredox-catalysis utilizes, by and large, ruthenium- or iridium-based complexes as catalysts, belonging to the scarcest metals on our planet. Making use of earth-abundant transition metal complexes faces the challenge of short excited-state lifetimes, significantly limiting the probability of intermolecular electron-transfer processes. Moreover, 3d-transition metal complexes, in contrast to their higher 4d- and 5d-homologs, are highly dynamic concerning ligand exchange, which is seen as a disadvantage due to the lack of defined photocatalytic active species. In this project, we investigated if this dynamic behavior can be turned into an advantage by opening the possibility of substrates directly interacting with copper complexes, and this way, opening new avenues for photoredox catalysis. We were successful in characterizing Cu(I)- and Cu(II)-substrate intermediates that are relevant for underlying photocatalyzed transformations. Especially we could show that Cu(II)-chloride complexes undergo light-induced metal-ligand homolysis on a time scale of <100 fs, thus pushing back the limits required for excited-state lifetimes, which opens not only the door for copper-, but also for iron-complexes having typical excited-state lifetimes in the picosecond range, to become suitable photocatalysts.
Publications
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Copper Makes the Difference: Visible Light-Mediated Atom Transfer Radical Addition Reactions of Iodoform with Olefins. ACS Catalysis, 10(17), 9899-9906.
Engl, Sebastian & Reiser, Oliver
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Direct Evidence of Visible Light-Induced Homolysis in Chlorobis(2,9-dimethyl-1,10-phenanthroline)copper(II). The Journal of Physical Chemistry Letters, 11(13), 5345-5349.
Fayad, Remi; Engl, Sebastian; Danilov, Evgeny O.; Hauke, Cory E.; Reiser, Oliver & Castellano, Felix N.
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Visible‐Light‐Induced Homolysis of Earth‐Abundant Metal‐Substrate Complexes: A Complementary Activation Strategy in Photoredox Catalysis. Angewandte Chemie International Edition, 60(39), 21100-21115.
Abderrazak, Youssef; Bhattacharyya, Aditya & Reiser, Oliver
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Copper(ii)-photocatalyzed decarboxylative oxygenation of carboxylic acids. Chemical Communications, 58(28), 4456-4459.
Reichle, Alexander; Sterzel, Hannes; Kreitmeier, Peter; Fayad, Remi; Castellano, Felix N.; Rehbein, Julia & Reiser, Oliver
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Copper(I) Photocatalyzed Bromonitroalkylation of Olefins: Evidence for Highly Efficient Inner‐Sphere Pathways. Angewandte Chemie International Edition, 62(16).
Reichle, Alexander; Koch, Magdalena; Sterzel, Hannes; Großkopf, Lea‐Joy; Floss, Johannes; Rehbein, Julia & Reiser, Oliver
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Copper Photocatalyzed Divergent Access to Organic Thio- and Isothiocyanates. ACS Catalysis, 14(7), 4847-4855.
Abderrazak, Youssef & Reiser, Oliver
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Wacker-type oxidation of styrenes with Markovnikov selectivity using copper as a site-selective sequential photooxidant–photoreductant. Catalysis Science & Technology, 14(14), 4068-4074.
Abderrazak, Youssef; Chinchole, Anurag & Reiser, Oliver
