Publication
869
J. Am. Chem. Soc. 141 (1), 89–93, 2019
DOI:10.1021/jacs.8b11262
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Elucidation of a Redox-Mediated Reaction Cycle for Nickel-Catalyzed Cross Coupling
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Rui Sun, Yangzhong Qin, Serge Ruccolo, Christoph Schnedermann, Cyrille Costentin, and Daniel G. Nocera
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
Laboratoire d’Electrochimie Moléculaire, Unité Mixte de Recherche Université − CNRS No. 7591, Bâtiment Lavoisier, Université Paris Diderot, Sorbonne Paris Cité, 15 rue Jean de Baïf, 75205 Paris Cedex 13, France
A reaction cycle for redox-mediated, Ni-catalyzed aryl etherification is proposed under both photoredox and electrochemically mediated conditions. We demonstrate that a self-sustained Ni(I/III) cycle is operative in both cases by chemically synthesizing and characterizing a common paramagnetic Ni intermediate and establishing its catalytic activity. Furthermore, deleterious pathways leading to off-cycle Ni(II) species have been identified, allowing us to discover optimized conditions for achieving self-sustained reactivity at a 15-fold increase in the quantum yield and a 3-fold increase in the faradaic yield. These results highlight the importance of leveraging insight of complete reaction cycles for increasing the efficiency of redox-mediated reactions.. |
