Cavedon, C.; Gisbertz, S.; Reischauer, S.; Vogl, S.; Sperlich, E.; Burke, J.H.; Wallick, R.F.; Schrottke, S.; Hsu, W.H.; Anghileri, L.; Pfeifer, Y.; Richter, N.; Teutloff, C.; Müller-Werkmeister, H.; Cambié, D.; Seeberger, P.H.; Vura-Weis, J.; van der Veen, R.M.; Thomas, A.; Pieber, B.: Intraligand Charge Transfer Enables Visible-Light-Mediated Nickel-Catalyzed Cross-Coupling Reactions. Angewandte Chemie - International Edition 61 (2022), p. e202211433/1-10
10.1002/anie.202211433
Open Accesn Version
Abstract:
We demonstrate that several visible-light-mediated carbon heteroatom cross-coupling reactions can be carriedout using a photoactive Ni(II) precatalyst that forms in situ from a nickel salt and a bipyridine ligand decorated with two carbazole groups (Ni(Czbpy)Cl2). The activation of this precatalyst towards cross-coupling reactions follows a hitherto undisclosed mechanism that is different from previously reported light-responsive nickel complexes that undergo metal-to-ligand charge transfer. Theoretical and spectroscopic investigations revealed that irradiation of Ni(Czbpy)Cl2 with visible light causes an initial intraligand charge transfer event that triggers productive catalysis. Ligand polymerization affords a porous, recyclable organic polymer for heterogeneous nickel catalysis of cross-coupling reactions. The heterogeneous catalyst shows stable performance in a packed-bed flow reactor during a week of continuous operation.