Innenrücktitelbild: Intraligand Charge Transfer Enables Visible‐Light‐Mediated Nickel‐Catalyzed Cross‐Coupling Reactions (Angew. Chem. 46/2022)

Abstract

Die … …v on Ni(Czbpy)Cl 2 ermçglicht Kohlenstoff-Heteroatom-Kreuzkupplungen mit sichtbarem Licht in Abwesenheit exogener Photokatalysatoren. Einzelheiten der Studie werden von Renske M. van der Veen, Arne Thomas,B artholomäus Pieber et al. in ihrem Forschungsartikel beschrieben (e202211433).

Ni‐Catalyzed Photochemical C−N Coupling of Amides with (Hetero)aryl Chlorides

“…[17] For electro-neutral, -rich and -deficient aryl chlorides, the desired aryl amides products were obtained in high yields (4-17). The aryl chlorides bearing electron-withdrawing substituents, such as cyano (11)(12), ester (49), CF 3 (13), and halogen (14-17), gave the desired products in excellent yields. Due to the use of a weak organic base, the cyano-containing amides were obtained in good yields (11)(12).…”

“…The aryl chlorides bearing electron-withdrawing substituents, such as cyano (11)(12), ester (49), CF 3 (13), and halogen (14-17), gave the desired products in excellent yields. Due to the use of a weak organic base, the cyano-containing amides were obtained in good yields (11)(12). Aryl chlorides containing polychlorinated arenes selectively afforded the monosubstituted amides with high yields (15,16,20).…”

“…Complementing the dual catalytic strategy, single Ni(II) catalyst mediated photochemical C−N coupling has been achieved, [10–13] taking the advantage of nickel photochemistry while avoiding the need to use exogenous photocatalyst. In our earlier studies, aryl chlorides were found to exhibit high reactivity and good functional group compatibility in some photochemical C−N coupling reactions under the direct irradiation of a Ni(II)‐bipyridine complex [13a,c–d] .…”

Recent Advance in Single Nickel Photocatalysis for Carbon‐Heteroatom Bond Formation

“…In 2022, Pieber, Thomas, and coworkers reported a new mechanistic model to access active Ni l ‐specie for cross‐coupling. A new bipyridine ligand bearing two carbazole units is mixed with NiCl 2• glyme to afford Ni(Czbbpy)Cl 2 complex, which can cause intraligand charge transfer (ILCT) to generate active Ni I complex for catalysis [24] . The Uv‐vis spectra in combination with time‐dependent density functional theory (TD‐DFT) revealed similar properties of Ni(Czbbpy)Cl 2 specie and unbounded ligand (Czbbpy) including the absorption band, extinction coefficient, and the fluorescence lifetime, which was ascribed to sharing the same origin.…”