The effect of added ligands on the reactions of [Ni(COD)(dppf)] with alkyl halides: halide abstraction may be reversible

Megan E. Greaves, Thomas O. Ronson, Feliu Maseras, David J. Nelson

Research output: Contribution to journalArticlepeer-review

1 Downloads (Pure)

Abstract

The reactions of dppf-nickel(0) with alkyl halides proceed via three-coordinate nickel(0) intermediates of the form [Ni(dppf)(L)]. The effects of the identity of the added ligand (L) on catalyst speciation and the rates of reactions of [Ni(COD)(dppf)] with alkyl halides have been investigated using kinetic experiments and density functional theory calculations. A series of monodentate ligands have been investigated in attempts to identify trends in reactivity. Sterically bulky and electron-donating ligands are found to decrease the reaction rate. It was found that (i) the halide abstraction step is not always irreversible and the subsequent recombination of a nickel(I) complex with an alkyl halide can have a significant effect on the overall rate of the reaction and (ii) some ligands lead to very stable [Ni(dppf)(L) 2] species. The yields of prototypical (dppf)nickel-catalyzed Kumada cross-coupling reactions of alkyl halides are significantly improved by the addition of free ligands, which provides another important variable to consider when optimizing nickel-catalyzed reactions of alkyl halides.

Original languageEnglish
Number of pages11
JournalOrganometallics
DOIs
Publication statusPublished - 16 Jun 2021

Keywords

  • nickel
  • homogeneous catalysis
  • cross-coupling
  • reaction mechanisms
  • organometallic chemistry

Fingerprint

Dive into the research topics of 'The effect of added ligands on the reactions of [Ni(COD)(dppf)] with alkyl halides: halide abstraction may be reversible'. Together they form a unique fingerprint.

Cite this