Projects per year
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.
- homogeneous catalysis
- reaction mechanisms
- organometallic chemistry
- 2 Finished
1/10/17 → 14/09/21
Project: Research Studentship Case - Internally allocated
Data for: "The Effect of Added Ligands on the Reactions of [Ni(COD)(dppf)] with Alkyl Halides: Halide Abstraction May Be Reversible"
Reactions of nickel(0) with organochlorides, organobromides, and organoiodides: mechanisms and structure/reactivity relationshipsGreaves, M. E., Johnson Humphrey, E. L. B. & Nelson, D. J., 7 May 2021, In: Catalysis Science and Technology. 11, 9, p. 2980-2996 17 p.
Research output: Contribution to journal › Review article › peer-reviewOpen AccessFile
Unexpected nickel complex speciation unlocks alternative pathways for the reactions of alkyl halides with dppf-nickel(0)Greaves, M. E., Ronson, T. O., Lloyd-Jones, G. C., Maseras, F., Sproules, S. & Nelson, D. J., 18 Sep 2020, In: ACS Catalysis. 10, 18, p. 10717-10725 9 p.
Research output: Contribution to journal › Article › peer-reviewOpen AccessFile