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Updated: Oct 23, 2025

Thermochemical Studies of NiII and ZnII Ternary Complexes Using Ion Mobility-Mass Spectrometry
Published on: June 8, 2022
Monovalent Nickel-Mediated Radical Formation: A Concerted Halogen-Atom Dissociation Pathway Determined by
1Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States.
Abstract:
The recent success of nickel catalysts in stereoconvergent cross-coupling and cross-electrophile coupling reactions partly stems from the ability of monovalent nickel species to activate C(sp3) electrophiles and generate radical intermediates. This electroanalytical study of the commonly applied (bpy)Ni catalyst elucidates the mechanism of this critical step. Data rule out outer-sphere electron transfer and two-electron oxidative addition pathways. The linear free energy relationship between rates and the bond-dissociation free energies, the electronic and steric effects of the nickel complexes and the electrophiles, and DFT calculations support a variant of the halogen-atom abstraction pathway, the inner-sphere electron transfer concerted with halogen-atom dissociation. This mechanism accounts for the observed reactivity of different electrophiles in cross-coupling reactions and provides a mechanistic rationale for the chemoselectivity obtained in cross-electrophile coupling over homocoupling.
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