Oxidative Addition and β‐Hydride Elimination by a Macrocyclic Dinickel Complex: Observing Bimetallic Elementary Reactions

Abstract

AbstractThe dinickel(I) complex Ni2(tBuPONNOPONNO), featuring a planar macrocyclic diphosphoranide ligand tBuPONNOPONNO, offers a unique architectural platform for observing bimetallic elementary reactions. Oxidative addition reactions of alkyl halides produce dinickel(II) complexes of the type Ni2(μ‐R)(μ‐X)(tBuPONNOPONNO). However, when R=Et β‐hydride elimination is observed to form a dinickel monohydride, with the rate dependent on the nature of X. DFT studies suggest a new mechanism for bimetallic β‐hydride elimination, where the rate dependence arises from the steric pressure imposed by the X group on the opposing trans face of the dinickel macrocycle. This work enhances understanding of bimetallic elementary reactions, particularly β‐hydride elimination, which have not been well‐explored for dinuclear systems.