Lewis Acid‐Promoted Oxidative Addition at a [Ni ⁰ (diphosphine) ₂ ] Complex: The Critical Role of a Secondary Coordination Sphere

Oxidative addition represents a critical elementary step in myriad catalytic transformations. Here, the importance of thoughtful ligand design cannot be overstated. In this work, we report intermolecular activation iodobenzene (PhI) at coordinatively saturated 18-electron [Ni0(diphosphine)2] complex bearing Lewis acidic secondary coordination sphere. Whereas alkyl-substituted diphosphine complexes Group 10 are known to unreactive such reactions, show that [Ni0(P2BCy4)2] (P2BCy4=1,2-bis(di(3-dicyclohexylboraneyl)-propylphosphino)ethane) is competent for room-temperature PhI cleavage give [NiII(P2BCy4)(Ph)(I)]. This difference oxidative reactivity has been scrutinized computationally – an outcome borne out ring-opening provide reactive precursor [Ni0(P2BCy4)2], “boron-trapped” 16-electron κ1-diphosphine Ni(0) complex. Moreover, formation [NiII(P2BCy4)(Ph)(I)] inherent P2BCy4 sphere: treatment adduct, [Ni0(P2BCy4)2(DMAP)8] with provides [NiII(P2BCy4)2(DMAP)8(I)]I via iodine-atom abstraction and not [NiII(Ph)(I)(diphosphine)] compound unusual sphere effect. Finally, 4-iodopyridine was surveyed, which resulted pyridyl-borane linked oligomer. The implications these outcomes discussed context designing strongly donating, yet labile ligands use bond relevant catalysis.