A d 10 Ni–(H 2 ) Adduct as an Intermediate in HH Oxidative Addition across a NiB Bond

Bifunctional EH activation offers a promising approach for the design of two‐electron‐reduction catalysts with late first‐row metals, such as Ni. To this end, we have been pursuing H 2 activation reactions at late‐metal boratranes and herein describe a diphosphine–borane‐supported Ni—(H 2 ) complex, [( Ph DPB i Pr )Ni(H 2 )], which has been characterized in solution. 1 H NMR spectroscopy confirms the presence of an intact H 2 ligand. A range of data, including electronic‐structure calculations, suggests a d 10 configuration for [( Ph DPB i Pr )Ni(H 2 )] as most appropriate. Such a configuration is highly unusual among transition‐metal H 2 adducts. The nonclassical H 2 adduct is an intermediate in the complete activation of H 2 across the NiB interaction. Reaction‐coordinate analysis suggests synergistic activation of the H 2 ligand by both the Ni and B centers of the nickel boratrane subunit, thus highlighting an important role of the borane ligand both in stabilizing the d 10 Ni—(H 2 ) interaction and in the H—H cleavage step.