Toggling the Z-type interaction off-on in nickel-boron dihydrogen and anionic hydride complexes

Abstract

Completing a series of nickel-group 13 complexes, a coordinatively unsaturated nickel-boron complex and its derivatives with a H₂, N₂, or hydride ligand were synthesized and characterized. The toggling “on” of a Ni(0)–B(III) inverse-dative bond enabled the stabilization of a nickel-bound anionic hydride with a remarkably low thermodynamic hydricity of kcal mol⁻¹ in THF. The flexible topology of the boron metalloligand confers both favorable hydrogen binding affinity and strong hydride donicity, albeit at the cost of high H₂ basicity during deprotonation to form the hydride.