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

Completing a series of nickel-group 13 complexes, a coordinatively unsaturated nickel-boron complex and its derivatives with a H 2 , N 2 , 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 H 2 basicity during deprotonation to form the hydride. The boron metalloligand indirectly distorts the Ni geometry to facilitate H 2 binding and stabilizes a reactive anionic Ni hydride via a direct Ni-B interaction.