Ni(I)-TPA stabilization by hydrogen bond formation on the second coordination sphere: a DFT characterization

Ni(I) compounds are less common than those of either Ni(0) or Ni(II). Recently, a series of Ni(I) tris(2-pyridylmethyl)amine (TPA) complexes were synthetized through the reduction of Ni(II)-TPA complexes and their stabilization was attributed to the formation of H-bonds (Chem. Commun., 2021, 57, 753-756). Because of the growing relevance of Ni(I) complexes in the field of catalysis, we targeted density functional theory simulations to fully characterize the Ni(I) and Ni(II) TPA complexes and understand the role of H-bonding in the stability of Ni(I)-TPA complexes. Our results prove the important contribution of H-bonding in the stability of TPA-Ni(I)-F complexes, which is estimated to increase the Ni(I)-F strength by about 6 to 15 kcal mol^-1.