EDA-NOCV Calculation for Efficient N 2 Binding to the Reduced Ni 3 S 8 Complex: Estimation of Ni-N 2 Intrinsic Interaction Energies.

The binding of the dinitrogen molecule to the metal center is the first and crucial step toward dinitrogen activation. Favorable interaction energies are desired by chemists and biochemists to study model complexes in the laboratory. An electrochemically reduced form of a previously isolated sulfur-bridged Ni 3 S 8 complex is inferred to bind N 2 at multiple Ni centers, and this bonded N 2 undergoes reductive protonation to produce hydrazine (N 2 H 4 ) as the product in the presence of a proton donor. Density functional theory (DFT) calculations and quantum theory of atoms in molecules (QTAIM) analysis have been carried out to shed light on the nature of N 2 binding to an anionic trinuclear Ni 3 S 8 complex. Additionally, energy decomposition analysis with the combination of natural orbital for chemical valence (EDA-NOCV) analysis has been performed to estimate the pairwise interaction energies between the Ni center and the N 2 molecule under experimental conditions.