Alkaline earth metal-assisted dinitrogen activation at nickel

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Dinitrogen (N2) is a stable molecule, making its activation and incorporation into metal complexes challenging.
• Trinuclear metal complexes with bridging ligands offer unique structural and electronic properties.

Purpose of the Study:

• To synthesize and characterize novel trinuclear nickel-dinitrogen complexes with alkaline earth metals.
• To investigate the structural, bonding, and electronic properties of these unique metal-nitrogen frameworks.

Main Methods:

• Reduction of a nickel precursor with elemental magnesium or calcium under dinitrogen atmosphere.
• X-ray crystallography for structural determination.
• Solution and solid-state spectroscopy (e.g., NMR, IR, UV-Vis) for characterization.
• Density Functional Theory (DFT) studies for electronic structure analysis.

Main Results:

• Successful synthesis of two rare trinuclear complexes, {iPr2NNNi(μ-N2)}2M(thf)4 (M = Mg, Ca).
• These complexes feature a linear [Ni-N2-M-N2-Ni] core with bridging end-on dinitrogen ligands.
• Structural and spectroscopic data confirmed the proposed structures and bonding.

Conclusions:

• The study reports the first examples of trinuclear nickel complexes with bridging dinitrogen ligands coordinated to magnesium and calcium.
• DFT calculations provide insights into the electronic structure and bonding interactions within these novel complexes.
• These findings contribute to the understanding of dinitrogen activation and metal-nitrogen bonding in polynuclear systems.