A dinuclear nickel(I) dinitrogen complex and its reduction in single-electron steps.

Area of Science:

• Inorganic chemistry
• Organometallic chemistry
• Nitrogen fixation

Background:

• Nitrogen gas (N(2)) is abundant but inert, posing a challenge for its chemical activation.
• Developing catalysts for N(2) activation is crucial for sustainable ammonia synthesis and nitrogen-based chemical production.
• Nickel complexes are explored as potential catalysts due to their diverse reactivity.

Purpose of the Study:

• To investigate the capability of beta-diketiminato nickel(I) complex fragments in activating N(2).
• To explore the role of electron reduction in further activating the coordinated N(2) molecule.
• To characterize the structure of the reduced nickel-nitrogen complex.

Main Methods:

• Synthesis of beta-diketiminato nickel(I) complex fragments.
• Coordination of dinitrogen (N(2)) to the nickel center.
• Electrochemical reduction of the coordinated N(2) complex in two single-electron steps.
• Structural characterization of the singly reduced complex using X-ray crystallography.

Main Results:

• Beta-diketiminato nickel(I) complex fragments successfully coordinate and activate N(2).
• The coordinated N(2) can be reduced stepwise, with the singly reduced species showing enhanced N-N bond activation.
• The structure of the singly reduced complex reveals a mu-eta(1):eta(1)-bound N(2) ligand.

Conclusions:

• Nickel(I) complexes featuring beta-diketiminato ligands are effective in initiating N(2) activation.
• Stepwise electrochemical reduction provides a pathway to further weaken and activate the N-N bond.
• This work offers insights into electron-mediated N(2) bond cleavage mechanisms relevant to nitrogen fixation.