A Phosphine-ß-diketiminate Nickel(I)-Complex for Small Molecule Activation

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Catalysis

Background:

• Subvalent nickel complexes are valuable in catalysis.
• Diketiminate ligands offer tunable electronic and steric properties.

Purpose of the Study:

• To synthesize and characterize a novel subvalent Ni(I) complex.
• To investigate the reactivity and small molecule activation capabilities of the Ni(I) complex.

Main Methods:

• Synthesis of a bis(diphenyl)-phosphine functionalized ß-diketimine ligand (PNac-H).
• Formation of the tetradentate PNNP-type Ni(I) complex [PNac-Ni].
• Characterization using single crystal X-ray diffraction, NMR, IR spectroscopy, and elemental analysis.

Main Results:

• A square planar Ni(I) complex stabilized by a tetradentate PNNP ligand was successfully synthesized.
• The Ni(I) complex demonstrated activation of small molecules including CH2X2 (X=Br, I), I2, and Ph2E2 (E=S, Se).
• Ligand design facilitated stabilization of the reactive Ni(I) species and enabled activation via hemilabile coordination and accessible axial sites.

Conclusions:

• The novel PNac-H ligand effectively stabilizes a reactive Ni(I) center.
• The Ni(I) complex exhibits significant small molecule activation potential, driven by its electronic properties and coordination environment.