Bis[μ-3-(pyridin-2-yl)pyrazolato]bis-[acetato-(3,5-dimethyl-1H-pyrazole)-nickel(II)]

Area of Science:

• Coordination Chemistry
• Inorganic Chemistry
• Crystallography

Background:

• Dinuclear metal complexes offer unique structural and electronic properties.
• Pyrazole ligands are versatile building blocks in coordination chemistry.
• Nickel(II) complexes are relevant in catalysis and materials science.

Purpose of the Study:

• To synthesize and characterize a novel dinuclear nickel(II) complex.
• To elucidate the crystal structure and coordination environment of the compound.
• To investigate the intermolecular and intramolecular interactions within the crystal lattice.

Main Methods:

• Synthesis of the title compound using nickel(II) acetate tetrahydrate, 3-(pyridin-2-yl)pyrazole (2-PyPzH), 3,5-dimethylpyrazole (Me2PzH), and triethylamine.
• Single-crystal X-ray diffraction analysis at 100 K to determine the crystal structure and symmetry.
• Analysis of coordination environment, including equatorial and axial ligand positioning.
• Identification of hydrogen bonding networks (C-H⋯O and N-H⋯O).

Main Results:

• The title compound, [Ni(μ-OOCCH3)(2-PyPz)(Me2PzH)]2 (1), was successfully synthesized.
• Compound 1 crystallizes in the monoclinic system (P21/n) with crystallographic inversion symmetry.
• The structure features a planar dinuclear Ni(II) core with an N4O2 coordination sphere.
• The nickel atoms are bridged by a deprotonated 2-PyPz ligand, and Me2PzH and acetate ligands occupy axial positions.
• Extensive inter- and intra-molecular hydrogen bonds (C-H⋯O and N-H⋯O) were observed.

Conclusions:

• The successful synthesis and structural determination of the dinuclear nickel(II) complex provide insights into its coordination chemistry.
• The planar Ni2 core and specific ligand arrangement highlight the versatility of pyrazole-based ligands in constructing complex metal architectures.
• The observed hydrogen bonding network plays a crucial role in stabilizing the crystal structure of compound 1.