A mesoionic carbene stabilized nickel(II) hydroxide complex: a facile precursor for C-H activation chemistry

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Coordination Chemistry

Background:

• Nickel(II) complexes are crucial in catalysis and materials science.
• Developing novel ligands is key to unlocking new reactivity in metal complexes.
• Tridentate ligands offer unique coordination environments for metal centers.

Purpose of the Study:

• To synthesize and characterize a novel nickel(II) hydroxide complex.
• To explore the reactivity of the new complex with various substrates.
• To investigate the potential of the complex in C-C bond formation and cleavage reactions.

Main Methods:

• Synthesis of nickel(II) hydroxide complex 2 via a stepwise extraction protocol.
• Characterization of complex 2 and its derivatives using spectroscopic techniques.
• Reaction of complex 2 with a range of E-H and C-H acidic compounds, silylated substrates, malonic acid dimethyl ester, and acetonitrile.

Main Results:

• High-yield synthesis of nickel(II) hydroxide complex 2 supported by a tridentate triazolylidene-carbazolid ligand.
• Complex 2 exhibits high basicity, enabling deprotonation/desilylation reactions.
• Synthesis of diverse functionalized nickel(II) complexes with trimethylsilylolate, trityl sulfide, tosyl amide, azido, pyridine, acetylide, fluoroarene, and enolate ligands.
• Complex 2 participates in Knoevenagel-type condensation and reacts with acetonitrile to form new complexes, demonstrating potential in C-C bond formation and cleavage.

Conclusions:

• The synthesized nickel(II) hydroxide complex is a highly basic and versatile reagent.
• The complex serves as a platform for generating a variety of novel functionalized nickel(II) complexes.
• The reactivity of complex 2 highlights its potential in synthetic organic chemistry, particularly in C-C bond formation and cleavage reactions.