Direct P-functionalization of azobenzene by a cationic phosphidozirconocene complex

Area of Science:

• Organometallic Chemistry
• Zirconium Chemistry
• Ligand Development

Background:

• Zirconocene complexes are versatile organometallic compounds.
• Azobenzene is a well-known organic molecule with diverse reactivity.
• Development of novel ligands is crucial for catalysis and materials science.

Purpose of the Study:

• To investigate the reaction between a cationic phosphidozirconocene complex and azobenzene.
• To elucidate the mechanism of the observed transformation.
• To synthesize and characterize new zirconium complexes and intermediates.

Main Methods:

• Reaction of [(η(5)-C5H5)2Zr(PCy2)][CH3B(C6F5)3] with azobenzene.
• Characterization of the resulting zirconium complex (2) and intermediate σ(H) adduct (1) using Nuclear Magnetic Resonance (NMR) spectroscopy.

Main Results:

• The reaction efficiently yields a zirconium complex (2) featuring a tridentate PNN ligand.
• A σ(H) adduct intermediate (1) was successfully characterized.
• The reaction mechanism involves cooperative nucleophilic substitution of hydrogen.

Conclusions:

• The study demonstrates a new synthetic route to zirconium complexes with PNN ligands.
• The cooperative nucleophilic substitution of hydrogen mechanism is proposed and supported by intermediate characterization.
• This work expands the known reactivity of phosphidozirconocene complexes.