Coordination chemistry with phosphine and phosphine oxide-substituted hydroxyferrocenes

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Catalysis

Background:

• Ferrocene derivatives are versatile ligands in organometallic chemistry.
• Unsymmetrical ferrocenes offer unique structural and electronic properties.
• Hydroxyferrocenes are valuable precursors for coordination complexes.

Purpose of the Study:

• Synthesize novel unsymmetrical hydroxyferrocenes.
• Explore the coordination chemistry of these ligands with transition metals (Pd, Rh, Group 4).
• Evaluate the catalytic activity of the resulting complexes in ethylene polymerization.

Main Methods:

• Synthesis of hydroxyferrocenes via lithiation and functionalization of dibromoferrocene.
• Coordination reactions with palladium, rhodium, and group 4 metal precursors.
• Characterization of complexes using spectroscopic and crystallographic methods.
• Testing catalytic performance in ethylene polymerization.

Main Results:

• Successfully synthesized new unsymmetrical hydroxyferrocenes.
• Obtained diverse palladium and rhodium complexes, including dinuclear species and chelating/pendant ligand arrangements.
• Investigated coordination with group 4 metals, observing chelating and pendant phosphine binding modes.
• Identified complexes as low to moderately active ethylene polymerization catalysts.
• Observed catalyst instability and short lifetimes, evidenced by residues in polymer products.

Conclusions:

• New hydroxyferrocene ligands provide access to novel organometallic complexes.
• These complexes exhibit limited but measurable activity in ethylene polymerization.
• Catalyst instability significantly impacts their practical application and lifetime.
• Further development is needed to enhance catalyst stability and performance.