Aluminum Tralen Complex Meditated Reversible-Deactivation Radical Polymerization of Vinyl Acetate

Area of Science:

• Polymer Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Reversible-deactivation radical polymerization (RDRP) is crucial for synthesizing polymers with controlled architectures.
• Developing efficient catalysts for RDRP of diverse vinyl monomers remains an active research area.

Purpose of the Study:

• To synthesize and characterize a new aluminum complex, Al(III)(tralen)Cl.
• To investigate the efficacy of Al(III)(tralen)Cl in mediating the RDRP of various vinyl monomers.
• To elucidate the mechanism of RDRP controlled by the aluminum complex.

Main Methods:

• Synthesis and characterization of the Al(III)(tralen)Cl complex.
• RDRP of vinyl acetate (VAc) and N-vinylpyrrolidone (NVP) using Al(III)(tralen)Cl.
• Polymerization of acrylates and styrene with Al(III)(tralen)Cl.
• Electron paramagnetic resonance (EPR) spectroscopy to study radical species.

Main Results:

• Al(III)(tralen)Cl successfully mediated the RDRP of VAc and NVP, exhibiting living polymerization characteristics.
• Controlled molecular weight increase with conversion and block copolymer formation were observed for VAc and NVP.
• Limited control was achieved in the polymerization of conjugated monomers like acrylates and styrene.
• EPR studies indicated the formation of a paramagnetic dormant species via single-electron transfer to the tralen ligand.

Conclusions:

• The Al(III)(tralen)Cl complex is an effective mediator for the RDRP of specific vinyl monomers, showcasing living polymerization behavior.
• The polymerization control is dependent on the monomer type, with limitations observed for conjugated monomers.
• The mechanism involves the formation of a paramagnetic dormant species, highlighting the role of single-electron transfer.