Atom transfer radical polymerization of methyl methacrylate at ambient temperature using a cationic ruthenium complex

INOR 351

Marc D. Scholten, mdscholt@stanford.edu and Robert M. Waymouth, waymouth@stanford.edu. Department of Chemistry, Stanford University, Stanford, CA 94305
Atom transfer radical polymerization (ATRP) has emerged as an important method for synthesizing living polymers with controlled molecular weights and narrow polydispersities. While many neutral metal complexes are ATRP catalysts, few cationic ATRP catalysts are known. Here we report the activity of complexes with the formula [Cp*Ru(TMEDA)(CH3CN)]+[PF6]- (TMEDA = tetramethylethylenediamine) in the ATRP of methyl methacrylate (MMA) at room temperature. Although polymerization kinetics are well behaved at low conversion, catalyst sequestration by polymer is evident past 50% conversion. Higher conversions are attainable at elevated temperature with some sacrifice of control.