Initiators for Continuous Activator Regeneration Atom Transfer Radical Polymerization of Methyl Methacrylate and Styrene with -Heterocyclic Carbene as Ligands for Fe-Based Catalysts.

Iron-based -heterocyclic carbene (FeX(NHC)) complexes were used in initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP). A series of ICAR ATRPs of methyl methacrylate (MMA) and styrene (St) were carried out using FeX(IDipp) where IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene with X = Cl () or Br () and FeX(HIDipp) (HIDipp =1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene) with X = Cl () or Br (). The polymerizations showed good activity, resulting in polymers with controlled molecular weights and narrow molecular weight distribution (MWD) with low loading of catalysts (50 ppm). In particular, and generated polymers with narrower MWD. For example, ICAR ATRP of MMA with 50 ppm catalysts () after 24 h at = 60 °C in 50% v/v anisole resulted in PMMA with / = 1.20 at 65% monomer conversion. ICAR ATRP of St after 72 h resulted in PSt with / = 1.15 at 53% monomer conversion.