Development of New Atom Transfer Radical Polymerization System by Iron (III)-Metal Salts Without Using any External Initiator and Reducing Agent

Atom transfer radical polymerization (ATRP) catalyzed by high oxidation state metal salts of FeX₃ is developed for the first time in the absence of both external initiator and reducing agent. Methyl methacrylate (MMA) and styrene are polymerized successfully using FeX₃/Phosphorous ligands with well-controlled molecular weight distributions (=1.5). The molecular weight of the polymers increases with monomer consumption with the progress of time and the polymerization behaviors show a decent ATRP trend. Activators and initiators are suggested to generate in situ by the addition reaction of MMA and one equivalent of FeX₃. The PMMA synthesized from without-initiator system is characterized by ¹H, ¹³C and DEPT (distortionless enhancement by polarization transfer nuclear magnetic resonance) nuclear magnetic resonance spectroscopy. Chain extension and copolymerization experiments prove the livingness of the obtained polymer. Methyl methacrylate (MMA) is polymerized successfully using FeX ₃/Phosphorous ligands in the absence of external alkyl halide initiators and reducing agents. The study shows that the radical could be formed by an addition of MMA with one equivalent of FeX₃, which may help to initiate the polymerization. The molecular weight of the polymer increases with monomer consumption with a decent atom transfer radical polymerization trend.