Photocatalyzed iron-based ATRP of methyl methacrylate using 1,3-dimethyl-2-imidazolidinone as both solvent and ligand
Photochemistry serves as a wonderful means to facilitate various chemical reactions and is indeed unique in its powerful ability to meet the energetic requirements for conducting processes that would not be accomplished using thermal counterparts. In this work, a novel photocatalyzed Fe-based atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was performed under UV irradiation, using ethyl 2-bromophenylacetate (EBPA) as the initiator, FeBr2 as the catalyst and 1,3-dimethyl-2-imidazolidinone (DMI) as both the solvent and ligand. The rate of the polymerization was relatively fast, as monomer conversion reached 91.2% at room temperature under UV irradiation (900 μW cm−2) at 360 nm within 26 h. Even when the target degree of polymerization was up to 1000, the molecular weight distribution obtained remained narrow and the molecular weight (Mn,GPC) was close to the corresponding theoretical value (Mn,th). The polymerization kinetics was studied in detail and the “living” features of this system were confirmed by performing successful chain extension experiments.