Living Radical Polymerization of N,N-Dimethylacrylamide with RuCl2(PPh3)3-Based Initiating Systems

N,N-Dimethylacrylamide (DMAA) was radically polymerized with RuCl2(PPh3)3 in conjunction with an alkyl halide (R−X; X = Br, Cl) as an initiator in the presence of Al(Oi-Pr)3 in toluene at 60−80 °C, where the polymerizations were much faster than that of methacrylates. Specifically with bromides as initiators [CCl3Br, CH3CH(CONMe2)Br, (CH3)2C(CONMe2)Br, and (CH3)2C(CO2Et)Br], the Ru(II) complex induced living radical polymerization of DMAA to give polymers with controlled molecular weights and relatively narrow molecular weight distributions (M̄ w/M̄ n ∼ 1.6). Similar living polymerizations were also possible for N,N-diethylacrylamide. 1H NMR analysis of the obtained polymers showed that the polymerization proceeds via activation of the C−Br terminal originating from the bromide initiators by the ruthenium complex.