Copolymerizations of 2-(dimethylamino)ethyl methacrylate with (methyl)acrylates initiated by a neutral Pd(II)-based complex

The copolymerization reactions of 2-(dimethylamino)ethyl methacrylate (DMAEMA) with methyl methacrylate (MMA), butyl methacrylate (n-BMA), methyl acrylate (MA), and butyl acrylate (n-BA), respectively, by an environmentally stable palladium acetylide Pd(PPh₃)₂(CCPh)₂ (PPP) have been investigated. PPP shows relatively high catalytic activity for these copolymerizations. Reactivity ratios of these copolymerizatins have been measured and calculated by the Kelen-Tüdös method for the first time, and their values are as follows: (1) r_DMAEMA=1.13, r_MMA=1.07; (2) r_DMAEMA=0.77, r_n-BMA=0.84; (3) r_DMAEMA=1.54, r_MA=0.09; (4) r_DMAEMA=0.71, r_n-BA=0.14. The mechanism of these copolymerizations was discussed and a radical mechanism was proposed.