Highly Tolerant Living/Controlled Anionic Polymerization of Dialkyl Acrylamides Enabled by Zinc Triflate/Phosphine Lewis Pair

Living polymerizations of polar vinyl monomers have been successful for decades. However, they still suffer the following challenges: fast propagation, air-moisture tolerance, and negligible side reactions even at elevated temperatures. Here, we developed an unprecedented polymerization that overcomes these limitations using a Lewis pair catalyst. The anionic polymerization of dialkyl acrylamides proceeded in a living/controlled matter using Zn(OTf)2/PPh3 within a wide temperature range of 25-100 °C for short times (1-10 min) even under open-air conditions. The recovery and reuse of Zn(OTf)2 without loss of polymerization activity were observed to be possible. The polymerization was retarded by excess Zn(OTf)2, the additive methanol, and water, indicating equilibriums of the propagating species with them. The putative propagating zinc triflate-ate complex was tolerant to the protic additives and significantly selective for the propagation.