Facilely Recyclable Cu(II) Macrocomplex with Thermoregulated Poly(ionic liquid) Macroligand: Serving as a Highly Efficient Atom Transfer Radical Polymerization Catalyst

Copolymer poly­(ionic liquids) (PILs) are fascinating new polymerized polyelectrolytes that can provide the properties of ionic liquids with others combined into one. In this work, a thermoregulated random copolymer PIL (PILL) with the side chains of both ionic liquids and atom transfer radical polymerization (ATRP) ligands was designed and synthesized to form a macrocomplex with CuBr₂ and serve as an ATRP catalyst to establish a thermoregulated phase separated catalysis (TPSC) system and further applied in a typical ICAR (initiators for continuous activator regeneration) ATRP process for the catalyst separation and recycling in situ for the first time. This novel TPSC system could simultaneously recycle transition metal catalyst and ligand easily just by changing temperature from polymerization temperature to room temperature. Additionally, even if the highly efficient recyclable PILL with Cu catalyst was separated facilely and reused 10 times in situ, it nearly did not sacrifice the controllability over polymerization. Furthermore, after polymerization and a TPSC process, the metal catalyst residual in the polymer solution phase remained just about 1.5 ppm, indicating highly efficient transition metal catalyst recycling efficiency.