Abstract: | A series of salen–Co (III )(X) complexes tethering quaternary ammonium salts are designed to investigate the influence of the axial group X in the complex and the anion Y of quaternary ammonium salt on the copolymerization of CO2 and PO . By copolymerization, the complex 9 , where X and Y are both 2,4‐dinitrophenolate, has the highest catalytic efficiency. When X is OAc and Y is BF4 −/NO3 −, the complexes 11/12 have lower catalytic efficiency. For the complex 10 , where X and Y are both OAc , the catalytic efficiency is the lowest. At the same time, complex 9 can produce the copolymer with the highest carbonate fraction and M n. And the best copolymerization conditions were as follows: reaction temperature 30°C, copolymerization time 24 h, and CO2 pressure 2 MPa with complex 9 . The thermal properties of the copolymers are also studied by differential scanning calorimetry (DSC) and thermogravimetry (TG) . |