The Effect of Oxygen to Salen-Co Complexes for the Copolymerization of PO/CO2

A series of Salen-Co(II) complexes were synthesized to study the effect of O(2)on the catalytic performance of Salen-Co complexes for the copolymerization of PO/CO2. The Salen-Co(II) complexes showed low activity on the cyclo-addition of CO(2)to PO with the aid of a cocatalyst such as PPNCl. Unexpectedly, with the addition of O-2, the activity of Salen-Co(II) complexes was obviously increased and 100% cyclic carbonate was obtained. As the pressure of O(2)increased, the activity of the complex also increased. With the existence of O-2, the activity of the complexes was influenced by their structures and the pressure of O-2, and the complexes with the conjugated structure showed higher activity. The structures of cocatalyst also played a crucial role as for the change of the activity. By altering the electrophilicity of Salen-Co(III), O(2)can also be used as cocatalyst for the copolymerization of PO/CO2.