Additive-Free Synthesis of Poly(phenylene oxide):  Aerobic Oxidative Polymerization in a Base-Condensed Dendrimer Capsule

The additive-free synthesis of poly(phenylene oxides) by aerobic oxidation was achieved using a copper complex in a dendritic phenylazomethine structure. The outer shell composed of Schiff base units assists the catalytic function of the inner Cu complex moiety. It is important that the hybrid structure should be designed with a rigid architecture not to deactivate the catalytic center. Due to the rigid π-conjugating structure of the phenylazomethine dendrimer, the metal center can retain its fine conformation. This catalyst drastically decreased the total waste required to produce the PPO derivatives and provided a new approach to green polymerization.