Synthesis of Poly(phenylene ethynylene) Using an Easily Recyclable Pd-Functionalized Magnetite Nanoparticle Catalyst

An easily recyclable catalyst has already been used in several cross-coupling reactions, resulting in many advantages compared to commonly used homogeneous catalysts. Despite all these implementations of such removable catalysts, they have never been employed in the synthesis of conjugated polymers. Therefore, a Pd-functionalized magnetite nanoparticle catalyst was successfully synthesized and implemented in the synthesis of poly­(phenylene ethynylene). Polymerization was performed using either an AB-monomer or A₂/B₂ monomers, and it occurred in a classical step-growth fashion. M_n values greater than 10 kg/mol were obtained. Because of the presence of magnetite nanoparticles, the catalyst could be removed and reused up to five times using magnetic precipitation. In addition, it reduces the amount of impurities present in the polymer, as a result of the presence of the Pd catalyst, up to 10 times, compared to a commonly used homogeneous catalysts such as Pd­(PPh₃)₄.