Pd(II)-Functionalized Polymeric Shell Encapsulated on Magnetite Nanocatalysts for C−C Coupling Reactions

A polymeric network grafted on the magnetite nanoparticles (Fe₃O₄@PAA−PPh₃) were found to aggregate in the form a cotton-ball like morphology, which exhibited a good loading of Pd(II) generally used as homogeneous catalyst in many coupling reactions. To prepare the Fe₃O₄@PAA−PPh₃ nanoplatform for loading Pd(II), Fe₃O₄ nanoparticles (NPs) functionalized with amines were coupled to polyacrylic acid (PAA), polyethylene amine (PEI) and triphenyl phosphine (PPh₃) sequentially using the HBTU-DIEA coupling method. The Pd(II)-loaded Fe₃O₄@PAA−PPh₃ catalyst showed better activity toward the representative Mizoroki-Heck type coupling reactions. The catalytic activity of Fe₃O₄@PAA−PPh₃ loaded with palladium was compared with the available homogenous and heterogeneous catalyst systems. This comparison seemed to suggest that Pd(II)-loaded Fe₃O₄@PAA−PPh₃ had higher turnover frequency, which could be a potential alternative to the existingnanoplatforms for loading homogeneous catalysts in terms of not only better turnover number and turnover frequency but also improved recyclability.