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

Abstract

A polymeric network grafted on the magnetite nanoparticles (Fe 3 O 4 @PAAÀ PPh 3 ) 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 Fe 3 O 4 @PAAÀ PPh 3 nanoplatform for loading Pd(II), Fe 3 O 4 nanoparticles (NPs) functionalized with amines were coupled to polyacrylic acid (PAA), polyethylene amine (PEI) and triphenyl phosphine (PPh 3 ) sequentially using the HBTU-DIEA coupling method. The Pd(II)-loaded Fe 3 O 4 @PAAÀ PPh 3 catalyst showed better activity toward the representative Mizoroki-Heck type coupling reactions. The catalytic activity of Fe 3 O 4 @PAAÀ PPh 3 loaded with palladium was compared with the available homogenous and heterogeneous catalyst systems. This comparison seemed to suggest that Pd(II)-loaded Fe 3 O 4 @PAAÀ PPh 3 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.

Nickel ferrite decorated noble metal containing nitrogen-doped carbon nanotubes as potential magnetic separable catalyst for dinitrotoluene hydrogenation

“…In the case of nanostructured catalysts, this requires some separation step (filtration, centrifugation), which is not efficient due to the small particle size 12 . Nanoparticles with magnetic properties (iron oxides, ferrites) have the particle size and surface polarity to ensure adequate dispersion stability during the hydrogenation process 13 , 14 . Another major advantage is that they can be separated from the liquid phase by a magnetic field, allowing the catalyst to be easily recovered after the synthesis 15 , 16 .…”