A way to prepare magnetically separable palladium nanocatalysts active in Heck reaction—SI-RAFT/MADIX polymerization for modification of magnetic nanoparticles

In terms of sustainable and “green” chemistry, recovery and reuse of the catalysts plays an important role. Easily recoverable heterogeneous catalysts are now a highly studied topic. Considering it, we have investigated magnetic iron oxide nanoparticles covered by polymeric shells with random structures as solid support for palladium catalysts. Polymerizable imidazolium derivative was synthesized to form imidazolium salt (N-heterocyclic carbene precursor) with an unsaturated vinyl bond. Subsequently, two different palladium salts were used to form palladium complexes on the solid surface. Two catalyst forms were produced depending on the palladium salt used: catalysts with N-heterocyclic carbene-palladium complexes and palladium nanoparticles (formed in situ, without the application of any reductive agent). Synthesized complexes were tested on their activity toward the Heck cross-coupling reaction, and the recyclability of chosen ones was also studied. The obtained polymeric-inorganic hybrids were characterized using FT-IR spectroscopy, SEM/EDX and TEM microscopy, XRD diffraction, and TGA thermal analyses.