Ligand-free, recyclable palladium-functionalized magnetite nanoparticles as a catalyst in the Suzuki-, Sonogashira, and Stille reaction

A magnetically reusable ligand-free Fe3O4 palladium functionalized catalyst system was successfully prepared without the use of reducing agents, but by making use of the reduction potential of magnetite. The stabilizer was variated depending on the investigated reaction, whereby poly(ethylene glycol) (PEG) stabilized nanoparticles were used for the Suzuki reaction, as it requires protic conditions, while oleic acid stabilized nanoparticles were used for the Sonogashira and Stille reaction. It was found that it was possible to perform the Suzuki reaction and the Sonogashira reaction resulting in good to excellent conversions under air. Despite the good results for the Suzuki and the Sonogashira reaction it was not possible to perform the Stille reaction using this easily synthesized catalyst system due to the poisoning of the reusable catalyst by the tin-compound. Furthermore, the reusable catalyst system was recycled and reused for five times, resulting in a separable, straightforward and less time-consuming catalyst system. (C) 2019 Elsevier B.V. All rights reserved.