Palladium nanoparticles immobilized on magnetic methionine-functionalized chitosan: A versatile catalyst for Suzuki and copper-free Sonogashira reactions of aryl halides at room temperature in water as only solvent

The preparation of an efficient heterogeneous catalyst system based on the immobilization of palladium nanoparticles on a magnetic nanoparticle core (ImmPd(0)-MNPs) is described. The new catalytic system was characterized using transmission and scanning electron microscopies, X-ray diffraction, energy-dispersive X-ray and Fourier transform infrared spectroscopies, thermogravimetric analysis, vibrating sample magnetometry and inductively coupled plasma analysis. We have demonstrated that ImmPd(0)-MNPs is an efficient and reusable catalyst for the Suzuki-Miyaura and Sonogashira coupling reactions of various types of aryl halides in water as a green and environmentally acceptable solvent. Moreover, the reactions were carried out efficiently at room temperature. The catalyst was easily separated using an external magnet from the reaction mixture and recycled ten times without significant loss of activity.