Pd-S-Benzylisothiourea on Fe3O4 magnetic nanoparticles: efficient and reusable nanocatalyst for organic reactions

Palladium is one of the most crucial metals in catalysis and it has been commonly applied as one of the most powerful tools for the organic reactions such as Carbon−Carbon bond formation or organic synthesis. In particular, palladium-catalyzed cross-coupling reactions of aryl halides such as Suzuki and Heck coupling reactions have become a powerful stay in modern synthetic organic chemistry for the preparation of natural products, agrochemicals, pharmaceuticals, biologically active compounds, herbicides, UV screens, preparation of hydrocarbons, polymers, liquid crystal materials and advanced materials [1]. Homogeneous Pd-catalysts have been extensively studied in synthetic organic chemistry because of their higher catalytic activity and selectivity. Removal of palladium from organic products at the end of the reaction is highly desirable because of its high cost and toxicity. Therefore, to combine the advantages of both heterogeneous and homogeneous catalysts, immobilization of homogeneous catalysts on the nanoparticles is the best choice, which efficiently bridges the gap between heterogeneous and homogeneous catalysts. However, the all supporting nanocatalyst have some disadvantages such as difficult or time consuming and expensive separation of fine particles from a reaction mixture. This drawback can be overcome by magnetic nanoparticles, which can be rapidly and easily isolated from the reaction mixture using an external magnet [2]. Herein, we reported a new complex of palladium that immobilized on Fe3O4 MNPs and further used as an excellent nano organometal catalyst for the Suzuki reaction and One-Pot synthesis of polyhydroquinoline derivatives, because polyhydroquinoline derivatives have been reported to possess a wide range of pharmaceutical activities and biological properties [3, 4].