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Fe 3 O 4 @SiO 2 @propyltriethoxysilane@o-phenylendiamine as an environmentallybenign functionalized silica-coated magnetic organometallic nanomaterial has been synthesized and characterized by Fourier transforms infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) images and energy dispersive X-ray (EDX) and vibrating sample magnetometer (VSM) analyses. Then, its catalytic activity was investigated for the one-pot three-component condensation reaction between dimedone, malononitrile and various substituted aromatic aldehydes to afford the corresponding 2-amino-4H-chromene derivatives under mild reaction conditions. This nanocatalyst can be easily recovered from the reaction mixture by using a magnet and reused for at least five times without significant decrease in catalytic activity.

Objective: Herein, a novel heterogeneous catalytic system constructed of iron oxide and palladium nanoparticles is presented. Firstly, a convenient synthetic pathway for the preparation of this catalytic system is introduced, then the application of the fabricated nanocomposite in the Pd-catalyzed C─C coupling reactions is monitored. High reaction yields (98%) have been obtained in short reaction time, by using this catalytic system. Materials and Methods: Fe3O4/P4VP-Pd catalytic system was fabricated via an in situ method by 4- vinylpyridine (4-VP). In this regard, all the essential structural analyses such as FT-IR, EDX, VSM, and TGA have been performed on the Fe3O4/P4VP-Pd catalytic system to investigate its properties. The spherical morphology of the NPs and their uniform size have also been studied by the SEM method. Further, the reaction progress was controlled by thin-layer chromatography. Finally, NMR analysis was used to identify the synthesized biphenyl pharmaceutical derivatives. Results: High efficiency of this catalytic system has been precisely investigated and the optimal conditions were determined. The catalytic process is carried out in 20 min, under mild conditions (room temperature). Then, the purification process is easily performed via magnetic separation of the catalyst NPs. After completion of the synthesis reaction, the NPs were collected, washed, and reused several times. Conclusion: Among recently reported heterogeneous catalytic systems, Fe3O4/P4VP-Pd is recommended due to its high catalytic performance, convenience of the preparation process, excellent biocompatibility, economic benefits, and well reusability. Overall, in order to save time in the complex synthetic processes and also prevent using so many chemical reagents and solvents for the purification process, the presented catalytic system could be suitable for scaling up and applying for the industrial applications.

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