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We report here, the synthesis of two types of heterogeneous nanoparticle catalysts viz., polymer-supported poly(propyleneimine)-G2 dendrimer stabilized gold nanoparticle catalysts using crosslinked poly(4-vinylpyridine) matrix (PSP4VP) as support material. The grafting of dendrimer on the surface of P4VP beads was characterized by FTIR spectrophotometer and CHN analyses. The immobilization of AuNPs was characterized by UV-Vis spectrum, SEM, and HRTEM studies. The resultant polymer-supported dendrimer stabilized AuNPs were used as a heterogeneous catalyst for the reduction of 4-nitrophenol. The catalytic activity is found to be excellent and it can also be reused many times by simple filtration and activity remains maintained.

Rapid synthesis of highly stable polymer-supported eosin Y for visible light-driven photoxidation of thioethers to sulfoxides and phenylboronic acids to phenols.

In recent past, magnetic catalyst has gained much attention because it can be easily separated from the reaction mixture. Herein we report a facile synthesis of magnetic carbon dot supported MnO 2 nanoparticles for the oxidative transformation of organic compounds. In the actual synthesis, initially Fe 3 O 4 nanoparticles were prepared by microwave assisted method and carbon dots were prepared instantaneously from glucose by simple incineration under closed condition. The synthesized carbon dots were coated over iron oxide nanoparticles via sonochemical deposition method. Further, magnetic carbon dot supported MnO 2 nanocomposite was synthesized by conventional homogeneous precipitation using potassium permanganate. The synthesized nanocomposite material was characterized using FT-IR, SEM, TEM, XRD and VSM techniques. The catalytic efficiency of the nanomaterial was successfully demonstrated for the oxidation of benzyl alcohols to benzaldehydes. The advantages of this method include, controlled oxidation of alcohols to aldehydes with broad substrate scope, the use of molecular oxygen as a green oxidant and beyond that a facile magnetic separation of the catalyst material. Moreover, the catalyst can be recycled for 5 times without much loss in its efficiency.