Funding information Semnan University Research CouncilThe purpose of this work was to synthesize and characterize a new magnetic polymer nanosphere-supported palladium(II) acetate catalyst for reactions requiring harsh conditions. In this regard, an air-stable, moisture-stable and highly efficient heterogenized palladium was synthesized by the coordination of palladium(II) acetate with poly(2-acrylamido-2-methyl-1-propanesulfonic acid)-grafted modified magnetic nanoparticles with a core-shell structure.The structure of the newly developed catalyst was characterized using various techniques. The catalytic activity of the resultant nano-organometallic catalyst was evaluated in Mizoroki-Heck and Suzuki-Miyaura reactions to afford the corresponding coupling products in good to excellent yields. High selectivity as well as outstanding turnover number (14 143, 4900) and turnover frequency (28 296, 7424) values were recorded for the catalyst in Suzuki-Miyaura and Mizoroki-Heck reactions, respectively. Magnetic separation and recycling of the catalyst for at least six runs became possible without any significant loss of efficiency or any detectable palladium leaching.

Funding information Semnan UniversityPolyamidoamine (PAMAM) is one of the most interesting types of hyperbranched polymers that carry a large number of amino groups on its surface. PAMAM has gained significant attention from synthetic organic chemists due to its structural characteristics, controllable structure, inner porosity, and ability to trap a wide range of ions and molecules. So, in this work, the PAMAM dendrimer was synthesized, grafted onto the surface of magnetite nanoparticles, and the resulting hybrid nanoparticles were then employed as suitable host for immobilizing cobalt nanoparticles. The newly developed catalyst was well characterized by Fourier transform-infrared, X-ray diffraction, thermogravimetric analysis, field emission-scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, element mapping and energy-dispersive X-ray analysis. The efficiency of the as-prepared nanocatalyst was evaluated for the Mizoroki-Heck crosscoupling reactions. The MNP@PAMAM-Co represented perfect catalytic efficiency and high selectivity for the Mizoroki-Heck cross-coupling reaction compared with previously reported catalysts. The catalyst separation from the reaction mixture was easily achieved with the assistance of an external magnetic field, and its recycling was also investigated for five consecutive runs. Hot filtration confirmed no leaching of the active metal during the Heck coupling.

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From the perspective of green chemistry, in catalytic systems, being low cost and eco‐friendly, in addition to high chemical and thermal stability, are requirements of support materials. In this regard, we used apple seed starch as an accessible, nontoxic, and cost‐effective support material. In order to take advantage of magnetic separation, the magnetite nanoparticles were chosen as an ideal pair for apple seed starch. Furthermore, during the Schiff base reaction, the magnetic apple seed starch was functionalized with 2,2′‐furil along with amine functionality to be used as a bio‐support for immobilization of cobalt. The introduction of cobalt had a significant effect on the greenness of the catalyst and reducing its price. FT‐IR, TGA, XRD, FE‐SEM, TEM, VSM, ninhydrin test, element mapping, AAS, and EDX analysis were applied to characterize the newly prepared catalyst. The effectiveness of this novel Schiff base supported catalyst was evaluated in the Mizoroki–Heck and the Suzuki–Miyaura coupling reactions. High reactivity and selectivity were among the most prominent characteristics of the catalyst as compared to previously reported catalysts. The longevity test and hot filtration showed the ability to use the catalyst at least 5 times and negligible cobalt leaching during the reaction, respectively. This work is the first report on the usage of apple seed starch as a supporting catalyst and 2,2′‐furil as a ligand in the catalyst modifications and catalytic activity. Accordingly, this can be the beginning of an attractive way in the design and synthesis of heterogeneous catalysts.

ARGHAN, M.; AMOOZADEH, A.; Synth. Commun. 42 (2012) 1, 33-39, http://dx.