Cobalt supported on dendronized magnetic nanoparticles: A new highly efficient and recyclable catalyst for the Mizoroki–Heck cross‐coupling reaction

Polyamidoamine (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 cross‐coupling 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.     

Magnetic apple seed starch functionalized with 2,2′‐furil as a green host for cobalt nanoparticles: Highly active and reusable catalyst for Mizoroki–Heck and the Suzuki–Miyaura reactions

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.     

A magnetically recoverable copper–salen complex as a nano-catalytic system for amine protection via acetylation using thioacetic acid

Research on Chemical Intermediates - A novel copper(II)–salen complex was immobilized on the surface of magnetite nanoparticles using chitosan as a linker. This system exhibits superior...     

Base-free green synthesis of copper(II) oxide nanoparticles using highly cross-linked poly(curcumin) nanospheres: synergistically improved antimicrobial activity

Research on Chemical Intermediates - Antimicrobial activity of metal containing formulas has drawn attention and been widely investigated. In this research, CuO/hc-pCUR nanocomposite composed of...     

Historical review of pharmacological development and dosimetry of PSMA-based theranostics for prostate cancer

Journal of Radioanalytical and Nuclear Chemistry - Many efforts have been made to introduce an appropriate radiopharmaceutical as a theranostic agent for metastatic castration-resistant prostate...     

Et3N catalyzed the diastereoselective synthesis of functionalized cyclohexanones by condensation of acetoacetanilide and various aldehydes in mild conditions

Research on Chemical Intermediates - A facile synthetic strategy has been reported for the diastereoselective synthesis of...     

Selective tetrahydropyranylation of alcohols and phenols using titanium(IV) salophen trifluoromethanesulfonate as an efficient catalyst

Titanium(IV) salophen trifluoromethanesulfonate, [Ti^IV(salophen)(OSO₂CF₃)₂], as a catalyst enables selective tetrahydropyranylation of alcohols and phenols with 3,4‐dihydro‐2H‐pyran. Using this catalytic system, primary, secondary and tertiary alcohols, as well as phenols, were converted to their corresponding tetrahydropyranyl ethers in high yields and short reaction times at room temperature. Investigation of the chemoselectivity of this method showed discrimination between the activity of primary alcohols in the presence of secondary and tertiary alcohols and phenols. This heterogenized catalyst could be reused several times without loss of its catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.