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Green nanocatalysts play a crucial role in organic synthesis. In this study, a novel approach utilizing marine diatom extract is presented for the production of tin oxide nanoparticles (SnO2 NPs). These NPs possess distinctive characteristics, including crystalline properties, a spherical shape, and an average size of 20 ± 2 nm. The reduction and surface coating of the NPs involve organic components derived from marine sources. The resulting SnO2 NPs serve as highly effective catalysts for the synthesis of chromeno[4,3‐b]quinoline derivatives, facilitated by ultrasound‐assisted reactions. This process demonstrates remarkable efficiency, yielding a variety of organic products with impressive results, reaching yields of 82–97% and requiring short reaction times. Moreover, the SnO2 nanocatalyst employed exhibits advantageous properties, such as low loading, durability, and the ability to be reused up to six cycles. [ABSTRACT FROM AUTHOR]

Addressed herein is the catalysis of bimetallic PdxNi1‐x and PdxCo1‐x nanoparticles (NPs) supported on a cryptomelane‐type manganese oxide (K‐OMS‐2) solid for the Suzuki–Miyaura cross‐couplings of phenylboronic acid with various aryl halides. Bimetallic PdxNi1‐x and PdxCo1‐x NPs were prepared by using a conventional one‐step impregnation–reduction method. Among these catalysts with different compositions of Ni and Pd or Co and Pd, the Pd0.2Ni0.8 and Pd0.2Co0.8 catalysts showed the highest activity in the Suzuki–Miyaura cross‐couplings of various aryl halides including iodides, bromides, and even chlorides with phenylboronic acid in ambient air and water under reflux conditions. The Suzuki–Miyaura cross‐coupling reaction proceeded efficiently in the presence of Pd0.2Ni0.8@K‐OMS‐2 and Pd0.2Co0.8@K‐OMS‐2 NPs under the optimized conditions in water. Pd0.2Ni0.8@K‐OMS‐2 and Pd0.2Co0.8@K‐OMS‐2 NPs provided high conversions up to 98% and 99% and turnover frequencies of 11,760 and 11,880 h−1 in the cross‐coupling of phenylboronic acid with 1‐bromo‐4‐nitrobenzene. More importantly, these new supported Pd0.2Ni0.8@K‐OMS‐2 and Pd0.2Co0.8@K‐OMS‐2 NPs were found to be highly durable nanocatalyst throughout the reusability experiments, and they maintain almost their inherent activity after 10th and 5th catalytic cycle, respectively. Bimetallic Pd0.2Ni0.8@K‐OMS‐2 and Pd0.2Co0.8@K‐OMS‐2 NPs were characterized by Fourier transform infrared spectroscopy (FT‐IR), transmission electron microscopy (TEM), scanning electron microscopy with energy dispersive X‐ray (SEM‐EDX), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and ICAPQ inductively coupled plasma mass spectroscopy (ICP‐MS) analyses. [ABSTRACT FROM AUTHOR]

A new, powerful and recyclable copper catalyst were prepared by heterogenization of copper chloride using of Fe3O4 nano particles modified with citric acid as a linker. This system can catalyze reduction of nitroaren compound to aniline derivatives in the presence of Sodium borohydride as a reduction agent in moderate to good yields. In addition, easy separation and recoverable with an external permanent magnet is the dominant properties of this catalyst (Cu2+-CA@Fe3O4). [ABSTRACT FROM AUTHOR]

A green, benign, heterogeneous, superparamagnetic catalyst (Glu.@Fe3O4) was synthesized and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and vibrating sample magnetometry. The prepared catalyst was used to achieve a high-efficiency, low-cost, eco-friendly and easy-to-handle protocol for synthesizing substituted pyrazole derivatives from aldehydes, malononitrile and phenylhydrazine. The catalyst was also used in chromene synthesis. Glucose coated on magnetic nanoparticles provided excellent catalytic activity. The catalyst could be recycled for up to four runs without significant loss in catalytic activity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]