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Nitrite (NO 2 −) is widely used as an additive to extend the shelf life of food products. Excessive nitrite intake not only causes blood-related diseases but also has the potential risk of causing cancers. A disposable screen-printed electrode was modified with nano‑palladium decorated bismuth sulfide microspheres (nanoPd@Bi 2 S 3 MS/SPE), and integrated with a smartphone-interfaced potentiostat to develop a portable, electrochemical nitrite sensor. NanoPd@Bi 2 S 3 MS was prepared by the hydrothermal reduction of a Bi 2 S 3 MS and Pd2+ dispersion and drop cast on the SPE. The nanoPd@Bi 2 S 3 MS/SPE was coupled with a smartphone-controlled portable potentiostat and applied to determine nitrite in food samples. The linear range of the sensor was 0.01–500 μM and the limit of detection was 0.0033 μM. The proposed system showed good repeatability, reproducibility, catalytic stability, and immunity to interferences. The proposed electrode material and a smartphone-based small potentiostat created a simple, portable, fast electrochemical sensing system that accurately measured nitrite in food samples. [Display omitted] • The proposed sensing platform showed high sensitivity toward nitrite detection. • Bismuth sulfide microspheres and nanoPd synergies maximized sensor performances. • The platform is selective, catalytically stable, and uses small sample volumes. • The proposed electrochemical sensing system is portable, simple, and fast. [ABSTRACT FROM AUTHOR]

Abstract Background The side reactions of dehalogenation or C–N coupling tend to occur when halogenated aromatic amines are prepared by catalytic hydrogenation reduction of halogenated aromatic nitro compounds. In this paper, we prepared the sub-microspherical Fe3O4@PDA-Pd NPs catalyst apply it efficiently in the hydrogenation reduction of halogenated aromatic nitro compounds to prepare the halogenated aromatic amines under atmospheric pressure. The catalyst shows a high selectivity of greater than 96% and can effectively inhibit the occurrence of the side reactions of dehalogenation and C–N coupling. Results The optimum condition of the hydroreduction reaction is when tetrahydrofuran is used as solvent and the reaction happens at 50 °C for 5 h. The selectivity of the chlorinated aromatic amine and the fluorinated aromatic amine products exceed 99% and the yield exceeds 90%. Only a small amount of dehalogenated products and C–N coupling by-products were produced in the brominated aromatic compound and the iodinated aromatic compound. Conclusion We developed a promising method for preparing the superparamagnetic and strongly magnetic Fe3O4@PDA core–shell sub-microsphere-supported nano-palladium catalyst for catalyzing the hydrogenation reduction of halogenated aromatic nitro compounds. The halogenated aromatic amines were efficiently and highly selectively prepared under atmospheric pressure, with the side reactions of dehalogenation and C–N coupling effectively inhabited simultaneously.

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Large-size, superparamagnetic, and highly magnetic Fe3O4@PDA core−shell submicrosphere-supported nano-palladium catalysts were prepared in this study. Dopamine was encapsulated on the surface of Fe3O4 particles via self-polymerization and then protonated to positively charge the microspheres. PdCl42− was dispersed on the surface of the microspheres by positive and negative charge attraction and then reduced to nano-palladium. With air as oxidant, the catalyst can successfully catalyze the dehydrogenation of benzyl alcohols to produce the corresponding aldehydes at 120 °C.

A mild and simple protocol is described for the palladium-catalyzed ligand-free Suzuki–Miyaura reaction of potassium aryltrifluoroborates in aqueous ethanol at room temperature. Palladium nanoparticles are generated in situ in the reaction and demonstrate high activity towards a wide range of aryl bromides and potassium aryltrifluoroborates, providing biphenyls in good to excellent yields. Interestingly, only 1 equiv of K 2 CO 3 is used in this catalytic system. Moreover, the key biaryl intermediate of 2-cyano-4′-methylbiphenyl within valsartan is prepared in a 95% yield after 2 h. [ABSTRACT FROM AUTHOR]

Abstract: Nano-palladium catalysts, prepared using the same procedure with the same metal content (3wt%) and two different supports, activated carbon (Pd/C) and activated carbon—multiwalled carbon nanotubes (Pd/C/CNT), are discussed. The simple technique of deposition reduction was applied in the preparation of these two types of Pd catalysts. TEM, XRD analysis, EXAFS signal analysis, and XANES were used for sample characterization. In both samples, transmission electron microscopy identified nanosized Pd particles with nearly spherical morphology but different sizes. The mean diameters of the particles on Pd/C and Pd/C/CNT were estimated to be 5.4nm and 7.8nm, respectively. The EXAFS signal analysis showed that Pd atoms on the particle surfaces were coordinated by 4 oxygens to form a PdO monolayer covering a metallic core. The XANES signal analysis indicated a smaller particle size for Pd/C (∅ 5nm) than for Pd/C/CNT (∅ 10nm), in good agreement with the TEM observations. [Copyright &y& Elsevier]

The Pd/La2O3catalyst was simply prepared from readily available reagents. The catalyst exhibited high activities in the Heck cross-coupling reaction and could be reused for several times without activity loss. In addition, the catalyst was characterized by the transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and inductively coupled plasma (ICP). Supplemental materials are available for this article. Go to the publisher's online edition ofSynthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistryto view the supplemental file. [ABSTRACT FROM PUBLISHER]

Abstract: The Suzuki–Miyaura reaction has been performed using a phosphine-free perfluoro-tagged palladium catalyst that is readily immobilized on fluorous silica gel through fluorous–fluorous interactions (Pd-1/FSG). The reactions are carried out under aerobic and phosphine-free conditions with excellent to quantitative product yields, and very low palladium content (<0.8ppm) in the products was detected by ICP-AES. The catalyst can be recovered by simple filtration and reused several times without significant loss of activity. [Copyright &y& Elsevier]

A new fluorous nano-palladium catalyst was prepared and characterized. The catalytic activity of the catalyst has been evaluated for the Suzuki reaction of aryl halides and aryl boronic acids to afford the corresponding products in high yields. The reaction proceeded smoothly in the presence of 0.1 mol% catalyst in EtOH/HO at room temperature. In addition, the catalyst could be recovered by fluorous liquid-liquid separation and reused for three times without significant loss of activity. Graphical Abstract: The Suzuki reaction catalyzed by a new fluorous nano-palladium catalyst to afford the products in high yields at room temperature has been described. The catalyst can be recovered by fluorous liquid-liquid separation and reused for several times without significant loss of activity. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Background: The side reactions of dehalogenation or C–N coupling tend to occur when halogenated aromatic amines are prepared by catalytic hydrogenation reduction of halogenated aromatic nitro compounds. In this paper, we prepared the sub-microspherical Fe3O4@PDA-Pd NPs catalyst apply it efficiently in the hydrogenation reduction of halogenated aromatic nitro compounds to prepare the halogenated aromatic amines under atmospheric pressure. The catalyst shows a high selectivity of greater than 96% and can effectively inhibit the occurrence of the side reactions of dehalogenation and C–N coupling. Results: The optimum condition of the hydroreduction reaction is when tetrahydrofuran is used as solvent and the reaction happens at 50 °C for 5 h. The selectivity of the chlorinated aromatic amine and the fluorinated aromatic amine products exceed 99% and the yield exceeds 90%. Only a small amount of dehalogenated products and C–N coupling by-products were produced in the brominated aromatic compound and the iodinated aromatic compound. Conclusion: We developed a promising method for preparing the superparamagnetic and strongly magnetic Fe3O4@PDA core–shell sub-microsphere-supported nano-palladium catalyst for catalyzing the hydrogenation reduction of halogenated aromatic nitro compounds. The halogenated aromatic amines were efficiently and highly selectively prepared under atmospheric pressure, with the side reactions of dehalogenation and C–N coupling effectively inhabited simultaneously. [ABSTRACT FROM AUTHOR]

Large-size, superparamagnetic, and highly magnetic Fe3O4@PDA core–shell submicrosphere-supported nano-palladium catalysts were prepared in this study. Dopamine was encapsulated on the surface of Fe3O4 particles via self-polymerization and then protonated to positively charge the microspheres. PdCl42− was dispersed on the surface of the microspheres by positive and negative charge attraction and then reduced to nano-palladium. With air as oxidant, the catalyst can successfully catalyze the dehydrogenation of benzyl alcohols to produce the corresponding aldehydes at 120 °C. [ABSTRACT FROM AUTHOR]