Shape-dependent catalytic activity of copper oxide-supported Pd(0) nanoparticles for Suzuki and cyanation reactions

Green Synthesis of CuO Nanoparticles Using Agaricus bisporus Extract as a Highly Efficient Catalyst for the Suzuki Cross-Coupling Reaction

Copper oxide nanoparticles (CuONPs) were synthesized using a rapid, eco-friendly, cost-effective, efficient, and biological method employing aqueous Agaricus bisporus extract as a capping and reducing agent. The formation of CuONPs was checked by UV-vis spectroscopy and was characterized by X-ray diffraction analysis (XRD), dynamic light scattering spectroscopy (DLS), transmission electron microscopy (TEM), and surface area and porosimetry analyzer. The characterization results showed that the synthesized nanoparticles had a spherical-like appearance and a crystal structure with 40-100 nm particle size. The green synthesized CuONPs were found to be an excellent and sustainable heterogeneous catalyst (TOF up to 29700 h-1 ) for the Suzuki C-C coupling of aryl halides with phenylboronic acid in a very short reaction time (10 minutes). Moreover, the easily recovered catalyst can be reused five times with just a negligible reduction in catalytic behavior.

Decorated palladium nanoparticles on chitosan/δ-FeOOH microspheres: A highly active and recyclable catalyst for Suzuki coupling reaction and cyanation of aryl halides

In this study, an eco-friendly and low cost magnetic nanocomposite consisting of chitosan/δ-FeOOH microspheres (CS/δ-FeOOH) was fabricated as a stabilizer by using a simple method. Pd nanoparticles (Pd NPs) were decorated on the designed CS/δ-FeOOH, and the resulting Pd NPs@CS/δ-FeOOH microspheres were employed as a heterogeneous catalyst in the construction of biaryl and benzonitriles. Pd NPs@CS/δ-FeOOH microspheres efficiently catalyzed the conversion of aryl iodides and bromides to the desired biaryls within 3 h. Moreover, Pd NPs@CS/δ-FeOOH microspheres showed high catalytic potential against synthesis of benzonitriles by providing yields up to of 99% within 4 h. More importantly, it was proved that Pd NPs@CS/δ-FeOOH microspheres were able to be easily recycled and reused up to eight runs for both reactions. This study reveals that Pd NPs@CS/δ-FeOOH microspheres are useful and recyclable nanocatalysts, which catalyze the synthesis of biaryl and benzonitriles with good reaction yields.

Towards high-performance heterogeneous palladium nanoparticle catalysts for sustainable liquid-phase reactions

A walk-through of nanoparticle–reactant/product, nanoparticle–support and support–reactant/product interaction effects on the catalytic performance of heterogeneous palladium catalysts in liquid-phase reactions.

Magnetic Lignosulfonate-Supported Pd Complex: Renewable Resource-Derived Catalyst for Aqueous Suzuki-Miyaura Reaction

A novel strategy is described to prepare magnetic Pd nanocatalyst by conjugating lignin with Fe3O4 nanoparticles via activation of calcium lignosulfonate, followed by combination with Fe3O4 nanoparticles. Tethering 5-amino-1H-tetrazole to calcium lignosulfonate-magnetite hybrid through 3-chloropropyl triethoxysilane enabled coordination of Pd salt with Fe3O4-lignosulfonate@5-amino-1H-tetrazole. The underlying changes of the lignosulfonate are identified, and the structural morphology of attained Fe3O4-lignosulfonate@5-amino-1H-tetrazole-Pd(II) (FLA-Pd) is characterized by Fourier transform infrared, thermogravimetry differential thermal analysis, energy-dispersive spectrometry, field-emission scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometer (VSM). The synthesized FLA-Pd displayed high activity for phosphine-free C(sp2)-C(sp2) coupling in water, and the catalyst could be reused for seven successive cycles.

Facile Microwave-Assisted Synthetic Approach to Palladium Nanoparticles Supported on Copper Oxide as an Efficient Catalyst for Heck and Sonogashira Cross-Coupling Reactions

A simple green one-step method for the synthesis of highly active palladium nanoparticles embedded on copper oxide as an efficient catalyst for ligand-free Heck and Sonogashira cross-coupling reactions has been developed. The synthetic approach is based on Microwave (MW)-assisted simultaneous chemical reduction of an aqueous solution of palladium and copper salts using hydrazine hydrate as the reducing agent. Selected characterization of the catalyst with transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction spectroscopy (XRD) reveal a size range of 25[Formula: see text][Formula: see text][Formula: see text]2[Formula: see text]nm for the generated catalyst nanoparticles with the highest catalytic activity. The use of the generated Pd/CuO nanoparticles is highly advantageous due to the use of ethanol/water as an environmentally green solvent under mild reaction conditions. Furthermore, the synthesized Pd/CuO nanoparticles catalyst can be recycled and re-used up to five times with negligible effect on the efficiency having turnover number up to 6000 and turnover frequency reaching 72[Formula: see text]000[Formula: see text]h[Formula: see text] for 20[Formula: see text]wt.% Pd loaded catalyst at 150∘C.

Microwave-assisted synthesis of palladium nanoparticles supported on copper oxide in aqueous medium as an efficient catalyst for Suzuki cross-coupling reaction

We report here a reliable green method for the synthesis of palladium nanoparticles supported on copper oxide as a highly active and efficient catalyst for Suzuki cross-coupling reaction. The experimental synthetic approach is based on microwave-assisted chemical reduction of an aqueous mixture of palladium and copper salt simultaneously using hydrazine hydrate as reducing agent. The catalyst was fully characterized using various techniques showing well-dispersed palladium nanoparticles. The catalytic activity and recyclability of the prepared catalyst were experimentally explored in the ligand-free Suzuki cross-coupling reaction with a diverse series of functionalized substrates. The synthesized Pd/CuO catalyst shows many advantages beside its high catalytic efficiency such as the recyclability of up to five times with negligible loss of catalytic activity, short reaction times, use of environmentally benign solvent systems, and mild reaction conditions.

Catalysis and photocatalysis by metal organic frameworks

This review aims to provide different strategies employed to use MOFs as solid catalysts and photocatalysts in organic transformations.

A brand-new catalytic system: a Pd-based catalyst directly attached on the inner walls of the reactor which independently catalyzed the Heck reaction

A Pd-based catalyst directly attached on the inner surface of the reactor as a new catalytic system has been achieved and developed via an electrospinning technique followed by an impregnation–reduction and a simple carbonization process.

Tetragonal Cu2Se nanoflakes: synthesis using selenated propylamine as Se source and activation of Suzuki and Sonogashira cross coupling reactions

The metastable tetragonal Cu2Se phase as nanoflakes has been synthesized for the first time by treating CuCl2 taken in a mixture (1:1) of 1-octadecene and oleylamine with H2N-(CH2)3-SePh dissolved in 1-octadecene. Powder X-ray diffraction (PXRD), HRTEM, SEM-EDX and XPS have been used to authenticate the nanoflakes. The XPS of Cu2Se nanoflakes indicates oxidation states of Cu and Se as +1 and -2 respectively. The size of the majority of Cu2Se nanoflakes was found to be between 12 and 14 nm. The nanoflakes have been explored for Suzuki and Sonogashira cross coupling reactions in the presence of TBAB in DMF and DMSO respectively. For Suzuki coupling conversion was found upto ∼86% in 15 h at 110 °C when loading of Cu was 1 mol%. In case of Sonogashira coupling conversion was found upto 82% in 15 h at 160 °C (Cu loading: 1 mol%). The catalytic efficiency of Cu2Se nanoflakes for Suzuki coupling reaction is greater than that for Sonogashira coupling. These nanoflakes have been found reusable for a second time. Most probably TBAB facilitates the release of CuBr from the nanoflakes which catalyze both reactions, as catalytic efficiency is very low in the absence of TBAB and CuBr has been found to activate readily both the coupling reactions. In comparison to many other copper based nano-crystals, the present nanoflakes are a better activator.

Ultrasounds in melted poly(ethylene glycol) promote copper-catalyzed cyanation of aryl halides with K(4)[Fe(CN)(6)]

Melted poly(ethylene glycols) (PEGs) were used for the first time as solvent for the sonochemically promoted cyanation of aryl halides employing inexpensive and safe K4[Fe(CN)6] and a relatively low amount of Cu-based catalyst. The Mw (weight-average polymer molecular weight) of PEG proved to notably influence the substrate conversion, which is indicative of a strong dependence of the sonication efficacy on solvent properties. Gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) contributed to the characterization of the polymer and the elucidation of the catalytic system.

Highly Efficient Synthesis of Arylnaphthalenes by Modified Fibre–Palladium(II) Complex Catalysed Suzuki Reaction in Air

The modified fibre–palladium(II) complex was a highly efficient, recoverable and heterogeneous catalyst giving high yields in the synthesis of arylnaphthalenes by a Suzuki reaction in air. The heterogeneous catalyst can be readily recovered by simple filtration and reused at least six times without significant reduction in its activity.

Facile approach to prepare Pd nanoarray catalysts within porous alumina templates on macroscopic scales

The separation and reuse of nanocatalysts remains a major challenge. Herein, we report a novel approach to prepare palladium nanowire array catalysts by reducting PdCl2 in the pores of anodic aluminum oxide (AAO) templates with backside Al sheets via a hydrothermal process. Suzuki coupling reactions and 4-nitrophenol (4-NP) reduction reactions were employed to study the catalytic activity of the nanocatalysts. The nanocatalysts demonstrated good activity, great thermal stability, easy separation, and excellent reusability in both Suzuki reaction and 4-NP reduction.

Shape-controlled nanostructures in heterogeneous catalysis

Nanotechnologies have provided new methods for the preparation of nanomaterials with well-defined sizes and shapes, and many of those procedures have been recently implemented for applications in heterogeneous catalysis. The control of nanoparticle shape in particular offers the promise of a better definition of catalytic activity and selectivity through the optimization of the structure of the catalytic active site. This extension of new nanoparticle synthetic procedures to catalysis is in its early stages, but has shown some promising leads already. Here, we survey the major issues associated with this nanotechnology-catalysis synergy. First, we discuss new possibilities associated with distinguishing between the effects originating from nanoparticle size versus those originating from nanoparticle shape. Next, we survey the information available to date on the use of well-shaped metal and non-metal nanoparticles as active phases to control the surface atom ensembles that define the catalytic site in different catalytic applications. We follow with a brief review of the use of well-defined porous materials for the control of the shape of the space around that catalytic site. A specific example is provided to illustrate how new selective catalysts based on shape-defined nanoparticles can be designed from first principles by using fundamental mechanistic information on the reaction of interest obtained from surface-science experiments and quantum-mechanics calculations. Finally, we conclude with some thoughts on the state of the field in terms of the advances already made, the future potentials, and the possible limitations to be overcome.

Synthesis of Aryl Nitriles using the Stable Aryl Diazonium Silica Sulfates

An efficient method for preparation of aryl nitriles is reported using Cu(I) to catalyse the reaction of aryl diazonium silica sulfates with sodium cyanide under mild conditions at room temperature in water. This method has the advantages of high yields, simple methodology, short reaction times and easy work-up.