Magnetic Nanoparticles‐Supported Palladium: A Highly Efficient and Reusable Catalyst for the Suzuki,Sonogashira, and Heck Reactions

A highly efficient, air‐ and moisture‐stable and easily recoverable magnetic nanoparticle‐supported palladium catalyst has been developed for the Suzuki, Sonogashira and Heck reactions. A wide range of substrates was coupled successfully under aerobic conditions. In particular, the performance of the magnetic separation of the catalyst was very efficient, and it is possible to recover and reuse it at least eight times without significant loss of its catalytic activity.     

A Reusable Polymer-Anchored Palladium(II) Schiff Base Complex Catalyst for the Suzuki Cross-Coupling,Heck and Cyanation Reactions

A new polymer-anchored Pd(II) complex has been synthesized, characterized and its catalytic activity was investigated for the Suzuki cross-coupling reaction between aryl halides and arylboronic acid in the presence of K₂CO₃ as a base, for Heck olefination of aryl halides with alkenes, and for cyanation reaction of aryl iodides with K₄Fe(CN)₆ in presence of Et₃N as base. The key features of the catalyst include rapid reactions with excellent conversion without the use of phosphine ligands and total stability under the reactions conditions. The catalyst was recovered by simple filtration and reused five-times without significant loss of catalytic activity.     

Anionic Pd(0) and Pd(II) intermediates in palladium-catalyzed Heck and cross-coupling reactions

The anions of PdCl(2)L(2) and Pd(OAc)(2), precursors of palladium(0) used in cross-coupling and Heck reactions, play a crucial role in these reactions. Tricoordinated anionic complexes Pd(0)L(2)Cl(-) and Pd(0)L(2)(OAc)(-) are the effective catalysts instead of the usually postulated Pd(0)L(2) complex. The anion ligated to the palladium(0) affects the kinetics of the oxidative addition to ArI as well as the structure and reactivity of the arylpalladium(II) complexes produced in this reaction. Thus, pentacoordinated anionic complexes are formed, ArPdI(Cl)L(2)(-) or ArPdI(OAc)L(2)(-), the precursor of neutral trans-ArPd(OAc)L(2), instead of the usually postulated trans-ArPdIL(2) complex (L = PPh(3)).     

Cu-SBTU@MCM-41: As an Efficient and Reusable Nanocatalyst for Selective Oxidation of Sulfides an Oxidative Coupling of Thiols

Silicon - Cu(II) complex with S-benzylisothiourea ligand was grafted into functionalized mesoporous MCM-41 (Cu-SBTU@MCM-41) and characterized by X-ray Diffraction (XRD), thermal gravimetric...     

Nanocrystalline Magnesium Oxide‐Stabilized Palladium(0): An Efficient and Reusable Catalyst for Suzuki and Stille Cross‐Coupling of Aryl Halides

A nanocrystalline magnesium oxide‐stabilized palladium(0) catalyst is prepared by counterion stabilization of PdCl₄²⁻ with nanocrystalline MgO followed by reduction. This ligand‐free heterogeneous nanocrystalline MgO‐stabilized nanopalladium [NAP Mg Pd(0)] catalyst using the basic MgO in place of basic ligands exhibits excellent activity in Suzuki and Stille cross‐coupling of haloarenes (chloro, bromo and iodo) to afford the unsymmetrical biaryls. The catalyst is quantitatively recovered by simple filtration and reused for four cycles with almost consistent activity.     

Fe3O4@HcdMeen-Pd(0) Organic–Inorganic Hybrid: As a Novel Heterogeneous Nanocatalyst for Chemo and Homoselective Heck C–C Cross-Coupling Synthesis of Butyl Cinnamates

Methyl-2-(1-methyl-2′-amino-ethane)amino-1-cyclopentenedithiocarbo-xylate was supported on the modified Fe₃O₄ MNPs. Afterwards, Pd(OAc)₂ was immobilized on the modified MNPs and, then, the nanoparticles were analyzed using FT-IR, XRD, EDS, ICP-OSE, SEM, TGA and VSM spectroscopy. The catalytic efficiency of the prepared heterogeneous Pd-NPs was successfully examined in “Heck cross coupling reaction”, involving the reaction of butyl acrylate with various aryl halides in water. The advantages of this strategy include, easy recovery and efficient reusability of the expensive Pd-NPs, obtaining high yields of the butyl cinnamate cross-coupled products, short reaction times, and being performed in water for a wide range of substrates.

Graphical Abstract

A novel HcdMeen-Pd(0) complex was synthesized on the surface of modified Fe₃O₄ MNPs and fully characterized by FT-IR, XRD, EDS, ICP-OSE, SEM, TGA and VSM spectroscopy analysis. The obtained complex was then used for Chemo And Homoselective Heck C–C cross-coupling synthesis of butyl cinnamates with in water as green solvent.

     

Pd(0)-catalyzed Heck reactions of isopropenyl acetate using bmim salts as pre-ligands

In the present paper, simple homogeneous catalytic protocols are presented for the production of methylketones under palladium catalysis from isopropenyl acetate and aryl or benzyl halides. Several reaction conditions were investigated and, although the use of Pd(OAc)₂/K₂CO₃/PPh₃ in ethanol gave the desired products in good yields, the use of bmim salts, to substitute PPh₃, as precursors of NHC ligands proved equally effective.     

An Efficient,Stable and Reusable Palladium Nanocatalyst: Chemoselective Reduction of Aldehydes with Molecular Hydrogen in Water

Palladium nanoparticles (Pd‐BNP) stabilized by a binaphthyl‐backbone can be efficiently used for the chemoselective reduction of aldehydes in the presence of hydrogen at room temperature in water. The Pd‐BNP catalyst is easily recovered and reused for five catalytic cycles.

     

Efficient Catalyst for Both Suzuki and Heck Cross‐Coupling Reactions: Synthesis and Catalytic Behaviour of Geometry‐ Constrained Iminopyridylpalladium Chlorides

A series of geometry‐constrained iminopyridyl‐palladium chlorides were synthesized and characterized. These phosphine‐free palladium complexes were explored for their catalytic activities in both Suzuki and Heck cross‐coupling reactions, achieving turnover numbers as high as 10⁶ towards various aryl bromides, even those containing various functionalities. In addition, the influence of substituents with steric and electronic factors was reflected by the differences observed in their activities.

     

Pd/Cu-Free Cobalt-Catalyzed Suzuki and Heck Using Green Bio-Magnetic Hybrid and DFT-Based Theoretical Study

Catalysis Letters - Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds...     

Fluorapatite‐Supported Palladium Catalyst for Suzuki and Heck Coupling Reactions of Haloarenes

A fluorapatite‐supported palladium catalyst (PdFAP) was synthesized by treatment of fluorapatite (prepared by incorporating the basic species fluoride ion into apatite in situ by co‐precipitation) with bis(benzonitrile)palladium(II ) chloride in acetone. The catalyst displayed high catalytic activity for Suzuki coupling of aryl iodides and bromides with boronic acids at room temperature and chloroarenes at 130 °C in the presence of tetrabutylammonium bromide to give biaryls in excellent yields. Heck olefination of chloroarenes was also successfully carried out by this catalyst. PdFAP was recovered quantitatively by simple filtration and reused with consistent activity. PdFAP was well characterized by XRD, FTIR, XPS, ICP‐AES, CO₂ TPD and CHN elemental analysis.     

A novel thermo and pH-double sensitive hydrogel immobilized Pd catalyst for Heck and Suzuki reactions in aqueous media

A novel Hydrogel (1) was prepared from N-isopropylacrylamide, 4-vinylpyridine and potassium acrylate by free radical cross-linking polymerization. Hydrogel (1) showed both thermosensitivity and pH-sensitivity, and exhibited high swelling capacity in water. Because Hydrogel (1) has porous structure in its network and good loading performance with Pd²⁺, it was used as “microreactor” for immobilization of metal nanoparticles. We chose Heck and Suzuki reaction of aryl halides in water as test reaction to probe the catalytic activity of such Hydrogel (1) supported palladium catalyst. As a result, the Hydrogel (1)-Pd (II) catalyst exhibited good catalytic activity in both Heck and Suzuki reactions. Moreover, the Hydrogel (1)-Pd (II) catalyst was easily recovered and recycled. The reuse experiments showed that it was recycled six times without obviously losing of catalytic activity.     

Palladium‐Iminodiacetic Acid Immobilized on pH‐Responsive Polymeric Microspheres: Efficient Quasi‐Homogeneous Catalyst for Suzuki and Heck Reactions in Aqueous Solution

The pH‐responsive core‐shell microspheres of poly(styrene‐co‐methylacrylic acid) (PS‐co‐PMAA) containing a polystyrene (PS) core and a poly(methylacrylic acid) (PMAA) shell are synthesized by one‐stage soap‐free copolymerization and the catalyst system palladium‐iminodiacetic acid (IDA‐Pd) is immobilized on the outer shell‐layer of the core‐shell microspheres to form the quasi‐homogeneous and easily accessible catalyst PS‐co‐PMAA‐IDA‐Pd. This quasi‐homogeneous PS‐co‐PMAA‐IDA‐Pd catalyst is highly dispersed in the reaction medium just like a homogeneous one and can be separated like a heterogeneous catalyst by adjusting the pH of the reaction medium. Suzuki reactions employing the quasi‐homogeneous PS‐co‐PMAA‐IDA‐Pd catalyst are efficiently performed in water as the sole solvent under mild conditions such as room temperature. The PS‐co‐PMAA‐IDA‐Pd catalyst is also used in Heck reactions of a wide range of aryl halides with styrene and proves to be efficient in aqueous solution. The PS‐co‐PMAA‐IDA‐Pd catalyst has a low leaching loss and can be reused at least 4 times without loss of activity.     

Palladium Nanoparticles Immobilized on Nano‐Silica Triazine Dendritic Polymer (Pdnp‐nSTDP): An Efficient and Reusable Catalyst for Suzuki–Miyaura Cross‐Coupling and Heck Reactions

A new catalyst based on palladium nanoparticles immobilized on nano‐silica triazine dendritic polymer (Pd_np‐nSTDP) was synthesized and characterized by FT‐IR spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X‐ray, transmission electron microscopy and elemental analysis. The size of the palladium nanoparticles was determined to be 3.1±0.5 nm. This catalytic system showed high activity in the Suzuki–Miyaura cross‐coupling of aryl iodides, bromides and chlorides with arylboronic acids and also in the Heck reaction of these aryl halides with styrenes. These reactions were best performed in a dimethylformamide (DMF)/water mixture (1:3) in the presence of only 0.006 mol% and 0.01 mol% of the catalyst, respectively, under conventional conditions and microwave irradiation to afford the desired coupling products in high yields. The Pd_np‐nSTDP was also used as an efficient catalyst for the preparation of a series of star‐ and banana‐shaped compounds with a benzene, pyridine, pyrimidine or 1,3,5‐triazine unit as the central core. Moreover, the catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity.