Suzuki Coupling Reactions In Water Research Articles

Acyl hydrazone‐based supramolecular polymer for ultrasensitive detection of Fe3+, Pd2+, H2PO4− and its application for Suzuki coupling reactions

A novel acylhydrazide‐based gelator (BE) was successfully built without the use of traditional fluorescent groups. Surprisingly, in 1,2‐propanediol, the BE can further self‐assemble into a stable supramolecular gel (OBE) and display significant blue‐white aggregation‐induced enhanced emission (AIEE). Interestingly, based on the excellent coordination capacity of acyl hydrazone bonds, the OBE demonstrated a sensitive response to Pd2+ and Fe3+, with corresponding lowest limits of detection of 21.8 and 37.3 ppb, respectively. More interesting, H2PO4− could only be constantly recognized by the Pd‐OBE (Pd2+ coordinated with OBE). Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), density functional theory (DFT) and rheological measurements, the self‐assembly process of OBE, and the ion recognition sensing mechanism were extensively examined. Moreover, xerogel OBE as supporter, a novel heterogeneous catalyst Pd/OBE is prepared. The catalyst displays outstanding activity and stability for Suzuki coupling reactions in water. It can be easily reused for at least five runs with no decrease in the catalytic activity.

Synthesis and characterization of new 3,3`-bipyrazole-4,4`-dicarboxylic acid derivatives and some of their palladium(II) complexes as pre-catalyst for Suzuki coupling reaction in water

The 1,3-dipolar cycloaddition reaction of bis-hydrazonyl chlorides with methyl propiolate afforded dimethyl 1,1¢-aryl-3,3`-bipyrazole-4,4`-dicarboxylates (5a,b). Heating the later compound 5a with a mixture of HCl/AcOH gave 3,3`-bipyrazole-5,5`-dicarboxylic acid derivative 6. Treatment of the hydrazonoyl chloride (1a) and 3,3`-bipyrazole-5,5`-dicarboxylic acid (6) with palladium(II) chloride gave the corresponding Pd-complexes 7 and 8, respectively. The catalytic activity of the prepared Pd-complexes was examined in the Suzuki cross-coupling reaction of phenylboronic acid with activated and deactivated aryl(hetaryl) bromides. The catalyst system provides very good to excellent yields, 85-94%. The structures of the obtained products were established from their elemental analysis, spectral data, XPS, EDX, and single crystal X-ray crystallography. Crystal data for C10H7N2O2 (6): triclinic, space group P-1 (no. 2), a = 3.9956(10) Å, b = 9.8917(18) Å, c = 10.810(3) Å, α = 94.167(15)°, β = 94.979(19)°, γ = 98.953(15)°, V = 418.83(16) Å3, Z = 2, T = 296.(2) K, μ(Cu Kα) = 0.887 mm-1, Dcalc = 1.484 g/cm3, 5469 reflections measured (11.72° ≤ 2Θ ≤ 133.24°), 1420 unique (Rint = 0.0633, Rsigma = 7.24%) which were used in all calculations. The final R1 was 0.1055 (>2sigma(I)) and wR2 was 0.3620 (all data).

Isinglass–palladium as collagen peptide–metal complex: a highly efficient heterogeneous biocatalyst for Suzuki cross-coupling reaction in water

The class of bio-nanocatalysts (BNCs) is an evolving innovation that synergistically assimilates advanced nanotechnology with biotechnology. BNCs promote green processes due to their low consumption of chemicals and the absence of toxic by-products. Isinglass (IG), from the Dutch huizenblaas (sturgeon bladder), containing approximately 98% protein collagen, is used to support the immobilization of palladium (Pd) nanoparticles. This process leads to Pd/IG composite, a new class of heterogeneous collagen peptides–metal BNCs that exhibit high catalytic activity and reusability for ligand-free Suzuki coupling reaction in water. Additionally, these BNCs are obviously active in the cross-coupling reaction between acid chloride and arylboronic acid, producing a high yield of the desired ketones. The synthesized BNCs are well-characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma, and transmission electron microscopy.

Poly(tetrafluoroethylene)-Stabilized Metal Nanoparticles: Preparation and Evaluation of Catalytic Activity for Suzuki, Heck, and Arene Hydrogenation in Water.

Poly(tetrafluoroethylene)-stabilized Pd nanoparticles (PTFE-PdNPs) were prepared in water with 4-methylphenylboronic acid as a reductant and characterized using powder X-ray diffraction, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Small PdNPs with a fairly uniform size were obtained in the presence of PTFE, whereas aggregation of palladium was observed in the absence of PTFE. PTFE-PdNPs showed high catalytic activity for the Suzuki coupling reaction in water and were reused without any loss of activity. No palladium species were observed by ICP-AES analysis in the reaction solution after the reaction, nor was any change in particle size observed after the recycle experiment. PTFE-PdNPs also exhibited excellent catalytic activity and reusability for the Heck reaction in water. Although palladium species were not detected in the reaction solution after the reaction, aggregates and smaller sizes of PdNPs were observed in the TEM image of the recovered catalyst. PTFE was also useful as the stabilizer of rhodium nanoparticles (RhNPs) prepared by reduction with NaBH4. PTFE-RhNPs showed high catalytic activity and reusability toward arene hydrogenation under mild conditions.

Size-tuned hydrogel network of palladium-confining polymer particles: a highly active and durable catalyst for Suzuki coupling reactions in water at ambient temperature

Poly(N-isopropylacrylamide)-based hydrogel particles (GPs) with different sized hydrogel networks were developed and used to confine a palladium (Pd) catalyst. The size of the gel network was tuned by varying the feed ratio of the cross-linking monomer. Nanosized-Pd(0) was loaded into the GPs, which contain a tertiary-amine ligand, via Pd-ion adsorption and subsequent reduction. The Pd-loaded GPs were used as the catalyst for a Suzuki coupling reaction between phenylboronic acid and 4-bromobenzoic acid in water at 30 °C. Due to the hydrophilic reaction platform provided by the hydrogel matrix of the GPs, the catalytic efficiencies of Pd-loaded GPs were significantly higher than those of commercially available Pd-loaded supports. Notably, the Pd-loaded GPs with the smallest gel networks were highly durable for Suzuki coupling reactions. It is plausible that the smaller network minimized or prevented the enlargement of Pd(0) during the catalytic cycle. The facile synthesis of the GPs, environmentally benign catalytic system, and high catalytic durability and activity of these Pd-loaded GPs are all important factors for the industrial application of these materials.

Palladium incorporated on carbonaceous catalyst for Suzuki coupling reaction in water

A new palladium incorporated carbonaceous catalyst Pd@CCSO3HNH2 was synthesized by introducing palladium on glucose derived carbocatalyst. The catalyst was well characterized and was used for the Suzuki coupling of phenyl boronic acid with different aryl halides under aqueous conditions. This green methodology represents a ligand free, cost-effective and operationally convenient method for the synthesis of a variety of biaryl’s under the conditions that are tolerant for a broad range of functional groups with good to excellent yields. Moreover, the catalyst could be easily recycled and reused at least five times without any significant loss of its catalytic activity.

Palladium Supported on Fluorite Structured Redox CeZrO4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

Pd on redox CeZrO4-δ catalysts was prepared, characterized and their activity was evaluated for Suzuki coupling reaction in water under reflux condition. Fresh and reduced form of 5 % Pd (R−Pd5) on CeZrO4-δ catalyst exhibited 100 % conversion in 2.5 and 1 h, respectively. R−Pd5 shows significant activity for wide range of substrate compatibility and for less reactive aryl bromides too. The mechanistic investigations proved the important role of redox CeZrO4-δ support on the catalytic activity. It was observed that the presence of oxygen vacancy along with Ce3+ enhances the activity. 1 wt % Pd photodeposited on pre-reduced CeZrO4-δ support requires a mere 20 min. for 100 % conversion of Suzuki coupling. Effect of metal dispersion and particle size on catalytic activity is also discussed. High Pd dispersion with small particle size (4±1 nm), particle size preservation after reaction, strong metal-support interaction and no leaching fully suggest the heterogeneous mechanism is operative for Suzuki coupling on 1 wt % Pd photodeposited on reduced CeZrO4-δ support. Present work hints the possibility of achieving high conversion for Suzuki reaction with very small amount of Pd through better dispersion by taking advantage of redox support and in water.

Nano tetraimine Pd(0) complex as an efficient catalyst for phosphine‐free Suzuki reaction in water and copper‐free Sonogashira reaction under aerobic conditions

A nano tetraimine Pd(0) complex catalyst was successfully used as an efficient heterogeneous catalyst for the phosphine‐free palladium‐catalysed Suzuki coupling reaction in water at 80 °C. This nano tetraimine Pd(0) complex was also used for copper‐free Sonogashira reaction in dimethylformamide at 100 °C. The catalyst was easily recovered from the reaction mixture by centrifugation and reused for at least six cycles without any significant loss in its catalytic activity. Analysis of the reaction mixture using inductively coupled plasma analysis showed that leaching of palladium from the catalyst was negligible. The reactions can be performed efficiently for aryl iodides, bromides and also chlorides. Copyright © 2016 John Wiley & Sons, Ltd.

ChemInform Abstract: Cross‐Coupling Reactions in Water Using Ionic Liquid‐Based Palladium(II)‐Phosphinite Complexes as Outstanding Catalysts.

Two new phosphinite ligands based on ionic liquids [(Ph2PO)C7H14N2Cl]Cl (1) and [(Cy2PO)C7H14N2Cl]Cl (2) were synthesized by reaction of 1-(3-chloro-2-hydoxypropyl)-3-methylimidazolium chloride, [C7H15N2OCl]Cl, with one equivalent of chlorodiphenylphosphine or chlorodicyclohexylphosphine, respectively, in anhydrous CH2Cl2 and under argon atmosphere. The reactions of 1 and 2 with MCl2(cod) (M=Pd, Pt; cod=1,5-cyclooctadiene) yield complexes cis-[M([(Ph2PO)C7H14N2Cl]Cl)2Cl2 ]a ndcis-[M(Cy2PO) C7H14N2Cl]Cl)2Cl2], respectively. All complexes were isolated as analytically pure substances and characterized using multinuclear NMR and infrared spectroscopies and elemental analysis. The catalytic activity of palladium complexes based on ionic liquid phosphinite ligands 1 and 2 was investigated in Suzuki cross-coupling. They showoutstanding catalytic activity in coupling of a series of aryl bromides or aryl iodides with phenylboronic acid under the optimized reaction conditions in water. The complexes provide turnover frequencies of 57 600 and 232 800h 1 in Suzuki coupling reactions of phenylboronic acid with p-bromoacetophenone or p-iodoacetophenone, respectively, which are the highest values ever reported among similar complexes for Suzuki coupling reactions in water as sole solvent in homogeneous catalysis. Furthermore, the palladium complexes were also found to be highly active catalysts in the Heck reaction affordingtrans-stilbenes. Copyright © 2014 John Wiley & Sons, Ltd. Additional supporting information may be found in the online version of this article at the publisher’s web-site.

Green and effective route for the synthesis of monodispersed palladium nanoparticles using herbal tea extract (Stachys lavandulifolia) as reductant, stabilizer and capping agent, and their application as homogeneous and reusable catalyst in Suzuki coupling reactions in water

A simple and eco‐friendly procedure has been devised for the green synthesis of palladium nanoparticles, using the aqueous extract of herbal tea (Stachys lavandulifolia), a renewable and nontoxic natural phyto‐exudate. The water‐soluble components of the extract act as reducing agent and stabilizer. This green route does not require a surfactant or capping agent for the growth of palladium nanoparticles. The generated nanoparticles were analysed using UV–visible spectroscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X‐ray analysis and inductively coupled plasma. The palladium nanoparticles having spherical shape and dimensions of between 5 and 7 nm were employed as a homogeneous catalyst for Suzuki coupling reactions conducted in water under mild conditions. Good yields of products, a facile work‐up, no evidence of leached palladium from the catalyst surface and smooth recovery of the catalysis by adding ethyl acetate, which could be reused at least eight times, confirm the very good efficiency of the catalytic reaction. Copyright © 2014 John Wiley & Sons, Ltd.

Cross‐coupling reactions in water using ionic liquid‐based palladium(II)–phosphinite complexes as outstanding catalysts

Two new phosphinite ligands based on ionic liquids [(Ph2PO)C7H14N2Cl]Cl (1) and [(Cy2PO)C7H14N2Cl]Cl (2) were synthesized by reaction of 1‐(3‐chloro‐2‐hydoxypropyl)‐3‐methylimidazolium chloride, [C7H15N2OCl]Cl, with one equivalent of chlorodiphenylphosphine or chlorodicyclohexylphosphine, respectively, in anhydrous CH2Cl2 and under argon atmosphere. The reactions of 1 and 2 with MCl2(cod) (M = Pd, Pt; cod = 1,5‐cyclooctadiene) yield complexes cis‐[M([(Ph2PO)C7H14N2Cl]Cl)2Cl2] and cis‐[M(Cy2PO)C7H14N2Cl]Cl)2Cl2], respectively. All complexes were isolated as analytically pure substances and characterized using multi‐nuclear NMR and infrared spectroscopies and elemental analysis. The catalytic activity of palladium complexes based on ionic liquid phosphinite ligands 1 and 2 was investigated in Suzuki cross‐coupling. They show outstanding catalytic activity in coupling of a series of aryl bromides or aryl iodides with phenylboronic acid under the optimized reaction conditions in water. The complexes provide turnover frequencies of 57 600 and 232 800 h−1 in Suzuki coupling reactions of phenylboronic acid with p‐bromoacetophenone or p‐iodoacetophenone, respectively, which are the highest values ever reported among similar complexes for Suzuki coupling reactions in water as sole solvent in homogeneous catalysis. Furthermore, the palladium complexes were also found to be highly active catalysts in the Heck reaction affording trans‐stilbenes. Copyright © 2014 John Wiley & Sons, Ltd.

Cyclopalladated ferrocenylimines with ester groups for Heck and Suzuki coupling reactions

Cyclopalladated ferrocenylimine dimers and cyclopalladated ferrocenylimine monomers were designed and prepared. They were characterized using 1H NMR, 13C NMR, and IR spectroscopies, and MS. The catalytic properties of these compounds in Heck and Suzuki coupling reactions in water or organic solvents were systematically investigated. The results showed that these catalysts could effectively catalyze Heck and Suzuki coupling reactions of aryl or heteroaryl halides in water or organic solvents.

Optimized Dispersion and Stability of Hybrid Fe3O4/Pd Catalysts in Water for Suzuki Coupling Reactions: Impact of Organic Capping Agents

AbstractPd nanoparticles were easily immobilized on Fe3O4 microspheres without any treatment such as functionalization with organic groups. The Fe3O4 microspheres were synthesized by using different capping agents, and the effect of the capping agents on the dispersion stability and catalytic activity of the Fe3O4/Pd composite for Suzuki coupling reactions in water were evaluated. The catalytic activity varied depending on the dispersion stability of Fe3O4/Pd catalysts in water. The Pd nanoparticles immobilized onto Fe3O4 microspheres capped with trisodium citrate showed strong dispersion stability in water over the reaction duration of seven days (at pH 7), high catalytic activity, and recyclability under mild conditions.

An easily prepared palladium-hydrogel nanocomposite catalyst for C–C coupling reactions

Palladium nanoparticles were efficiently prepared in situ by sodium cyanoborohydride reduction of Pd(ii) at room temperature using calcium-cholate hydrogel fibers as templates. The PdNPs self-organize on the gel fibers, which supports the controlled growth as well as stabilization of PdNPs. The hybrid xerogel was used as an efficient catalyst for the Suzuki coupling reaction in water.

Palladium(ii)-(E,N,E) pincer ligand (E = S/Se/Te) complex catalyzed Suzuki coupling reactions in water via in situ generated palladium quantum dots

The (E,N,E) pincer ligands (ArECH2CH2)2NH (L1/L2: Ar = Ph, E = S/Se; L3: Ar = CH3O-p-C6H4, E = Te) synthesized by reaction of PhS(-)/PhSe(-)/CH3O-p-C6H4Te(-) with bis(2-chloroethyl)amine react with Na2PdCl4 in aqueous ethanol, resulting in nearly square planar diamagnetic complexes [Pd(L)Cl]Cl (1-3), where L = L1-L3. All the ligands (L1-L3) and their complexes (1-3) have been characterised with (1)H, (13)C{(1)H}, (77)Se{(1)H} and (125)Te{(1)H} NMR spectra and high resolution mass spectrometry. The single crystal structures (determined with X-ray diffraction) of 2 and 3 have been solved (Pd-Se: 2.4104(5)/2.4222(6) Å; Pd-Te: 2.560(2)/2.588(2) Å). The conversions for Suzuki-Miyaura coupling (SMC) of various aryl bromides with phenylboronic and 4-formyl/acetyl phenylboronic acid in water using 2-3 mol% of each of the complexes 1-3 have been found good. Complexes 1 and 2 show better catalytic activity than 3, as higher yields were observed with them in a relatively short time. The coupling reactions appear to be catalyzed with Pd(0) nanoparticles (NPs) generated in situ in the course of reaction. The NPs have been isolated and HRTEM studies on them have revealed their size as ∼1-3 nm. The SEM-EDX indicates their protection with organochalcogen fragments. Addition of TBAB was essential in some cases to get good yield of cross coupled product. The isolated NPs show catalytic activity for SMC independently. The yields of cross coupled product were excellent when NPs were reused. The two phase test suggests a relatively low contribution of homogeneous Pd species in catalysis.

Superb efficient and recycle polymer-anchored systems for palladium catalyzed Suzuki cross-coupling reactions in water

A set of three new polymer-anchored palladium(II) Schiff base catalysts have been synthesized, characterized and their catalytic activity was investigated in the Suzuki cross-coupling reaction between aryl halides and arylboronic acid in the presence of Cs2CO3 as a base. They show excellent catalytic activity in coupling of aryl bromides or aryl iodide with phenylboronic acid under the optimized reaction conditions in water. Polymer–anchored Pd(II) complexes provided turnover frequency of 29,700 or 58,200h−1 in Suzuki coupling reactions of phenylboronic acid with p-bromoacetophenone or p-iodobenzene, respectively, which are the highest values ever reported for the Suzuki coupling reactions in water as sole solvent. The catalyst 1 could be used for 15 reaction cycles in the Suzuki coupling of p-acetobromobenzene at 100°C with no loss of catalytic activity.

Palladium supported on natural phosphate: Catalyst for Suzuki coupling reactions in water

The Suzuki–Miyaura coupling reaction is one of the most important synthetic catalytic reactions developed in the 20th century. However, the use of toxic organic solvents for this reaction still poses a scientific challenge and is an aspect of economical and ecological relevance. The use of water as a reaction medium overcomes this issue. In the present work, we described efficient Suzuki coupling reactions in water, without any phase transfer reagents and it is possible to couple challenging substrates like aryl chlorides. Notably, this protocol also works with ultra-low loading of catalyst with high turnover numbers.

Phosphine-free polystyrene-supported palladium(II) complex as an efficient catalyst for the Heck and Suzuki coupling reactions in water

Abstract A palladium complex, 1-phenyl-1,2-propanedione-2-oxime thiosemi-carbazone-functionalized polystyrene resin supported Pd(II), is found to be a highly active catalyst for the Heck reaction of methyl acrylate with aryl halides and Suzuki reaction of phenylboronic acid with aryl iodides and bromides, giving excellent yields. The reactions were performed under phosphine-free conditions in an air atmosphere. The palladium catalyst is easily separated, and can be reused for several times without a significant loss in its catalytic activity.

A supramolecular peptide nanofiber templated Pd nanocatalyst for efficient Suzuki coupling reactions under aqueous conditions

A bioinspired peptide amphiphile nanofiber template for formation of one-dimensional Pd nanostructures is demonstrated. The Pd and peptide nanocatalyst system enabled efficient catalytic activity in Suzuki coupling reactions in water at room temperature. The nanocatalyst system can be easily separated and reused in successive reactions without significant loss in activity and structural integrity.

Linear Polystyrene-Stabilized Palladium Nanoparticles-Catalyzed C–C Coupling Reaction in Water

Linear polystyrene-stabilized PdO nanoparticles (PS-PdONPs) were prepared in water by thermal decomposition of Pd(OAc)(2) in the presence of polystyrene. The immobilization degree of palladium was dependent on the molecular weight of polystyrene, while the size of the Pd nanoparticles was not. Linear polystyrene-stabilized Pd nanoparticles (PS-PdNPs) were also prepared using NaBH(4) and phenylboronic acid as reductants. The catalytic activity of PS-PdONPs was slightly higher than that of PS-PdNPs for Suzuki coupling reaction in water. PS-PdONPs exhibited high catalytic activity for Suzuki and copper-free Sonogashira coupling reactions in water and recycled without loss of activity.