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Herein, we report anomalous glucose (Glc)-responsive gelation/solation in 3-aminophenylboronic acid-modified hyaluronic acid. With 5-20 mM Glc, gelation occurred, resulting in the formation of crosslinks via Glc, which could reversibly bind to the two boronic acid sites. Solation was induced at Glc concentrations of >80 mM., This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

The reduction of gold ions using four different types of mild reducing agents was carried out in the presence of poly(n-isopropylacrylamide), PNIPAM, particles under light irradiation at room temperature. Simply controlling the concentration ratios of the gold ions to reductants allowed for the systematic formation of physically encapsulated gold nanoparticles (AuNPs) within the PNIPAM particles due to the presence of weak interactions between the guest AuNPs and host PNIPAM particles. After the examination of the structural and physical properties of the AuNPs and their loading efficiency, the composite particles were extensively utilized in the aerobic homocoupling of phenylboronic acid in EtOH to examine their catalytic properties associated with the rate of reaction, selectivity, and activation energy (Ea). All composite particles showed the highly selective formation of the biphenyl product and comparable Ea values, regardless of the size and distribution of the encapsulated AuNPs as catalysts. However, the way the AuNPs were formed within the PNIPAM particles notably influenced the rate of reaction. As such, developing a simple approach to optimize the encapsulation degree of AuNPs and their structural features in the presence of polymer particles can be applied to designing diverse metal-polymer composite particles for rapid and effective catalytic systems.

A series of nanocatalysts derived from immobilization of palladium nanoparticles (Pd NPs) into three dimensional (3D) tube-type architecture of nitrogen (N) functionalized and without functionalized mesoporous carbon CMK-9 is developed by dual agents chemical reduction approach. Herein, for the first time N-functionalized CMK-9 is explored as supports to immobilize Pd NPs and use as multifunctional catalysts for Suzuki-Miyaura cross-coupling reaction, reduction of 4-nitrophenol and hydrodechlorination of chlorobenzene. The Pd@N-CMK-9 catalysts show excellent activities with 100% conversion for Suzuki-Miyaura reaction between iodobenzene and phenylboronic acid and turnover frequency up to 1992 h−1. When use as catalyst for reduction of 4-nitrophenol to 4-aminophenol, it delivers an outstanding rate constant of 4.22 × 10-2 s−1 with activity parameter of 51719 s-1g−1 with respect to only Pd content. The nanocatalysts also demonstrate 100% conversion of chlorobenzene to benzene within 1 h. In addition, the catalyst exhibits remarkable catalytic stability for several cycles without any significant loss of products. The excellent catalytic activities can be attributed to synergistic effect of uniformly dispersed Pd NPs, favorable interaction between metal and support, and tubular interconnected mesoporous framework of N-functionalized CMK-9 that accelerate mass transportation. The present work signifies the versatility of Pd@N-CMK-9 nanocatalysts for various catalytic reactions.

Pd–N-heterocyclic carbine complex immobilized on magnetic nanoparticles is synthesized and characterized by different techniques such as FT-IR, XPS, TEM, EDX, FESEM, VSM, TGA, and ICP. The synthesized catalyst was used as a new water dispersible heterogeneous catalyst in the fluoride-free Hiyama, Suzuki–Miyaura and cyanation reactions in pure water. By this method, different types of biaryls and aryl nitriles were synthesized in good to high yields by the reaction of a variety of aryl iodides, bromides and chlorides with triethoxyphenylsilane, phenylboronic acid and K4[Fe(CN)6]·3H2O, respectively. The presence of sulfonates as hydrophilic groups on the surface of the catalyst confers a highly water dispersible, active and yet magnetically recoverable Pd catalyst. The possibility to perform the reaction in water as a green medium, ease of the catalyst recovery and reuse by magnetic separation, and the absence of any additives or co-solvents make this method as an eco-friendly and economical protocol for the synthesis of biaryl derivatives and aryl nitriles. We acknowledge the financial support for this research by the University of Birjand Research Council and also access to the XPS facilities of the Central Technical Services of the University of Alicante.

A Pd-catalyzed domino reaction of 1,8,13-tribromo-9-methoxytriptycenes is reported. Under conventional Suzuki coupling conditions, the triptycenes underwent multiple transformations to give 1,9-bridged triptycenes. Based on mechanistic investigations, a single Pd catalyst functions as Pd0 , PdII and PdIV species to catalyze four distinct processes: (1) aryl to alkyl 1,5-Pd migration, (2) intramolecular arylation, (3) homocoupling of phenylboronic acid and (4) Suzuki coupling. DFT calculations revealed that 1,5-Pd migration likely proceeds via both concerted PdII and stepwise PdIV routes. Asymmetric synthesis of the chiral triptycenes, as well as optical resolution, and further transformation are also reported.

3-Chloropropyltrimethoxysilane (CPTMS) was grafted on the surface of silica coated Fe3O4 core (Fe3O4@MCM-41) and then condensed with thiocarbohydrazide (TCH) to obtain Fe3O4@MCM-41-CPS-TCH. Then the heterogeneous Fe3O4@MCM-41-CPS-TCH-Pd nanocatalyst was synthesized by adding palladium(II) chloride to functionalized Fe3O4@MCM-41. The resultant nanomaterials were characterized using several techniques such as FT-IR, XRD, FE-SEM, HRTEM, EDS, BET, VSM, XPS, AAS and TGA. Then, the efficiency of this Palladium based magnetic nanocomposite was examined as catalyst for the preparation of biaryl derivatives using the Suzuki coupling of phenylboronic acid with various aryl halides in H2O/EtOH as a green solvent. The as-synthesized nanocomposite was also checked for the Heck–Mizoroki coupling reaction of various aryl halides and styrene. This catalytic system was easily retrieved by a magnetic field and reused for several times without distinct reduction in catalytic activity.

Objective: Aminomethylphenol molecules have wider applications in pharmaceuticals, agrochemicals, plant protection and promising functional materials. The development of an efficient and practical method to prepare this class of compound is highly desirable from both environmental and economical points of view. Materials and Methods: In order to establish an effective synthetic method for preparing aminomethylphenol derivatives, the Petasis borono-Mannich reaction of salicylaldehyde, phenylboronic acid and 1,2,3,4- tetrahydroisoquinoline was selected as a model reaction. A variety of reaction conditions are investigated, including solvent and temperature. The generality and limitation of the established method were also evaluated. Results and Discussion: It was found that model reaction can be carried out in cyclopentyl methyl ether at 80 °C under catalyst-free conditions. This protocol, with broad substrate applicability, the reaction of various arylboronic acid, secondary amine and salicylaldehyde proceeded smoothly under optimal reaction conditions to afford various aminomethylphenol derivatives in high yields. A practical, scalable, and high-yielding synthesis of aminomethylphenol derivatives was successfully accomplished. Conclusion: A catalyst-free practical method for the synthesis of minomethylphenol derivatives based on Petasis borono–Mannich (PBM) reaction of various arylboronic acid, secondary amine and salicylaldehyde in cyclopentyl methyl ether has been developed. The salient features of this protocol are avoidance of any additive/catalyst and toxic organic solvents, use of cyclopentyl methyl ether as the reaction medium, clean reaction profiles, easy operation, and high to excellent yield.

The rapid drug release and poor self-healing properties of drug-loaded hydrogels largely limit their practical application. Herein, we present a simple method to prepare hydrogels with self-healing, drug hosting and pH-sensitive properties for sustained drug release. First, salicylic acid was loaded into β-CD through host–guest interactions. The hydrogel was then constructed through the polymerization of acrylamide using cyclodextrin-phenylboronic acid as a reversible, pH-sensitive cross-linker. The obtained hydrogel exhibited outstanding stretchability (1150%), good tensile strength (42 kPa), excellent self-healing properties (90%) and high biocompatibility. Besides, the introduction of the cyclodextrin-phenylboronic acid cross-linker endowed the hydrogel with pH-sensitive and sustained drug release properties. These functions enable cyclodextrin-phenylboronic acid cross-linked hydrogels to be drug hosting, self-healing and pH-sensitive flexible materials for sustained drug release, making them a powerful platform for various biomedical applications.

We report a supramolecular nanosphere with a diameter of 8.65 nm built in an aqueous solution via dynamic binding of glucose to a thiol ligand bearing a phenylboronic acid group, 4-mercaptophenylboronic acid (4-MPBA), as a hydrophilic component in combination with a hydrophobic thiol ligand, 1-octanethiol (n-C8H17SH), in the presence of Ag+. Highly hydrophilic glucose binding to two neighboring boronic acid groups from 4-MPBA ligands on their Ag+ coordination polymeric backbone, on which the hydrophobic n-C8H17SH ligands locate inwards, drives the coordination polymers into nanospheres. The supramolecular nanospheres are of small diameters with narrow size distribution characteristic of glucose among the tested monosaccharides including fructose and xylose.

Owing to the abundant functional groups present in the chitosan polymer, high density catalytic tiny gold particles with greater dispersion can be anchored on the chitosan powder using simple mortar and pestle. Chitosan-supported gold nanoparticles (NPs) with excellent control of size and shape were rapidly synthesized in gram-scale by solid-grinding without the need of any toxic solvents. The structure of catalysts and products was established by advanced instrumental and spectroscopic methods. The supported gold NPs functions as a heterogeneous catalyst for the homocoupling of phenylboronic acid and the aerobic oxidation of benzyl alcohol in water. The catalytic behaviour and activity of supported gold NPs was tuned/modulated by varying the ratio of chitosan polymer and gold precursor. Comparative studies showed that the solid chitosan supported gold catalyst exhibits superior catalytic activity and selectivity than the well known hydrophilic polymer-stabilized gold NPs catalysts prepared by the conventional solution-based methods.

Two novel water-soluble mononuclear Cu(II) and VO(II)-complexes (CuSL and VOSL, respectively) were synthesized from easily accessible 2-((naphthalen-1-ylimino)methyl)phenolate sodium sulfonate as a Schiff base ligand (HSL). HSL, CuSL and VOSL were characterized by various spectral tools. Their catalytic potential was investigated and compared in 1,2-cyclohexene epoxidation using H2O2 or tBuOOH as an oxidizing agent, and in C―C cross-coupling protocols, including Suzuki-Miyaura and Sonogashira reactions, under homogeneous reaction conditions. Both complexes exhibited good catalytic potential in the epoxidation reaction. VOSL complex with the high oxidation state metal ion (VIV) exhibited slightly better performance in the epoxidation reaction, provided 93, 77 and 89% yield in acetonitrile, water and under solvent free condition. In contrast CuSL complex provided 89, 71 and 79% yield under the same reaction condition. While in Suzuki-Miyaura and Sonogashira C―C reactions using phenylboronic acid or phenylacetylene with aryl halides, CuSL afforded better catalytic potential (89% for Suzuki-Miyaura and 77% yield for Sonogashira C―C products) than VOSL catalyst (73% and 51% yield respectively). DFT studies were also carried to understand the catalytic behavior of CuSL and VOSL catalysts in their catalytic processes. Additionally HSL, CuSL and VOSL were also explored for their biological potential against some pathogens strains, as antimicrobial, antioxidant and anticancer agents. Both complexes (CuSL and VOSL) showed better inhibiting potential than their free ligand. The complex ctDNA-interaction was examined by UV–vis. spectrophotometry, viscosity measurements and gel electrophoresis to determine the nature of binding. Additionally, molecular docking was also carried out for better understanding.

The novel heterogeneous bimetallic nanoparticles of Cu–Co were synthesized based on magnetic nanoparticles, and the magnetic nanocatalyst was characterized by XRD, FE-SEM, EDX mapping, BET, TEM, HRTEM, FTIR, TGA, and VSM. This catalyst was successfully applied as a recyclable magnetically catalyst in Heck, Suzuki, and C–N cross-coupling reactions with various aryl halides (iodides, bromides, and chlorides as challengeable substrates), with olefins, phenylboronic acid, and amines, respectively. We considered the rise of synergetic effects from the different Lewis acid and Bronsted acid sites present in the catalyst. The catalyst was synthesized with cheap, available materials and a simple synthesis method. The catalyst can be separated easily using an external magnet. It was recycled for more than ten runs without a sensible loss of its catalytic activity, and no significant leaching of the Cu and Co quantity was observed. The significant benefits of the method are high-level generality, simple operation, and there are no heavy metals and toxic solvents. This is a quick, easy, efficacious and environmentally friendly protocol, and no by-products are formed in the reaction. These features make it an appropriate practical alternative protocol. In comparison with recent works, the other advantage of this catalyst is the synthesis of a wide variety of C–C and C–N bond derivatives (more than 40 derivatives). The other significant advantage is the low temperature of the reaction and the use of the least possible amount of the catalyst (0.003 g). The efficiency was good to excellent and the catalyst selectivity has been high. We aspire that our study inspires more interest to design novel catalysts based on using low-cost metal ions (such as cobalt and copper) in the cross-coupling reactions.

Inspired by the recent experimental reports on boron containing compounds to be active and biomimetic for carbon capture, we report the mechanistic details of CO2 hydration activities of boronic acids using density functional theory calculations. Four boronic acids were analyzed, viz., [3-methyl-6-(1H-pyrazol-1-yl)phenyl]boronic acid, 3-aminophenylboronic acid, 2,6-dibromophenylboronic acid and 2,6-bis(trifluoromethyl)phenylboronic acid. Free energy landscapes were developed for the hydration reaction. 2,6-Dibromophenylboronic acid showed the highest turnover frequency. Computational NMR and FTIR spectra for various intermediates of the reaction were analyzed and compared with experimental spectra. The energetics as well as the spectral analyses confirmed the biomimetic mechanism for CO2 hydration over all the boronic acid catalysts under investigation.

Specifically designed electrochemical sensors are standing out as alternatives to enzyme-based biosensors for the sensing of metabolites. In our previous works, we developed a new electrochemical assay based on cyclodextrin supramolecular complexes. A ferrocene moiety (Fc) was chemically modified by phenylboronic acid (4-Fc-PB) and combined with two different kinds of cyclodextrins (CDs): β-CD and β-CD modified by a dipicolylamine group (dpa-p-HB-β-CDs) for the sensing of fructose and adenosine-triphosphate (ATP), respectively. The aim of the present work is to better comprehend the features underlining the aforementioned complex formation. For the first time, a study about inclusion phenomena between the 4-Fc-PB electroactive probe with β-CD and with dpa-p-HB-β-CD was performed by using nuclear magnetic resonance (NMR) analysis. In particular, we focused on providing insights on the interaction involved and on the calculation of the binding constant of 4-Fc-PB/β-CD supramolecular complex, and elucidation about a drift in the time observed during the control experiments of the electrochemical measurements for the 4-Fc-PB/dpa-p-HB-β-CD supramolecular complex. In this sense, this paper represents a step further in the explanation of the electrochemical results obtained, pointing out the nature of the interactions present both in the formation of the inclusions and in the sensing with the analytes.

Nickel catalysts represent a low cost and environmentally friendly alternative to palladium-based catalytic systems for Suzuki–Miyaura cross-coupling (SMC) reactions. However, nickel catalysts have suffered from poor air, moisture, and thermal stabilities, especially at high catalyst loading, requiring controlled reaction conditions. In this report, we examine a family of mono- and dinuclear Ni(II) and Pd(II) complexes with a diverse and versatile α-diimine ligand environment for SMC reactions. To evaluate the ligand steric effects, including the bite angle in the reaction outcomes, the structural variation of the complexes was achieved by incorporating iminopyridine- and acenaphthene-based ligands. Moreover, the impact of substrate bulkiness was investigated by reacting various aryl bromides with phenylboronic acid, 2-naphthylboronic acid, and 9-phenanthracenylboronic acid. Yields were the best with the dinuclear complex, being nearly quantitative (93–99%), followed by the mononuclear complexes, giving yields of 78–98%. Consequently, α-diimine-based ligands have the potential to deliver Ni-based systems as sustainable catalysts in SMC.

The Suzuki-Miyaura cross-coupling reaction is an effective process for C-C bond formation in organic synthesis. Herein, we report a NiO nanodot-decorated Pd/SiC catalyst, synthesized by atomic layer deposition, which shows high photocatalytic activity for the Suzuki-Miyaura coupling of both aryl bromides and chlorides with phenylboronic acid at 30 °C in air. The Mott-Schottky contact in SiC/Pd enhances the rapid transfer of the photogenerated electrons from SiC to Pd nanoparticles. Moreover, the energy different between the highest occupied molecular orbital of the ultrafine NiO nanodots and the Fermi level of Pd forces a spontaneous electron transfer from NiO to Pd. As a result, the concentrated electrons in the Pd nanoparticles can facilitate the cleavage of C-Br or C-Cl bonds, which normally requires rather high temperatures in thermal processes. The holes left on the SiC support can assist the cleavage of the C-B bond.

The hexagonal mesoporous organic–inorganic hybrid as a new nanocatalyst was prepared by the treatment of SBA-15 with (3-chloropropyl)triethoxysilane, the 2,4,6-triamino pyrimidine ligand, and then PdCl2 to obtain the SBA-15-propyl-triamino pyrimidine@Pd called as SBA-Pr-3AP@Pd, which was examined through Suzuki–Miyaura cross-coupling reaction by several aryl halides and phenylboronic acid under mild conditions in high yield.

In this work, Pd nanoparticles (Pd-NPs) were decorated on modified magnetic nanoparticles (MNPs) and used as an efficient and recyclable catalyst for the Suzuki cross-coupling reaction of aryl halides with phenylboronic acid (PhB(OH)2) in a green solvent. The prepared nanocomposite was characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transforms infrared spectroscopy, X-ray powder diffraction, thermogravimetric analysis/differential thermal analysis, and vibrating sample magnetometry. All analyses confirmed the successful modification of MNPs and immobilization of Pd on modified MNPs. This catalyst exhibited superior catalytic activity and stability in the suzuki cross-coupling reaction of PhB(OH)2 and aryl halide derivatives. This protocol includes some advantages, such as magnetically reusability of the catalyst, mild experimental conditions, green solvent, excellent yields of the product (52–98%), and short reaction times (4–33 min). The catalyst could be reused for six successive runs without any significant loss of its efficiency.

A new and efficient N-heterocyclic carbene (NHC)-palladium(II) complex immobilized on graphene oxide (NHC-Pd@GO) has been successfully designed and synthesized. The prepared NHC-Pd@GO heterogeneous catalyst was fully characterized using a combination of fourier transform infrared spectroscopy (FTIR), inductively coupled plasma-optical emission spectroscopy (ICP-OES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller surface area analysis (BET). This new air- and moisture-stable NHC-Pd@GO heterogeneous catalytic system was found to be a highly active catalyst in the Suzuki–Miyaura cross-coupling between phenylboronic acid and various aryl halides (bromides/chlorides/iodides) and in the reduction of nitroarenes. These organic transformations were best performed in an aqueous ethanol and aqueous methanol solvent system respectively with low catalyst loading under mild reaction conditions. Furthermore, NHC-Pd@GO heterogeneous catalyst could be recovered easily and reused at least eleven times in Suzuki–Miyaura cross-coupling and nine times in reduction of nitroarenes without any considerable loss of its catalytic activity. The stability and good selectivity of the NHC-Pd@GO heterogeneous catalyst in recycling experiments signify that it could be useful for practical application in various organic transformations.

Stille coupling was applied to synthesize microporous organic polymers (MOPs). Metallic Pd was in situ self-supported during the networking of 1,3,6,8-tetrabromopyrene with 1,4-bis(tributylstannyl)benzene to form Stille coupling-based MOP (St-MOP)@Pd. The size of St-MOP particles and the amount of metallic Pd in St-MOP@Pd depended on the amount of Pd catalyst. As the amount of Pd catalyst increased, the size of St-MOP particles decreased with an increase of metallic Pd, due to the increased St-MOP nuclei in the early growth stage of St-MOP. The St-MOP bearing pyrenes showed absorption and emission of visible light and St-MOP@Pd showed excellent catalytic performance in the visible light-driven Suzuki–Miyaura coupling. The optimal St-MOP@Pd-2 (0.14 mol% Pd) showed a TON of 657 and a TOF of 219 h−1 in the visible light-driven Suzuki–Miyaura coupling of 1-acetyl-4-bromobenzene and phenylboronic acid at 25 °C. The optimal amount of St-MOP and metallic Pd in St-MOP@Pd was critical to achieve excellent catalytic performance. The overall photocatalytic principles of St-MOP@Pd were rationalized by computational simulation.

Horseradish peroxidase (HRP) is a classic cis-diol-containing glycoprotein and can be extracted from horseradish plants; it has low loading capacity and enzyme stability in the separation process. Functionalized magnetic nanoparticles have been proved to be effective for the separation and purification of glycoproteins. In this work, dendrimeric phenylboronic acid-functionalized magnetic graphene oxide nanoparticles (d-PBA-GO@Fe3O4@PEI) were synthesized via dendrimer-assisted multivalent synergistic binding. The boronic acid in the dendrimeric magnetic nanoparticles provided docking sites for cis-diol-containing biomolecules. d-PBA-GO@Fe3O4@PEI exhibited excellent performance in the separation of HRP with a binding capacity as high as 557.75 mg g−1. The magnetic nanoparticles also exhibited excellent recyclability. It was found that the nanoparticles had satisfactory performance for the separation and purification of HRP from the crude extract of horseradish; moreover, the HRP structure remained unchanged before and after the elution process. The outstanding adsorption performance (high adsorption capacity and specific recognition) makes the nanoparticles promising for the separation and purification of glycoproteins in the future industrial production.

In this study, a novel carbon nanotube (CNT) based nanocatalyst (Ni@Pd/CNT) was synthesized by modifying CNTs using Ni@Pd core-shell nanoparticles (NPs). Ni@Pd/CNT was used in catalytic carbonylative cross-coupling between 4-iodoanisole and phenylboronic acid. The Ni@Pd NPs possessed a magnetic nickel (Ni) core with a palladium (Pd) structural composite shell. Thus, the use of Ni had led to a reduced consumption of Pd without sacrificing the overall catalytic performance, simultaneously making it reusable as it could be conveniently recovered from the reaction mixture by using an external magnetic field. Immobilization of the Ni@Pd NPs on carbon nanotubes not only prevented their aggregation, but also significantly enhanced the accessibility of the catalytically active sites. The abovementioned approach based on carbon nanotubes and Ni@Pd NPs provided a useful platform for the fabrication of noble-metal-based nanocatalysts with easy accessibility and low cost, which may allow for an efficient green alternative for various catalytic reductions.

Domino oxidation-Suzuki–Miyaura cross-coupling of benzyl alcohols with phenylboronic acid and domino reduction-C–N cross-coupling of the nitro compounds with aryl halides were carried out using a strong Ni/Pd bimetallic redox catalyst. The catalyst bearing a copolymer with two Ni/Pd coordinated metals in porphyrin (derived from demetalated chlorophyll b) and salen-type ligands, and pyridine moiety as a base functionality all immobilized on magnetite NPs was synthesised and characterized. The domino oxidation cross-coupling reaction was accomplished under molecular O2 in the absence of any hydride acceptor or/and base. Also, the domino reduction C–N cross-coupling reaction was performed in the presence of NaBH4 without the need for any base and co-reductant. This multifunctional catalyst gave moderate to good yields for both coupling reactions with high chemoselectivity. A wide investigation was conducted to determine its mechanism and chemoselectivity.

We have developed an efficient method for Cu-ACP-Am-Fe3O4@SiO2 catalyzed Chan–Lam coupling of phenylboronic acid with primary amine furnished secondary amines. The catalyst offered virtues like mild reaction conditions, magnetically separable, and reusable and exhibits excellent performance in terms of good product yield and high turnover number.

Suzuki coupling is an important, extensively investigated, and manifold approach for C–C bond construction in synthetic chemistry. However, to date, the reaction has been extensively investigated under thermal conditions using palladium-based catalysts. The development of solar light assisted noble-metal free Suzuki coupling represents a green and sustainable approach for such types of reactions. Herein, we describe an efficient, facile, and cost-effective photocatalytic approach for C–C bond formation between aryl halides and phenylboronic acid via Suzuki-cross-coupling using a cobalt(II) phthalocyanine complex grafted onto a nickel oxide semiconductor at room temperature (RT) and atmospheric pressure. A number of substituted aryl halides have been successfully investigated using the developed protocol and afforded modest to high yields of the desired biphenyls. The possible mechanistic pathway suggested that the formation of photogenerated aryl radical cations from the phenylboronic acid followed by its coupling with aryl radical anions generated from the electron-activated aryl halides resulted in the corresponding biaryls. Importantly, the physical mixture of both components, i.e., CoPc and NiO, showed poor efficiency as compared to the developed hybrid photocatalyst. The recovered photocatalyst could readily be recycled for at least six runs without a significant decrease in the activity.

This work describes a simple procedure for the synthesis of highly nitrogen-rich covalent organic polymers using commercially available starting materials like melamine and cyanuric chloride as a solid heterogeneous catalyst Cu/TCOP under solvothermal conditions. The structural properties of the as-synthesized solid heterogeneous catalyst were determined by X-ray diffraction (XRD), diffuse reflectance spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), 13C-CP MAS nuclear magnetic resonance spectroscopy and X-ray photoelectron spectroscopy. The catalytic activity of Cu/TCOP was investigated by focusing on the oxidation of phenylboronic acid under atmospheric conditions in an aqueous medium, achieving a very good yield up to 99%. The reaction performance was evaluated considering the effect of various parameters, such as the amount of the catalyst, reaction time, temperature, and the amount of the base and solvent. The Cu/TCOP catalyst is completely recoverable in a facile manner from the reaction mixture and the efficiency of the copper nanocatalyst can be recovered after five cycles.

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 C 10 H 7 N 2 O 2 (6): triclinic, space group P-1 (no. 2), a = 3.9956(10) A, b = 9.8917(18) A, c = 10.810(3) A, α = 94.167(15)°, β = 94.979(19)°, γ = 98.953(15)°, V = 418.83(16) A 3 , Z = 2, T = 296.(2) K, μ(Cu Kα) = 0.887 mm -1 , D calc = 1.484 g/cm 3 , 5469 reflections measured (11.72° ≤ 2Θ ≤ 133.24°), 1420 unique ( R int = 0.0633, R sigma = 7.24%) which were used in all calculations. The final R 1 was 0.1055 (>2sigma(I)) and wR 2 was 0.3620 (all data).

Timely lysosome escape is of paramount importance for endocytosed nanomedicines to avoid premature degradation under the acidic and hydrolytic conditions in lysosomes. Herein, we report an exciting finding that phenylboronic acid (PBA) modification can greatly facilitate the lysosome escape of cylindrical polymer brushes (CPBs). On the basis of our experimental results, we speculate that the mechanism is associated with the specific interactions of the PBA groups with lysosomal membrane proteins and hot shock proteins. The featured advantage of the PBA modification over the known lysosome escape strategies is that it does not cause significant adverse effects on the properties of the CPBs; on the contrary, it enhances remarkably their tumor accumulation and penetration. Furthermore, doxorubicin was conjugated to the PBA-modified CPBs with a drug loading content larger than 20%. This CPBs-based prodrug could eradicate the tumors established in mice by multiple intravenous administrations. This work provides a novel strategy for facilitating the lysosome escape of nanomaterials and demonstrates that PBA modification is an effective way to improve the overall properties of nanomedicines including the tumor therapeutic efficacy.

Cellulose, as a green and available phytochemical, was immobilized on the surface of magnetite nanoparticles then doped with imidazole and Co. complex (Fe3O4@CNF ∼ ImSBL ∼ Co.) and used as a water-dispersible, recyclable and efficient nano catalyst for the synthesis of C−C cross-coupling reactions including fluoride-free Hiyama and Suzuki reactions in an aqueous medium as an efficient and vital solvent, due to their high application and importance in various fields of science. Different spectroscopic and microscopic techniques were used for the catalyst characterization such XRD, FESEM, TEM, FT-IR, EDX, DLS, VSM, UV-Vis, and ICP analyses. The presence of imidazole as ionic section tags with hydrophilic character on the Co-complex supported on magnetic nanoparticles provides dispersion of the catalyst particles in water, which leads to both higher catalytic performance and also facile catalyst recovery and reuse six times by successive extraction and final magnetic separation. High catalytic activity was found for the catalyst and high to excellent efficiency was obtained for all Suzuki (80–98% yield; E factor: 1.1–1.9) and Hiyama (87–98% yield; E factor: 0.26–1.1) derivatives in short reaction times under mild reaction conditions in the absence of any hazardous or expensive materials. There is not any noticeable by-product found whether for Suzuki or Hiyama derivatives, which reflects the high selectivity and also the lower the E factor the more favorable is the process in view of green chemistry. The bi-aryls were achieved from the reaction of various aryl iodides/bromides and even chlorides as the highly challenging substrates, which are more available and cheaper, with triethoxyphenylsilane or phenylboronic acid. To prove the performance of the catalyst components (synergistic of SBL ∼ Co. and IL), its different homologs were incorporated individually and studied for a model reaction. Exclusively, this is an introductory statement on the use of Cobalt binuclear symmetric ionic liquid catalysts in Hiyama reactions.

In this paper, we report an effective ultrasound method for the synthesis of Pd/H-MOR, which was used as a catalyst in the Suzuki-Miyaura coupling of aryl halides with phenylboronic acid. The structure and morphology of the as-prepared catalysts were fully characterized by X-ray diffraction (XRD), N2 sorption isotherms, scanning electron microscopy (SEM), and an inductively coupled plasma-atomic emission spectrometer (ICP-AES). The advantages of Pd/H-MOR in the coupling reaction are green solvents, high yields, absence of ligands, and recyclability. The catalysts were easily reused at least ten times without significant deterioration in catalytic activity. In addition, this protocol was used in the marketed anti-tumor drug crizotinib synthesis.

The Pd catalyst for Suzuki–Miyaura or the other C–C coupling reactions is one of the central tools in organic synthesis related to medicine, agricultural chemicals and advanced materials. However, recycling palladium is a bottleneck for developing the extreme potential of Pd in chemistry. Herein, we established a new heterogeneous Pd catalytic system in which the catalyst is a nanopetal-gathered flower-like microsphere self-assembled from PdCl2 and alkyl-linked bis-theophyllines. The microflowers catalyzed quantitatively the reaction of aryl bromides and phenylboronic acid in aqueous media at room temperature. It was found that the reaction proceeds better in an air atmosphere than in nitrogen gas even though the Pd(II) species employed was lowered to 0.001 mol% in the substance. Very interestingly, the microflowers could be recycled 20 times without deactivation in the C–C coupling reaction between bromobenzene and phenylboronic acid in the presence of sodium chloride. We found that the sodium chloride added played an important role in maintaining the morphology of microflowers and preventing the formation of metallic Pd particles.

Palladium is one of the best metal catalysts for Suzuki cross-coupling reaction to synthesize unsymmetrical biaryl compounds. However, homogeneous palladium (Pd) is limited in an industrial scale due to the high cost, separation, removal, and recovery issues. In this paper, a novel, high activity magnetic nanoparticles (Fe3O4@SiO2-APBA-Pd) catalyst was prepared by a simple, cost-effective procedure. The as-prepared functional nanoparticles (Fe3O4@SiO2-APBA) with boric acid group immobilized Pd through adding Pd(OAc)2 to Fe3O4@SiO2-APBA in absolute ethanol and maintaining for a certain time under a nitrogen atmosphere. The as-prepared catalyst was characterized by FT-IR, SEM, EDX, TEM, ICP-MS, XPS, and XRD. The results showed that the Pd (0.2–0.6 nm) was successfully anchored on the magnetic silica material with boric acid group. The amount of Pd was 0.800 mmol g−1. This magnetic nanostructure (8–15 nm) is especially beneficial as a nanocatalyst because each nanoparticle can catalyze a reaction in a certain time without steric restriction, which could effectively improve the reaction efficiency. The current nanoparticles with the Pd catalyst could be used as a novel, green, and efficient heterogeneous catalyst for Suzuki reactions. This catalyst showed promising catalytic activity and excellent yields toward 14 kinds of Suzuki coupling reactions under mild reaction conditions, which was similar to homogeneous Pd and many reported heterogeneous Pd catalysts. In addition, the turnover number (TON) and turnover frequency (TOF) for the Suzuki reaction were high. TOF and TON were 9048 h−1 and 20 250 for the Suzuki reaction of bromobenzene and phenylboronic acid. Furthermore, the nanoparticles could be easily separated by a magnet, and could be used repeatedly seven times without any significant loss in activity.

A simple preparation of catalysts with high catalytic activity and superior cycling stability is very desirable. In this contribution, magnetic carbon nanotube functionalized by polythiophene (CNT–Fe3O4–PTh) acts as an efficient and retrievable host for copper nanoparticles to prepare CNT–Fe3O4–PTh–Cu(I) as a nontoxic and inexpensive catalyst. FT-IR, TGA, EDX, VSM, XRD, FE-SEM, TEM, and AAS techniques were employed to characterize the structure of the synthesized magnetic heterogeneous nanocomposite. Thereafter, the catalytic application of the catalyst was evaluated for the phosphine- and palladium-free Suzuki–Miyaura cross-coupling reaction in water/ethanol as a green media in short reaction times with good to excellent yields. Various derivatives of biaryl compounds were synthesized by reaction of aryl halides and phenylboronic acid. Simple methodology and easy workup, short reaction times, elimination of volatile and toxic solvents, biocompatible reaction conditions, and high yields are some advantages of this protocol. Moreover, the catalyst showed a good reusability owing to its magnetic properties and was recycled several times without appreciable decrease in its catalytic efficiency. Copper(I) nanoparticles supported on magnetic carbon nanotube functionalized by polythiophene (CNT–Fe3O4–PTh–Cu(I)), was prepared and used for ligand- and palladiumfree Suzuki–Miyaura cross-coupling reaction in water/ethanol as a green media in short reaction times with good to excellent yields. Reusability and stability tests demonstrated that the as prepared catalyst can be recycled with a negligible loss of its activity.

Here a novel Pd supported polymeric magnetic nanoparticles with urea-pyridine bridge (denoted as Fe3O4@/Urea-Pyridine/Pd) was synthesized and characterized. The Fe3O4@/Urea-Pyridine/Pd nanocatalyst was synthesized via a four steps process by using Fe3O4 nanoparticles, 3‐(triethoxysilyl) propylisocyanate (TESPIC), 2,6 bis(propyl-triethoxysilylureylene) pyridine (BPS) and palladium chloride. The synthesized polymeric Fe3O4@/Urea-Pyridine/Pd nanocatalyst was analyzed through different analytical techniques, including FT-IR, NMR, XRD, VSM, TGA, DTA, ICP, FESEM, EDX, and BET. The described palladium supported polymeric magnetic nanoparticles with urea-pyridine bridge (Pd-MNPs) was used for the C–C and C–N coupling of phenylboronic acid with various amines and aryl halides in DMF as well as Sonogashira and Suzuki reactions in aqueous solution. Also, the Fe3O4@/Urea-Pyridine/Pd nanocatalyst exhibited high structural stability and excellent recyclability.

The Pd leaching behaviour of a strongly acid (Lewatit K2629) versus strongly basic (Lewatit MP500 OH) ion exchange resin supported Pd nanoparticle (Pd-NP) catalyst is elucidated in the Suzuki reaction between iodobenzene and phenylboronic acid with K2CO3 as base in 1:1 (v/v) DMF/H2O at 40 °C. Reaction and leaching kinetic analyses combined with hot filtration tests indicated heterogeneous-homogeneous catalysis for both Pd-NP catalysts. More particularly, leaching experiments showed that for Pd-NP Lewatit K2629, Pd-NP as well as molecular Pd2+ leaching (as phenylpalladium(II)hydroxide complexes) occurred due to, respectively, the disturbance of the electrostatic NP stabilization by dissociated K2CO3 and reaction with iodobenzene and hydroxide. For Pd-NP Lewatit MP500 OH, however, molecular Pd2+ leaching induced by iodobenzene, dominates. Hence, the resin functionality determines the contribution of each leaching pathway. Furthermore, at high conversions, Pd re-deposition occurred due to the decreased amount of leaching inducing reagents causing enlarged NPs in the resin which leached less in subsequent runs.

The intermolecular radical addition to the carbonyl group is difficult due to the facile fragmentation of the resulting alkoxyl radical. To date, the intermolecular radical addition to ketones, a valuable approach to construct quaternary carbon centers, remains a formidable synthetic challenge. Here, we report the first visible-light-induced intermolecular alkyl boronic acid addition to α-ketoacids enabled by the Lewis acid activation. The

In the current research, preparation, characterization and catalytic application of a novel Schiff-base/Pd complex immobilized onto graphene oxide (GO–SB/Pd) are investigated. The GO–SB/Pd was characterized using Fourier transform infrared spectroscopy, thermal gravimetric analysis, diffuse reflectance UV–Vis, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) analysis. It was found that the GO–SB/Pd is an efficient catalyst in the Suzuki–Miyaura cross-coupling of phenylboronic acid with aryl halides. Moreover, the catalyst could be easily recycled and reused for several times without discernible loss in activity.

Five novel dioxime ligands (L (1-5) H 2 ) were synthesized in various yields under suitable conditions. Novel nano-Fe 3 O 4 -supported compounds (Fe 3 O 4 /L (1-5) ) based on dioxime ligands were also prepared. Subsequently, hybrid materials Fe 3 O 4 /L (1-5) /Pd(II) were fabricated by the reaction of Fe 3 O 4 /L (1-5) with Pd(AcO) 2 in acetonitrile. All synthesized nanoparticles were characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), X-ray diffraction (XRD), inductively coupled plasma analysis (ICP), differential scanning calorimetry (DTA), and thermogravimetric analysis (TGA). The spectroscopic results show that the magnetite (Fe 3 O 4 ) nanoparticles are in nano size since crystal sizes are Fe 3 O 4 , Fe 3 O 4 /L (1-5) , and Fe 3 O 4 /L (1-5) /Pd(II) MNPs possess cubic structure having the lattice parameter between 8.31 and 8.40 A. The structure and the lattice parameters are in good agreement with the literature reported data. The Fe 3 O 4 /L (1-5) /Pd(II) nanocatalysts showed high activities in the Suzuki-Miyaura cross-coupling of different aryl halides including iodides, bromides and even chlorides with phenylboronic acid under green and aerobic conditions. More importantly, the reusability experiments revealed that Fe 3 O 4 /L (1-5) /Pd(II) catalysts were durable by almost maintaining their inherent activity after 5 catalytic cycles.

Rigid pyridylphenylene dendrons were shown to successfully function as capping molecules for stabilization of both magnetite and Pd nanoparticles (NPs) to form hydrophobic, magnetically recoverable catalysts. However, syntheses in colloidal solutions require large amounts of dendrons and are difficult to scale up. Here, we developed a strategy for the nanocomposite formation by immobilization of the pyridylphenylene dendrons (D) on magnetic silica (Fe3O4-SiO2, MS) surface via the formation of ether or amide bonds, depending on the structure of flexible linkers on the MS surface and dendron focal groups. Both approaches allow attachment of small amounts of the dendrons with high surface coverage and impart amphiphilicity to the final composite. After the binding to the MS surface, the dendron pyridine moieties readily complex with Pd acetate, leading to a “cocktail” of Pd2+ and Pd0 species (the latter forming Pd NPs) due to partial reduction by composite functional groups. The MS-D-Pd nanocomposites were tested in the model Suzuki-Miyaura cross-coupling reaction of 4-Br-anisole and phenylboronic acid to evaluate their performance in hydrophilic conditions. MS-D-Pd demonstrated excellent performance, even at a very small amount of the catalyst, which is assigned to exceptional stabilization by dendritic ligands, allowing prevention of the metal leaching and preservation of catalytic properties upon magnetic separation. The immobilization of rigid hydrophobic dendrons on the hydrophilic magnetic support may allow one to extend the scope of catalytic reactions due to catalyst amphiphilicity.

Magnetic mesoporous silica nanocomposite, Fe3O4-MCM-41, was functionalized with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPS) and then condensed with 5,5′-methylene bis(salicylaldehyde), followed by N(4)-phenylthiosemicarbazide to produce a ONS Schiff base grafted nanocomposite. Finally, by adding palladium(II) acetate, the palladium Schiff base complex was immobilized on magnetic nanocomposite. The characterization of new nanocomposites was carried out by means of several techniques such as FT-IR, XRD, FE-SEM, HRTEM, EDS, BET, VSM, XPS, DRS and TGA. The new nanocatalyst, Fe3O4@MCM-41-SB-Pd, was used in synthesis of symmetrical and unsymmetrical biaryl compounds via the Suzuki–Miyaura cross-coupling of phenylboronic acid with aryl halides. This catalyst was easily recovered by applying an external magnetic field and reused for several times without significant loss of its catalytic activity. Also the ability of synthesized mesoporous nanocomposites for enzyme immobilization was investigated and results showed that they efficiently immobilized α-amylase enzyme.

[NiBr2(PPh3)2] and [NiBr2(dppe)] are prepared from nickel bromide hydrate and phosphine. These brightly colored coordination compounds are then converted into the related organometallic compounds trans-[NiBr(Mes)(PPh3)2] and [NiBr(Mes)(dppe)] (Mes = 2,4,6-Me3C6H2) by reaction with the Grignard reagent MesMgBr. Characterization of the compounds is accomplished by a combination of UV–vis and multinuclear NMR spectroscopies. [NiBr(Mes)(dppe)] is a highly active precatalyst for the Suzuki–Miyaura cross-coupling of 4′-bromoacetophenone and phenylboronic acid. The catalytic reaction is complete in as little as 15–20 min with only a 1 mol % precatalyst loading, and the reaction can be carried out in air. Results are assessed by 1H NMR spectroscopy, or the solid 4-acetylbiphenyl product can be isolated following aqueous workup and recrystallization. The experiments are flexible and accommodate a variety of laboratory schedules and student skill levels. Each experimental component has been designed to be completed within a 3 h laboratory period.

An efficient protocol for C–C coupling has been developed using three iodo-bridged copper(I) complexes as catalysts. Complexes [CuI(bpy)]2 (1), [CuI(phen)]2·DMF (2), and [CuI(Mephen)]2 (3) were successfully synthesized via solvothermal method (bpy = 2,2′-dipyridyl, phen = 1,10-phenanthroline, and Mephen = 2,9-dimethylphenanthroline). The self-coupling reaction of phenylboronic acid was selected as a model reaction to evaluate the catalytic property of the complexes. Moreover, this method tolerates various substituents on the arylboronic acids such as halogens, carbonyls, and nitro groups. It shows that the iodo-bridged Cu(I) center serves as the active site to activate molecular oxygen during the catalytic process. The result illustrates that these complexes were found to be excellent catalysts for self-coupling of arylboronic acids under mild conditions.

WOS: 000470943900121, PubMed: 30974140, In this study, a novel highly efficient heterogeneous palladium catalyst (GG-Pd) was prepared using guar gum, which is an environmentally friendly, easily available, fairly cheap, and renewable natural bio-polymer. Detailed characterization of GG-Pd catalyst was successfully performed by FT-IR, TG/DTG, SEM, EDS, XRD, and ninhydrin test, and it was evaluated as a heterogeneous catalyst against Suzuki-Miyaura coupling reactions of a series of aryl halides with phenylboronic acid. Catalytic performance studies showed that GG-Pd efficiently catalyzed Suzuki cross coupling reactions under solvent-free media and for a very short reaction time (5 min). Moreover, reusability tests showed that GG-Pd catalyst could be reused at least ten times with a minor decrease of its catalytic performance. Additionally, it was found that palladium leaching from the designed support was very minimal. This study shows that GG-Pd catalyst is a very useful and highly stable heterogeneous catalyst for Suzuki-Miyaura coupling reactions in terms of high catalytic performance and recyclability. (C) 2019 Elsevier B.V. All rights reserved.

Mesoporous silica-supported Rh complex catalysts were prepared by simple silane-coupling, followed by complexation, and characterized by FT-IR, SEM, Rh K-edge XAFS, and elemental analysis. Local structures of the Rh complexes in each sample were almost similar to those of a nonporous silica-supported diaminorhodium complex. Co-immobilization of a tertiary amine on the same silica surface induced slight changes to the Rh complex structure in the case of the support with smaller pores. The prepared catalysts showed high activity for the 1,4-addition reaction of phenylboronic acids. Co-immobilization of the tertiary amine increased the reaction rate by more than 7-fold, with turnover number of nearly 8500. The catalytic performance achieved with this novel system is with much higher than that reported previously with a nonporous silica-supported catalyst. The mesoporous silica-supported Rh complex-tertiary amine showed a wide substrate scope, including unsaturated ketones and nitriles. This co-immobilized tertiary amine may activate phenylboronic acid to enhance its reactivity in the transmetalation step with Rh-OH species.