Suzuki Coupling Reaction Research Articles

Green synthesis of palladium nanoparticles mediated by Acer L. leaves as reducing agent, stabilizer, and carrier for Suzuki reaction

Plant fiber‐supported palladium nanocatalysts (Pdx/FAL) with high catalytic activity and good stability were synthesized by one‐pot method using Na2PdCl4 as palladium source, Acer L. leaves as reducing agent, stabilizer, and carrier without adding chemical reducing agents or stabilizers. The as‐prepared catalysts were characterized by XRD, FT‐IR, SEM, TEM, and so forth. During the preparation process, the extraction of organic matter from Acer L. leaves, the reduction and stabilization of Pd2+, and the loading of palladium nanoparticles (PdNPs) were carried out simultaneously, which greatly simplified the preparation steps and reduced the cost. Oxygen‐ and nitrogen‐containing groups in the Acer L. leaf extract preferentially formed complexes with Pd2+, and then, the polyphenols reduced Pd2+ to Pd0, which ensured that PdNPs with small particle sizes were formed and embedded in porous plant fibers (extraction residue of Acer L. leaves) with oxygen‐containing groups, thereby improving the catalytic activity and stability of the catalyst. The characterization results showed that the prepared PdNPs with a face‐centered cubic structure were uniformly distributed on the support, and the average particle size was 3.08 nm. The Suzuki coupling reaction of 4‐bromonitrobenzene and phenylboronic acid by the prepared catalysts at 40°C showed that the reaction yield could reach 97.72%, and the TOF could reach 3,240.6 h−1, exhibiting high catalytic performance. The reaction of 4‐bromotoluene with phenylboronic acid gave a yield of 98.58%, which remained above 90% after seven repetitions. This article provided a simple, high‐performance, and eco‐friendly synthesis idea for nanopalladium catalysts.

Synthesis, characterization and catalytic activities of palladium(II)-imidazopyridine

The ligand 2-phenylimidazo(1,2-α)pyridine (1) was synthesized by neat reaction 2-aminopyridine and 1-bromo-acetophenone; reaction of 1 with acetonitrile solution of PdCl2 leads to [Pd(1)Cl2(CH3CN)] (2). Refluxing [Pd(1)Cl2(CH3CN)] (2) in pyridine leads to [Pd(1)Cl2(py)] (3).The complexes were characterized by various spectroscopic techniques and the solid state structure of 2 was elucidated by single crystal X-ray diffraction (SCXRD) analyses. SCXRD analyses support the square planar geometry of 2. A series of DFT calculations were also performed to gain further insight into the respective structures of the complexes. From molecular hardness calculation it is observed slightly better reactivity of 2 compared to 3. Molecular Hirshfeld surface analyses support various non-covalent secondary interactions that observed in packing of solid state structure of 2. Complexes 2 and 3 were found to facilitate Suzuki coupling reactions under relatively mild conditions and slightly better yields were obtained in case of 2.

Total Synthesis and Anti-Inflammatory Evaluation of Osajin, Scandenone and Analogues.

In this study, the total synthesis of osajin, scandenone and their analogues have been accomplished. The key synthetic steps include aldol/intramolecular iodoetherification/elimination sequence reactions and a Suzuki coupling reaction to assemble the tricyclic core, chemoselective propargylation and Claisen rearrangement reactions to obtain natural compounds. In addition, we also designed and synthesized twenty-five natural product analogues. All synthetic compounds were screened for anti-inflammatory activity against tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Collectively, Compound 39e and 39d were considered as promising lead compounds for further development.

Linkage Isomers of Triangular Pd Metallacycles and Catalysis in Aqueous Suzuki Coupling Reaction.

The water-soluble trinuclear Pd metallacycles [Pd(tmeda)(4-Spy)]3(X)3 (tmeda = tetramethylethylenediamine, X = OTf, 2; NO3, 3) were synthesized from the ambidentate ligand 4-pyridylthiolate (Spy-) and [Pd(tmeda)X2] in 80 and 70% yield, respectively. Two possible linkage isomers are found in solution (slow interconversion found in the NMR) and in the solid state. Density functional calculations showed that the energy of the isomer with a D3-symmetric arrangement of the SPy ligand and all Pd atoms having N∧NPdSN coordination is only 7 kcal/mol lower. When reacting [Pd(tmeda)(NO3)2] with 4,4'-biphenyldithiolate (S2bph2-), the tetranuclear [{Pd(tmeda)}4(μ-S2bph)2](NO3)4 (1) was formed. A new type of undecanuclear Pd cluster was separated as a minor product from an acetone solution of 2 in air. The new complexes represent the first examples of water-soluble Pd metallacycles constructed from a pyridine-thiolate ligand. They show catalytic activity with turnover numbers ranging from 9 to 420 in aqueous Suzuki cross-coupling reactions using phenyl boronic acid and a number of aryl halides. An optimized system gave a TON of 6,900,000 and a TOF of 492,857 h-1. The catalyst could be reused eight times, and the activity has been attributed to the formation of PdNPs.

Novel pyrenylbenzylidene-malononitrile derivative mixed with cellulose acetate electrospun nanofibrous sheets for hydrazine detection

A new pyrenylbenzylidene–malononitrile (P2) was successfully synthesized via the Suzuki coupling reaction and Knoevenagel condensation using nano Cu as a catalyst. Nanofiber sheet mixed with compound 2 detects and responds to hydrazine vapor with a detection limit of 0.005% (w/v).

Recyclable LaF3·Pd nanocatalyst in Suzuki coupling: green synthesis of biaryls from haloarenes and phenylboronic acids.

Herein we prepared the novel LaF3·Pd nanocatalyst characterized by XRD and TEM analysis. The nanocatalyst was applied in Suzuki coupling reaction for the synthesis of biaryls in aqueous medium from readily available aryl halides (bromides and iodides) and substituted phenylboronic acids in the presence of K2CO3 as the base at 70 °C. The present method is capable of giving the C-C coupled product in good to excellent yields (up to 97%). The reactions were conducted under green conditions in aqueous medium and the nanocatalyst used in this study was recyclable. The recyclability and reusability of the catalyst was checked for seven consecutive cycles without significant loss in reactivity.

One-step Mo-doped praseodymium oxide construction of oxygen vacancies for efficient photothermal co-catalytic Suzuki coupling reaction

The photothermal synergistic catalytic Suzuki coupling reaction is a sustainable approach to generate biphenyl compounds using clean and renewable solar energy. The one-step Mo doping engineering resulted in more oxygen vacancies and surface free electrons on the PrxOy surface of hollow porous nanotube morphology. Subsequently, energy-efficient and environmentally friendly catalysts (PdO/PrxOy−Moz) with higher catalytic activity were successfully prepared by deposition precipitation method. The concave and convex surfaces of the carriers could better capture visible light. Mo doping greatly extends the visible absorption range of PrxOy. More OVs defects in the PrxOy−Moz carrier inhibit the complexation of photogenerated electron-hole pairs and induce the transfer of free and photogenerated electrons to Pd. The electron-rich Pd accelerated the oxidative addition step of aryl halides to aryl phenylboronic acids, which greatly improved the catalytic performance of PdO/PrxOy−Moz in the photothermal co-catalytic Suzuki coupling reaction.

Synthesis, design, biological and anti-oxidant assessment of some new 9H-carbazole derivatives

This research includes the synthesis of 9H-carbazole compounds (1-7) through the prepared ester by condensation 9H-Carbazole with chloroacetic acid in the presence of triethylamine and benzene as a solvent. The compound (3) was prepared from ester and ethanol in the presence of H2SO4 as catalyst by using MWI. The synthesis of amide carbazole derivatives (3,4,5) was accomplished by using microwave irradiation with aromatic amine (p-, o-bromoaniline and m-chloroaniline). The synthesis of derivatives (6,7) was performed by Suzuki coupling reaction during which derivative (5) was treated with aryl boronic acid using pd(pph3)4 ʺpalladium-tetrakis(triphenyl phosphine)ʺ as a catalyst via oxidation, transformation and reduction steps. The synthesized compounds were evaluated by FT-IR, 1H-NMR, 13C-NMR spectra. The assay of biological/antibacterial activity of synthesized compounds against two types of bacteria i.e. gram-positive (Staphy. Aureus) and gram-negative (E. coli) were performed. The results exhibited excellent activity of all synthesized compounds as compared with ciprofloxacin drug. The antioxidant activity of the synthesized compounds using DPPH test showed good findings.

Triazine‐based mesoporous organic polymers as palladium supports: physicochemical properties, porosity and catalytic performance in Suzuki coupling reaction

AbstractThis article reports the preparation of new mesoporous triazine‐based organic polymers and their characterization. The polymers were synthesized via a nucleophilic condensation reaction between cyanuric chloride and bisphenols or aromatic diamine linkers. As a result, two types of triazine‐based polymers were prepared: triazine‐ether and triazine‐amine polymers. The polymers reveal a mesoporous nature with surface area values ranging between 345 and 1275 m2 g−1 and mesopore volume between 0.273 and 1.03 cm3 g−1. These values were determined from argon gas isotherms at 87 K. The pore size distribution also confirmed the micro–mesoporosity, which reached up to 3.0 nm for all polymers. The triazine‐amine polymer shows good thermal oxidative stability up to 450 °C. Motivated by the mesopore size, the new polymers were also employed as palladium nanoparticle supports. The X‐ray diffraction technique indicated the successful incorporation of palladium nanoparticles, and Fourier transform infrared measurements proved that the framework of the polymers was retained after forming palladium supports. To ensure the catalytic reactivity of palladium nanoparticles, we employed one example as a catalyst in a Suzuki coupling reaction. The catalyst exhibited remarkable recyclability, maintaining catalytic efficiency through seven cycles, thereby enabling the use of palladium‐loaded triazine‐based polymeric catalysts in a variety of organic reactions in future. © 2023 Society of Industrial Chemistry.

Thienothiophene and biphenyl based conjugated porous polymer as a photocatalyst for visible light induced free radical and cationic polymerization

Over the last few decades, photopolymerization has been the center of great attention owing to a variety of desirable features such as mild reaction conditions, cost efficiency and especially, spatiotemporal controllability. In particular, visible light induced polymerizations have been attracting considerable attention due to the concerns on cost efficiency, light penetration and environment safety. In this work, a crosslinked conjugated polymer, TT-BP, was designed and synthesized by Pd (0) catalyzed Suzuki coupling reaction. It was used as a photocatalyst for visible light induced free radical and cationic polymerizations in the presence of diphenyliodonium salt. The reactions were performed for 8 and 24 h in high yields, for which the photocatalyst TT-PB was used repeatedly for each reaction. The maximum conversion reached to 76 % in free radical polymerization of MMA, while the maximum conversion was obtained in cationic polymerization of IBVE with 82 %. This report on reusable conjugated polymer that have been used as a photocatalyst during free-radical and cationic photopolymerizations may lead to the emergence of a new perspective for photocatalyst and photopolymerization processes.

Organic field-effect transistors based on two-dimensional molecular crystals of thiophene/selenophene-based triacene asymmetric derivatives as active layer

From 2,5-di(trimethylsilanyl)dithieno[2,3-b:3′,2′-d]thiophene ((TMS)2-DTT) and (TMS)2-diseleno[2,3-b:3′,2′-d]thiophene ((TMS)2-DST), asymmetric organic semiconductor materials (E)− 2-(4-octylstyryl)− 5-phenyl-DTT (PEP-DTT) and (E)− 2-(4-octylstyryl)− 5-phenyl-DST (PEP-DST) were synthesized via bromination, Suzuki coupling, deprotection, formylation and Wittig reactions, with the yields of 48% and 28%, respectively. Apart from the synthetic work, two-dimensional molecular crystals (2DMCs) with a growth size of few hundreds of micrometers of PEP-DTT and PEP-DST were successfully realized for organic field-effect transistors (OFETs) devices through “layer-defining strategy”. Bottom-gate/top-contact OFETs on the basis of PEP-DTT and PEP-DST 2DMCs as active layers displayed p-channel features with maximum mobility of 2.04 and 1.36 cm2 V−1 s−1, respectively.

Unveiling the potential of Pd(II)‐covalent organic polyimide framework in Suzuki coupling reactions: A study on synthesis, characterization, and catalytic efficiency

In this research, a highly effective heterogeneous Pd catalytic system was conceived by immobilizing Pd(II) onto a substrate composed of covalent organic polyimide frameworks (PI‐COF). The synthesized catalyst underwent comprehensive characterization using techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption analysis (Brunauer–Emmett–Teller [BET]), Fourier transform infrared (FT‐IR), thermogravimetric analysis (TGA), and inductively coupled plasma atomic emission spectroscopy (ICP‐AES). Subsequently, the catalytic activity of this immobilized Pd catalyst was explored in the context of the Suzuki reaction. The reactions at 70°C up to 1 h under a normal atmosphere in water result in biaryls at good to excellent yields (>90%). More importantly, the leaching of Pd(II) during the reaction process could be negligible (about 0.5 ppm), which is crucially important when preparing bioactive species. The loading of Pd(II) ions on the PI‐COF was 0.49 mmol/g. The catalyst exhibited exceptional performance, demonstrating remarkable efficacy in catalyzing a wide range of aryl halides (excluding aryl chlorides) when reacted with phenylboronic acid under environmentally friendly reaction conditions. Notably, the catalyst exhibited robust recyclability, retaining its catalytic activity throughout 5 reaction cycles without any significant decrease.

I2/CAN as a Mild and Efficient Reagent for Oxidative Csp3‐Csp2 Cleavage of 3,3′‐Bis‐7‐azaindolylmethane: A Rapid One‐Pot Access to 3‐Formyl and 3‐Iodo‐7‐azaindoles

AbstractThe combination of I2/CAN has emerged as a mild and powerful reagent for the oxidative Csp3‐Csp2 cleavage of 3,3′‐bis‐7‐azaindolylmethane to provide a quantitative combined yield of 3‐formyl and 3‐iodo‐7‐azaindole in a one‐pot reaction at RT. A plausible mechanism and characterization, including XRD, has been described. The synthetic transformations of title compounds were explored by reduction, Click, reductive amination, and Suzuki coupling reaction.

Impact of the position of nitrogen atom on the liquid crystal, optical and multi-stimuli response behaviors of rod-like mesogens containing multiple functional building blocks

Two novel rod-like mesogens containing one cyanostyrene, one pyridine and one pyrene as π-conjugate rigid core were designed and synthesized by Suzuki coupling and Knoevenagel reactions. The effect of the position of nitrogen-atom on the thermodynamic behavior, liquid crystalline self-assembly, optical behavior, mechanochromism behavior and acidochromism behavior was investigated. The rod-like mesogen in which the nitrogen atom is adjacent to the pyrene displays a phase transition from smectic A to smectic C by increasing temperature, whereas the other rod-like mesogen can only self-assemble into smectic C phase. This difference in mesophase transition behavior might be attributed to the position of nitrogen-atom which induces the change in molecular configuration. Both mesogens exhibit positive solvatochromism and high fluorescence in both solution state and aggregated state which might be attributed to the intramolecular charge transfer and twisted molecular configurations, respectively. Reversible mechanochromism behavior due to changes in molecular stacking and acidochromism behavior due to protonation and deprotonation were also achieved. These multi-stimuli responsive behaviors of the designed rod-like mesogens demonstrate potential applications in the field of multifunctional materials.

In Situ Green Generation of Palladium Nanoparticles on Reduced Graphene Oxide and Its Catalytic Activity for Suzuki Coupling Reactions

In Situ Green Generation of Palladium Nanoparticles on Reduced Graphene Oxide and Its Catalytic Activity for Suzuki Coupling Reactions

Synthesis and characterization of a new semiconducting indacenodithiophene-carbazole derivative with interesting optical and electronic properties

A novel indacenedithiophene derivative 9,9'-((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(4,1-phenylene))bis(9H-carbazole) (IDT-CB) by a Suzuki coupling reaction was synthesized, its chemical structure was confirmed by 1H-NMR and 13C-NMR, as well as FTIR. Opto-electronic properties were measured in solution and thin solid films through UV-Vis absorbance and photoluminescence (PL) in solution was also determined. UV-Vis absorption was observed at λmax=425 nm, and the optical band gap was 2.59 eV. The HOMO-LUMO frontier orbitals were determined by cyclic voltammetry (CV) with HOMO=−5.9 eV and LUMO=−3.89 eV, then, a band gap of 2.01 eV was estimated. Photoluminescence had a maximum emission at 556 nm. OLED devices were constructed from the compound IDT-CB as emitting layer (EL), with the simple structure glass/ITO/PEDOT:PSS(40 nm)/IDT-CB(52 nm)/FM. Previously, the chemical compound was solubilized in THF at 5 mg/mL and corresponding analyses in thin films and OLED fabrication were carried out. Solution processable yellow-greenish OLEDs were assembled by spin coating with CIE coordinates (0.38, 0.51). J-V plots, as well as luminance, were determined, a turn-on-voltage of 5.76 V and maximum luminance of 1000 cd/m2 were reached.

CuNPs@Al2O3-cellulose composite for the ligand-free Suzuki cross-coupling reactions in batch and continuous flow process

In the present work, we synthesized recyclable CuNPs@Al2O3-CELL composite from an inexpensive and commercially available synthetic reagent by a simple method. The catalyst was characterized by various techniques such as TGA (Thermogravimetric analysis), SEM (Scanning electron microscope), TEM (Transmission electron microscopy), XPS (X-ray photoelectron spectroscopy), EDS (Energy dispersive spectroscopy), and AAS (Atomic Absorption Spectroscopy). The composite was applied for the Suzuki coupling reactions in the batch and flow process. The aryl halides were easily coupled with arylboronic acids in 95 % ethanol at 78 °C. We systematically investigated the role of reaction temperature, solvent, and catalyst loading, on the transient and steady-state behavior of the flow reactor through an automated flow chemistry platform. The CuNPs@Al2O3-CELL catalytic particles demonstrate minimal deactivation and leaching over a continuous Suzuki coupling reaction at a 20 min nominal residence time at 100 °C. Moreover, the catalyst can be recovered by simple filtration and reused at least five times with a moderate decrease in product yield. The excellent activity and stability of the catalyst have been attributed to the strong chelation of the Cu species with hydroxyl functional groups of the Al2O3-CELL composite. The catalytic system was highly efficient in Suzuki coupling of various aryl bromides with different aryl boronic acids, yielding good to excellent product yields (80–96 %) with a TON of 15.914–19.066 and TOF of 2.649–9.533 h−1.

Anthracene-based fluorescent conjugated porous polymers for highly sensitive detection of 2,6-dichloro-4-nitroaniline pesticide in a water environment

Designing fluorescent probes to achieve sensitive and rapid detection of pesticide 2,6-dichloro-4-nitroaniline (DCNA) in a water environment is highly appealing. Here, anthracene-based fluorescent conjugated porous polymers (ACPP) with a partially π-extension wall have been synthesized via a Suzuki coupling reaction for sensitive and rapid detection of DCNA pesticide. The unique pore structure extending anthracene unit into the pore not only improve the host-guest interaction of the polymer and analytes, but also increase the possibility of photoinduced electron transfer (PET) by shortening the electron hopping distance, thus improving the fluorescence detection performance. Benefiting from the synergistic effects of competitive energy absorption, PET and host-guest interaction, the ACPP can be used to detect DCNA pesticide with fast response (<2 s) and high quenching constant (Ksv = 3.8 × 105 M−1). The ACPP-based portable test strips and sol-gel sensors were successfully applied to the portable detection of DCNA in real food samples.

Fe3O4@void@C-Schiff-base/Pd yolk-shell nanostructures as an effective and reusable nanocatalyst for Suzuki coupling reaction

This article describes the synthesis of a novel Yolk-Shell structured Magnetic Yolk-Shell Nanomaterials Modified by Functionalized Carbon Shell with Schiff/Palladium Bases (Fe3O4@void@C-Schiff-base/Pd). The designed Fe3O4@void@C-Schiff-base/Pd catalyst was characterized using several techniques such as Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD) and Inductively coupled plasma (ICP). The Fe3O4@void@C-Schiff-base/Pd was used as powerful catalyst for preparation Suzuki reaction in short reaction times and high yield in H2O at 60 °C and presence of potassium carbonate base. This nanocatalyst was magnetically recovered and reused several times with keeping its efficiency.

The effect of fluorination on the liquid crystal and optical behaviors of amphiphilic cyanostilbene-based mesogens

Three series of amphiphilic mesogens containing a cyanostilbene core with zero, one or two lateral fluorine atoms, which attach one polar glycerol group at one end and three lipophilic alkyl chains at the other end were synthesized by Suzuki coupling and Knoevenagel reactions. The thermodynamics, liquid crystalline and photophysical properties of these amphiphilic mesogens were evaluated by polarized optical microscopy, differential scanning calorimetry, small-angle X-ray diffraction, density functional theory calculation, absorption and emission spectra. The non-fluoro and mono-fluoro amphiphilic mesogens display a mesophase transition from hexagonal columnar phase to three-dimensional micellar cubic phase with Im3¯m lattice by the increase of temperature or the elongation of terminal lipophilic alkyl chains. The bi-fluoro amphiphilic mesogens can only self-organize into hexagonal columnar mesophase. Similar spectral properties and weak solvatochromism in these amphiphilic mesogens are observed attributed to the weak intramolecular charge transfer and weak influence of fluorine atom on the electronic properties in both ground and excited states. In addition, aggregation-induced emission behavior could be achieved in these amphiphilic mesogens due to the twisted molecular configuration. Therefore, complex self-assembly structures and interesting photophysical properties may be altered by varying the degree of fluorination of amphiphilic mesogens, which could promote the application of liquid crystalline materials.