Pd-catalyzed Suzuki Coupling Reaction Research Articles

Zero Energy Heating of Solvent with Network-Structured Solar-Thermal Material: Eco-Friendly Palladium Catalysis of the Suzuki Reaction.

Solar-thermal materials absorb sunlight and convert it into heat, which is released into the surrounding medium. Utilization of solar energy for solvent heating can be a potential method of eco-friendly organic reactions. However, to date, significant heating of the entire volume of a solvent by 1 sun illumination has not been reported. In the present work, a network structure of solar-thermal materials has been proposed for zero energy heating of a solvent under 1 sun illumination. A network-structured solar-thermal material with an additional catalytic function was fabricated by sputtering palladium into a melamine sponge. The nanocrystalline palladium-decorated melamine sponge (Pd-sponge) has excellent sunlight absorption properties in the entire wavelength range that enable efficient solar-thermal conversion. The Pd-sponge can reduce heat loss to the surroundings by effectively blocking thermal radiation from the heated solvent. The temperature of the reaction solution with the ethanol-water mixture filled in the Pd-sponge increased from 23 to 59 °C under 1 sun illumination. The elevated temperature of the reaction solutions by solar-thermal conversion successfully accelerated the heterogeneous Pd-catalyzed Suzuki coupling reactions with high conversions. Easy and low-energy-consuming multicycle use of the solar-thermal and catalytic properties of the Pd-sponge has also been demonstrated.

Synthesis of electron-rich thiophene triphenylamine based organic material for photodiode applications

In this paper, a new electron-rich π-conjugated organic material, 4,4'-(thiophene-3,4-diyl)bis(N,N-diphenylaniline) (bisTPAT), which contain thiophene skeleton as the central core with bistriphenylamine side groups as the electron-rich unit and/or donor groups at the 3- and 4-positions, was designed for photodiode application. The bisTPAT was efficiently synthesized via the Pd-catalyzed Suzuki coupling reaction between 3,4-dibromo-thiophene (3) and (4-(diphenylamino)phenyl)boronic acid 4. Structural, optical, and chemical features of the bisTPAT material and thin film form -was characterized by NMR, FTIR, HRMS, UV–Vis spectroscopy, and SEM/EDX analysis techniques. Subsequently, bisTPAT/n-Si device fabrication was carried out by using the spin coating method. Current-voltage (I–V) measurements were performed to determine the characteristic properties of the device under different operating conditions. According to I–V measurements taken under illumination conditions, the fabricated device has photoresponse characteristics in the reverse bias region. Therefore, the fabricated device can be employed as a photodiode for optoelectronic applications. Additionally, the photodiode parameters, such as ideality factor (n), barrier height (Φb), series resistance (Rs), photosensitivity (S), photoresponsivity (R), photodetectivity (D*), open-circuit voltage (Voc), and short-circuit current (Isc), were analyzed under the light intensity of 100 mWcm−2. Finally, capacitance-voltage (C–V) measurements were carried out to obtain important information about the diode's interfacial characteristics at different frequencies. The results show that the calculated parameters such as diffusion potential (Vd) and carrier concentration are sensible to frequency changes.

SYNTHESIS AND ANTIBACTERIAL EVALUATION OF 3-ARYL INDAZOLES

A series of 3-aryl indazoles 4a-4j were obtained by Pd catalyzed Suzuki coupling reaction. All the substrates were obtained in good yields under moderate reaction conditions. Next, the prepared compounds 4a-4j were screened for their antibacterial activity. The anti-bacterial activities of the prepared compounds were investigated against three bacterial strains i.e. Xanthomonas campestris, Escherichia coli, Bacillus megaterium. The anti-bacterial evaluation studies of these 3-aryl indazoles revealed that some of these test compounds possess moderate in vitro antibacterial activity.

AIE-active discotic LC containing tetraphenylethylene and α-cyanostilbene: Synthesis, self-assembly and photophysical properties

ABSTRACT A novel α-cyanostilbene-containing tetraphenylethylene-based discotic LC with 3,4,5-tridecyloxy benzene units at the terminal was synthesized by Ti-catalyzed McMurry coupling, Pd-catalyzed Suzuki coupling and Knoevenagel reactions as key steps. The liquid crystal and photophysical properties were well demonstrated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray scattering (XRD), molecular dynamics (MD) and optical experiments. The compound could self-assemble into Colhex/p6mm mesophase in a wide temperature range. It is interesting that two discotic molecules formed one columnar slice, which was attributed to the twisted conformation of propeller-like TPE and α-cyanostilbene. The photophysical properties of the TPE-based DLCs including solvatochromism and aggregation-induced emission (AIE) behaviors were systematically investigated demonstrating large Stokes shifts, high fluorescence quantum yields and strong fluorescence in both solution and aggregated states. This work indicated that the combination of different AIE-active units into one LC molecule could induce complex self-assembly structure and excellent fluorescence properties.

First biscyanovinyl diphenylfluorenone-based hexacatenars: synthesis, liquid crystal and photophysical properties

ABSTRACT In this paper, a series of hexacatenars, where the central fluorenone is connected two α-cyanostilbene which is substituted with 3,4,5-trialkoxybenzyl, was synthesized by Pd-catalyzed Suzuki coupling and Knoevenagel reaction as key steps. The LC characteristics, photophysical and electrochemical behaviors were evaluated by using POM, DSC, TGA, XRD, DFT calculations, UV-vis spectroscopy, photoluminescence measurements and CV. A rare mesophase sequence from Colhex/p6mm to Colrec/p2mm was observed and the mesophase width increased upon terminal chain elongation. The photophysical behaviors in different solutions and aggregated states indicated that these compounds exhibited solvatochromism, fluorescence quantum yields and aggregation-induced emission (AIE) behaviors. The electrochemical behaviors in thin film indicated these compounds show low band gap. DFT calculations of the investigated hexacatenars were accomplished to determine the structural, electronic and intermolecular interaction properties.

Multifunctional conjugated microporous polymers with pyridine unit for efficient iodine sequestration, exceptional tetracycline sensing and removal

In this work, two multifunctional conjugated microporous polymers (CMP-LS7–8) were obtained via the Pd-catalyzed Suzuki coupling reactions of 2,4,6-tris(4-bromophenyl)pyridine with two aromatic borates. The Brunauer–Emmett–Teller (BET) surface areas of CMP-LS7–8 were calculated to be 507 and 2028 m2 g–1. CMP-LS7–8 exhibit excellent volatile iodine adsorption about 2.77 and 5.29 g g–1, respectively, and outstanding reversible adsorption. High adsorption capacity should be attributed to an integrated effect by excellent porous characteristics, effective sorption sites, and expanded π-conjugated network. In addition, this platform integrated two functions of sensing and adsorption of tetracycline (TC) into one material. The excellent luminescence of CMP-LS7–8 can be effectively quenched by TC, which demonstrates they can be acted as new sensitive and selective fluorescence probes toward TC. Simultaneously, CMP-LS7–8 also display high adsorption ability of TC. The adsorption kinetics of TC suggested that the process of adsorption followed a pseudo-second-order model, and the adsorption behaviour of these polymers fitted with the Langmuir model. These results suggest that CMP-LS7–8 posess high volatile iodine capture and exceptional TC detection and removal performance, which can be promising candidates for environmental remediation.

Synthesis of cyclopentadienyl iron complexes with substituted phenylene ligands via Suzuki coupling

Cationic cyclopentadienyl iron complexes of substituted phenylenes [CpFe(p-CH3-C6H4-Ar)]PF6 and [CpFe(p-Ar-C6H4-Ar)]PF6 were obtained in 37–73% yields by Pd-catalyzed Suzuki coupling reactions of [CpFe(p-CH3-C6H4-Cl)]PF6 and [CpFe(p-Cl-C6H4-Cl)]PF6 with polyarylboronic acids Ar-B(OH)2 (Ar = biphenyl, naphthyl, phenanthryl, bithienyl). The complex [CpFe(p-CH3-C6H4-Cl)]PF6 also underwent Sonogashira-type coupling with phenylacetylene to give the compound [CpFe(p-CH3-C6H4-CC-Ph]PF6 in 26% yield. Such coupling reactions represent an alternative approach to [CpFe(arene)]PF6 complexes, which are typically obtained from ferrocene via Bolesova-Nesmeyanov reaction under harsh conditions (AlCl3, >100 °C). The structures of the products of Suzuki reaction were established by single-crystal X-ray diffraction analysis.

One-pot synthesis of conjugated microporous polymers loaded with superfine nano-palladium and their micropore-confinement effect on heterogeneously catalytic reduction

How to efficiently control the metal sites in carriers is of great importance in the design of high-efficiency heterogeneous catalysts, but still remains to be difficult. Herein, we provide an efficient one-pot strategy to design conjugated microporous polymers (CMPs) loaded with superfine palladium (Pd) sites, referring a Pd-catalyzed Suzuki coupling reaction and pyrolysis reduction process. Beneficial from micropore-confinement effect by CMPs, the size of deposited Pd can be well controlled (lower than 2 nm), exhibiting excellent catalytic activity on p-nitrophenol reduction. Super small size of Pd sites and the retainment of pores during the Pd formation is thought to be the main reason for high catalytic activity of the Pd/CMPs catalysts. It expands the exploration and development of heterogeneous catalysts by micropore-confined strategy.

Rhodium(II)-Catalyzed Dehydrogenative Silylation of Biaryl-Type Monophosphines with Hydrosilanes.

A rhodium-catalyzed system is introduced for in situ modification of biaryl-type monophosphines with hydrosilanes through a PIII -chelation-assisted dehydrogenative silylation reaction. A series of ligands containing silyl groups with different steric and electronic properties were obtained with excellent regioselectivities. This method offers many advantages, including the use of commercially available phosphines, no requirement for an external ligand or oxidant, a broader substrate scope, high efficiency, and access to a single regioisomer. Based on the outstanding properties of the parent scaffolds, the silyl-substituted phosphines serve as excellent ligands in Pd-catalyzed asymmetric Suzuki coupling reactions.

Selective arylation of phenol proteted propygyl bromide via pd-catalysed Suzuki coupling reaction: synthesis, mechanistic studies by DFT calculations and Their Pharmacological Aspects"

Biaryls are the potential source of synthetic drugs. The present study describes the synthesis of a series of functionalized biphenyl derivatives (3a-3g) using Pd-catalyzed Suzuki coupling reaction. The experimental results revealed the facile synthesis of biphenyl derivatives (3a-3g) with notably high yield (80-88%). Density functional theory (DFT) studies were performed by Gaussian 09 software in order to rationalize the selectivity of coupling at C-Br bond instead of C-Cl bond. In addition of synthesis, the biological activities (biofilm inhibition, hemolytic and anti-thrombolytic) of these novel compounds were investigated. These results exhibited good biofilm inhibition (5.86-65.8%), hemolytic (1.32-30.1%) and anti-thrombolytic activities (9.64-42.5%), indicating the potential use of these compounds for pharmaceutical applications

Pronounced effect of pore dimension of silica support on Pd-catalyzed Suzuki coupling reaction under ambient conditions

The pore size of the mesoporous silica support affects the reactivity of heterogeneous palladium catalysts in the Suzuki reaction under ambient conditions, which is leveled at higher temperature.

Aggregation-induced emission enhancement in charge-transporting derivatives of carbazole and tetra(tri)phenylethylene

New tri- or tetraphenylethylene-substituted phenylcarbazole derivatives exhibiting aggregation-induced emission were synthesized by the synthetic route including Pd-catalyzed Suzuki or Buchwald-Hartwig coupling and Heck reactions. The results of evaluation of the thermal, optical, electrochemical, photophysical, and charge-transporting properties of the synthesized derivatives are presented. The compounds possess high thermal stabilities with 5% weight loss temperatures exceeding 350 °C. Some of the synthesized compounds form glasses with glass transition temperature ranging from 77 to 114 °C. Their maximum fluorescence intensity wavelengths are in the range of 472–498 nm. The highest photoluminescence quantum yield of 43.9% was observed for the solid sample of 2-(4-(4-(1,2,2-triphenylvinyl)phenylethenyl)phenyl)-9-ethylcarbazole. The electron photoemission spectra of the films of the synthesized compounds revealed ionization potentials of 5.49–5.74 eV. Hole drift mobilities in the layers of 9-phenylcarbazole para-substituted with tri- or tetraphenylethylene moities reached 10−3 cm2 V−1 s−1 at moderate electric fields, as established by the time-of-flight technique.

Pd-Catalyzed Suzuki coupling reactions of aryl halides containing basic nitrogen centers with arylboronic acids in water in the absence of added base

Successful Suzuki reactions of basic nitrogen containing aryl chlorides/bromides with arylboronic acids in water without added base, partially or entirely under acidic conditions.

Excellent deep-blue emitting materials based on anthracene derivatives for non-doped organic light-emitting diodes

Two deep-blue emitting materials 2-tert-butyl-9,10-bis(3,5-diphenylphenyl)anthracene (An-1) and 2-tert-butyl-9,10-bis(3,5-diphenylbiphenyl-4′-yl)anthracene (An-2) were successfully synthesized by the Pd-catalyzed Suzuki coupling reaction. Both of these compounds have high thermal stabilities and show strong deep-blue emission as solid-state film as well as in n-hexane solution. Two non-doped electroluminescent devices employing An-1 and An-2 as emitting layers were fabricated by vacuum vapor deposition. These devices exhibited highly efficient and stable deep-blue emission with high color purity. The CIE coordinate and maximum EQE of An-1 based device are 4.2% and (0.16, 0.06), respectively. Device based on An-2 achieved a maximum EQE of 4.0% and a CIE coordinate of (0.16, 0.10).

Promoting Pd-catalyzed Suzuki coupling reactions through near-infrared plasmon excitation of WO3−x nanowires

We have prepared Pd-loaded plasmonic WO3−x nanowires with retained strong plasmon absorption in the visible and NIR region, and demonstrated that the plasmon excitation of WO3−x nanowires by long wavelength irradiation can greatly promote Suzuki coupling reactions catalyzed by the attached Pd nanoparticles in terms of the main product yield and selectivity, which is attributed to the photothermal effect with strong localized plasmon heating on the WO3−x nanowire surface. Our studies reveal that the contributions of plasmon excitation can not only affect the reactions directly involving the plasmonic structure itself, but also assist the reactions catalyzed by the third-part materials attached on the plasmonic structure surface.

ChemInform Abstract: One‐Pot Synthesis of 2,3‐Diarylbenzofurans via Sequential Iodocyclization and Pd‐Catalyzed Suzuki Coupling Reactions of 2‐Alkynylanisoles with Boronic Acids in Water.

Abstract An efficient approach for the one-pot synthesis of 2,3-diarylbenzofurans via sequential iodocyclization and Pd-catalyzed Suzuki coupling reaction of 2-alkynylanisoles with boronic acids in water is reported. The protocol utilizes water as the solvent and there is no need to isolate the intermediate 3-iodine-2-arylbenzofurans, which exemplifies the ideal of green chemistry. Various 2-alkynylanisoles and boronic acids can participate in the reactions, providing a series of 2,3-diarylbenzofurans for drug discovery in moderate to good yields.

An in situ generated achiral Cu(II)-containing polymer complex sensor for enantioselective recognition induced from L-/D-histidine enantiomers.

A novel achiral polymer P-1 is synthesized by the polymerization of (2,5-bis(octyloxy)-1,4-phenylene)diboronic acid (M-1) with pyridine-2,6-diylbis(methanylylidene)bis(4-iodoaniline) (M-2) via Pd-catalyzed Suzuki coupling reaction. The tridentate ligand in the main chain backbone can further coordinate with Cu(2+) to afford the corresponding achiral copper-containing polymer complex P-2, which selectively responds to L-/D-histidine with significant fluorescence enhancement over other amino acids. Interestingly, P-2 exhibits obvious CD response toward L- or D-histidine compared with its model compound MC, indicating that this kind Cu(II)-containing polymer complex sensor can be used as an effective chemosensor for enantioselective recognition of histidine enantiomers by means of CD spectroscopy.

One-Pot Synthesis of 2,3-Diarylbenzofurans via Sequential Iodocyclization and Pd-Catalyzed Suzuki Coupling Reactions of 2-Alkynylanisoles with Boronic Acids in Water

An efficient approach for the one-pot synthesis of 2,3-diarylbenzofurans via sequential iodocyclization and Pd-catalyzed Suzuki coupling reaction of 2-alkynylanisoles with boronic acids in water is reported. The protocol utilizes water as the solvent and there is no need to isolate the intermediate 3-iodine-2-arylbenzofurans, which exemplifies the ideal of green chemistry. Various 2-alkynylanisoles and boronic acids can participate in the reactions, providing a series of 2,3-diarylbenzofurans for drug discovery in moderate to good yields.

Ferrocenyl pyrazaboles: design, synthesis, structure, and properties

This article reports the design and synthesis of donor-acceptor-donor type ferrocenyl-substituted pyrazaboles by the Pd-catalyzed Suzuki and Sonogashira coupling reactions. The photophysical and electrochemical behaviors of the ferrocenyl-substituted pyrazaboles were found to be dependent on the nature and length of the spacer groups. The single crystal X-ray structures of ferrocenyl-substituted pyrazaboles 11a, 11b, and 11d were obtained, which reveals that the pyrazabole core exists in chair, planar, and boat conformations. The crystal structures show marvelous supramolecular interactions. The pyrazaboles 11a-11g show good thermal stability, which increases with the length of spacer. The computational study reveals donor-acceptor interactions in ferrocenyl pyrazaboles. The computational results show good agreement with the experimental results.

Indeno[2,1-c]fluorene-based blue fluorescent oligomers and polymers: Synthesis, structure, photophysical and electroluminescence properties

An alkylated skeleton of indeno[2,1-c]fluorene, viewed as a positional isomerism of indeno[1,2-b]fluorene, was developed to construct several conjugated oligomers and polymers through a Pd-catalyzed Suzuki coupling reaction for organic light-emitting diodes. Single crystal analysis indicated that the structure of indeno[2,1-c]fluorene was twisted due to close H---H contacts in the crowded region of molecules. P1–P3 showed good solubility in common organic solvents as well as facile film forming properties. In comparison with linear n-alkyl-substituted oligo(indeno[1,2-b]fluorene)s and poly(indeno[1,2-b]fluorene)s (2,8-PIFs), the absorption and emission features of twisted n-alkyl-substituted oligo(indeno[2,1-c]fluorene)s and poly(indeno[2,1-c]fluorene) (P1) in dilute solution exhibited a correlation to the conjugation length and obviously blue-shifted due to the distorted backbones. All polymers emitted strong blue fluorescence with very narrow full widths at half-maximum (fwhm) (about 50 nm) in dilute solution and in thin film. Electroluminescent (EL) devices with the configuration of ITO/PEDOT:PSS/PVK/polymers/Ba/Al were fabricated to achieve blue EL emission with maximum brightness up to 2800 cd/m2 at a bias of 10 V. The EL devices using P2 as the active materials showed a maximum external quantum efficiency of 1.2% and a maximum luminous efficiency of 1.5 cd/A. Our investigations demonstrate that indeno[2,1-c]fluorene moiety might be regarded as a potential building skeleton to develop the effective blue and UV light-emitting materials.