613-40-1Relevant academic research and scientific papers
Suzuki–Miyaura cross-coupling reaction assisted by palladium nanoparticles-decorated zeolite 13X nanocomposite: a greener approach
Deepika, Raja,Sethuraman, Mathur Gopalakrishnan
, (2022/01/22)
Heterogeneous catalysts govern the field of catalysis due to their easy separation from a reaction mixture, reusability, and prevention of agglomeration, making them more efficient catalysts than homogeneous catalysts. Herein, we report the eco-friendly synthesis of a novel heterogeneous catalyst, viz. palladium nanoparticles (Pd NPs) decorated over zeolite 13X nanocomposite using dried fruits of Terminalia chebula Retz. as the reducing and stabilizing agent and its performance as a promising catalyst for the Suzuki–Miyaura coupling reactions. The particle size, crystallinity, morphology, and textural properties of the catalyst were identified using Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HR-TEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis which confirmed the presence of palladium nanoparticles on the surface of zeolite 13X. The FESEM images revealed the presence of spherical-shaped Pd NPs over the cubical particles of zeolite 13X. The average particle size of the palladium nanoparticles was found to be in the range of 6–7?nm and was polycrystalline in nature. From BET analysis, it was inferred that the decoration of Pd NPs decreased the surface area of zeolite 13X (615.5 m2/g to 548.334 m2/g), thus leaving pores unoccupied. This study showed the efficiency of this novel catalyst in the formation of biaryl derivatives using low palladium loadings (0.0012?mol%) giving good to excellent yields (90–99%) within short reaction times (10–225?min) with high TONs (> 79,000) and TOFs (> 21,000). Both electron-donating and electron-withdrawing aryl halides and aryl boronic acids reacted smoothly in the presence of K2CO3 as a base and EtOH/H2O (1:1) as the solvent. Besides, the catalyst could be recycled and reused for 5 consecutive runs with minimal loss of its efficiency. The supremacy of this catalyst could well be exploited in future for various organic transformations. Graphical abstract: [Figure not available: see fulltext.].
The site-selectivity and mechanism of Pd-catalyzed C(sp2)-H arylation of simple arenes
Kim, Daeun,Choi, Geunho,Kim, Weonjeong,Kim, Dongwook,Kang, Youn K.,Hong, Soon Hyeok
, p. 363 - 373 (2021/01/14)
Control over site-selectivity is a critical challenge for practical application of catalytic C-H functionalization reactions in organic synthesis. Despite the seminal breakthrough of the Pd-catalyzed C(sp2)-H arylation of simple arenes via a concerted metalation-deprotonation (CMD) pathway in 2006, understanding the site-selectivity of the reaction still remains elusive. Here, we have comprehensively investigated the scope, site-selectivity, and mechanism of the Pd-catalyzed direct C-H arylation reaction of simple arenes. Counterintuitively, electron-rich arenes preferably undergo meta-arylation without the need for a specifically designed directing group, whereas electron-deficient arenes bearing fluoro or cyano groups exhibit high ortho-selectivity and electron-deficient arenes bearing bulky electron-withdrawing groups favor the meta-product. Comprehensive mechanistic investigations through a combination of kinetic measurements and stoichiometric experiments using arylpalladium complexes have revealed that the Pd-based catalytic system works via a cooperative bimetallic mechanism, not the originally proposed monometallic CMD mechanism, regardless of the presence of a strongly coordinating L-type ligand. Notably, the transmetalation step, which is influenced by a potassium cation, is suggested as the selectivity-determining step.
Pd Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
Li, Tang,Pang, Wan,Wang, Jie,Zhang, Xiaoli,Zhao, Zesheng
, (2021/07/31)
Abstract: A heterogeneous single-site catalyst Pd@MOF-808 was successfully synthesized by water-based, green synthesis procedure. The catalytic experiments exhibited the Pd@MOF-808 promoted efficiently the Suzuki–Miyaura coupling reaction without the assistance of organic phosphine ligands at atmospheric pressure conditions. The catalyst also could be applied in the gram-scale synthesis of industrially anti-inflanmatory analgestic Fenbufen. Graphic Abstract: [Figure not available: see fulltext.]
Switching from biaryl formation to amidation with convoluted polymeric nickel catalysis
Sen, Abhijit,Dhital, Raghu N.,Sato, Takuma,Ohno, Aya,Yamada, Yoichi M.A.
, p. 14410 - 14418 (2020/12/21)
A stable, reusable, and insoluble poly(4-vinyl-pyridine) nickel catalyst (P4VP-NiCl2) was prepared through the molecular convolution of poly(4-vinylpyridine) (P4VP) and nickel chloride. We proposed a coordination structure of the Ni center in the precatalyst based on elemental analysis and Ni K-edge XANES, and we confirmed that it is consistent with Ni K-edge EXAFS. The Suzuki?Miyaura-type coupling of aryl halides and arylboronic esters proceeded using P4VP-NiCl2 (0.1 mol % Ni) to give the corresponding biaryl compounds in up to 94% yield. Surprisingly, when the same reaction of aryl halides and arylboronic acid/ester was carried out in the presence of amides, the amidation proceeded predominantly to give the corresponding arylamides in up to 99% yield. In contrast, the reaction of aryl halides and amides in the absence of arylboronic acid/ester did not proceed. P4VP-NiCl2 successfully catalyzed the lactamization for preparing phenanthridinone. P4VP-NiCl2 was reused five times without significant loss of catalytic activity. Pharmaceuticals, natural products, and biologically active compounds were synthesized efficiently using P4VPNiCl2 catalysis. Nickel contamination in the prepared pharmaceutical compounds was not detected by ICP-MS analysis. The reaction was scaled to multigrams without any loss of chemical yield. Mechanistic studies for both Suzuki?Miyaura and amidation were performed.
Design and synthesis of immobilised orthopalladated catalyst for C–C coupling
Pattanayak, Poulami,Parua, Sankar Prasad,Chattopadhyay, Surajit
, p. 410 - 415 (2018/11/01)
The new azo ligand 2-(2-(p-tolyldiazenyl)phenylamino)acetic acid, H2L, [formulated as H3CC6H4-N = N-C6H4-N(H)(CH2COOH)] was prepared. Reaction of H2L with Na2PdCl4 afforded the orthopalladated mononuclear [(HL)PdCl] complexes. The uncoordinated free dangling carboxylic acid function was recognized and confirmed by X-ray crystallographic studies. The [(HL)PdCl] complex was immobilized on Merrifield resin tethering with the free carboxylic acid function of the complex. Catalytic activity of orthpalladated [(HL)PdCl] complex in homogeneous media and Merrifield supported immobilized complex in heterogeneous phase, toward Suzuki cross-coupling reactions, were examined.
Chan-Evans-Lam Amination of Boronic Acid Pinacol (BPin) Esters: Overcoming the Aryl Amine Problem
Vantourout, Julien C.,Law, Robert P.,Isidro-Llobet, Albert,Atkinson, Stephen J.,Watson, Allan J. B.
supporting information, p. 3942 - 3950 (2016/05/24)
The Chan-Evans-Lam reaction is a valuable C-N bond forming process. However, aryl boronic acid pinacol (BPin) ester reagents can be difficult coupling partners that often deliver low yields, in particular in reactions with aryl amines. Herein, we report effective reaction conditions for the Chan-Evans-Lam amination of aryl BPin with alkyl and aryl amines. A mixed MeCN/EtOH solvent system was found to enable effective C-N bond formation using aryl amines while EtOH is not required for the coupling of alkyl amines.
Sulfadiazine iron palladium nano-composite particle and preparation method thereof
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Paragraph 0034; 0035, (2018/02/04)
The invention discloses a sulfadiazine iron palladium nano composite particle and a preparation method thereof. According to the invention, two metal salt solutions, at a certain ratio, are added in a sulfadiazine-containing organic ligand. The obtained product is subjected to hydrothermal reaction at a certain temperature. After the reaction is over, the obtained product is cooled to the room temperature, filtered and dried to obtain a corresponding metal-ligand nano composite particle. The method is simple in preparation process, low in cost and suitable for mass production. Through controlling the amounts of reactants, the reaction time and the reaction temperature, the particle size of the sulfadiazine iron palladium nano composite particle and the dispersibility thereof are effectively controlled. The prepared sulfadiazine iron palladium nano composite particle is a functionalized nano particle containing iron and palladium, and is stable in performance. The particle can be used for catalyzing the C-C bond coupling reaction, and is high in catalytic efficiency. The yield can be up to over 95% by adopting the particle. Therefore, the sulfadiazine iron palladium nano composite particle has a wide application prospect in the catalysis field.
Hierarchical nanospheres based on Pd nanoparticles dispersed on carbon coated magnetite cores with a mesoporous ceria shell: A highly integrated multifunctional catalyst
Li, Yinle,Zhang, Zhuqing,Shen, Jianfeng,Ye, Mingxin
, p. 16592 - 16601 (2015/09/28)
The design and fabrication of core-shell nanostructures with steerable morphologies and tailored performances have aroused abundant scientific studies for organic transformations. We here report the preparation of multifunctional and highly efficient core-shell microspheres, which bear a carbon-protected magnetic Fe3O4 core, a transition layer of active Pd nanoparticles (NPs) and an outer shell of mesoporous CeO2 (mCeO2). The composition and structure of the as-prepared Fe3O4@C-Pd@mCeO2 were thoroughly characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy and Brunauer-Emmett-Teller measurements. The well-designed microspheres have high dispersibility, convenient magnetic separability and good reusability as heterogeneous nanoreactors due to their unique structure. We illustrate the high efficiency of these nanocomposites in mediating the Suzuki-Miyaura cross-coupling reaction and the reduction reaction of 4-nitrophenol (4-NP). The enhanced catalytic activity can be attributed to the synergistic effect between the CeO2 nanoparticles and noble metal NPs. A mechanism was further proposed to explain the improved catalytic activity. This peculiar core-shell nanostructure renders the nanospheres to be an approachable and attractive catalyst system for various catalytic organic industrial processes.
Trace amount CuII (ppm) and mixture design of CuII/PdII catalyzed Suzuki cross-coupling reactions based on the cooperative interaction of metal with a conjugated pyridylspirobifluorene
Li, Xing,Zhang, Jie,Zhao, Yayun,Zhao, Xiuhua,Li, Feng,Li, Taohai,Li,Chen, Liang
supporting information, p. 6265 - 6270 (2015/03/18)
Self-assembly of Cu/psf sheets and layer-by-layer (LbL) growth of PEI-(Cu/psf)n films were carried out and characterized (psf = 2,2′,7,7′-tetra(4-pyridyl)-9,9′-spirobifluorene). A mixture design was performed to evaluate the singular and combined catalytic effects of Cu(ii), Pd(ii) and psf ligands in the Suzuki cross-coupling reactions. The results showed that copper exhibited high catalytic activities in the presence of psf ligands. The (CuII/psf)n films were used as the reservoirs of catalysts capable of gradually discharging highly active catalytic moieties to promote the coupling reactions with ultra low Cu-loadings (as low as 1.4 × 10-5 mol%). This journal is
Palladium-catalyzed Suzuki cross-coupling of phenylhydrazine or (phenylsulfonyl)hydrazine
Li, Yahui,Liu, Wei,Tian, Qingshan,Yang, Qing,Kuang, Chunxiang
, p. 3307 - 3312 (2014/06/09)
The palladium-catalyzed Suzuki cross-coupling of phenylhydrazine or (phenylsulfonyl)hydrazine was developed for the preparation of biaryl compound in high yields. Moreover, these hydrazines were also used in other cross-coupling reactions, and a possible pathway of this reaction was examined. Copyright
