- Synthesis, structural characterization and catalytic activity of two N-heterocyclic carbene-phosphine palladium(II) complexes
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Two new N-heterocyclic carbene (NHC)-phosphine palladium(II) complexes Pd(IMeo)PPh3I2 1 and Pd(IMeo) P(C6H 4-p-Me)3I2 2 (IMeo = 1,3-di-4-methoxyphenyl- imidazolin-2-ylidene) have been easil
- Xu, Chen,Hao, Xin-Qi,Li, Zhen,Dong, Xin-Ming,Duan, Lu-Meng,Wang, Zhi-Qiang,Ji, Bao-Ming,Song, Mao-Ping
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- Visual observation of redistribution and dissolution of palladium during the Suzuki-Miyaura reaction
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(Chemical Presented) Now you see it, now you don't: A specially designed reactor that heats only a small area of Pd foil during a Suzuki-Miyaura coupling permits observation of the surface changes during the reaction. Dissolution of Pd occurs only in the heated zone, and only in the presence of aryl iodide, whereas deposition of Pd occurs preferentially on the unheated zones adjacent to the reactive zone. SEM and XPS are employed to probe the surface before and after reaction.
- MacQuarrie, Stephanie,Horton, J. Hugh,Barnes, Jack,McEleney, Kevin,Loock, Hans-Peter,Crudden, Cathleen M.
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- Palladium(II) complexes featuring bidentate pyridine-triazole ligands: Synthesis, structures, and catalytic activities for Suzuki-Miyaura coupling reactions
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Preparation of the Pd(II) complexes containing 2-(4-R-1,2,3-triazol-1-yl) pyridine [R = C6H5 (1), NC5H4 (2), n-C6H13 (3)] were described. Crystal structures of 1 and 2 revealed a square planar geometry with bidentate ligand coordination to Pd using different N donor of the triazole ring. Catalytic studies indicated that 1-3 exhibited moderate to high activity for Suzuki-Miyaura coupling between aryl bromides and phenylboronic acid under mild and aerobic conditions.
- Jindabot, Sudarat,Teerachanan, Kriengkamol,Thongkam, Pech,Kiatisevi, Supavadee,Khamnaen, Tossapol,Phiriyawirut, Phairat,Charoenchaidet, Sumate,Sooksimuang, Thanasat,Kongsaeree, Palangpon,Sangtrirutnugul, Preeyanuch
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- Catalytic cross-coupling reaction of aryl iodides with triarylbismuths by an N-heterocyclic carbene-PdCl2 based on benzo-9-crown-3 catalyst at room temperature
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We have developed the N-heterocyclic carbene ligand/PdCl2 catalyst for C[sbnd]C coupling reaction of aryl iodides and organobismuths at room temperature. The established catalytic system exhibited high cross-coupling reactivity between a variety of orgnobismuths and aryl iodides in the presence of K2CO3 as base in NMP or DMSO at room temperature. The simple and efficient transformation can tolerate either electron-withdrawing or electron-donating functional groups. It was notably found that both aryl bromide and aryl chloride generated moderate to good yields of the corresponding biphenyl products using 5 mol% of PPh3/ligand 5 (1:1) as catalyst.
- Liu, Jia-Qi,Yang, Jun-Juan,Li, Jun-Fei,Li, Kai,Xiao, Xue-Dong,Bai, Ya-Li,Wang, Jun-Wen
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- Highly Efficient and Accelerated Suzuki Aryl Couplings Mediated by Phosphine-Free Palladium Sources
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Suzuki aryl cross-couplings employing aryl bromides and aryl iodides proceed under mild conditions (65 deg C) with high efficiency (substrate-to-catalyst ratios in excess of 500) in the presence of phosphine-free palladium catalysts derived from palladium acetate, Pd2(dba)3*C6H6 (dba = dibenzylideneacetone), and 3-C3H5)PdCl>2.Phosphine inhibition is shown to play a key role in limiting catalytic efficiency; qualitative comparison studies show that the phosphine-free systems are 1-2 orders of magnitude more active than phosphine-supported catalytic systems.Pd4 proved to be the least active of the catalytic species screened.The phosphine-free methodology appears to be generally applicable; cross-couplings of aryl iodides yielding biaryls 6 and 7 proceed without noticeable steric or electronic effects.Cross-couplings employing aryl bromides are insensitive to electronic effects in the synthesis of 6 but are slowed by steric hindrance in the synthesis of 7.Acceleration of cross-coupling is observed in the presence of polar cosolvents and at high pH.
- Wallow, Thomas I.,Novak, Bruce M.
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- Pd nanocatalyst adorned on magnetic chitosan?N-Heterocyclic carbene: Eco-compatible suzuki cross-coupling reaction
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A novel magnetic-functionalized-multi-walled carbon nanotubes?chitosan N-heterocyclic carbene-palladium (M-f-MWCNTs?chitosan-NHC-Pd) nanocatalyst is developed in two steps. The first step entails the fabrication of a three-component cross-linking of chitosan utilizing the Debus-Radziszewski imidazole approach. The second step comprised the covalent grafting of prepared cross-linked chitosan to the outer walls of magnetically functionalized MWCNTs (M-f-MWCNTs) followed by introducing PdCl2 to generate the m-f-MWCNTs?cross-linked chitosan with a novel NHC ligand. The repeated units of the amino group in the chitosan polymer chain provide the synthesis of several imidazole units which also increase the number of Pd linkers thus leading to higher catalyst effciency. The evaluation of catalytic activity was examined in the expeditious synthesis of biaryl compounds using the Suzuki cross-coupling reaction of various aryl halides and aryl boronic acids; ensuing results show the general applicability of nanocatalyst with superior conversion reaction yields, high turnover frequencies (TOFs) and turnover numbers (TON). Meanwhile, nanocatalyst showed admirable potential in reusability tests, being recycled for five runs without losing significant activities under optimum reaction conditions. The successfully synthesis of catalyst and its characterization was confirmed using the Fourier transform infrared spectrometer (FT-IR), spectrometer transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photo-electron spectroscopy (XPS) and thermogravimetric analysis (TGA).
- Sedghi, Roya,Heidari, Bahareh,Shahmohamadi, Hatef,Zarshenas, Pourya,Varma, Rajender S.
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- Immobilization of palladium(II)-containing bis(imidazolium) ligand on ion-exchange resins: Efficient and reusable catalysts for C-C coupling reactions
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Suzuki reactions catalysed by a palladium(II) complex of a functionalized bis(imidazolium) ligand, PdII(BIM), immobilized on Dowex 50 WX8 and Amberlite IR-120 ion-exchange resins as heterogeneous, recyclable and active catalysts are reported. The catalysts, PdII(BIM)@Amberlite IR-120 and PdII(BIM)@Dowex 50 WX8, were characterized using Fourier transform infrared and diffuse-reflectance UV-visible spectroscopies and scanning electron microscopy. These heterogeneous catalysts are oxygen-insensitive and air- and moisture-stable in C-C coupling reactions, and are reusable several times without significant loss of their catalytic activity.
- Pahlevanneshan, Zari,Moghadam, Majid,Mirkhani, Valiollah,Tangestaninejad, Shahram,Mohammadpoor-Baltork, Iraj,Khosropour, Ahmad R.
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- Palladium nanoparticles supported in a polymeric membrane: An efficient phosphine-free "green" catalyst for Suzuki-Miyaura reactions in water
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Palladium(0) nanoparticles supported on a polymeric membrane, CA/Pd(0), were found to be a highly efficient "dip catalyst" (heterogeneous catalyst) for Suzuki-Miyaura cross-coupling reactions. Iodo-, bromo- and electron-poor chloroarenes coupled with phenylboronic acid under eco-friendly conditions (i.e., phosphine-free and with water as the solvent) to give excellent yields. The CA/Pd(0) was prepared initially via the synthesis of Pd(0) by hydrogen decomposition of Pd(acac)2 dissolved in BMI·BF4 ionic liquid at 75°C for 1.0 hour to yield a black suspension (nanoparticles with a diameter of 2.7 ± 0.4 nm). These nanoparticles were washed with acetone and dried under reduced pressure. The Pd(0) nanoparticles were subsequently added to a cellulose acetate solution with acetone to generate the CA/Pd(0) polymeric membrane. The CA/Pd(0) "dip catalyst" was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron-dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). This journal is the Partner Organisations 2014.
- Faria, Vinicius W.,Oliveira, Deyvid G. M.,Kurz, Marcia H. S.,Goncalves, Fabio F.,Scheeren, Carla W.,Rosa, Gilber R.
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- Nickel stabilized by triazole-functionalized carbon nanotubes as a novel reusable and efficient heterogeneous nanocatalyst for the Suzuki-Miyaura coupling reaction
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An interesting nanotube based nickel nanocatalyst was successfully prepared through "click" reaction of azide-functionalized nanotube with propargyl alcohol followed by immobilization of nickel nanoparticles. The as-prepared nanocatalysts behave as very efficient heterogeneous catalysts in the Suzuki-Miyaura cross coupling reaction in terms of activity and recyclability.
- Hajipour, Abdol. R.,Abolfathi, Parisa
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p. 110622 - 110628
(2016)
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- An efficient clean and sustainable methodology for catalytic C-C coupling process over a Pd-free magnetically recoverable cobalt catalyst
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The Suzuki and Sonogashira coupling reactions are important processes in organic synthesis. However, to date, these reactions have been extensively examined using Pd-based catalysts in toxic organic solvents. Therefore, developing clean and inexpensive methodologies for these reactions remained a major challenge. Herein, by taking the advantages of thiol-ene click reaction, an easy and robust strategy for surface modification of magnetic graphene oxide with a dendrimer structure was successfully developed. Dendrimer-functionalized magnetic graphene oxide was then applied for the immobilization of Co nanoparticles. Transmission electron microscopy exhibited a homogeneous distribution of Co nanoparticles with the size of about 3 nm. The resultant nanocomposite revealed high efficiency in catalytic Suzuki and Sonogashira reactions in non-hazardous and sustainable deep eutectic solvents (DESs). The DES and catalyst were simply recycled five times with gradual slight decrease in the yield of the reactions. More importantly, the catalyst was magnetically isolated at the end of the recycling process. Overall, the utilization of DES as an environmentally friendly and recoverable reaction medium, as well as replacing the low-cost cobalt catalyst as an alternative to expensive Pd catalyst along with the facile catalyst isolation by employing an external magnetic field, make the present protocol promising from economic and green chemistry points of view for the clean C-C coupling reactions.
- Masteri-Farahani, Majid,Niakan, Mahsa
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- Silk?Fibroin-Supported Palladium Catalyst for Suzuki-Miyaura and Ullmann Coupling Reactions of Aryl Chlorides
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Recently, we have reported the preparation of a silk fibroin-supported Palladium catalyst (Pd/SF) and its use in the Suzuki-Miyaura cross-coupling of aryl iodides. Since its synthetic applicability and structural features are still far from being fully ex
- Albano, Gianluigi,Farinola, Gianluca M.,Giannini, Cinzia,Musio, Roberta,Omenetto, Fiorenzo G.,Rizzo, Giorgio,Sibillano, Teresa
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- Palladium-catalyzed aryl group transfer from triarylphosphines to arylboronic acids
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A study of Pd-catalyzed arylation of arylboronic acids with triarylphosphines is presented. Various parameters of this transformation, such as the oxygen presence, choice of solvent, temperature, palladium source, bases and oxidants, were tested and the optimal conditions of the aryl transfer were determined. The effect of electron-withdrawing and electron-donating substituents on the aryl groups of both reactants was also investigated. The unusual transfer of the acetate group from Pd(OAc)2 to p-nitrophenylboronic acid in the presence of PAr3 is reported. A plausible mechanism of the Pd-catalyzed aryl group transfer from PAr3 to the arylboronic acid is proposed.
- Enright, Dale R.,Gogate, Akash R.,Smoliakova, Irina P.,Vasireddy, Purna C. R.
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- Biaryl Coupling of Aryldiazonium Salts and Arylboronic Acids Catalysed by Gold
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A gold-catalysed coupling of aryldiazonium salts with arylboronic acids is described. The reactions proceed in satisfactory yields under irradiation with blue LEDs in the presence of KF and a catalytic amount of ascorbic acid. Notably, 4-nitrobenzendiazonium tetrafluoroborate is sufficiently reactive to undergo the coupling with a variety of arylboronic acids in the absence of aryl radical initiators. The coupling is applicable for electron-donating and electron-withdrawing groups present at the para, ortho, and meta positions of both substrates.
- Medina-Mercado, Ignacio,Porcel, Susana
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- Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
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Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
- Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
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p. 15665 - 15673
(2021/11/16)
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- Triptycene ring metal palladium compound and application thereof
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The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
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Paragraph 0085-0092
(2021/02/24)
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- Base-Free Cross-Couplings of Aryl Diazonium Salts in Methanol: PdII–Alkoxy as Reactivity-Controlling Intermediate
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Pd-catalyzed cross-coupling reactions of aryl diazonium salts are generally assumed to proceed via cationic PdII intermediates which in turn would be highly reactive in the subsequent transmetalation step. Contrary to this belief, we herein report our observation and rationalization of opposing reactivities of ArN2+ in Suzuki (=effective) and Stille (=ineffective) cross-couplings in MeOH. Our systematic experimental and computational studies on the roles of transmetalating agent, solvent, base and the likely involvement of in situ formed diazoether derivatives challenge the currently accepted mechanism. Our data suggest that the observed solvent dichotomy is primarily due to PdII-methoxy intermediates being formed, which are unreactive with arylstannanes, but highly reactive with arylboronic acids, complementing the Suzuki “Pd-oxy” mechanism with the direct demonstration of transmetalation of a PdII-alkoxy complex. Lewis acids were found to circumvent this reactivity divergence, promoting efficient couplings regardless of the employed conditions or coupling partners.
- Sanhueza, Italo A.,Klauck, Felix J. R.,Senol, Erdem,Keaveney, Sinead T.,Sperger, Theresa,Schoenebeck, Franziska
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supporting information
p. 7007 - 7012
(2021/03/01)
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- Highly Active Fe3O4@SBA-15@NHC-Pd Catalyst for Suzuki–Miyaura Cross-Coupling Reaction
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A novel Pd-NHC functionalized magnetic Fe3O4@SBA-15@NHC-Pd was synthesized and used as an efficient heterogeneous catalyst in the Suzuki–Miyaura C–C bond formation reactions. The Fe3O4@SBA-15@NHC-Pd characterized by X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy?(TEM), Energy Dispersive X-ray analysis (EDX), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA). The Inductively Coupled Plasma-Optical emission spectroscopy (ICP-OES)?analysis was used to determine the exact amount of Pd (0.33?wt%) in Fe3O4@SBA-15@NHC-Pd. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the catalyst's structure, while no reducing agent was used. The NHC moieties in the catalyst structure could be stabilize Pd(0) nanoparticles prevents agglomeration. The magnetic catalyst was effectively used in the Suzuki–Miyaura cross-coupling reaction of substituted phenylboronic acid derivatives with (hetero)aryl bromides in the presence of a K2CO3 at room temperature in aqueous media and magnetic catalyst could be simply extracted from the reaction mixture by an external magnet. Different aryl bromides were converted to coupled-products in excellent yields with spectacular TOFs values (up to 1,960,339?h?1); in the presence of 1?mg of Fe3O4@SBA-15@NHC-Pd catalyst (contains 3.1 × 10–6?mol% Pd) at room temperature in aqueous media. After reusability experiments, it is found that this catalyst was effectively used up to ten times in the reaction with almost consistent catalytic efficiency. A decrease in the activity of the 10th reused catalyst was found as 9%. Graphic Abstract: [Figure not available: see fulltext.]
- ?zdemir, ?smail,Akko?, Mitat,Alt?n, Serdar,Bu?day, Nesrin,Ya?ar, Sedat
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- Fe-MIL-101 modified by isatin-Schiff-base-Co: a heterogeneous catalyst for C-C, C-O, C-N, and C-P cross coupling reactions
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A metal-organic framework functionalized with a cobalt-complex is preparedviapost-synthetic modification of Fe-MIL-101-NH2. Initially, Fe-MIL-101-NH2reacted with isatin to produce Fe-MIL-101-isatin-Schiff-base, which can anchor the cobalt by the addition of cobalt acetate. The resulting MOF-Co catalyst is characterized by employing multiple techniques. This new modified MOF acts as a heterogeneous and recyclable catalyst for efficient Ullmann, Buchwald-Hartwig, Hirao, Hiyama and Mizoroki-Heck cross-coupling reactions of several aryl halides/phenylboronic acid/phenyltosylate with phenols, anilines/heterocyclic amines, triethyl phosphite, triethoxyphenylsilane and alkenes and generates the expected coupling products in good to high yields.
- Farrokhi, Alireza,Rouzifar, Majid,Sansano, José Miguel,Sobhani, Sara
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p. 19963 - 19976
(2021/11/12)
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- Valorisation of urban waste to access low-cost heterogeneous palladium catalysts for cross-coupling reactions in biomass-derived γ-valerolactone
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Herein we report a simple protocol for the valorisation of a common urban biowaste. The lignocellulosic biomass obtained after the pre-treatment of pine needle urban waste is efficiently transformed into a low-cost support (PiNe) for the immobilization of Pd nanoparticles. The final Pd/PiNe heterogeneous catalyst features a small particle size (4.5 nm) and a metal loading (9.9 wt%) comparable with most commercially available and generally used counterparts. In this contribution, we tested the catalytic efficiency of the Pd/PiNe system in two representative cross-couplings, Heck and Hiyama reactions, and compared the results obtained with commercial Pd/C catalyst. The good reactivity in the biomass-derived solvent (GVL) confirms that the Pd/PiNe heterogeneous catalyst is a valid system that can be integrated into a waste valorization chain within a circular economy approach. In addition, the efficiency of the catalyst has also been extended to perform the challenging consecutive Hiyama-Heck reaction to afford differently substituted (E)-1,2-diarylethenes.
- Valentini, Federica,Ferlin, Francesco,Lilli, Simone,Marrocchi, Assunta,Ping, Liu,Gu, Yanlong,Vaccaro, Luigi
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supporting information
p. 5887 - 5895
(2021/08/23)
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- Aerobic Cu and amine free Sonogashira and Stille couplings of aryl bromides/chlorides with a magnetically recoverable Fe3O4@SiO2 immobilized Pd(II)-thioether containing NHC
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Two value added C–C cross coupling reactions; Sonogashira and Stille couplings were achieved at milder conditions in the catalytic presence of a magnetically recoverable heterogeneous catalyst Fe3O4@SiO2@NHC^SPh-Pd(II). The catalyst was earlier reported for Suzuki-Miyaura reaction, and as an extension of its catalytic efficiency, the Stille and Sonogashira cross coupling reactions under aerobic condition has been explored in present report. The Sonogashira coupling of aryl bromides and terminal alkynes produced an excellent yield (~96% at 0.25 mol% Pd) of the desired coupling product under copper and amines free conditions. Moreover, an excellent Stille coupling of readily available and more latent aryl chlorides and trialkylstannane was obtained (yields up to 95% at 0.25 mol% Pd) in absence of toxic fluorides additives. The broad substrate scope of the catalyst for both the coupling reactions and the magnetically recoverable feature of catalyst make this reaction highly desirable for industrial applications of present heterogeneous catalysis.
- Khandaka, Himanshu,Sharma, Kamal Nayan,Joshi, Raj Kumar
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supporting information
(2021/02/20)
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- Surface engineered Iridium-based magnetic photocatalyst paving a path towards visible light driven C-H arylation and cyanation reaction
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The report presents the fabrication and application of a highly versatile, magnetic and robust iridium based photoredox nanocatalyst. Herein, Ir(PPy)3 based photocatalyst sites have been chemically engineered over the magnetic nanoparticles to encompass the captivating features of homogeneous iridium photocatalyst with the magnetically recyclable core. A household photoreactor was designed and fabricated to achieve highly selective visible light driven oxidative C-H arylation and C-H cyanation under sustainable and ambient reaction conditions utilizing the Ir@PyBz@ASMNPs photoredox nanocatalyst. The environment friendly Ir@PyBz@ASMNPs shows excellent photocatalytic activity, broad substrate adaptability and outstanding recyclability compared to the analogous homogeneous catalysts. Indeed, the Ir@PyBz@ASMNPs possess some key features including high surface area, high iridium metal loading and excellent stability. This work is expected to enlighten and provide new insights in the rational design of high performance and recoverable photoredox nanocatalyst through surface engineering strategy.
- Gaur, Rashmi,Gawande, Manoj B.,Kaushik, Bhawna,Rana, Pooja,Sharma, Priti,Sharma, Rakesh K.,Yadav, Priya,Yadav, Sneha
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p. 297 - 308
(2021/08/23)
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- Synthesis of arylboronates via the Pd-catalyzed desulfitative coupling reaction of sodium arylsulfinates with bis(pinacolato)diboron
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The desulfitative borylation reaction of sodium arylsulfinates with bis(pinacolato)diboron or bis(neopentylglycolato)diboron under palladium catalysis has been developed, allowing selective C-B bond formation to give arylboronates with a range of functional groups in moderate to good yields under mild reaction conditions. A gram-scale preparation as well as the cascade Suzuki-Miyaura cross-coupling of arylboronates demonstrated the potential practical utility in organic synthesis.
- Qiu, Di,Li, Songyi,Yue, Guanglu,Mao, Jinshan,Xu, Bei,Yuan, Xinyu,Ye, Fei
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supporting information
(2021/11/04)
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- Fe3O4-SAHPG-Pd0 nanoparticles: A ligand-free and low Pd loading quasiheterogeneous catalyst active for mild Suzuki–Miyaura coupling and C-H activation of pyrimidine cores
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This paper reports a green magnetic quasiheterogeneous efficient palladium catalyst in which Pd0 nanoparticles have been immobilized in self-assembled hyperbranched polyglycidole (SAHPG)-coated magnetic Fe3O4 nanoparticles (Fe3O4-SAHPG-Pd0). This catalyst has been used for effective ligandless Pd catalyzed Suzuki–Miyaura coupling reactions of different aryl halides with substituted boronic acids at room temperature and in aqueous media. Herein, SAHPG is used as support; it also acts as a reducing agent and stabilizer to promote the transformation of PdII to Pd0 nanoparticles. Also, this environmental friendly quasiheterogeneous catalyst is employed for the first time in the synthesis of new pyrimido[4,5-b]indoles via oxidative addition/C-H activation reactions on the pyrimidine rings, which were obtained with higher yield and faster than when Pd(OAc)2 was used as the catalyst. Interestingly, the above-mentioned catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled several times with no significant decrease in the catalytic activity.
- Azizollahi, Hamid,Eshghi, Hossein,García-López, José-Antonio
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- Suzuki coupling reactions catalyzed by Schiff base supported palladium complexes bearing the vitamin B6 cofactor
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Novel Schiff bases were synthesized by condensing aromatic amines with pyridoxal-5’-phosphate and characterized by using FT-IR, 1H NMR, and 13C NMR spectroscopic techniques. The resulting Schiff bases were utilized as bidentate ligands, coordinating via imine nitrogen and phenolate oxygen atoms, to stabilize palladium ions. Aryl substituents on imine nitrogen allowed for fine tuning of the stereoelectronic properties of the Schiff bases. The catalytic activity of the selected palladium complexes was investigated in the Suzuki cross-coupling reaction of a series of aryl halides with boronic acids in H2O/EtOH (1:1). Out of four complexes investigated in the cross-coupling reactions, Pd(L8)2, bearing a methoxy substituent on aryl imine, showed the highest activity at low catalyst loading. The scope of the reaction was also investigated with 26 samples.
- Neshat, Abdollah,Gholinejad, Mohammad,?zcan, Hafize,Khosravi, Faezeh,Mobarakeh, Ali Mousavizadeh,Zaim, ?mer
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- Molecular engineered palladium single atom catalysts with an M-C1N3subunit for Suzuki coupling
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Single atom catalysis has emerged as a powerful technique for catalysis due to its outstanding performance and atom economy. Controlling the hybridization of the atom with its environment is crucial in determining the selectivity and/or yield of the reaction. However, the single atom environment is usually ill-defined and hard to predict because the pyrolysis process used in preparing SACs damages the original status of the precursors in the catalyst preparation. A molecular engineering approach to synthesize single atom catalysts (SACs) on a heterogeneous template provides a strategy to make SACs with a highly uniform coordinating environment. Herein, we report the preparation of a molecular engineered Pd single atom catalyst with a pre-defined M-N3C1 coordination (Pd-N3C1-SAC) using a structure-rigid Pd-N3C1 porphyrin as the precursor, which shows more efficient Suzuki coupling compared with the SAC with Pd-N4 coordination. The origin of the high activity of the Pd-N3C1-SAC is revealed through density functional theory calculations, where a lower reaction barrier for the rate-determining oxidative addition is identified. This journal is
- Liu, Jia,Chen, Zhongxin,Liu, Cuibo,Zhang, Bao,Du, Yonghua,Liu, Chen-Fei,Ma, Lu,Xi, Shibo,Li, Runlai,Zhao, Xiaoxu,Song, Jingting,Sui, Xin Zhi,Yu, Wei,Miao, Ling,Jiang, Jianjun,Koh, Ming Joo,Loh, Kian Ping
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supporting information
p. 11427 - 11432
(2021/05/19)
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- Pd(OAc)2-biuret: A highly efficient, low cost and phosphine-free catalyst system for biaryl synthesis under aerobic conditions at room temperature
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A highly efficient, less expensive and phosphine-free protocol for the Suzuki-Miyaura cross-coupling reactions of aryl halides and aryl boronic acids in iPrOH-H2O solvent under aerobic conditions has been developed. The results demonstrate that the biuret played a crucial role and making this protocol highly efficient. The Pd(OAc)2-biuret system exhibited superb catalytic activity towards the Suzuki-Miyaura cross-coupling reaction of a wide range of aryl halides with aryl boronic acids at room temperature, giving high yields even under very low catalytic loading. This system offers an attractive alternative to the existing protocols since the reaction proceeds in green solvent at room temperature with working simplicity, shorter reaction time, cost-effectiveness and provides the desired products in high yields. The effect of solvent, base as well as catalyst loading on the cross-coupling reaction of aryl halide with arylboronic acid is also described.
- Saikia, Bishwajit
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- Pd nanoparticles supported on cubic shaped ZIF-based materials and their catalytic activates in organic reactions
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Pd nanoparticles decorated on cubic shaped ZIF-based materials have been successfully prepared. The nanocomposites have been characterized by X-ray diffraction, field emission scanning electron microscopy, N2 sorption analysis, and transmission
- Dabiri, Minoo,Fazli, Hassan,Movahed, Siyavash Kazemi,Salarinejad, Neda
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- Hydrophilic role of deep eutectic solvents for clean synthesis of biphenyls over a magnetically separable Pd-catalyzed Suzuki-Miyaura coupling reaction
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The development of an efficient and sustainable catalytic system for the preparation of biphenyls through the Suzuki-Miyaura coupling reaction is still a great challenge to green chemistry. Encouraging the prevailing challenge, in the present work, a heterogeneous Pd catalyst was synthesized through a green method and used for the production of biphenyls in deep eutectic solvents (DESs) as green reaction media. In order to prepare the catalyst, magnetite-graphene oxide nanocomposite was modified with cellulose via the click reaction and applied as support for Pd nanoparticles. Cellulose acted as both reducing and stabilizing agent for Pd nanoparticles and eliminated the requirement of a reducing agent. The prepared catalyst was characterized by different methods such as FT-IR, EDX, EDX-mapping, XPS, SEM, TEM, XRD, VSM, and ICP-OES analyses. Catalytic properties of the obtained catalyst was explored in the coupling reaction of aryl halides with aryl boronic acids in different hydrophilic and hydrophobic DESs. The presence of cellulose with hydrophilic character on the structure of catalyst offered well dispersion of the catalyst in hydrophilic DESs, which led to enhancement of its catalytic activity. Among various hydrophilic DESs, the DES composed of dimethylammonium chloride and glycerol was verified as the most effective solvent for the preparation of biphenyls. The catalyst was compatible with a variety of substrates, with which all the Suzuki coupling products were achieved in high to excellent yields. Thanks to the low solubility of catalyst and DES in organic solvents, the separated aqueous phase containing both of the catalyst and DES could be readily recovered by evaporating water and reused up to five successive runs with a stable activity. This simple and new separation strategy provided a clean and highly efficient synthetic methodology for the synthesis of various biphenyls. Moreover, hot filtration test efficiently confirmed that the catalyst is heterogeneous and completely stable under reaction conditions.
- Karimi, Sabah,Masteri-Farahani, Majid,Niakan, Mahsa,Shekaari, Hemayat
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- Introduction of a Recyclable Basic Ionic Solvent with Bis-(NHC) Ligand Property and The Possibility of Immobilization on Magnetite for Ligand- and Base-Free Pd-Catalyzed Heck, Suzuki and Sonogashira Cross-Coupling Reactions in Water
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A new versatile and recyclable NHC ligand precursor has been developed with ligand, base, and solvent functionalities for the efficient Pd-catalyzed Heck, Suzuki and Sonogashira cross-coupling reactions under mild conditions. Furthermore, NHC ligand precursor was immobilized on magnetite and its catalytic activity was also evaluated towards the coupling reactions as a heterogeneous catalyst. The NHC ligand precursor was prepared with imidazolium functionalization of TCT followed by a simple ion exchange by hydroxide ions. However, the results revealed an excellent catalytic activity for the both homogeneous and heterogeneous catalytic systems. 1.52?g.cm?3 and 1194 cP was obtained for the density and viscosity of the NHC ligand precursor respectively. On the other hand, the heterogeneous type could be readily recovered from the reaction mixture and reused for several times while preserving its properties. Heterogeneous nature of the magnetic catalyst was studied by hot filtration, mercury poisoning, and three-phase tests. High to excellent yields were obtained for all entries for the both homogeneous and heterogeneous catalysts, which reflects the high consistency of the catalyst. Graphic Abstract: [Figure not available: see fulltext.]
- Min, Qingwang,Miao, Penghua,Chu, Deyu,Liu, Jinghan,Qi, Meijuan,Kazemnejadi, Milad
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p. 3030 - 3047
(2021/02/16)
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- Magnetic covalently immobilized nickel complex: A new and efficient method for the Suzuki cross-coupling reaction
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In this study, an efficient procedure was reported to prepare Fe3O4@SiO2 magnetic nanoparticles (MNPs) with immobilized nickel NPs. In order to increase the activity of this catalyst, creatine as a ligand with high content of nitrogen atoms was linked onto the magnetic core–shell structure. Then, Ni(II) ions were coordinated on the surface of the silica-coated MNPs and reduced to Ni(0) NPs to obtain the final catalyst. The catalytic activity of the prepared catalyst was studied for the synthesis of biaryl derivatives via the Suzuki–Miyaura cross-coupling reaction in high yields. The catalyst could also be recovered and reused with no loss of activity over five successful runs.
- Keyhaniyan, Mahdi,Khojastehnezhad, Amir,Eshghi, Hossein,Shiri, Ali
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- Sustainable and recyclable magnetic nanocatalyst of 1,10-phenanthroline Pd(0) complex in green synthesis of biaryls and tetrazoles using arylboronic acids as versatile substrates
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A magnetic nanocatalyst was purveyed as a heterogeneous recoverable palladium-based catalyst anchored on green, sustainable and phosphine free support. Resulted Fe3O4@SiO2-Phen-Pd(0) nanocatalyst bearing powerful phenanthroline ligand was thoroughly characterized by physicochemical approaches like UV–vis, FT-IR, EDX, XRD, TGA, ICP, VSM, DLS, FESEM, and TEM analyses. After finding trustable data, the obtained magnetic catalyst was considered to be applied in the Suzuki-Miyaura type C-C couplings and getting corresponding tetrazoles using arylboronic acid derivatives as alternate precursors of aromatic halides and stupendous data were observed.
- Bagherzadeh, Nastaran,Sardarian, Ali Reza,Eslahi, Hassan
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- An easily fabricated palladium nanocatalyst on magnetic biochar for Suzuki-Miyaura and aryl halide cyanation reactions
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Biochar is a carbon-rich solid, the surface of which is covered with a high density of functional carbonyl, hydroxyl and carboxylic acid groups. In this work, palladium nanoparticles were embedded on magnetic biochar and a new reusable and environmentally-friendly catalyst was developed and applied for the promotion of Suzuki-Miyaura C-C coupling and cyanation reactions. The high-carbon (77%), low-ash content (5.8%) and the relatively high surface area (266 m2g?1) of pine tree biochar (PTB) suggested that it might be highly suitable as a catalyst substrate. The Fe3O4-Pd-biochar nanocomposite was successfully characterized using SEM, TEM, EDX, FT-IR, BET and XRD. Its catalytic role was initially evaluated usingp-NO2C6H4I as a model reactant (for both types of reactions) and later for the production of biaryls and benzonitriles from a wide range of aryl halides under mild reaction conditions. Biaryls and benzonitriles were characterized using GC-MS. In the case of the Suzuki-Miyaura reaction, the optimum yield of 98% was obtained with a catalyst concentration of 0.04 mol%, microwave irradiation of 400 W, and a residence time of 5 min, using K2CO3as the base. With respect to the cyanation reaction, dimethylformamide, Na2CO3and 6 h were the optimum solvent, base and reaction duration, respectively. Subsequently, the nanocatalyst showed excellent catalytic activity in both reactions, achieving >88% yields in most cases, regardless of the aryl iodide or bromide used and the type of substitution.
- Turun?, Ersan,Akay, Sema,Baran, Talat,Kalderis, Dimitrios,Tsubota, Toshiki,Kayan, Berkant
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p. 12519 - 12527
(2021/07/25)
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- Efficient visible-light-driven Suzuki coupling reaction over Co-doped BiOCl/Ce-doped Bi2O2CO3composites
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Suzuki coupling reaction is a widely practiced protocol in organic synthesis for the formation of C-C bonds. The conventional process for this reaction usually involves high temperatures and noble metals. Hence, the development of a green, cost-effective photocatalytic system is an attractive and challenging strategy for the reaction. Here, we report a modified palladium-free Co-doped BiOCl/Ce-doped Bi2O2CO3(CBCB) composite, which shows high photocatalytic activity under white LED irradiation. At room temperature, an excellent yield (91%) of the desired cross-coupling product biphenyl was obtained in environmentally friendly solvents. Density functional calculations, together with the experimental results, show that the presence of Co and Ce ions results in the appearance of some impurity levels near the Fermi level of pure BiOCl and Bi2O2CO3, which decreases their forbidden bandwidth, thus ensuring higher light absorption and superior electronic conductivity. Moreover, the intimate interfacial contact between Co-doped BiOCl and Ce-doped Bi2O2CO3planes has a significant impact on the separation and transfer of photoinduced charge carriers, which ultimately leads to a remarkable increase in visible-light-driven photocatalytic activity.
- Zhao, Dan-Xia,Lu, Guo-Ping,Cai, Chun
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supporting information
p. 1823 - 1833
(2021/03/09)
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- Polydopamine-Encapsulated Dendritic Organosilica Nanoparticles as Amphiphilic Platforms for Highly Efficient Heterogeneous Catalysis in Water
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Aqueous heterogeneous catalysis is a green, sustainable catalytic process that attracts increasing attention, but it often suffers from poor mass transfer, substrate adsorption and catalyst dispersion. Herein, we synthesized a type of amphiphilic core-shell catalysts with a hydrophilic polydopamine (PDA) shell and a hydrophobic dendritic organosilica nanoparticle (DON) core for heterogeneous catalysis in water. The hydrophilic shell allowed the catalyst dispersing well in water, and the hydrophobic core facilitated the absorption of organic reactants. The hierarchical core-shell structure facilitated rational arrangement of the location of catalytic species to match the reaction sequence. The obtained metal, enzyme and metal-enzyme amphiphilic catalysts demonstrated improved stability, selectivity and activity in aqueous reactions, including Pd-catalyzed cross-couplings (Suzuki, Liebeskind-Srogl, Heck and Sonogashira), enzymatic enantioselective reduction, chemoenzymatic cascade synthesis of chiral compounds and chemoenzymatic cascade degradation of organophosphates. The amphiphilic catalysts could be easily in situ recovered, and their high catalytic performance was sustained for five cycles.
- Gao, Jing,Guo, Na,Jiang, Yanjun,Liu, Guanhua,Liu, Pengbo,Liu, Yunting,Wang, Zihan,Zhang, Lei
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supporting information
p. 1975 - 1982
(2021/06/09)
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- Green and sustainable palladium nanomagnetic catalyst stabilized by glucosamine-functionalized Fe3O4@SiO2 nanoparticles for Suzuki and Heck reactions
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A novel magnetic and heterogeneous palladium-based catalyst stabilized by glucosamine-functionalized magnetic Fe3O4@SiO2 nanoparticle was synthesized. The strategy relies on the covalently bonding of glucosamine to cyanuric chloride-functionalized magnetic nanoparticles followed by complexation with palladium. The structure of magnetic nanocatalyst was fully determined by FT-IR, XRD, DLS, FE-SEM, TEM, ICP, UV-Vis, TGA, VSM, and EDX. The obtained results confirmed that the palladium nanoparticles stabilized by glucosamine immobilized onto the magnetic support exhibited high activity in cross-coupling reactions of Suzuki-Miyaura and Mizoroki-Heck. Various aryl halides were coupled with arylboronic acid (Suzuki cross-coupling reaction) and olefins (Heck reactions) under the green conditions to provide corresponding products in high to excellent yields. Interestingly, the catalyst can be easily isolated from the reaction media by magnetic decantation and can subsequently be applied for consecutive reaction cycles (at least seven times) with no notable reduction in the catalytic activity.
- Eslahi, Hassan,Sardarian, Ali Reza,Esmaeilpour, Mohsen
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- Preparation of Ni-microsphere and Cu-MOF using aspartic acid as coordinating ligand and study of their catalytic properties in Stille and sulfoxidation reactions
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In this study, the thermal and catalytic behavior of Ni-microsphere and Cu-MOF were investigated with aspartic acid as the coordinating ligand with different morphologies. The Ni-microsphere and Cu-MOF with aspartic acid, as the coordinating ligand, were prepared via a solvothermal method. The morphology and porosity of the obtained Ni microsphere and Cu-MOF were characterized by XRD, FTIR, TGA, DSC, BET and SEM techniques. The catalytic activity of the Ni-microsphere and Cu-MOF was examined in Stille and sulfoxidation reactions. The Ni microsphere and Cu-MOF were easily isolated from the reaction mixtures by simple filtration and then recycled four times without any reduction of catalytic efficiency.
- Ghorbani-Choghamarani, Arash,Bastan, Hosna,Kakakhani, Zahra,Taherinia, Zahra
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p. 14905 - 14914
(2021/05/19)
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- Water-Dispersible Pd–N-Heterocyclic Carbene Complex Immobilized on Magnetic Nanoparticles as a New Heterogeneous Catalyst for Fluoride-Free Hiyama, Suzuki–Miyaura and Cyanation Reactions in Aqueous Media
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Abstract: 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. Graphic Abstract: A new water dispersible heterogeneous Pd–N-heterocyclic carbene for the efficient fluoride-free Hiyama, Suzuki–Miyaura and cyanation reactions in pure water is developed.[Figure not available: see fulltext.].
- Chahkamali, Farhad Omarzehi,Sansano, José Miguel,Sobhani, Sara
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- Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
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A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
- Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
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p. 9561 - 9568
(2021/08/06)
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- [Pd(4-R3Si-IPr)(allyl)Cl]/K2CO3/EtOH: A highly effective catalytic system for the Suzuki-Miyaura cross-coupling reaction
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A series of R3Si-NHC-Pd complexes 1Pd-7Pd was successfully tested as a pre-catalyst for the Suzuki-Miyaura cross-coupling reaction of aryl chlorides and arylboronic acid derivatives to form a wide range of valuable biphenyl products. Use of the readily available weakly basic potassium carbonate as a base and the highly polar protic ethanol as the reaction solvent gave the target coupling products in good-to-excellent yields. The experimental data pointed to the crucial importance of the preliminary pre-catalyst activation step [i.e., the conversion of Pd(II) to Pd(0)], which is remarkably facilitated by the electron-donating trialkylsilyl groups on the NHC ligands of 1Pd–7Pd, thereby rendering them superior compared to the commercially available IPr-Pd complexes. Computational analysis revealed the mechanism of the Pd(II)→Pd(0) activation step, demonstrating the critical role of the reaction solvent and the base in the preference of our 1Pd–7Pd pre-catalysts, for which this step is both thermodynamically and kinetically more feasible.
- Choe, Yoong-Kee,Choi, Jun-Chul,Faried, Miftah,Fukaya, Norihisa,Lee, Vladimir Ya.,Matsumoto, Kazuhiro,Mizusaki, Tomoteru,Putro, Wahyu S.,Seo, Yuto,Takagi, Yukio
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- Efficient photocatalytic chemoselective and stereoselective C-C bond formation over AuPd@N-rich carbon nitride
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Heterogeneous chemoselective or stereoselective C-C coupling reactions remain extremely challenging in traditional organic synthesis. Here, we constructed a AuPd@N-rich carbon nitride (NRCN) photocatalyst through simple ammonia solution heat treatment of carbon nitride and then AuPd NP loading. AuPd@NRCN exhibited extraordinary light color promoted catalytic performance in C-C bond formation under visible light in air. Surprisingly, both high chemoselectivity to unsymmetrical Ullmann biaryl products and satisfactory stereoselectivity to Z-type Heck reaction products could be achieved by changing the light source color. Various substrates exhibited great potential for the economical synthesis of unsymmetrical biaryl products and Z-type olefins. Efficient visible light promoted C-I bond activation accompanied with improved photocatalytic coupling reaction efficiency over AuPd@NRCN was verified firstly by in situ DRIFTS. Considering that the Ullmann cross-coupling reaction is a multi-photon reaction, the improved photocatalytic performance in the Ullmann cross-coupling reaction using a combination of light sources with different colors might be due to the activation of different substrates and/or steps requiring different energies, and the combination of the two energy sources was beneficial for improving the activation efficiency of different substrates and/or steps. The activation of iodobenzene and styrene in the Heck reaction with light was also beneficial to the formation of the stilbene product. The light color promoted chemoselectivity and stereoselectivity are expected to have profound impact on organic synthetic methodology improvement. This journal is
- Jiang, Heyan,Xu, Jie,Zhang, Sishi,Cheng, Hongmei,Zang, Cuicui,Bian, Fengxia
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p. 219 - 229
(2021/01/28)
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- Effect of Alkyl Structures on the Anti-stacking and Anchoring of Pd/Diamine-Functionalized Graphene Nanoparticles in Application in Suzuki Reaction
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Three diamines (1,8-diaminooctane/p-phenylenediamine/biphenylenediamine) with different alkyl groups were used to synthesize the functionalized graphene networks. Pd as the common metal catalyst was used to explore the effects of alkyl types of diamines on anti-stacking, metal anchoring ability of functional graphene and hence the catalytic performance. The results were discussed by characterization of the material and its catalytic properties. All catalysts showed excellent catalytic performance on the Suzuki cross-coupling reaction with a high yield of up to 100%. The p-phenylenediamine and biphenylenediamine functionalized graphene with larger specific surface area was beneficial to improve the stability of the graphene catalyst and maintain good catalytic activity after 5 cycles. The Pd nanoparticles in 1,8-octanediamine materials have smaller size and a smaller loading with the same or even better catalytic performance than p-phenylenediamine, biphenylenediamine materials, due to the stronger electron donating ability of N of octanediamine than that of p-phenylenediamine.
- Tian, Yinbing,Tang, Zijie,Ru, Yu,Wang, Yuanyuan,Dai, Liyi
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p. 2745 - 2754
(2021/08/09)
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- Copper catalysed Gomberg-Bachmann-Hey reactions of arenediazonium tetrafluoroborates and heteroarenediazonium o-benzenedisulfonimides. Synthetic and mechanistic aspects
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Gomberg-Bachmann-Hey reactions were carried out in the presence of copper as a catalyst and gave rise to biaryls or heterobiaryls in good yields and in mild reaction conditions. A computational study of some key points of the reaction was performed. The results are coherent with the experimental data and confirm some aspects of the mechanism. The reaction free energies for the reduction in benzene by CuI of a set of 40 (hetero)arenediazonium tetrafluoroborates were calculated. Both the experiments and the calculations showed that in the coupling with substituted solvents (toluene, bromobenzene, nitrobenzene and anisole) the binding to the ortho position was always favoured.
- Antenucci, Achille,Barbero, Margherita,Dughera, Stefano,Ghigo, Giovanni
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- Precatalyst or dosing-device? The [Pd2{μ-(C6H4) PPh2}2{μ-O2C(C6H5)}2] complex anchored on a carboxypolystyrene polymer as an effective supplier of palladium catalytically active nanoparticles for the Suzuki-Miyaura reaction
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A new catalyst has been synthesized from the precursor [Pd2{μ-(C6H4) PPh2}2 {μ-O2C(C6H5)}2] immobilized on a carboxypolystyrene polymer that exhibits an excellent dispersion of the Pd (II) centers, reusability, and catalytic activity in front of phenyl bromides. The activity of this new material was studied in detail for the Suzuki-Miyaura reaction and compared to that of Pd nanoparticles (NPs) supported on UVM-7 (a mesoporous silica), and Pd NPs stabilized with polyvinylpirrolydone. The homogeneous/heterogeneous character of the catalytic process was determined from the results of the hot-filtration, centrifugation, poisoning, three phases tests, and from differential sensitivity kinetic assays. Changes in the palladium oxidation state, and the size and morphology of the Pd NPs formed during several reusing catalytic cycles were determined by XPS, and by SEM and STEM-HAADF respectively. Kinetic and structural analyses concluded that the new material behaved as a supplier of active Pd(0) NPs to the Suzuki-Miyaura catalytic cycle, which was determined to be driven mainly by the palladium fraction present in solution.
- ángeles úbeda,Amorós, Pedro,Sánchez-Royo, Juan F.,El Haskouri, Jamal,Dolores Marcos,Pérez-Pla, Francisco
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- A ferrocene-templated Pd-bearing molecular reactor
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High-yield, chromatography-free syntheses of a ferrocene-templated molecular cage and its Pd-bearing derivative are presented. The formation of a symmetric cage-type structure was confirmed by single-crystal X-ray diffraction analysis. The Pd-bearing cage was used as an innovative catalyst for the efficient synthesis of 1,1'-biphenyls under mild conditions. The presented catalyst is reusable and 1,1'-biphenyls can be obtained efficiently in a gram scale process.
- Gunka, Piotr A.,Kasprzak, Artur
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supporting information
p. 6974 - 6979
(2020/06/04)
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- Palladium Nanoparticles Immobilized with Polymer Containing Nitrogen-Based Ligand: A Highly Efficient Catalyst for Suzuki–Miyaura and Mizoroki–Heck Coupling Reactions
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Abstract: An outstanding heterogeneous catalyst was successfully prepared by immobilization of palladium nanoparticles (Pd NPs) with polymer containing 4′‐(4‐hydroxyphenyl)‐2,2′:6′,2″‐terpyridine (HPTPy) ligand. The polymer cross‐linked with trimethylolpropane triacrylate (TMPTA) units was synthesized by polymerization of itaconic acid-HPTPy (ITC-HPTPy) monomer (so-called cross‐linked poly (ITC- HPTPy)). The cross‐linked poly (ITC-HPTPy) can stabilize the Pd NPs effectively against aggregation, thereby improving the catalytic efficiency of Pd NPs. The presence of Pd NPs on the polymer was confirmed by various physicochemical techniques. The resulting cross‐linked poly (ITC-HPTPy)-Pd was applied as a highly effective recyclable catalyst in Suzuki–Miyaura and Mizoroki–Heck coupling reactions under low Pd-loading conditions and straightforward methods, and provided the corresponding products with excellent yields (up to 98%), high catalytic activities (TOF up to 213?h?1). The catalyst can be separated from the reaction mixture by centrifugation and can be reused consecutive six times with slight reduction in catalytic activity. Graphic Abstract: Pd NPs immobilized with polymer containing terpyridine ligand are highly active heterogeneous catalysts for Suzuki–Miyaura and Mizoroki–Heck coupling reactions.[Figure not available: see fulltext.].
- Targhan, Homa,Hassanpour, Alireza,Sohrabnezhad, Samira,Bahrami, Kiumars
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p. 660 - 673
(2019/11/03)
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- Design, Synthesis, Characterization and Application of BNPs@SiO2(CH2)3NH-CC-AMP-Pd (0) as a New Reusable Nano-Catalyst for Suzuki and Heck Cross-Coupling Reactions
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Abstract: A simple and effective method was used for the successful preparation of the Boehmite@(CH2)3NH-CC-AMP-Pd (0) NPs as an environmentally friendly heterogeneous nano-catalyst. The synthesized nano-catalyst was well identified by different techniques like FT-IR, XRD, XPS, TEM, SEM, EDX, TGA, mapping, and ICP analysis. The BNPs@SiO2(CH2)3NH-CC-AMP-Pd was used as a recoverable nano-catalyst for Suzuki‐Miyaura and Mizoroki‐Heck coupling reactions under mild, green and sustainable conditions with excellent yields (H2O, EtOH as solvent for Suzuki reaction and solvent-free conditions for Heck reaction). Also, the distribution of palladium on the catalyst surface is uniform and the average palladium size is between 20 and 30?nm. Compared to similar works, this protocol has some of the important aspects such as: thermal and mechanical stability of the catalyst, low palladium leaching (9.7%), the simplicity of the preparation, the availability of raw materials, not expensive, no need for neutral atmosphere, appropriate times, green conditions, use low amount of catalyst (1.42?mol%) and reused catalyst for several consecutive times (at least seven times). Graphic Abstract: [Figure not available: see fulltext.]
- Khodamorady, Minoo,Bahrami, Kiumars
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p. 1571 - 1590
(2019/12/11)
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- Carbazole based Electron Donor Acceptor (EDA) catalysis for the synthesis of biaryl and aryl-heteroaryl compounds
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A highly regioselective, carbazole based Electron Donor Acceptor (EDA) catalyzed synthesis of biaryl and aryl-heteroaryl compounds is described. Various indole and carbazole derivatives were screened for the Homolytic Aromatic Substitution (HAS) reaction. Tetrahydrocarbazole (THC) was very efficient for the HAS transformation and proceeded via a complex formation between diazonium salt and electron rich tetrahydrocarbazole. The UV-Vis spectroscopy technique has been used to confirm the complex formation. The in situ generated EDA complex even in a catalytic amount is found to be efficient for the Single Electron Transfer (SET) process without any photoactivation. Biaryl compounds, 2-phenylfuran, 2-phenylthiophene, and 2-phenylpyrrole and bioactive compounds such as dantrolene and canagliflozin have been synthesized in moderate to excellent yields.
- Annes, Sesuraj Babiola,Ramesh, Subburethinam,Saravanan, Subramanian,Saritha, Rajendhiran
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supporting information
p. 2510 - 2515
(2020/04/15)
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- Method for synthesizing nitrobiphenyl
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The invention relates to a method for synthesizing nitrobiphenyl. The nitrophenylamine which is low in price and benzene are mixed in a solvent which contains halogenated organic acid, halogenated metal salt and nitrite and react, and then the nitrobiphenyl is obtained by aftertreatment. The raw materials are simple and are easily obtained, and are low in cost. Meanwhile, reaction conditions are mild, aftertreatment is simple, and industrialization is facilitated.
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Paragraph 0048-0055
(2020/07/24)
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- Air-Stable Fe3O4@SiO2-EDTA-Ni(0) as an Efficient Recyclable Magnetic Nanocatalyst for Effective Suzuki-Miyaura and Heck Cross-Coupling via Aryl Sulfamates and Carbamates
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The synthesis of inexpensive and novel air-stable Ni(0) nanoparticles immobilized on the EDTA-modified Fe3O4@SiO2 nanocatalyst was investigated in Suzuki-Miyaura and Heck cross-coupling reactions. This catalytic system displayed a greatly improved substrate scope for the carbon–carbon bond formations starting from a wide range of green and economical electrophiles aryl and heteroaryl carbamates and sulfamates via highly efficient method under mild, operationally simple reaction conditions. The synthesized heterogeneous catalyst was also fully characterized by FT-IR, TEM, XRD, DLS, FE-SEM, UV–Vis, EDX, XPS, TGA, NMR, VSM, ICP and elemental analysis techniques. The heterogeneous magnetic nanocatalyst can easily be recovered by an external magnetic field and reused for the next reactions for at least seven times with negligible leaching of catalyst and no substantial decrement in the activity. All these highlights have made the present protocol an interesting, simple and environmentally benign process with low catalyst loading and easy manipulations.
- Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
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- Facile and economical Miyaura borylation and one-pot Suzuki–Miyaura cross-coupling reaction
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Facile and economical method for Miyaura borylation reaction between B2pin2 and aryl bromides is reported. The catalytic system containing 2 mol% PdCl2(PPh3)2 and KOAc serves to enable borylations to occur under solvent-free and atmospheric conditions. The developed protocol can be applied to synthesize symmetrical and unsymmetrical biaryls via one-pot two-step Suzuki–Miyaura cross-coupling reaction and also offers the up-scalability.
- Boontiem, Phongsakorn,Kiatisevi, Supavadee
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- G-C3N4/γ-Fe2O3/TiO2/Pd: A new magnetically separable photocatalyst for visible-light-driven fluoride-free Hiyama and Suzuki-Miyaura cross-coupling reactions at room temperature
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In this paper, a new visible-light harvesting photocatalyst denoted as g-C3N4/γ-Fe2O3/TiO2/Pd was successfully fabricated and fully characterized by different techniques including FT-IR, XPS, XRD, TEM, SEM, elemental mapping, VSM, DRS, and ICP analysis. The as-prepared catalyst was utilized as an efficient magnetically separable photocatalyst in the fluoride-free Hiyama and Suzuki-Miyaura cross-coupling reactions at room temperature under visible light irradiation. By using this approach good to excellent yields of biaryls were achieved from the reaction of various aryl iodides/bromides and even chlorides as highly challenging substrates, which are more available and cheaper than aryl iodides and bromides, with triethoxyphenylsilane or phenylboronic acid. The superior photocatalytic activity of g-C3N4/γ-Fe2O3/TiO2/Pd could be attributed to the synergistic catalytic effects of Pd nanoparticles and g-C3N4/γ-Fe2O3/TiO2. Utilizing a sustainable and safe light source, no need to use any additive or heat, using an eco-friendly solvent and long-term stability and magnetic recyclability of the catalyst for at least seven successive runs are the advantages that support the current protocol towards green chemistry.
- Jahanshahi, Roya,Khazaee, Asma,Sobhani, Sara,Sansano, José Miguel
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p. 11513 - 11526
(2020/07/27)
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- A hydrophilic heterogeneous cobalt catalyst for fluoride-free Hiyama, Suzuki, Heck and Hirao cross-coupling reactions in water
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A hydrophilic heterogeneous cobalt catalyst of chitosan, denoted as mTEG-CS-Co-Schiff-base, has been successfully prepared. This newly synthesized catalyst was characterized by different methods such as XRD, FE-SEM, TEM, TGA, FT-IR, 13C{1H} CP/MAS NMR, XPS and ICP analyses. The catalyst displayed excellent activity for the palladium and fluoride-free Hiyama, Suzuki, Heck and Hirao reactions of various aryl iodides, bromides and chlorides (i.e., the most challenging aryl halides which are cheaper and more widely available than aryl iodides and bromides) in water. The presence of triethylene glycol tags with hydrophilic character on the Co-complex supported on chitosan provides dispersion of the catalyst particles in water, which leads to higher catalytic performance and also facile catalyst recovery by successive extraction. It was reused for at least six successive runs without any discernible decrease in its catalytic activity or any remarkable changes in catalyst structure. The use of water as a green solvent, without requiring any additive or organic solvent, as well as use of a low cost and abundant cobalt catalyst instead of expensive Pd catalysts along with the catalyst recovery and scalability, make this method favorable from environmental and economic points of view for the C-C and C(sp2)-P coupling reactions. Notably, this is the first report on the application of a cobalt catalyst in Hiyama reactions.
- Sobhani, Sara,Hosseini Moghadam, Hadis,Skibsted, J?rgen,Sansano, José Miguel
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p. 1353 - 1365
(2020/03/11)
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- NHC-Pd complex heterogenized on graphene oxide for cross-coupling reactions and supercapacitor applications
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N-heterocyclic carbene (NHC)-palladium(II) complex (GO@NHC-Pd) was synthesized on graphene oxide (GO) support via a simple and cost-effective multistep approach. The spectroscopic, microscopic, thermal, and surface analyses of GO@NHC-Pd confirmed the successful formation of the catalyst. The investigation of catalytic activity showed that GO@NHC-Pd was very effective in Suzuki–Miyaura as well as Hiyama cross-coupling. Being heterogeneous in nature, GO@NHC-Pd was recovered after each reaction cycle easily and reused for up to nine and six cycles in Suzuki–Miyaura and Hiyama cross-coupling, respectively, without significant loss of activity. Further exploration of the supercapacitor performance of GO@NHC-Pd catalyst assembled in a two-electrode cell configuration shown a maximum attained capacitance of 105.26 F/g at a current density of 0.1 A/g with good cycling stability of 96.89% over 2,500 cycles.
- Kandathil, Vishal,Siddiqa, Aisha,Patra, Abhinandan,Kulkarni, Bhakti,Kempasiddaiah, Manjunatha,Sasidhar,Patil, Shivaputra A.,Rout, Chandra Sekhar,Patil, Siddappa A.
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- A facile synthesis of mesoporous graphitic carbon nitride supported palladium nanoparticles as highly effective and reusable catalysts for Stille coupling reactions under mild conditions
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The development of a Stille coupling protocol that is operable under moderate conditions without using a base is highly required for the synthetic organic chemistry community, which requires an efficient nanocatalyst. In this respect, addressed herein is a facile one-pot synthesis of mesoporous graphitic carbon nitride (mpg-CN) supported Pd NPs, denoted as mpg-CN/Pd hereafter, and investigation of their catalytic activity in Stille cross-coupling reactions for the first time. It has been demonstrated that mpg-CN nanosheets can serve as not only a support material but also a stabilizer for the generation of 4.5 nm Pd NPs. The ecofriendly generated heterogeneous nanocatalyst was characterized by TEM, XRD, XPS, BET surface area and ICP-MS analysis. The mpg-CN/Pd nanocatalysts showed high activity in the Stille coupling reaction of a variety of electron-deficient and electron-rich aryl iodides/bromides and two different organostannanes with a wide substrate scope to afford the corresponding biaryls without using any bases and additional ligands under relatively mild conditions. The catalyst can be easily recovered from the reaction medium by centrifugation. It can be reused at least 5 times without any loss of activity.
- Cetin, Sultan,Kalay, Erbay,Kolemen, Safacan,Metin, ?nder
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p. 6714 - 6723
(2020/05/16)
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- Ultrafine Pd nanoparticles loaded benzothiazole-linked covalent organic framework for efficient photocatalytic C-C cross-coupling reactions
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We proposed a strategy that a benzothiazole-linked covalent organic framework (TTT-COF) was used as a substrate to prepare metal composite photocatalyst Pd NPs?TTT-COF. Firstly, benzothiazole linked TTT-COF exhibited superior chemical stability and photoresponse. Moreover, a finer particle size (2.01 nm) and more uniform distribution of Pd NPs were observed in Pd NPs?TTT-COF owing to the binding interaction between Pd NPs and S in benzothiazole groups. Pd NPs?TTT-COF exhibited superior efficiency and reusability in photocatalytic C-C cross-coupling reactions. Mechanism study suggested that photogenerated electrons and holes on TTT-COF played important roles in these reactions. This journal is
- Cai, Yaqi,Niu, Hongyun,Xu, Lin,Yang, Yongliang,Zhang, Hui,Zhao, Weijia
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p. 29402 - 29407
(2020/10/02)
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- N-Nitroheterocycles: Bench-Stable Organic Reagents for Catalytic Ipso-Nitration of Aryl- And Heteroarylboronic Acids
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Photocatalytic and metal-free protocols to access various aromatic and heteroaromatic nitro compounds through ipso-nitration of readily available boronic acid derivatives were developed using non-metal-based, bench-stable, and recyclable nitrating reagents. These methods are operationally simple, mild, regioselective, and possess excellent functional group compatibility, delivering desired products in up to 99% yield.
- Budinská, Alena,Katayev, Dmitry,Passera, Alessandro,Zhang, Kun
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supporting information
(2020/03/30)
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- A Facile Synthesis of Pd–C3N4@Titanate Nanotube Catalyst: Highly Efficient in Mizoroki–Heck, Suzuki–Miyaura C–C Couplings
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Abstract: A Pd–C3N4@titanate nanotube (Pd–C3N4@TNT) catalyst workable in water medium, robust against leaching and agglomeration was prepared in a facile synthetic procedure using quite common chemicals such as TiO2 powder, urea and palladium acetate. The Pd–C3N4@TNT catalyst has been characterized by BET surface area and pore size distribution, X-ray diffraction, solid-state 13C NMR spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The Pd–C3N4@TNT is a green catalyst for the Miziroki–Heck and Suzuki–Miyaura C–C coupling reactions in water medium with high efficiency (??99% product yields) due to atomic level immobilization of Pd in C3N4 networked titanate nanotubes. Pd–C3N4@TNT is robust against leaching and agglomeration due to stable and furthermore it is recyclable and usable at least for five repeated cycles. The use of water as solvent, absence of leaching and agglomeration, recyclability and reusability ascertains the greenness of Pd–C3N4@TNT) catalyst and process. Graphic Abstract: Novel Pd–C3N4@titanate nanotube catalyst prepared from bulk TiO2 and urea by simple hydrothermal and thermal pyrolysis followed by immobilization of Pd is active and selective for Mizoroki–Heck, Suzuki–Miyaura C–C couplings in water medium.[Figure not available: see fulltext.].
- Velpula, Venkata Ramana Kumar,Ketike, Thirupathaiah,Paleti, Gidyonu,Kamaraju, Seetha Rama Rao,Burri, David Raju
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- Palladium Nanoparticles Anchored on Thiol Functionalized Xylose Hydrochar Microspheres: An Efficient Heterogeneous Catalyst for Suzuki Cross-Coupling Reactions
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Abstract: Novel thiol functionalized xylose hydrochar microspheres supported palladium nanoparticles (C–SH–Pd) were synthesized by gentle heating of palladium (II) acetate and thiol functionalized xylose hydrochar (C–SH) in ethanol. The as-prepared C–SH–Pd exhibited high catalytic activity towards Suzuki reactions with a yield of high up to 100%. Moreover, it could be reused for at least five times without heavily loss of the catalytic activity. The amount of palladium entrapped on C-SH microspheres was measured by AAS and found to be 1.42?mmol/g. Leaching studies showed that the filtrate contained less than 0.2?ppm Pd. Due to the superior catalytic performance and stability of the C–SH–Pd catalyst, it can be exploited in other cross coupling reactions in the long run. Graphic Abstract: [Figure not available: see fulltext.].
- Huang, Pingquan,Zeng, Xiaoyan,Du, Fan,Zhang, Lei,Peng, Xinwen
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p. 1011 - 1019
(2019/11/13)
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- Self-Assembling Supramolecular Hybrid Hydrogel Beads
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With the goal of imposing shape and structure on supramolecular gels, we combine a low-molecular-weight gelator (LMWG) with the polymer gelator (PG) calcium alginate in a hybrid hydrogel. By imposing thermal and temporal control of the orthogonal gelation methods, the system either forms an extended interpenetrating network or core–shell-structured gel beads—a rare example of a supramolecular gel formulated inside discrete gel spheres. The self-assembled LMWG retains its unique properties within the beads, such as remediating PdII and reducing it in situ to yield catalytically active Pd0 nanoparticles. A single PdNP-loaded gel bead can catalyse the Suzuki–Miyaura reaction, constituting a simple and easy-to-use reaction-dosing form. These uniquely shaped and structured LMWG-filled gel beads are a versatile platform technology with great potential in a range of applications.
- Piras, Carmen C.,Slavik, Petr,Smith, David K.
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supporting information
p. 853 - 859
(2019/12/24)
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