- Acceleration of Suzuki coupling reactions by abundant and non-toxic salt particles
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Enhancement of reaction efficiency using non-toxic, abundant, and cheap additives is an interesting topic in green chemistry. In this paper, we report the first work to study the effect of salt particles on organic reactions in different solvents, in which the salts were not soluble, and it was discovered that NaCl, KCl, Na2SO4 and K2SO4 particles could considerably accelerate Suzuki coupling reactions catalyzed by the Pd nanocatalysts. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) studies indicated that there exist strong interactions between the salts and the catalyst (Pd) and between the salts and the reactants, which are important reasons for the synergistic effect of the catalyst and the salts. The application of salt particles suspended in organic reaction systems may become a useful strategy to develop new and green reaction routes.
- Zhang, Binbin,Song, Jinliang,Liu, Huizhen,Shi, Jinghua,Ma, Jun,Fan, Honglei,Wang, Weitao,Zhang, Peng,Han, Buxing
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- Transfer of heterocyclic carbene ligands from chromium to gold, palladium and platinum
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The reaction of pentacarbonyl(pyrazolin-3-ylidene)chromium complexes, {A figure is presented} (2a-c) (R = Ph (a), C6H4NMe2-4 (b); (C5H4)FeCp (c)), with [AuCl(SMe2)], H[AuCl4], [PdCl2(NCPh)2] and [PtCl2(NCPh)2] gives, by transfer of the heterocyclic carbene ligand, new chloro pyrazolin-3-ylidene complexes of gold(I) and gold(III), dichloro bis(pyrazolin-3-ylidene) palladium and dichloro bis(pyrazolin-3-ylidene) platinum in high yield. The chloride ligand in {A figure is presented} (Fc = (C5H4)FeCp) is readily displaced by trifluoroacetate. The analogous substitution of iodide for the chloride ligands in {A figure is presented} (M = Pd, Pt) give the corresponding diiodo complexes although in a much slower reaction. In contrast, the reaction of silver trifluoroacetate with {A figure is presented} affords a binuclear Pd-Ag complex containing two pyrazolin-3-ylidene and three trifluoroacetate ligands two of whom occupy bridging positions between Pd and Ag. The reactions of the pyrazolidin-3-ylidene complex {A figure is presented} (R = C6H4NMe2-4) with [AuCl(SMe2)] and [PdCl2(NCPh)2] yield chloro pyrazolidin-3-ylidene gold and dichloro bis(pyrazolidin-3-ylidene) palladium complexes. The related dichloro bis(tetrahydropyrimidin-4-ylidene) palladium complex is formed in the reaction of {A figure is presented} with the palladium complex [PdCl2(NCPh)2]. The solid-state structures of several of these heterocyclic carbene complexes including the structure of the binuclear Pd-Ag complex are established by X-ray structure analyses.
- Kessler, Florian,Szesni, Normen,Maa?, Chaya,Hohberger, Christiane,Weibert, Bernhard,Fischer, Helmut
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- Supramolecular Nanotubules as a Catalytic Regulator for Palladium Cations: Applications in Selective Catalysis
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Despite the recent development of highly efficient and stable metal catalysts, conferral of regulatory characteristics to the catalytic reaction in heterogeneous systems remains a challenge. Novel supramolecular nanotubules were prepared by alternative stacking from trimeric macrocycles, which was found to be able to coordinate with Pd cations. The Pd complexes exhibited a high catalytic performance for C?C coupling reaction. Notably, the tubular catalyst was observed to be controlled by supramolecular reversible assembly and showed superior heterogeneous catalytic activity, which was maintained for a number of cycles or reuse under an aerobic environment. Furthermore, the supramolecular catalyst showed unprecedented selectivity for the multifunctional coupling reaction and was able to serve as a new constructor of asymmetrical compounds.
- Wu, Shanshan,Li, Yongguang,Xie, Siying,Ma, Cong,Lim, Joonwon,Zhao, Jiong,Kim, Dae Seok,Yang, Minyong,Yoon, Doong Ki,Lee, Myongsoo,Kim, Sang Ouk,Huang, Zhegang
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Read Online
- Recycling Oryza sativa wastes into poly-imidazolium acetic acid-tagged nanocellulose Schiff base supported Pd nanoparticles for applications in cross-coupling reactions
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A green and sustainable heterogeneous nanocatalyst for the Suzuki reaction was fabricated by refining rice straw to ionic nanocellulose Schiff base (NCESB) which was employed for bio-reduction of Pd(II) into Pd nanoparticles (Pd NPs) and immobilization of these NPs to fabricate the desired nanocatalyst (NCESB@Pd). The TEM image revealed well-dispersed PdNPs with sizes of 5–23 nm. The new nanocatalyst displayed amazing activity in catalyzing coupling reactions of a wide range of halobenzenes with phenylboronic acid at 50 °C (reaction time 15–60 min) and even at room temperature (reaction time 120 min). The NCESB@Pd nanocatalyst exhibited excellent recyclability (up to five catalytic runs) without a significant loss of its activity or identity. Therefore, the new ionic nanocatalyst may open a new window for a novel generation of ionic low-cost green and highly effective nanocatalysts for organic transformation reactions.
- Elshaarawy, Reda F. M.,Yahya, Rana
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- Organocatalytic synthesis of (Het)biaryl scaffoldsviaphotoinduced intra/intermolecular C(sp2)-H arylation by 2-pyridone derivatives
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A uniqueN,O-bidentate ligand 6-oxo-1,6-dihydro-pyridone-2-carboxylic acid dimethylamide (L1) catalyzed direct C(sp2)-H (intra/intermolecular) arylation of unactivated arenes has been developed to expedite access to (Het)biaryl scaffolds under UV-irradiation at room temperature. The protocol tolerated diverse functional groups and substitution patterns, affording the target products in moderate to excellent yields. Mechanistic investigations were also carried out to better understand the reaction pathway. Furthermore, the synthetic applicability of this unified approach has been showcasedviathe construction of biologically relevant 4-quinolone, tricyclic lactam and sultam derivatives.
- Das, Tapas Kumar,Kundu, Mrinalkanti,Mondal, Biswajit,Ghosh, Prasanjit,Das, Sajal
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p. 208 - 218
(2021/12/29)
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- Sterically enhanced 2-iminopyridylpalladium chlorides as recyclable ppm-palladium catalyst for Suzuki–Miyaura coupling in aqueous solution
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Sterically hindered 2-iminopyridine derivatives and their palladium chlorides complexes are designed and prepared, which efficiently promote the Suzuki–Miyaura coupling (SMC) reaction in aqueous solution. Besides the good to excellent yields and broad substrate scope, these catalysts can be reused for at least four new batches of the substrates. Spontaneous separation of coupling products in the aqueous reaction medium is the additional striking feature of this catalytic process. Furthermore, catalytic performance of palladium complexes bearing the azo-bridged phenyl groups was greatly influenced by the UV irradiation due to the cis/trans photoisomerization of azo unit of the catalysts. In conclusion, titled palladium complexes provide a green, sustainable, cost-effective, and convenient process to synthesize SMC products at multi-gram-scale reaction.
- Lin, Wenhua,Zhang, Liping,Ma, Yanping,Liang, Tongling,Sun, Wen-Hua
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- A Photoreactive Iron(II) Complex Luminophore
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Controlling the order and lifetimes of electronically excited states is essential to effective light-to-potential energy conversion by molecular chromophores. This work reports a luminescent and photoreactive iron(II) complex, the first performant group homologue of prototypical sensitizers of ruthenium. Double cyclometalation of a phenylphenanthroline framework at iron(II) favors the population of a triplet metal-to-ligand charge transfer (3MLCT) state as the lowest energy excited state. Near-infrared (NIR) luminescence exhibits a monoexponential decay with τ = 2.4 ns in the solid state and 1 ns in liquid phase. Lifetimes of 14 ns at 77 K are in line with a narrowing of the NIR emission band at λem,max = 1170-1230 nm. Featuring a 3MLCT excited-state redox potential of -2 V vs the ferrocene/ferrocenium couple, the use of the Fe(II) chromophore as a sensitizer for light-driven synthesis is exemplified by the radical cross-coupling of 4-chlorobromobenzene and benzene.
- Argüello Cordero, Miguel A.,Berkefeld, Andreas,Leis, Wolfgang,Lochbrunner, Stefan,Schubert, Hartmut
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supporting information
p. 1169 - 1173
(2022/02/05)
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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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- METHOD FOR PRODUCING HALOGEN COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for efficiently producing an aromatic compound containing a halogen group(s). SOLUTION: Provided is a method for producing a halogen compound represented by the following general formula (1), comprising reacting an iodine compound represented by the following general formula (2) and a compound represented by the following general formula (3) in the presence of a transition metal compound, at least one phosphine compound selected from the group consisting of 1,1'-bis(diphenylphosphino)ferrocene and 4,5'-bis(diphenylphosphino)-9,9'-dimethylxanthene, and a base. (In the formula, Ar1 and Ar2 each independently represent a C1-40 organic group; X represents a bromine group, a chlorine group, a fluorine group, or a trifluoromethanesulfonate group, and when there are a plurality of X's, they may be the same or different; n represents an integer equal to or larger than 1; R's each independently represent a hydrogen atom, a C1-4 alkyl group, or a phenyl group, and two R's may be linked to form a ring containing oxygen atoms and a boron atom.) SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0054-0060; 0072-0074; 0091-0093
(2021/09/29)
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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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- 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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- 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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- Magnetite@MCM-41 nanoparticles as support material for Pd-N-heterocyclic carbene complex: A magnetically separable catalyst for Suzuki–Miyaura reaction
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The Magnetite@MCM-41@NHC@Pd catalyst was obtained with Pd metal bound to the NHC ligand anchored to the surface of Fe3O4@MCM-41. It was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy disperse X-ray analysis (EDX), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The amount of Pd in the Magnetite@MCM-41@NHC@Pd was measure by inductively coupled plasma–optical emission spectroscopy (ICP-OES) analysis. The catalytic activity of Magnetite@MCM-41@NHC@Pd heterogeneous catalyst done on Suzuki–Miyaura reactions of aryl halides with different substituted arylboronic acid derivatives. All coupling reactions afforded excellent yields and up to 408404 Turnover Frequency (TOF) h?1 in the presence of 2 mg of Magnetite@MCM-41@NHC@Pd catalyst (0.0564 mmol g?1, 0.01127 mmol% Pd) at room temperature in 2-propanol/H2O (1:2). Moreover, Magnetite@MCM-41@NHC@Pd catalyst was recover by applying the magnet and reused for another reaction. The catalyst showed excellent structural and chemical stability and reused ten times without a substantial loss in its catalytic performance.
- Akko?, Mitat,Bu?day, Nesrin,Alt?n, Serdar,Ya?ar, Sedat
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- Direct bromodeboronation of arylboronic acids with CuBr2 in water
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An efficient and practical method has been developed for the preparation of aryl bromides via the direct bromodeboronation of arylboronic acids with CuBr2 in water. This strategy provides several advantages, such as being ligand-free, base-free, high yielding, and functional group tolerant.
- Tang, Yan-Ling,Xia, Xian-Song,Gao, Jin-Chun,Li, Min-Xin,Mao, Ze-Wei
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supporting information
(2021/01/05)
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- Anchored PdCl2 on fish scale: an efficient and recyclable catalyst for Suzuki coupling reaction in aqueous media
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PdCl2 anchored on fish scale (FS) complex were intended to a heterogeneous catalyst for ligand-free Suzuki coupling reaction in aqueous media. The catalyst FS-PdCl2 was characterized by FT-IR, powder XRD, XPS and SEM. FS-PdCl2 complex has been successfully implemented for Suzuki coupling reactions of various halogenated aromatics with arylboronic acid to provide the corresponding biaryl compounds under environmentally friendly conditions (40 °C, water solvent). Moreover, the efficient catalyst shows excellent stability and recyclability, and its catalytic activity without any decrease after 8 times consecutive reused.
- Yang, Quanlu,Yang, Fawang,Zhang, Ying,Hou, Juanjuan,Li, Jiankun,Cheng, Jinkui,Wu, Shang,Zhan, Huiying,Zhang, Xinghui,Shi, Haixiong
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supporting information
(2020/12/25)
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- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
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A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
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supporting information
p. 2095 - 2103
(2021/03/26)
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- End-Functionalization of Diarylethene for Opto-Electronic Switching with High Fatigue Resistance
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A molecular and synthetic approach to strengthen the switching performance of diarylethene (DAE)-based organic transistors is proposed. By tuning the length of alkyl side chains of the biphenyl unit attached to 1,2-bis(5-biphenyl-2-methylthien-3-yl)perfluorocyclopentene (DAE), we show that the molecular environment for reversible photoisomerization of DAEs can be optimized. Four different DAEs are synthesized with different alkyl chains (DAE_C0, DAE_C1, DAE_C6, and DAE_C10), and ITIC is chosen to construct a semiconductor matrix to maximize the quantum yield of photoconversion considering the complementary absorption range of both materials. From photophysical, structural, and morphological analyses, the longer alkyl chains inhibit intermolecular aggregation between DAEs and allow more hydrophobic surface properties of DAEs, thus improving molecular miscibility with ITIC. The improved molecular compatibility of DAEs with ITIC makes the overall bulk heterojunction film amorphous, allowing more free volume for reversible photoisomerization. Consequently, DAE_C6 exhibits the maximum quantum yield for both photocyclization and photocycloreversion, enabling high light-controlled on/off ratios in photoswitchable transistors. Furthermore, the exceptionally high DAE_C6 quantum yield enables robust fatigue resistance under repeated photoswitching with only a 30% decrease in the on/off ratio after 100 cycles. Overall, this work shows that not only the energy level but also the molecular compatibility can endow significant switching performances for molecular switches.
- Hassan, Syed Zahid,Yu, Seong Hoon,So, Chan,Moon, Dohyun,Chung, Dae Sung
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p. 403 - 412
(2021/01/13)
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- Hydrogen-Bond-Donor Solvents Enable Catalyst-Free (Radio)-Halogenation and Deuteration of Organoborons
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A hydrogen bond donor solvent assisted (radio)halogenation and deuteration of organoborons has been developed. The reactions exhibited high functional group tolerance and needed only an ambient atmosphere. Most importantly, compared to literature methods, our conditions are more consistent with the principals of green chemistry (e.g., metal-free, strong oxidant-free, more straightforward conditions).
- Yang, Yi,Gao, Xinyan,Zeng, Xiaojun,Han, Junbin,Xu, Bo
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supporting information
p. 1297 - 1300
(2020/12/23)
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- Photoelectric properties of aromatic triangular tri-palladium complexes and their catalytic applications in the Suzuki-Miyaura coupling reaction
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The photoelectric properties and catalytic activities of substituted triphenylphosphine and sulfur/selenium ligand supported aromatic triangular tri-palladium complexes1-4, abbreviated as [Pd3]+, were investigated. The cyclic voltammogram of [Pd3]+in CH3CN-nBu4NPF6showed a single quasi-reversible wave which was consistent with their robust property and provided preliminary proof for their electron transfer processes in catalysis. With excitation at 267 nm, [Pd3]+exhibited strong ratiometric fluorescence at 550 and 780 nm at a temperature gradient from 77 K to 287 K. These peculiar triangular tri-palladium complexes showed excellent catalytic activities and exclusive reactivity with aryl iodides over the other halogenated aromatics in the Suzuki-Miyaura coupling reaction. The electronic and steric hindrance effects of substituents on the aryl iodides and aryl boronic acids including heteroaromatics like pyridine, pyrazine and thiophenes were explored and most substrates achieved up to 99% of yields. (2-[1,1′-Biphenyl]-2-ylbenzothiazole) which was analogous to the selective cyclooxygenase-2 (COX-2) inhibitors was also synthesized with our tri-palladium catalyst and gave good isolated yield (94%). The study of the catalytic process revealed that the mechanism of the reaction may involve the replacement of the sulphur ligand on [Pd3]+by iodine from aryl iodides, which was beneficial for the matching of C-I bond energy.
- Li, Jia,Li, Xujun,Liu, Xiang,Maestri, Giovanni,Malacria, Max,Wang, Xiaoshuang,Wang, Yanlan,Wu, Lingang
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supporting information
p. 11834 - 11842
(2021/09/06)
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- Easy conversion of nitrogen-rich silk cocoon biomass to magnetic nitrogen-doped carbon nanomaterial for supporting of Palladium and its application
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In this study, magnetic nitrogen-doped carbon (MNC) was fabricated through facile carbonization and activation of natural silk cocoons containing nitrogen and then combined with Fe3O4 nanoparticles to create a good support material for palladium. Palladium immobilization on the support resulted in the formation of magnetic nitrogen-doped carbon-Pd (MNC-Pd). The prepared heterogeneous catalyst was well characterized using FT-IR, TGA, EDX, FE-SEM, XRD, VSM, and ICP-OES techniques. Thereafter, the synthesis of biaryl compounds was conducted to investigate the catalyst performance via the reaction of aryl halides and phenylboronic acid. Further, the catalyst could be used and recycled for six consecutive runs without any significant loss in its activity.
- Akbarzadeh, Parisa,Koukabi, Nadiya
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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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- Pd Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
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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.]
- Li, Tang,Pang, Wan,Wang, Jie,Zhang, Xiaoli,Zhao, Zesheng
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- Near-field enhancement by plasmonic antennas for photocatalytic Suzuki-Miyaura cross-coupling reactions
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It is well documented that placing a plasmonic antenna close to catalytically active nanoparticles can enhance their catalytic activity in chemical reactions via the near-field enhancement effect. Less known is whether and how the near-field enhances the reactivity of the reactant substrates involved in these reactions. Herein, we prepared an “antenna-reactor” catalyst with Au nanoparticles absorbing light as an optical antenna and the adjacent Pd nanoparticles acting as a chemical reactor to study the near-field enhancement effect in Suzuki–Miyaura cross-coupling reaction involving various substrates. The results showed that the activity of Pd nanoparticles were significantly enhanced in the presence of Au antennas. Excessively increasing the density of Au antennas, however, suppressed the reaction due to the interaction between neighboring electromagnetic hot spots. Moreover, the near-field affected different substrates in different extents, enhancing more to reactions that involve substrates with higher electron cloud density at the reactive center. The overall effect of the near-field to the catalytic reactions was proved to be an integrated result of the effect of Au nanoparticle density and reactive center electron cloud density. This study provides enriched understanding for the near-field enhancement effect in photocatalytic reactions with various substrates, and deepened insights for new “antenna-reactor” photocatalyst design.
- Han, Chenhui,Gómez, Daniel E.,Xiao, Qi,Xu, Jingsan
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p. 205 - 211
(2021/04/27)
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- Charge Neutral [Cu2L2] and [Pd2L2] Metallocycles: Self-Assembly, Aggregation, and Catalysis
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A range of morphologically distinct metallosupramolecular Cu(II) and Pd(II) complexes has been constructed, based on the tritopic ligand 1,1′,1″-(benzene-1,3,5-triyl)tris(4,4-dimethylpentane-1,3-dione) (H3L). By control of the reaction conditions, it is possible to generate distinct coordination assemblies possessing either macrocyclic or polymeric structures and more importantly distinct activity in catalysis of the Suzuki-Miyaura cross-coupling.
- Ko?odziejski, Micha?,Brock, Aidan J.,Kurpik, Gracjan,Walczak, Anna,Li, Feng,Clegg, Jack K.,Stefankiewicz, Artur R.
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p. 9673 - 9679
(2021/06/30)
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- N-Methylphenothiazine S-Oxide Enabled Oxidative C(sp2)–C(sp2) Coupling of Boronic Acids with Organolithiums via Phenothiaziniums
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Herein, we report the development of a transition-metal-free oxidative C(sp2)–C(sp2) coupling of readily available boronic acids and organolithiums via phenothiazinium ions. Various biaryl, styrene, and diene derivatives were obtained using this reaction system. The key to this process is N-methylphenothiazine S-oxide (PTZSO), which allows efficient conversion of boronic acids to phenothiazinium ions. The mechanism of phenothiazinium formation using PTZSO was investigated using theoretical calculations and experiments, which provided insight into the unique reactivity of PTZSO.
- Yoshida, Tatsuki,Honda, Yuki,Morofuji, Tatsuya,Kano, Naokazu
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supporting information
p. 9664 - 9668
(2021/12/17)
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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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- Aryl Radical Selectivity in Biphasic Systems
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Aryl radicals generated in the aqueous phase of biphasic mixtures have-regardless of a comparably low polarity- A strong preference to react with aromatic substrates in the aqueous phase and not to undergo phase-transfer into a lipophilic phase, independent from the presence of a surfactant. These results represent an important prerequisite toward future studies in biological systems, which typically consist of various compartments of either hydrophilic or lipophilic character.
- Altmann, Lisa-Marie,Fürst, Michael C. D.,Gans, Eva I.,Heinrich, Markus R.,Pratsch, Gerald,Zantop, Viviane
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supporting information
(2020/01/31)
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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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- Palladium (II)–Salan Complexes as Catalysts for Suzuki–Miyaura C–C Cross-Coupling in Water and Air. Effect of the Various Bridging Units within the Diamine Moieties on the Catalytic Performance
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Water-soluble salan ligands were synthesized by hydrogenation and subsequent sulfonation of salens (N,N’-bis(slicylidene)ethylenediamine and analogues) with various bridging units (linkers) connecting the nitrogen atoms. Pd (II) complexes were obtained in reactions of sulfosalans and [PdCl4]2?. Characterization of the ligands and complexes included extensive X-ray diffraction studies, too. The Pd (II) complexes proved highly active catalysts of the Suzuki–Miyaura reaction of aryl halides and arylboronic acid derivatives at 80 ?C in water and air. A comparative study of the Pd (II)–sulfosalan catalysts showed that the catalytic activity largely increased with increasing linker length and with increasing steric congestion around the N donor atoms of the ligands; the highest specific activity was 40,000 (mol substrate) (mol catalyst × h)?1. The substrate scope was explored with the use of the two most active catalysts, containing 1,4-butylene and 1,2-diphenylethylene linkers, respectively.
- Bunda, Szilvia,Joó, Ferenc,Kathó, ágnes,Udvardy, Antal,Voronova, Krisztina
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supporting information
(2020/09/18)
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- Arylation of aryllithiums with: S-arylphenothiazinium ions for biaryl synthesis
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Aryllithiums are one of the most common and important aryl nucleophiles; nevertheless, methods for arylation of aryllithums to produce biaryls have been limited. Herein, we report arylation of aryllithiums with S-arylphenothiazinium ions through selective
- Morofuji, Tatsuya,Yoshida, Tatsuki,Tsutsumi, Ryosuke,Yamanaka, Masahiro,Kano, Naokazu
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supporting information
p. 13995 - 13998
(2020/11/21)
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- Switching from biaryl formation to amidation with convoluted polymeric nickel catalysis
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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.
- Sen, Abhijit,Dhital, Raghu N.,Sato, Takuma,Ohno, Aya,Yamada, Yoichi M.A.
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p. 14410 - 14418
(2020/12/21)
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- A two-dimensional amide-linked covalent organic framework anchored Pd catalyst for Suzuki-Miyaura coupling reaction in the aqueous phase at room temperature
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A two-dimensional amide-linked covalent organic frameworks (2D-COFs) supported Pd catalysis system was synthesized. Fourier transformed Infrared (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used to characterize the prepared catalyst. Electron microscopes (SEM and TEM) are employed to know the morphologies of the synthesized catalysts. The catalyst is an efficient heterogeneous catalyst for Suzuki-Miyaura coupling reaction, exhibits high catalytic activity for various aryl halides and aryl boronic acids in aqueous media at room temperature. More importantly, the catalyst with high stability could be easily recycled for at least nine runs without decrease of the catalytic activity.
- Wu, Shang,Ding, Ning,Jiang, Pengwei,Wu, Lan,Feng, Qiaoliang,Zhao, Lianbiao,Wang, Yanbin,Su, Qiong,Zhang, Hong,Yang, Quanlu
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supporting information
(2020/12/02)
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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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- NaH-mediated direct C-H arylation in the presence of 1,10-phenanthroline
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Transition-metal-free coupling of haloarenes with unactivated arenes has been developed in the presence of NaH and 1,10-phenanthroline. Various haloarenes bearing methyl, methoxy, halogen (fluoride, chloride, and bromide), cyano, trifluoromethyl, ester, and amide groups can be cross-coupled with unactivated arenes, or heteroarenes in this reaction.
- Nozawa-Kumada, Kanako,Iwakawa, Yuki,Onuma, So,Shigeno, Masanori,Kondo, Yoshinori
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supporting information
p. 7773 - 7776
(2020/07/27)
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- Anchoring Pd(OAc)2 on amide-bonded covalent organic frameworks: An efficient heterogeneous Pd@OC-MA catalyst for Suzuki-Miyaura coupling reactions in water
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Nitrogen-rich of a melamine-based mesoporous covalent organic frameworks (COFs) materials were synthesized and used as a carrier to support a Pd(OAc)2. The Pd@OC-MA revealed an efficient catalytic activity and selectivity for Suzuki-Miyaura coupling reactions in an environmentally friendly water medium at room temperature. Specifically, it had moderate to excellent conversion for inactive chlorinated aromatic hydrocarbons. The catalyst was synthesized simply, had high stability and good selectivity, and was easy to recycle. Excellent catalytic activity of the Pd@OC-MA was also observed after five consecutive cycles.
- Wu, Shang,Zhang, Ying,Jiang, Hongyan,Wu, Lan,Ding, Ning,Jiang, Pengwei,Zhang, Hong,Zhao, Lianbiao,Yin, Fenping,Yang, Quanlu
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supporting information
(2020/11/02)
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- Immobilized Pd on Eggshell Membrane: A powerful and recyclable catalyst for Suzuki and Heck cross-coupling reactions in water
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A stable heterogeneous palladium catalysts, the waste eggshell membrane (ESM) anchored Pd complex, was synthesized by a simple and green technique. The catalyst obtained can display an outstanding catalytic activity for Suzuki and Heck coupling reactions in water media. The reactions of various aryl halides with aryl boronic acids and terminal alkenes provided the corresponding products in moderate to excellent yields. More importantly, this novel and efficient catalyst with high stability can be easily reused for at least twelve times with no decrease of the catalytic activity, performing an endurable and wide tolerance of the substrates. Facile synthesis, high catalytic activity, and recyclability make these catalysts interesting for further studies.
- Wu, Shang,Jiang, Hongyan,Zhang, Hong,Zhao, Lianbiao,Yuan, Peilin,Zhang, Ying,Su, Qiong,Wang, Yanbin,Wu, Lan,Yang, Quanlu
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- Organocatalyst in Direct C(sp2)-H Arylation of Unactivated Arenes: [1-(2-Hydroxyethyl)-piperazine]-Catalyzed Inter-/Intra-molecular C-H Bond Activation
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This article describes the identification of 1-(2-hydroxyethyl)-piperazine as a new, cost-effective, highly efficient organocatalyst, which promotes both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in the presence of potassium tert-butoxide. While the inter-molecular C-H arylation of unactivated benzenes with aryl halides (Ar-X; X = I, Br, Cl) toward biaryl syntheses underwent smoothly in the presence of only 10 mol percent organocatalyst, the intra-molecular C-H arylation catalytic system composed of 40 mol percent each of the catalyst and the additive (4-dimethylaminopyridine (DMAP)). The novel catalyst was also able to perform both inter- A nd intra-molecular direct arylations simultaneously in a single pot. The mechanistic studies confirmed the involvement of aryl radical anions and proceeded via a single-electron-transfer (SET) mechanism. The large substrate scope, high functional group tolerance, competition experiments, gram-scale synthesis, and kinetic studies further highlight the importance and versatile nature of the methodology as well as the compatibility of the new catalyst. To the best of our knowledge, this is the first report on any organocatalyst that reported detailed investigations of both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in a single representation.
- Yadav, Lalit,Tiwari, Mohit K.,Shyamlal, Bharti Rajesh Kumar,Chaudhary, Sandeep
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p. 8121 - 8141
(2020/07/16)
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- Immobilized Pd on a NHC functionalized metal–organic framework MIL-101(Cr): an efficient heterogeneous catalyst in Suzuki?Miyaura coupling reaction in water
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A novel Pd?NHC functionalized metal–organic framework (MOF) based on MIL-101(Cr) was synthesized and used as an efficient heterogeneous catalyst in the C-C bond formation reactions. Using this heterogeneous Pd catalyst system, the Suzuki?Miyaura coupling reaction was accomplished well in water, and coupling products were obtained in good to excellent yields in short reaction time. The Pd?NHC?MIL-101(Cr) was characterized using some different techniques, including Fourier transform-infrared, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, inductively coupled plasma and elemental analysis. The microscopic techniques showed the discrete octahedron structure of MIL-101(Cr), which is also stable after chemical modification process to prepare the catalyst system. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the structure of the catalyst, while no reducing agent was used. It seems that the NHC groups and imidazolium moieties in the structure of the MOF can reduce Pd (II) to Pd (0) species. This modified MOF substrate can also prevent aggregation of Pd nanoparticles, resulting in high stability of them in organic transformation. The Pd?NHC?MIL-101(Cr) catalyst system could be simply extracted from the reaction mixture, providing an efficient synthetic method for the synthesis of biaryls derivatives using the aforementioned coupling reaction. The Pd?NHC?MIL-101(Cr) catalyst could be recycled in this organic reaction with almost consistent catalytic efficiency.
- Khalafi-Nezhad, Ali,Niknam, Esmaeil,Panahi, Farhad
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- Oxidative bromination of non-activated aromatic compounds with AlBr3/KNO3 mixture
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Bromination of non-activated aromatic compounds with reaction mixture containing KNO3 and AlBr3 was studied in liquid substrates and in solvent. Aluminium bromide has three different roles in this reaction mixture. First, it is a source of bromide ions, which are essential in oxidative bromination application. Second, it acts as a catalyst, and lastly, it forms acidic environment via its hydrolysis, which is necessary for enhancement of the oxidising properties of nitrate ions. It was shown that when changing the reaction conditions, different side reactions (like nitration or Friedel–Crafts type arylation) can occur. However, it is possible to guide the reaction path and receive the desired outcome by choosing the suitable reaction conditions. In addition, it was shown that there has to be water content in this reaction mixture as the bromine formation rate depends on it, while there exists an optimal volume of water, where bromine formation is the fastest.
- Rahu, Ida,J?rv, Jaak
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p. 1219 - 1227
(2019/11/13)
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- Suzuki-miyaura cross-coupling of 1,8-diaminonaphthalene (dan)-protected arylboronic acids
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We report a Suzuki-Miyaura cross-coupling reaction of 1,8-diaminonaphthalene (dan)-protected arylboronic acids in the presence of KOt-Bu, which does not require the removal of the dan moiety. Notably, the use of aryl-B(dan) in the Suzuki-Miyaura reaction provides a complementary solution to the protodeboronation problems. The base KOt-Bu plays a crucial role for the promotion of these cross-coupling reactions as it enables the formation of a borate salt. This reaction protocol was extended to the one-pot sequential Suzuki-Miyaura cross-coupling reaction of 4-[(pin)B]C6H4-B(dan), wherein the "less reactive" aryl-B(dan) moiety was cross-coupled preferentially.
- Mutoh, Yuichiro,Yamamoto, Kensuke,Saito, Shinichi
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p. 352 - 357
(2019/12/24)
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- Bioinspired Palladium Nanoparticles Supported on Soil-Derived Humic Acid Coated Iron-Oxide Nanoparticles as Catalyst for C–C Cross-Coupling and Reduction Reactions
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Abstract: Pd nanoparticles supported on humic acid-coated nanoferrites as magnetically-recoverable catalyst was expediently prepared from inexpensive precursors and characterized by techniques such as SEM, TEM, XPS, FT-IR, XRD, ICP-AES, EDX. The as made catalyst displayed an admirable catalytic activity towards the Suzuki–Miyaura cross-coupling reaction of aryl halides (or) aryl diazonium salts with aryl boronic acid in non-toxic solvent EtOH/water under mild conditions. The same catalyst showed high efficiency for the Heck reaction of aryl halides with styrene was carried out with high efficiency offering good yields under ligand-free conditions. Additionally, the reduction of olefins using molecular hydrogen was also achieved using the same catalyst under ambient and base-free conditions affording the products in good to excellent yields. The magnetic activity of nano-Fe3O4 allowed the effortless recovery of the catalyst and demonstrated subsequent recyclability up to 5 cycles without a significant loss in the activity. Graphical Abstract: [Figure not available: see fulltext.].
- Chinchole, Anurag N.,Dubey, Abhishek V.,Kumar, A. Vijay
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p. 1224 - 1236
(2019/02/26)
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- Base-free Pd-MOF catalyzed the Suzuki-Miyaura cross-coupling reaction of arenediazonium tetrafluoroborate salts with arylboronic acids
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A convenient and environmental benign synthesis of biaryls has been demonstrated by a straightforward reaction catalyzed by the palladium-containing metal-organic framework (Pd-MOF) [Pd (2-pymo)2]n (2-pymo = 2-pyrimidinolate). A series of functionalized biaryl derivatives have been synthesized in good to excellent yields by the Suzuki-miyaura cross-couplings of sustainable arenediazonium salts with a variety of arylboronic acids and the reactions were catalyzed by the Pd-MOF using methanol as a benign solvent. Those base- and additive-free catalytic reactions proceeded smoothly under non-anhydrous and non-degassed condition. Such transformation avoided high reaction temperature, tolerated many functional groups and presented a wide substrate scope. The catalyst could be recovered by filtration and reused for four successive cycles before collapse of the MOF structure.
- Liu, Yangyang,Wang, Jie,Li, Tang,Zhao, Zesheng,Pang, Wan
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- Ferrocene-Labeled Carbon-Encapsulated Iron Nanoparticles: The First Magnetic Nanocatalysts for C-H Arylation toward 1,1′-Biphenyl Formation
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The first magnetic nanocatalysts for C-H arylation toward 1,1′-biphenyl formation are described. The nanocatalysts are based on conjugates of ferrocene and carbon-encapsulated iron nanoparticles. The highest catalytic activity was found for ferrocene conjugated to carbon-encapsulated iron nanoparticles via the N-methylpyrrolidine moiety. In the presence of the nanocatalyst, various 1,1′-biphenyls can be obtained in high yields (84-90%). The effect of substitution of the aniline's phenyl ring on the reaction yield is also included in this work. The nanocatalyst can be easily separated from the reaction mixture and can be reused in up to four reaction cycles without any loss of its high catalytic activity. Our work sheds light on a potential application of functionalized carbon-encapsulated iron nanoparticles in modern industrial organic processes toward more economical manufacturing of organic compounds.
- Kasprzak, Artur,Bystrzejewski, Michal,Poplawska, Magdalena
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supporting information
p. 409 - 415
(2019/03/11)
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- Inorganic–organic hybrid nano magnetic based nickel complex as a novel, efficient and reusable nanocomposite for the synthesis of biphenyl compounds in green condition
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The carbon–carbon cross coupling reactions through transition-metal-catalyzed processes has been significantly developed for their important synthetic applications. A novel and fantastic nickel-based catalyst supported on bis (propyl malononitrile) (NiFe2O4@SiO2-BPMN-Ni) was easily prepared and evaluated as heterogeneous nanocatalyst in Suzuki cross coupling reaction of various aryl halides and phenylboronic acid. The catalyst prepared and characterized by using fourier transform infrared (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), thermo gravimetric analysis (TGA) and vibrating sample magnetometer (VSM) techniques. Compare to the previous works, this procedure have advantages such as easy workup, high yields of products, environmentally benign and short reaction times. The catalyst can be separated by external magnet and reused six times without any significant loss of activity which is an additional sustainable characteristic of this method. The products have been confirmed by spectroscopic and physical data such as; IR, 1H NMR, and melting point.
- Naeimi, Hossein,Kiani, Fatemeh
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p. 163 - 169
(2019/01/14)
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- Pd embedded N, S co-doped graphene wrapped core-shell magnetic nanospheres: Engineered stable nanocatalyst for Suzuki couplings
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Designed nitrogen and sulfur co-doped graphene wrapped magnetic core-shell supported Pd nanoparticles were synthesized through the following steps. Firstly, Fe3O4 was prepared, coated with silica and then functionalized with amine groups to create a positive charge on the structure for enhancing the interaction of the Fe3O4@SiO2 with graphene oxide. Secondary, the pre-catalyst wrapped with graphene to enhance adsorption of aromatic substrates through π–π stacking. Thirdly, graphene was doped with nitrogen and sulfur to increase the grafting of Pd in hybrid. Finally, Pd NPs were attached on the surface of pre-engineered structure to produce Fe3O4@SiO2@N,S-wG@Pd which exhibited high performance in Suzuki reactions. This superior activity can be indexed to the incorporation of N and S atoms into graphene led to high anchoring and well-dispersion of Pd NPs on the nanocomposite surface offering large amounts of active centers, that strongly increased the interaction between Pd and substrates to decreases Pd leaching.
- Rohani, Sahar,Mohammadi Ziarani, Ghodsi,Badiei, Alireza
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- Palladium-catalysed room-temperature Suzuki–Miyaura coupling in water extract of pomegranate ash, a bio-derived sustainable and renewable medium
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An agro waste-derived, ‘water extract of pomegranate ash’ (WEPA), has been utilized for the first time as a renewable medium for Pd(OAc)2-catalysed Suzuki–Miyaura cross-coupling at room temperature. This method offers a simple and sustainable synthesis of biaryls from aryl halides and arylboronic acids under ligand- and external base-free aerobic and ambient conditions. This method has been found effective for both activated and unactivated aryl halides in the production of biaryls with moderate to nearly quantitative yields. The protocol shows high chemoselectivity over identical/similar reactive sites in aryl halides (i.e. selectivity over identical halogens or different halogens of aryl halides). This method exhibits high regioselectivity, i.e. the selective reactivity of a halogen over other identical halogens at different positions on the aromatic nucleus. Therefore, we disclose here a clean, benign, substantial chemo- and regioselective and highly economic alternative method for the palladium-assisted synthesis of biaryls using an agro waste-derived medium.
- Appa, Rama Moorhy,Prasad, S. Siva,Lakshmidevi, Jangam,Naidu, Bandameeda Ramesh,Narasimhulu, Manchala,Venkateswarlu, Katta
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- Biochar as heterogeneous support for immobilization of Pd as efficient and reusable biocatalyst in C–C coupling reactions
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Biochar is a stable and carbon-rich solid which has a high density of carbonyl, hydroxyl and carboxylic acid functional groups on its surface. In this work, the surface of biochar nanoparticles (BNPs) was modified with 3-choloropropyltrimtoxysilane and further 2-(thiophen-2-yl)-1H-benzo[d]imidazole was anchored on its surface. Then, palladium nanoparticles were fabricated on the surface of the modified BNPs and further the catalytic application was studied as recyclable biocatalyst in carbon–carbon coupling reactions such as Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions. The structure of the catalyst was characterized using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, X-ray diffraction and atomic absorption spectroscopy. The catalyst can be reused several times without a decrease in its catalytic efficiency. In addition to the several advantages reported, application of biochar as catalyst support for the first time is a major novelty of the present work.
- Moradi, Parisa,Hajjami, Maryam,Valizadeh-Kakhki, Fatemeh
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- Hydrodehalogenation of Aryl Halides through Direct Electrolysis
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A catalyst- and metal-free electrochemical hydrodehalogenation of aryl halides is disclosed. Our reaction by a flexible protocol is operated in an undivided cell equipped with an inexpensive graphite rod anode and cathode. Trialkylamines nBu3N/Et3N behave as effective reductants and hydrogen atom donors for this electrochemical reductive reaction. Various aryl and heteroaryl bromides worked effectively. The typically less reactive aryl chlorides and fluorides can also be smoothly converted. The utility of our method is demonstrated by detoxification of harmful pesticides and hydrodebromination of a dibrominated biphenyl (analogues of flame-retardants) in gram scale.
- Ke, Jie,Wang, Hongling,Zhou, Liejin,Mou, Chengli,Zhang, Jingjie,Pan, Lutai,Chi, Yonggui Robin
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supporting information
p. 6911 - 6914
(2019/05/10)
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- C?I-Selective Cross-Coupling Enabled by a Cationic Palladium Trimer
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While there is a growing interest in harnessing synergistic effects of more than one metal in catalysis, relatively little is known beyond bimetallic systems. This report describes the straightforward access to an air-stable Pd trimer and presents unambiguous reactivity data of its privileged capability to differentiate C?I over C?Br bonds in C?C bond formations (arylation and alkylation) of polyhalogenated arenes, which typical Pd0 and PdI-PdI catalysts fail to deliver. Experimental and computational reactivity data, including the first location of a transition state for bond activation by the trimer, are presented, supporting direct trimer reactivity to be feasible.
- Diehl, Claudia J.,Scattolin, Thomas,Englert, Ulli,Schoenebeck, Franziska
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supporting information
p. 211 - 215
(2018/12/13)
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- ipso-Bromination/iodination of arylboronic acids: Poly(4-vinylpyridine)-Br2/I2 complexes as safe and efficient reagents
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Poly(4-vinyl pyridine) supported bromine/iodine complexes were prepared and probed for ipso-bromination/iodination of arylboronic acids. These solid complexes with catalytic amount of additive are found to be safe and efficient reagent system for the ipso-bromination/iodination. The reaction occurs under mild conditions and tolerates various functional groups resulting in products with high selectivity and yields.
- Fu, Fang,Gurung, Laxman,Czaun, Miklos,Mathew, Thomas,Prakash, G.K. Surya
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supporting information
(2019/08/26)
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- Mechanism of Cu-catalyzed aryl boronic acid halodeboronation using electrophilic halogen: Development of a base-catalyzed iododeboronation for radiolabeling applications
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An investigation into the mechanism of Cu-catalyzed aryl boronic acid halodeboronation using electrophilic halogen reagents is reported. Evidence is provided to show that this takes place via a boronate-driven ipso-substitution pathway and that Cu is not required for these processes to operate: General Lewis base catalysis is operational. This in turn allows the rational development of a general, simple, and effective base-catalyzed halodeboronation that is amenable to the preparation of 125I-labeled products for SPECT applications.
- Molloy, John J.,O'rourke, Kerry M.,Frias, Carolina P.,Sloan, Nikki L.,West, Matthew J.,Pimlott, Sally L.,Sutherland, Andrew,Watson, Allan J. B.
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supporting information
p. 2488 - 2492
(2019/04/10)
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- Modification of boehmite nanoparticles with Adenine for the immobilization of Cu(II) as organic–inorganic hybrid nanocatalyst in organic reactions
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Boehmite nanoparticles are aluminum oxide hydroxide (γ‐AlOOH) particles, which has large specific surface area (>120 m2 g?1) and can be prepared using an inexpensive procedure in water. Herein, we present an economical, simple, and environmentally friendly route for the preparation of a copper catalyst on Adenine coated boehmite nanoparticles (Cu–Adenine@boehmite). This catalyst has been characterized by several techniques such as SEM, XRD, AAS, ICP and TGA analysis. Cu–Adenine@boehmite was applied as highly efficient and reusable nanocatalyst in carbon–carbon coupling reactions between various aryl halides and sodium tetraphenyl borate, phenylboronic acid, or 3,4-diflorophenylboronic acid under aerobic conditions, palladium-free and phosphine-free ligand. Also this catalyst was applied for the synthesis of polyhydroquinoline derivatives. In continuation, selective oxidation of sulfides to sulfoxides using hydrogen peroxide (H2O2) was studied in the presence of Cu–Adenine@boehmite as catalyst. The synthesis of sulfoxides using H2O2 in the presence of Cu–Adenine@boehmite does not generate waste and any byproducts. This catalyst was reused for several times in C–C coupling reaction without loss of its catalytic activity. Reused catalyst was characterized by SEM, XRD and ICP techniques. Heterogeneity and stability of Cu–Adenine@boehmite were studied by hot filtration test, poisoning test and ICP analysis.
- Ghorbani-Choghamarani, Arash,Moradi, Parisa,Tahmasbi, Bahman
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- Involving Single-Atom Silver(0) in Selective Dehalogenation by AgF under Visible-Light Irradiation
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The dehalogenation-arylation and the hydrodehalogenation of various types of organic halides are selectively realized using AgF and visible light without any organic additives under mild conditions. Single-atom silver(0) (denoted as SAAg) serves as the catalytically active center, and the TOF of SAAg reaches 6000 h-1. This elusive activity of Ag is beyond that expected from its ionic, nano, or bulk forms.
- Wu, Wenli,Cui, Enxin,Zhang, Yun,Zhang, Chen,Zhu, Feng,Tung, Chen-Ho,Wang, Yifeng
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p. 6335 - 6341
(2019/07/04)
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