- PALLADIUM-CATALYZED DESULFONYLATIVE COUPLING OF ARYLSULFONYL CHLORIDES WITH ACRYLATE ESTERS UNDER SOLID-LIQUID PHASE TRANSFER CONDITIONS
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The reaction of arylsulfonyl chlorides with acrylate esters in the presence of a catalytic amount of PdCl2(PhCN)2 under solid-liquid phase transfer conditions gives the corresponding 3-aryl-2-propenoates in good yields.
- Miura, Masahiro,Hashimoto, Hideo,Itoh, Kenji,Nomura, Masakatsu
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- Synthesis and structural characterization of 20-membered macrocyclic rings bearing: Trans -chelating bis(N-heterocyclic carbene) ligands and the catalytic activity of their palladium(ii) complexes
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Macrocycles consisting of a 20-membered ring containing two imidazolium salt functionalities and of the formula [PhCH2N(CH2CH2CH2)Im(CH2CH2CH2)2][Br]2 (Im = imidazole = 3a, benzimidazole = 3b) were synthesized in 70-75% yields. These salts serve as precursors to macrocycles containing two N-heterocyclic carbene (NHC) moieties. Reaction of the macrocyclic salts 3a and 3b with silver oxide afforded macrocyclic-bis(NHC)silver(i) complexes 4a and 4b. Single-crystal X-ray diffraction studies of macrocyclic-bis(NHC)silver(i) complex 4a revealed a tetranuclear silver core with a short Ag-Ag distance (2.9328 ?). Complexes 4a and 4b serve as carbene transfer reagents to Pd. The treatment of macrocyclic-bis(NHC)silver(i) complexes 4a and 4b with one equivalent of PdCl2(MeCN)2 in methylene chloride afforded square-planar trans-macrocyclic-bis(NHC)Pd(ii)X2 complexes 5a and 5b. Preliminary screening of these palladium complexes showed they are competent precatalysts for Heck and Suzuki coupling reactions.
- Thapa, Rajesh,Kilyanek, Stefan M.
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- Silver, palladium and rhodium complexes of acenaphthylene-anullated N-heterocyclic carbene ligands: A comparative study
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The newly prepared carbene precursor 1,3-dimesitylacenaphtho[1,2-d] imidazolinium chloride, (NHC-H)Cl, 3, could be readily converted into the NHC-silver(I) complex, 4, which is an efficient carbene transfer agent and has been used to synthesise thione 5, trans-[PdCl2(NHC)2], 6 and [RhCl(NHC)(COD)], 7. All compounds synthesised were characterised by elemental analysis, NMR spectroscopy and the molecular structures of the thione 5 and complex 7 were determined by X-ray crystallography. Complex 7 was converted into cis-[RhCl(NHC)(CO)2] and the electron donating properties and trans influence of the NHC ligand were compared with nonanullated counterparts. The catalytic activity in the Heck reaction of 6 and the in situ formed palladium complex was evaluated. The activity of the in situ formed complexes for the Heck coupling of alkenes was high. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Tuerkmen, Hayati,Sahin, Onur,Bueyuekguengoer, Orhan,Cetinkaya, Bekir
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- Palladium immobilized on: In situ cross-linked chitosan superfine fibers for catalytic application in an aqueous medium
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Chitosan composite superfine fibers with a diameter of 321 ± 99 nm were prepared by electrospinning with PEO as the co-spinning polymer and itaconic acid as the in situ cross-linking agent. Itaconic acid was homogeneously dispersed in chitosan fibers and the in situ cross-linking endowed the prepared chitosan composite fibers with improved solvent resistance, thermostability and mechanical strength. Palladium species immobilized on these annealed chitosan fibers can efficiently catalyze the reduction reaction of 4-nitrophenol as well as the Mizoroki-Heck reaction of aromatic iodides with n-butyl acrylate in an aqueous medium. Furthermore, the larger fiber structure can facilitate the recovery and reuse of the palladium catalyst. The remarkable catalytic performance and easy recovery make this novel fiber-supported palladium catalyst hold great potential applications in green chemistry.
- Liang, Lulu,Nie, Li,Jiang, Minjuan,Bie, Fusheng,Shao, Linjun,Qi, Chenze,Zhang, X. Man,Liu, Xuejing
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- Catalytic Performance Studies of New Pd and Pt Schiff Base Complexes Covalently Immobilized on Magnetite Nanoparticles as the Environmentally Friendly and Magnetically Recoverable Nanocatalyst in C–C Cross Coupling Reactions
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Abstract: Synthesis and characterization of new magnetically recoverable and high-performance nanocatalysts of Pd and Pt Schiff base complexes on magnetite nanoparticles were considered. Catalytic activity of these nanocatalysts was explored in Suzuki and Heck cross coupling reactions. The catalysts can be easily reused fourth consecutive runs without significant loss of catalytic efficiency.
- Rezaei,Naghipour,Fakhri
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- Novel triphenylarsinyl-functionalized N-heterocyclic carbene ligands in palladium-catalyzed C-C coupling reactions
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Synthesis of novel triphenylarsinyl-functionalized N-heterocyclic carbene pre-ligands starting from N,N-dimethylbenzylamine, chlorodiphenylarsine and different 1-substituted imidazoles and their characterization by NMR and X-ray analysis is reported. Furt
- Stiemke, Frank,Gjikaj, Mimoza,Kaufmann, Dieter E.
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- Coupling reactions of aromatic halides with palladium catalyst immobilized on poly(vinyl alcohol) nanofiber mats
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Nanoporous poly(vinyl alcohol) (PVA) nanofiber mats prepared by means of electrospinning have been used for the immobilization of palladium catalyst. Thermal treatment of the palladium-loaded PVA nanofiber mats results in the cross-linking of the matrix PVA molecules as well as the reduction of the divalent palladium (Pd2+) into zerovalent palladium (Pd0) species. The palladium oxidation states were examined by X-ray photoelectron spectroscopic (XPS) analysis. The PVA nanofiber morphology was characterized by scanning electron microscopy (SEM). The catalytic activity and recyclability of the prepared heterogeneous palladium catalysts have been evaluated for the Ullmann, Heck-Mizoroki and Sonogashira coupling reactions of aromatic halides. The large structure of the Pd/PVA nanofiber mats can greatly facilitate its separation and recycling, and the high catalytic activity and stability of the prepared Pd/PVA nanofiber mats have been attributed to the chelation of palladium species with the abundant hydroxyl functional groups on the PVA matrix surface area.
- Shao, Linjun,Ji, Weixin,Dong, Pengdu,Zeng, Minfeng,Qi, Chenze,Zhang, Xian-Man
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- Gelatin-pyrolyzed mesoporous N-doped carbon supported Pd as high-performance catalysts for aqueous Heck reactions
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Nitrogen-doped mesoporous carbon-supported Pd (Pd@N-C) catalysts were prepared by pyrolyzing gelatin/templates/PdCl2 hydrogels under N2 atmosphere at 800°C. Using poly (ethylene glycol) block poly (propylene glycol) block poly (ethyl
- Yang, Shuai,Chen, Yuli,Huang, Shuaijian,Deng, Lu,Wu, Yuanyuan,Zheng, Xiu,Omonov, Shakhzodjon,Zeng, Minfeng
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- Tetramethylguanidine as an inexpensive and efficient ligand for the palladium-catalyzed Heck reaction
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An inexpensive and efficient Pd(OAc)2/tetramethylguanidine (TMG) or PdCl/TMG catalytic system has been developed for the Heck reaction of an olefin with an aryl halide. The TONs were up to 1000000 when iodobenzene was used as the substrate with butyl acrylate as the reactant. In addition, [Pd(TMG)4]Cl2(H2O)8, an air-stable compound, effectively promoted the Heck reaction, which demonstrated that TMG acted as a ligand in this reaction system. Georg Thieme Verlag Stuttgart.
- Li, Shenghai,Xie, Haibo,Zhang, Suobo,Lin, Yingjie,Xu, Jianing,Cao, Jungang
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- Ligand-free heck coupling and homocoupling of aryl halides in the presence of tetrabutylammonium nitrate
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Tetrabutylammonium nitrate is reported as an effective reusable medium, suitable reducing and stabilizing agent for the Heck coupling reaction of aryl iodides and bromides with styrene and n-butyl acrylate. The efficient phosphine-free, palladium-catalyzed homocoupling reaction of aryl iodides and bromides is also demonstrated in the presence of tetrabutylammonium nitrate. The ionic liquid, still containing Pd (0) complex, is easily recovered and reused in several runs without losing its efficiency.
- Nowrouzi, Najmeh,Tarokh, Dariush
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- Pd-Catalyzed desulfitative arylation of olefins by: N -methoxysulfonamide
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A novel Pd-catalyzed protocol for the desulfitative Heck-type reaction of N-methoxy aryl sulfonamides with alkenes was reported. The cross-coupling reaction was performed successfully with a variety of olefins to obtain aryl alkenes. Different substituents on the aromatic ring of N-methoxysulfonamides were also found to be compatible with the reaction conditions. Expectedly, the reaction proceeds through CuCl2-promoted generation of the nitrogen radical and subsequent desulfonylation under thermal conditions to afford the aryl radical for the Pd-catalyzed coupling reaction. N-Methoxysulfonamide was further exploited for the synthesis of symmetrical biaryls in the presence of CuCl2. This journal is
- Ojha, Subhadra,Panda, Niranjan
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supporting information
p. 1292 - 1298
(2022/02/19)
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- Pd supported on clicked cellulose-modified magnetite-graphene oxide nanocomposite for C-C coupling reactions in deep eutectic solvent
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Cellulose-modified magnetite-graphene oxide nanocomposite was prepared via click reaction and utilized for immobilization of palladium (Pd) nanoparticles without using additional reducing agent. The abundant OH groups of cellulose provided the uniform dispersion and high stability of Pd nanoparticles, while magnetite-graphene oxide as a supporting material offered high specific surface area and easy magnetic separation. The as-prepared nanocomposite served as a heterogeneous catalyst for the Heck and Sonogashira coupling reactions in various hydrophilic and hydrophobic deep eutectic solvents (DESs) as sustainable and environmentally benign reaction media. Among the fifteen DESs evaluated for coupling reactions, the hydrophilic DES composed of dimethyl ammonium chloride and glycerol exhibited the best results. Due to the low miscibility of catalyst and DES in organic solvents, the separated aqueous phase containing both of the catalyst and DES can be readily recovered by evaporating water and retrieved eight times with negligible loss of catalytic performance.
- Karimi, Sabah,Masteri-Farahani, Majid,Niakan, Mahsa,Shekaari, Hemayat
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- A comparative study of palladium-based coordination compounds with bidentate (N,N, P,P and P,O) ligands; Design, synthesis, X-ray structural, catalytic activity and DFT studies
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This account describes our recent studies on four new asymmetric cyclometallated Pd(II) complexes with a formula [L1 → Pd ← L2](ClO4) (L1 = benzylamine and L2 = bis (diphenylphosphino) methane oxide (
- Babaee, Heshmatollah,Javad Sabounchei, Seyyed,Naghipour, Ali,Notash, Behrouz,Sayadi, Mohsen,Sedghi, Asieh
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- Palladium nanoparticles encapsulated in polyimide nanofibers: An efficient and recyclable catalyst for coupling reaction
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In this study, palladium-encapsulated poly(amic acid) (Pd@PAA) nanofibers were prepared by electrospinning, followed by thermal imidization to synthesize palladium-encapsulated polyimide (Pd@PI) nanofibers. Scanning electron microscopy (SEM) images confirmed the preparation of uniform and smooth Pd@PAA and Pd@PI nanofibers. Thermogravimetric analysis (TGA) results reveal that the Pd@PI nanofibers possessed excellent thermal stability. The dispersion of palladium nanoparticles in the polyimide nanofibers was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The catalysis results show that this Pd@PI fibrous catalyst was very efficient to catalyze the cross-coupling reactions of aromatic iodides with n-butyl acrylate (Heck reaction) or phenylboronic acid derivatives (Suzuki reaction) to afford the desired products in good to excellent yields. Moreover, the Pd@PI catalyst could be easily separated and recovered from the reaction mixture by simple filtration due to the regular fibrous structure and reused for 10 times for both Heck and Suzuki reactions without obvious loss of its initial catalytic activity. Thus, the Pd@PI nanofiber catalyst holds great potential in chemical industry in terms of its excellent catalytic activity and stability.
- Du, Yijun,Gou, Faliang,Gao, Danning,Liu, Zhifeng,Shao, Linjun,Qi, Chenze
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- Palladium schiff base complex immobilized on magnetic nanoparticles: An efficient and recyclable catalyst for Mizoroki and Matsuda-Heck coupling
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The present work elucidates the catalytic efficiency of palladium Schiff base complex immobilized on amine functionalized magnetic nanoparticles for Heck coupling of structurally different aryl halide/arenediazonium tetrafluoroborate with styrene/acrylate/acrylonitrile. Matsuda-Heck coupling proceeds in aqueous media at room temperature whereas Mizoroki-Heck coupling was carried out at 80 °C. Both reactions were successfully furnished with low catalyst loading. The catalyst was easily separated from reaction mixture and reused up to six times without significant loss of catalytic activity.
- Vibhute, Sandip P.,Mhaldar, Pradeep M.,Shejwal, Rajendra V.,Rashinkar, Gajanan S.,Pore, Dattaprasad M.
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supporting information
(2020/03/23)
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- Encapsulating palladium nanoparticles inside ethylenediamine functionalized and crosslinked chlorinated poly(vinyl chloride) nanofibers as an efficient and stable heterogeneous catalyst for coupling reactions
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Palladium chloride and chlorinated poly (vinyl chloride) (CPVC) mixture were prepared into homogeneous solution, followed by electrospinning to make uniform nanofibers with average diameter of ~460 nm. Then, these composite nanofibers were treated in ethy
- Du, Yijun,Qi, Chenze,Qin, Min,Shao, Linjun,Tao, Hongyu,Wang, Qingqing
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- C–C Cross-Coupling Reactions of Organosilanes with Terminal Alkenes and Allylic Acetates Using PdII Catalyst Supported on Starch Coated Magnetic Nanoparticles
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Starch coated magnetic nanoparticles supported palladium catalyst has been explored to perform C–C cross coupling reactions, such as oxidative Heck coupling and Tsuji–Trost allylic coupling using organosilicon compounds as one of the coupling partners. The biopolymer coated magnetic catalyst was very easy to recover magnetically and was efficiently recycled in the subsequent batches. All the reactions were performed in air and thus the necessity of air and moisture free reaction condition is avoided. The present protocols show wide substrate scope and good yields of the products.
- Patra, Debabrata,Panja, Subir,Saha, Amit
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supporting information
p. 878 - 883
(2020/02/13)
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- Highly active homoleptic nickel(II) bis-N-heterocyclic carbene catalyst for Suzuki–Miyaura and Heck cross-coupling reactions
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New homoleptic nickel(II) biscarbene complex was synthesized and structurally characterized. The complex depicted the excellent catalytic activities with only 3 mol% catalyst loading along with wide substrate scope for the Suzuki–Miyaura cross-coupling reactions (twenty six examples) and Heck coupling reactions (eighteen examples).
- Nirmala, Muthukumaran,Arruri, Sathyanarayana,Vaddamanu, Moulali,Karupnaswamy, Ramesh,Mannarsamy, Maruthupandi,Adinarayana, Mannem,Ganesan, Prabusankar
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supporting information
p. 125 - 134
(2018/11/23)
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- NHC stabilized Pd nanoclusters in the Mizoroki-Heck reaction within microemulsion: exploring the role of imidazolium salt in rate enhancement
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We report the significant rate enhancement of the Mizoroki-Heck reaction by in situ generated palladium nanoclusters within the confined space of water-in-oil (w/o) mixed microemulsion (μE) formulated by sodium dodecylsulfate (SDS), polyoxyethylene (23) l
- Ghosh, Koena,Dhara, Shubhajit,Jana, Sourav,Das, Subhomoy,Roy, Sudeshna
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p. 1993 - 2001
(2019/01/28)
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- N-HETEROCYCLIC CARBENE (NHC) BASED LIGANDS AND RELATED METHODS
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Polydentate macrocyclic NHCs (NHC ligands) and related methods are disclosed. Such ligands advantageously facilitate a variety of ligand coordination modes and stabilize oxidation states of metal complexes with a number of coordination environments and shapes. The NHC ligands described herein comprise pendant groups configured to facilitate a variety of reactions including: cis-trans isomerization, proton shuttling and facilitating changes in coordination environments as a result of redox reactions.
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Paragraph 0042; 0043; 0045
(2019/03/02)
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- Tetranuclear Palladium Complexes of Abnormal N-Heterocyclic Carbene Ligands and their Catalytic Activities in Mizoroki-Heck Coupling Reaction of Electron-Rich Aryl Chlorides
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Based on the ligand scaffold of an imidazolyl/benziimidazolyl moiety and a N-CH2C(=O)NHPh substituent, two series of ligand precursors with ortho hydroxy groups incorporated on the N-phenyl rings were prepared. The structural fine tuning of the ligand scaffold allowed the synthesis of tetranuclear palladium complexes with abnormal N-heterocyclic carbene (aNHC) ligands. For precursors with C2-methyl blocking groups, pyridine-assisted C?H bond activation led to the formation of mononuclear tridentate palladium aNHC complexes or tetranuclear complexes with tridentate CNO donors. Representative mononuclear and tetranuclearpalladium aNHC complexes were structurally characterized by X-ray diffraction studies, revealing very short Pd?C bond distances. The tetranuclear palladium aNHC complexes were very effective in catalyzing Mizoroki-Heck coupling reaction, and were capable of employing a range of aryl chlorides including deactivated substrates with low palladium loading of 0.2 mol%. (Figure presented.).
- Lee, Jhen-Yi,Su, Yong-Siang,Wang, Yu-Shan,Lee, Hon Man
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p. 4714 - 4726
(2019/09/03)
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- Mizoroki–Heck Cross-Coupling of Acrylate Derivatives with Aryl Halides Catalyzed by Palladate Pre-Catalysts
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The Mizoroki–Heck (MH) reaction involving aryl halides with various acrylates and acrylamides has been studied using air and moisture-stable imidazolium-based palladate pre-catalysts. These pre-catalysts can be converted into Pd-NHC species (NHC = N-heterocyclic carbene) under catalytic conditions and are capable of facilitating the Mizoroki–Heck reaction of aryl halides with various acrylates. The effects of solvent, catalyst loading, temperature and bases on the reaction outcome have been investigated. Various coupling partners were tolerated under the optimal reaction conditions catalyzed by palladate 1, [SIPr·H][Pd(η3-2-Me-allyl)Cl2]. The efficiency of the optimized synthetic methodology was tested on various aryl halides and substituted acrylates as well as acrylamides. The MH reaction yielded the coupled products in good to excellent isolated yields (up to 98%).
- Islam, Mohammad Shahidul,Nahra, Fady,Tzouras, Nikolaos V.,Barakat, Assem,Cazin, Catherine S. J,Nolan, Steven P.,Al-Majid, Abdullah Mohammed
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supporting information
p. 4695 - 4699
(2019/11/13)
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- A tailored polymeric cationic tag-anionic Pd(ii) complex as a catalyst for the low-leaching Heck-Mizoroki coupling in flow and in biomass-derived GVL
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The [PdCl4]2- palladium complex has been immobilized on a polystyrene-type resin loaded with pincer-type imidazolium ionic tag binding sites. The catalytic system (Pd(ii)-POLI-TAG) has proved to be highly active in the definition of an efficient protocol for the Heck-Mizoroki coupling reaction under batch and flow conditions. Importantly, it is shown to be highly robust in combination with a safe non-toxic reaction medium, i.e. biomass-derived GVL, since it could be reused for multiple runs without significantly losing its activity.
- Mahmoudi, Hamed,Valentini, Federica,Ferlin, Francesco,Bivona, Lucia Anna,Anastasiou, Ioannis,Fusaro, Luca,Aprile, Carmela,Marrocchi, Assunta,Vaccaro, Luigi
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supporting information
p. 355 - 360
(2019/01/28)
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- Facile synthesis of a recyclable Pd-rGO/CNT/CaFe2O4 nanocomposite with high multifunctional photocatalytic activity under visible light irradiation
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We report a facile method to synthesize a magnetically separable Pd-rGO/CNT/CaFe2O4 photocatalyst. The incorporation of CNTs into rGO can form a conductive network structure to bridge the gaps between rGO sheets. This conductive netw
- Bagherzadeh, Mojtaba,Kaveh, Reyhaneh,Mahmoudi, Hamed
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p. 16257 - 16266
(2019/07/16)
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- PdII Immobilized on Ferromagnetic Multi-Walled Carbon Nanotubes Functionalized by Aminated 2-Chloroethylphosphonic Acid with S -Methylisothiourea (FMMWCNTs@CPA@SMTU@PdII NPs) Applied as a Highly Efficient and Recyclable Nanostructured Catalyst for Suzuki-Miyaura and Mizoroki-Heck Cross-Coupling Reactions in Solvent-Free Conditions
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The new ferromagnetic nanostructured FMMWCNTs@CPA@SMTU@PdII NPs (IV) as an eco-friendly heterogeneous nanocatalyst with a particle size of ~20-30 nm reported earlier by our group has been found to be very effective for Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions at ambient temperature. The procedure has been applied for a wide range of aryl halides, arylboronic acids, and alkenes. The magnetic separation by an external magnetic field, mild reaction conditions, and catalyst reusability up to four times without significant decrease in catalytic activity (reduced catalytic activity from 11 to 18 % in the fifth, sixth, and seventh cycles) made the present method sustainable and economically viable for C-C cross-coupling reactions.
- Ghasemzadeh, Maryam Sadat,Akhlaghinia, Batool
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p. 674 - 692
(2019/07/12)
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- Linear polystyrene-stabilized Rh(III) nanoparticles for oxidative coupling of arylboronic acids with alkenes in water
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Linear polystyrene-stabilized Rh(III) nanoparticles (PS-Rh(III)NPs) were obtained when an aqueous solution of RhCl3 was stirred at 90 °C in the presence of KOH, 4-methylphenylboronic acid, and linear polystyrene, as indicated by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). PS-Rh(III)NPs exhibited high catalytic activity for the oxidative coupling of arylboronic acids with alkenes. In contrast, PS-Rh(0)NPs prepared with NaBH4 had little activity for the same reaction.
- Ohtaka, Atsushi,Fukui, Shiho,Sakon, Akira,Hamasaka, Go,Uozumi, Yasuhiro,Shinagawa, Tsutomu,Shimomura, Osamu,Nomura, Ry?ki
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- A Palladium NNC-Pincer Complex as an Efficient Catalyst Precursor for the Mizoroki?Heck Reaction
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The Mizoroki?Heck reaction of aryl halides (iodides, bromides, or chlorides) with activated alkenes in the presence of a palladium NNC-pincer complex at ppb to ppm loadings gave the corresponding internal alkenes in excellent yields. The total turnover number and turnover frequency reached up to 8.70×108 and 1.21×107 h?1 (3.36×103 s?1), respectively. The catalyst was applied in a ten-gram-scale synthesis of the UV-B sunscreen agent octinoxate (2-ethylhexyl 4-methoxycinnamate). Reaction-rate analyses, transmission electron microscopic examination of the reaction mixture, and poisoning tests suggested that a monomeric palladium species is the catalytically active species in the catalytic cycle. (Figure presented.).
- Hamasaka, Go,Ichii, Shun,Uozumi, Yasuhiro
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supporting information
p. 1833 - 1840
(2018/04/05)
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- Organometallic polymer-functionalized Fe3O4 nanoparticles as a highly efficient and eco-friendly nanocatalyst for C–C bond formation
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A magnetically recoverable biopolymer-based nanocatalyst was prepared through the covalent immobilization of a chitosan-bound 2-hydroxynaphthaldehyde Pd complex on the surface of superparamagnetic nanoparticles. The nanocatalyst was characterized by FTIR, X-ray powder diffraction and scanning electron microscopy, revealing an average particle size of 70?nm. The catalyst shows high thermostability by thermogravimetric analysis. Estimated Pd loading by inductively coupled plasma atomic emission analysis was found to be 0.348?mmol?g?1. The nanocatalyst exhibits excellent catalytic performance in Suzuki couplings of various aryl halides with phenylboronic acid, and Heck reactions of iodo- and bromoarenes with butylacrylate. The catalyst can be easily separated from the reaction mixture with an external magnet and reused consecutively four times without significant loss in activity.
- Fakhri, Akram,Naghipour, Ali
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p. 463 - 472
(2018/04/17)
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- Synthesis of a novel ZnO nanoplates supported hydrazone-based palladacycle as an effective and recyclable heterogeneous catalyst for the Mizoroki-Heck cross-coupling reaction
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A new hydrazone-based palladacycle complex was successfully prepared onto ZnO nanoplates support and was fully identified by using a variety of methods such as energy dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller analysis (BET), inductively coupled plasma technique (ICP), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The morphology of nanoplates support has been also confirmed by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). Furthermore, it was shown that ZnO nanoplates supported hydrazone-based palladacycle can act as a highly efficient heterogeneous catalyst for the Mizoroki-Heck cross-coupling reaction with excellent yields. The reaction was successfully carried out between aryl iodides, bromides or even aryl chlorides with a variety of olefins. Additionally, it is possible to isolate the catalyst from the reaction mixture and reused for eight sequential cycles without remarkable decrease in catalytic activity.
- Nouri, Fatemeh,Rostamizadeh, Shahnaz,Azad, Mohammad
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p. 664 - 673
(2017/12/15)
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- A practical method for heterogeneously-catalyzed Mizoroki–Heck reaction: Flow system with adjustment of microwave resonance as an energy source
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The microwave-assisted and continuous-flow Mizoroki–Heck reaction using a heterogeneous palladium catalyst supported on the anion-exchange resin DIAION WA30 (7% Pd/WA30) is described. The microwave resonance is finely adjusted to 2.4 GHz according to the electric permittivity of the reaction medium for efficient heating. Organic solvents, such as acetonitrile, N,N-dimethylacetamide, and toluene, can be sufficiently heated even with a low intensity of microwave irradiation in a 7% Pd/WA30-packed, glass tube-shaped catalyst cartridge, which was designed based on the electric permittivity of the solvents. The catalyst cartridge can be continuously reused at least 5 runs without exchange.
- Ichikawa, Tomohiro,Mizuno, Masahiro,Ueda, Shun,Ohneda, Noriyuki,Odajima, Hiromichi,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
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p. 1810 - 1816
(2018/03/07)
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- An efficient palladium catalyzed Mizoroki-Heck cross-coupling in water
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The homogeneous Pd-catalysed Mizoroki-Heck coupling reaction was successfully performed in water in the absence of any additives under aerobic conditions. The various key reaction parameters that affect the yield of the desired cross-coupling product were optimized. The Pd(PPh3)4/Et3N/H2O/98 °C catalyst system was found to be highly active (TOF = 12 to 14 h-1) towards achieving excellent yield of the Mizoroki-Heck coupling products for a wide range of electron-withdrawing as well as electron-donating aryl bromides and chlorides in the shortest reaction time. Pd(PPh3)4 catalyst deactivation during the Mizoroki-Heck coupling reaction was investigated and to evolve a strategy for achieving ten times Pd-metal recyclability without appreciable loss of its activity. Thus, the proposed mechanism provides access to a variety of olefins in aqueous medium, making this protocol eco-friendly.
- Jadhav, Sanjay N.,Rode, Chandrashekhar V.
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supporting information
p. 5958 - 5970
(2017/12/26)
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- Palladium Stabilized by Amino-Vinyl Silica Functionalized Magnetic Carbon Nanotube: Application in Suzuki–Miyaura and Heck–Mizoroki Coupling Reactions
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Abstract: This study describes an investigation on Suzuki and Heck cross-couplings of aryl electrophiles in the presence of heterogeneous Pd nanoparticles supported on amino-vinyl silica functionalized magnetic carbon nanotube. The core–shell contains CNT@Fe3O4@SiO2-Pd in which the functionalized SiO2 helps the stabilization of Pd nanoparticles and also responsible for the reduction of Pd(II) to Pd(0) without the need for adding external reducing agents. All of the reactions were done under phosphine-free condition. Graphical Abstract: [Figure not available: see fulltext.]
- Khalili, Dariush,Banazadeh, Ali Reza,Etemadi-Davan, Elham
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p. 2674 - 2687
(2017/09/06)
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- Macrocyclic Pd(II) dithiolate complexes as catalysts in Heck reactions
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The supramolecular palladium dithiolate complexes, [Pd2(dppe)2{S(C6H4)nS}]2(OTf)4and [Pd2(dppe)2(SCH2C6H4CH2S)]
- Mane, Pravin A.,Dey, Sandip,Vivekananda
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supporting information
p. 25 - 29
(2016/12/23)
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- Fe3O4@Boehmite-NH2-CoII NPs: An inexpensive and highly efficient heterogeneous magnetic nanocatalyst for the Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions
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Herein we report the synthesis of a magnetically separable core-shell-like Fe3O4@Boehmite-NH2-CoII NPs as an environmentally friendly heterogeneous catalyst. The as-prepared nanocatalyst was well characterized by various techniques such as FT-IR, XRD, BET, TEM, FE-SEM, EDX, TGA, H2-TPR, VSM, ICP-OES and elemental analysis and evaluated for the Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions in a green solvent (H2O). The results of characterization studies revealed the superparamagnetic behavior of the Fe3O4 NP core encapsulated by a Boehmite NP shell. Also, it was clearly found that the size of the particles was about 13-54 nm. In comparison with previously reported catalysts, Fe3O4@Boehmite-NH2-CoII NPs exhibited perfect catalytic efficiency for the Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions under mild conditions without using toxic solvents. The concerted effects between individual components of the catalyst and also its unique egg-like nanostructure led to the high catalytic performance of Fe3O4@Boehmite-NH2-CoII NPs. Also, the introduction of Co significantly lowers the cost of the catalyst. More importantly, the longevity of the nanocatalyst was studied and it was found that the magnetic nanocatalyst was stable under the reaction conditions and could be easily reused for at least seven consecutive cycles without a discernible decrease in its catalytic activity or metal leaching.
- Mohammadinezhad, Arezou,Akhlaghinia, Batool
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p. 5625 - 5641
(2017/12/06)
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- Chitosan microspheres-supported palladium species as an efficient and recyclable catalyst for Mizoroki-Heck reaction
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Chitosan microspheres-supported palladium catalysts (Pd@CM) for Mizoroki-Heck reaction have been successfully prepared by electrospraying PdCl2/chitosan mixture in a trifluoroacetic acid (TFA) aqueous solution. Swelling capacity measurement and thermal analysis demonstrated that the palladium species in the chitosan microspheres could cross-link the chitosan efficiently. FT-IR spectra demonstrated that the chitosan in the microspheres could be cross-linked by glutaraldehyde, and the formed Schiff bond could chelate the palladium species efficiently. High resolution transmission electron microscopy (HR-TEM) indicated that the entrapment of palladium species in chitosan microspheres could enhance its dispersion. Mizoroki-Heck reaction catalysis results demonstrated that the catalytic activity of Pd@CM was associated with the size of chitosan microspheres. The Pd@CM with a suitable size was even more active than the catalyst with palladium species adsorbed on the surface of chitosan microspheres (Pd-CM). Moreover, the entrapment of palladium species in chitosan microspheres could reduce its aggregation and leaching in the catalysis procedure, which in turn increased the reusability of Pd@CM catalyst. The high catalytic activity and stability of Pd@CM have been attributed to the entrapment of palladium species within the cross-linked chitosan microspheres and the chelation of palladium species with the abundant amine and hydroxyl groups on chitosan chain.
- Shao, Linjun,Qi, Chenze
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p. 8156 - 8165
(2017/08/15)
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- In situ generation of highly active bis(N-heterocyclic)carbene palladium as an efficient catalyst in direct S-arylation of methylphenyl sulfoxide and the Heck reaction: Ligand steric effects in product selectivity
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The use of 1,3-bis(N-heterocyclic)carbene ligands with different alkyl wingtip groups (alkyl = methyl, isopropyl and tert-butyl) is an effective method for the palladium-catalysed direct S-arylation of methylphenyl sulfoxide and C–C coupling of various of aryl halides with alkenes. The reactions proceed in moderate to good yields. Interestingly, it is shown experimentally that, by using bulkier bidentate N-heterocyclic carbene ligands, more selective catalytic systems towards cis products in Heck coupling reactions can be achieved.
- Bagherzadeh, Mojtaba,Mousavi, Narges-Alsadat,Jamali, Sirous
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- Silver(I) and palladium(II) complexes of new pentamethylene-functionalized bis-imidazolium dication ligands and its application in Heck and Suzuki-Miyaura coupling reaction
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Two new pentamethylene-functionalized bis-imidazolium dication ligands L1 and L2 (L1 = 1,5-bis(4-(imidazolium-1-yl-phenol)pentane dibromide; L2 = 1,5-bis(1-vinylimidazolium-1-yl)pentane dibromide) bearing IP (4-(imidazol-1-yl)phenol) and VI (1-vinylimidazole)-functionality have been prepared via the reaction of 1,5-dibromopentane with a substituted imidazole derivative. The bis-imidazolium dication ligands L1 and L2 on reaction with Ag2O in DCM:MeOH, followed by anion substitution with AgBF4 led to the formation of silver(I) complexes [Ag2(PC(CH2)5CP)2][BF4]2 (PC(CH2)5CP = 1,5-bis(4-(imidazolium-1-yl-phenol) pentane (1) and [Ag2(VC(CH2)5CV)2][BF4]2 (VC(CH2)5CV = 1,5-bis(1-vinylimidazolium-1-yl)pentane (2). Transmetalation of the bis-NHC ligand from [Ag2(PC(CH2)5CP)2][BF4]2 and [Ag2(VC(CH2)5CV)2][BF4]2 by palladium(II) salt [PdCl2(CH3CN)2] in DMSO gave [PdCl(PC(CH2)5CP)(CH3CN)]BF4 (3) and [PdCl(VC(CH2)5CV)(CH3CN)]BF4 (4), respectively. The new ligands as well as their silver(I) and palladium(II) complexes have been characterized by elemental analysis, electronic, IR, 1H and 13C NMR, and FAB-MS spectroscopy. The molecular structure of the representative ligand L1 has been determined by single crystal X-ray analysis. The palladiumII NHC complexes 3 and 4 exhibited good activity in a model Heck and Suzuki-Miyaura coupling reaction.
- Trivedi, Manoj,Bhaskaran,Singh, Gurmeet,Kumar, Abhinav,Rath, Nigam P.
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- Synthesis, crystal structure study and high efficient catalytic activity of di-μbromo-trans–dibromobis[(benzyl)(4-methylphenyl)(phenyl)phosphine] dipalladium(II) in Suzuki–Miyaura and Heck–Mizoroki C–C coupling reactions
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The current research aims to present a straightforward synthesis of binuclear palladated triphenylphosphine derivative by the reaction of the phosphonium salt [(PhCH2)P(Ph)2(Ph-4-CH3)]Br with palladium(II) chloride and to afford the dimeric palladated complex {Pd[P(Ph)(CH2Ph)(Ph-4-CH3)]((μ-Br)Br)}2. Moreover, elemental analysis (CHN), FT-IR, 1H, 31P, 13C NMR and X-ray crystallography led to the characterization of the obtained compound. Finally, This compound was found to be an efficient catalyst in C–C bond formation between various aryl halides with phenylboronic acid (Suzuki–Miyaura reaction) and aryl halides with n-butyl acrylate (Heck–Mizoroki reaction).
- Ghorbani-Choghamarani, Arash,Naghipour, Ali,Babaee, Heshmatollah,Notash, Behrouz
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p. 517 - 524
(2016/10/25)
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- Immobilized Pd(0) nanoparticles on phosphine-functionalized graphene as a highly active catalyst for Heck, Suzuki and N-arylation reactions
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In this study, a phosphine group was chemically grafted to the surface of graphene in order to prepare a reusable ligand with high surface area, incorporating a phosphine moiety. The treatment of graphene oxide (GO) with hydroxide followed by an aqueous work-up yields an OH-functionalized graphene material (GOH) via ring-opening of the epoxide groups. Reaction of GOH with chlorodiphenylphosphine (ClPPh2) gives a new material, GOPPh2 (PFG), which can be used for stabilization of metal nanoparticles or complexation of transition metals in order to prepare a reusable metal catalyst. Stabilization of palladium nanoparticles on the surface of GOPPh2 resulted in the production of an efficient heterogeneous Pd catalyst (PFG-Pd) for application in C-C and C-N bond formation reactions. The PFG-Pd catalyst was characterized using some different microscopic and spectroscopic techniques such as FT-IR, XRD, TEM, SEM, EDX, and ICP analysis. The applicability of the PFG-Pd catalyst was evaluated in Heck, Suzuki and N-arylation reactions. The catalyst system showed high catalyst activity in these processes and the target products were obtained in high isolated yields. The PFG-Pd catalyst was reusable in these reactions for at least 5 times with no significant decrease in its catalytic activity.
- Fareghi-Alamdari, Reza,Haqiqi, Mohsen G.,Zekri, Negar
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p. 1287 - 1296
(2016/02/19)
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- Heterogeneous Fe3O4@chitosan-Schiff base Pd nanocatalyst: Fabrication, characterization and application as highly efficient and magnetically-recoverable catalyst for Suzuki-Miyaura and Heck-Mizoroki C-C coupling reactions
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An environmentally friendly palladium-based catalyst supported on magnetite nanoparticles was successfully prepared. FT-IR, XRD, VSM, SEM, EDS and TGA studies have been used to characterize the nanocatalyst. The catalytic activity of the as-prepared catalyst was evaluated as a heterogeneous catalyst for the Suzuki-Miyaura carbon-carbon cross-coupling reaction of aryl halides and phenylboronic acid. Furthermore, it was found that the catalyst showed a high activity for the Mizoroki-Heck reaction of aryl halides and n-butyl acrylate. Interestingly, the novel catalyst could be recovered in a facile manner from the reaction mixture and recycled consecutive five runs without any significant loss in activity.
- Naghipour,Fakhri
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- Maghemite decorated with ultra-small palladium nanoparticles (γ-Fe2O3-Pd): Applications in the Heck-Mizoroki olefination, Suzuki reaction and allylic oxidation of alkenes
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A nanocatalyst comprising ultra-small Pd/PdO nanoparticles (57Fe M?ssbauer spectroscopy. The cost-effective catalyst could be easily separated from the reaction mixture by using an external magnet and reused four times without any loss of activity; chemical stability and recyclability aspects of the catalyst were investigated.
- Rathi, Anuj K.,Gawande, Manoj B.,Pechousek, Jiri,Tucek, Jiri,Aparicio, Claudia,Petr, Martin,Tomanec, Ondrej,Krikavova, Radka,Travnicek, Zdenek,Varma, Rajender S.,Zboril, Radek
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p. 2363 - 2373
(2016/05/19)
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- Suzuki, Stille and Heck cross-coupling reactions catalyzed by Fe3O4@PTA-Pd as a recyclable and efficient nanocatalyst in green solvents
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The use of a supported Pd complex on magnetic nanoparticles as an efficient and green catalyst for the Suzuki, Stille and Heck cross-coupling reactions is presented. The present research is focused on investigating the recycling, reusability and stability of the catalyst in the reaction. The recycled Fe3O4@PTA-Pd catalyst was used at least five times with comparable activities to that of the fresh catalyst. The catalytic coupling of 4-bromotoluene as a model reaction suggested that there was no leached palladium in the reaction mixture. The structure of the catalyst was characterized by TGA, EDS, ICP-OES, XRD, VSM, FT-IR and SEM analysis.
- Ghorbani-Choghamarani, Arash,Norouzi, Masoomeh
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p. 6299 - 6307
(2016/07/19)
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- Green and efficient procedure for Suzuki-Miyaura and Mizoroki-Heck coupling reactions using palladium catalyst supported on phosphine functionalized ZrO2 NPs (ZrO2@ECP-Pd) as a new reusable nanocatalyst
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In this article, palladium supported on phosphine functionalized ZrO2 NPs (ZrO2@ECP-Pd) has been introduced as a novel and efficient nanocatalyst for Suzuki-Miyaura and Mizoroki-Heck reactions. This new catalyst was prepared from the reaction of Pd(OAc)2 and PPh2-functionalized ZrO2 NPs, and then characterized using FT-IR, XRD, SEM, TEM, TGA and ICP techniques. The above experimental results showed that the synthesized catalyst existed as spheres with a mean size range of 10-40 nm. The prepared ZrO2@ECP-Pd nanocatalyst was shown to be highly efficient in the Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions of a wide range of aryl halides including electron-rich and electron-poor aryl iodides/bromides, and heteroaryl iodides, affording the corresponding products in good to excellent yields in short reaction times. The notable feature of the present protocol is the use of water and [bmim]PF6 as environmentally benign solvents, which eliminate the need of toxic solvent. In addition to the aforementioned favorable properties, the nanocatalyst can be recovered and reused for the subsequent reactions (at least six times) without any appreciable loss of efficiency.
- Zarghani, Monireh,Akhlaghinia, Batool
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p. 1192 - 1200
(2016/11/02)
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- Palladiumimmobilized on chitosan nanofibers cross-linked by glutaraldehyde as an efficient catalyst for the Mizoroki–Heck reaction
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Nonwoven chitosan (CS) nanofiber mats were successfully prepared by the electrospinning of the mixture of CS and poly(ethylene oxide) (PEO) in acetic acid aqueous solution. The CS/PEO fiber mats were treated with glutaraldehyde aqueous solution to stabili
- Wang,Xu,Shao,Qi
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p. 354 - 359
(2016/07/06)
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- Compositions containing ionic liquids and their uses, in particular in organic synthesis
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An ionic liquid is used as liquid matrix for organic synthesis in homogeneous phase on soluble support, the ionic liquid being presented in liquid or solid form at ambient temperature, of formula A1+X1?, A1+ representing a cation, functional or non-functional, or a mixture of cations in which either none of the cations is functional or at least one of the cations is functional, and X1? an anion, functional or non-functional, or a mixture of anions in which either none of the anions is functional or at least one of the anions is functional.
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Page/Page column 45; 46; 47; 50
(2016/10/17)
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- Ligand-free Pd catalyzed cross-coupling reactions in an aqueous hydrotropic medium
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A simple, efficient and ligand-free protocol for the Suzuki-Miyaura reaction and base-free Heck-Matsuda reactions under mild reaction conditions have been developed over palladium supported on activated carbon (Pd/C) in an aqueous hydrotropic solution. The catalyst Pd/C was fully characterized by TG-DTA, SEM, EDS, XRD, XPS, BET and ICP-AES analyses. This green methodology represents a cost-effective and operationally convenient method for the synthesis of a variety of biaryls, prochiral ketones, and acrylates under the conditions that are tolerant for a broad range of functional groups with good to excellent yields. The developed Pd/C-aqueous hydrotrope combined catalytic system is well suited for the 3R approach (reducible, robust, and recyclable) for different cross-coupling reactions without an appreciable loss of its activity.
- Jadhav, Sanjay N.,Kumbhar, Arjun S.,Rode, Chadrashekhar V.,Salunkhe, Rajashri S.
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supporting information
p. 1898 - 1911
(2016/04/19)
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- Regioselective aerobic oxidative Heck reactions with electronically unbiased alkenes: Efficient access to α-alkyl vinylarenes
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Branched-selective oxidative Heck coupling reactions have been developed between arylboronic acids and electronically unbiased terminal alkenes. The reactions exhibit high catalyst-controlled regioselectivity favoring the less common branched isomer. The reactions employ a catalyst composed of Pd(TFA)2/dmphen (TFA = trifluoroacetate, dmphen = 2,9-dimethyl-1,10-phenanthroline) and proceed efficiently at 45-60 °C under 1 atm of O2 without requiring other additives. A broad array of functional groups, including aryl halide, allyl silane and carboxylic acids are tolerated.
- Zheng, Changwu,Stahl, Shannon S.
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supporting information
p. 12771 - 12774
(2015/08/18)
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- An Abnormal N-Heterocyclic Carbene-Based Palladium Dimer: Aqueous Oxidative Heck Coupling under Ambient Temperature
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Herein we report the synthesis of a new abnormal N-heterocyclic carbene (aNHC)-based ligand and its use in synthesizing an acetate bridged C-H activated palladium dimer (1). In complex 1, the carbene ligand displays an abnormal mode of binding with the palladium(II) ion. We used complex 1 as a catalyst for the oxidative Heck coupling reaction of arylboronic acids with electron-deficient as well as electron-rich olefins at ambient temperature in water to produce selectively the β-arylated products in good to excellent yields.
- Hota, Pradip Kumar,Vijaykumar, Gonela,Pariyar, Anand,Sau, Samaresh Chandra,Sen, Tamal K.,Mandal, Swadhin K.
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supporting information
p. 3162 - 3170
(2015/11/03)
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- 1,1′-methylene-3,3′-bis[(N -(tert -butyl)imidazol-2-ylidene] and Its effect in palladium-catalyzed C-C coupling
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A catalytic system utilizing a chelate carbene ligand containing bulk tert-butyl groups is described for palladium-catalyzed Heck and Suzuki coupling reactions. The Heck reaction focused on the coupling of different aryl bromides with mono- and 1,1-disubstituted olefins while the Suzuki reaction involved the coupling of aryl bromides and phenylboronic acid to afford the corresponding biphenyls. The catalyst system performs well with low Pd(OAc)2 levels (0.025 mol% Pd). In all cases with monosubstituted olefins, the trans-configured products were obtained, while the results of Heck reaction of 1,1-disubstituted olefins exhibited a high selectivity favoring the terminal product.
- Nadri, Shirin,Rafiee, Ezzat,Jamali, Sirous,Joshaghani, Mohammad
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supporting information
p. 619 - 624
(2015/03/14)
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- Mesoporous silica MCM-41 supported N-heterocyclic carbene-Pd complex for heck and sonogashira coupling reactions
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Heterocyclic carbene-Pd complex was anchored onto the mesoporous silica MCM-41 which exhibits high catalytic activity in Heck reaction under phosphine free reaction conditions for the reaction of iodo/bromoarenes with olefinic compounds such as butyl acry
- Sarkar, Shaheen M.,Yusoff, Mashitah Mohd,Rahman, Md. Lutfor
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- Heck, Suzuki and Sonogashira cross-coupling reactions using ppm level of SBA-16 supported Pd-complex
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SBA-16 supported 1,2-diaminocyclohexane Pd-complex (100-500 mol ppm of Pd) was found to be an efficient catalyst in the palladium-catalyzed Mizoroki-Heck, Suzuki-Miyaura and copper-free Sonogashira cross-coupling reactions of aryl halides under mild reaction conditions. The Pd-complex efficiently promoted all of these coupling reactions with appropriate coupling partners to afford the corresponding coupling products with almost quantitative yield. The supported Pd-complex was readily recovered and used five times without a significant loss of its catalytic activity.
- Sarkar, Shaheen M.,Rahman, Md. Lutfor,Yusoff, Mashitah Mohd
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p. 3564 - 3570
(2015/05/20)
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- Magnetically-recoverable Schiff Base Complex of Pd (II) Immobilized on Fe3O4@SiO2 Nanoparticles: An Efficient Catalyst for Mizoroki-Heck and Suzuki-Miyaura Coupling Reactions
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The activity of Pd(II)-Schiff base complexmolecules grafted on the surface of Fe3O4@SiO2 particles were investigated in the palladium-catalyzed coupling reactions of aryl halides with alkenes (Mizoroki-Heck reaction) and phenylboronic acids (Suzuki-Miyaura reaction) in the absence of phosphorous ligands. This method shows notable advantages such as heterogeneous nature of the catalyst, excellent yields, short reaction times, easy preparation, simplicity of operation, and cleaner reaction profiles. The catalyst can be separated from the reaction mixture by applying a permanent magnet externally and can be reused for several times without significant loss of activity. Also, the amount of palladium leaching has been determined by ICP analysis.
- Esmaeilpour, Mohsen,Javidi, Jaber
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p. 614 - 626
(2018/01/18)
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- NiCl2·6H2O: an efficient catalyst precursor for phosphine-free Heck and Sonogashira cross-coupling reactions
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An efficient and simple protocol for the Heck reaction of aryl iodides and bromides using NiCl2·6H2O as the pre-catalyst is presented. The reactions proceed well in ethylene glycol in the absence of phosphine ligands and reducing agent. Compared to the frequently used expensive palladium catalysts, the use of nickel catalyst has an economic advantage and hence, remains attractive for large or industrial scale preparations. The efficient copper- and phosphine-free Sonogashira coupling reaction of aryl iodides is also demonstrated using this catalytic system.
- Nowrouzi, Najmeh,Zarei, Marjan
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p. 7847 - 7852
(2015/09/15)
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- Preparation and characterization of palladium nanoparticles supported on phosphinated poly(Vinyl Alcohol) as new recyclable catalyst and their application for heck cross-coupling reactions
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Diphenylphosphinated poly(vinyl alcohols) (DPP-PVA) were synthesized by the insertion of chlorodiphenylphosphine to PVA in the presence of triethyl amine as base. The structure of this new polymer was confirmed by FT-IR and NMR spectroscopy. This polymer can be used as ligand for the preparation of nanoparticles of palladium. The complexation of PVA-grafted phosphinite with palladium(II) acetate was carried out to obtain the heterogeneous catalytic system. X-ray diffraction techniques, X-ray photoelectron spectroscopy, and transmission electron microscopy imaging revealed that palladium was dispersed into the nanometer scale through the support. This catalytic system showed excellent activity in the cross-coupling Heck reactions of olefinic compounds with aryl iodides, bromides as well as chlorides and gave high yields within short reaction times. Elemental analysis of Pd by the inductively coupled plasma technique on the supported catalyst exhibited low leaching of the metal into the solution. The catalyst can be reused several times in the repeated Heck reaction cycles without considerable loss in its activity.
- Ebrahimzadeh, Farzaneh,Tamami, Bahman
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p. 144 - 157
(2015/05/20)
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- Bulky monodentate biphenylarsine ligands: Synthesis and evaluation of their structure effects in the palladium-catalyzed Heck reaction
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Biphenyl-based arsine ligands were prepared in two-step fashion by Pd-catalyzed arsination and microwave-assisted Suzuki-Miyaura coupling, providing sterically demanding arsine ligands in overall isolated yields up to 82 % as air-stable solids. Short reaction times were achieved with the assistance of microwave irradiation in the direct and simple described protocol for the synthesis of biarylarsine ligands. The activities of the biphenyl arsine ligands were explored in Pd-catalyzed Heck coupling. As a general trend, the ligands with "blocked" ortho-positions on the non-arsine-containing ring of the biphenyl backbone performed more efficiently in the coupling reaction. This catalytic system allowed several interesting stilbenes to be obtained in very good yields. Sterically demanding biphenyl-based arsine ligands were prepared in high overall yields by microwave-assisted Suzuki-Miyaura coupling. The ligands were evaluated in the Pd-catalyzed Heck coupling reaction; the most active were those with "blocked" ortho-positions on the non-arsine-containing ring of the biphenyl backbone.
- Quinteros, Gisela J.,Uberman, Paula M.,Martín, Sandra E.
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supporting information
p. 2698 - 2705
(2015/04/27)
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