3218-36-8Relevant articles and documents
Highly efficient polymer-based nanoreactors for selective oxidation of alcohols in water
Chen, Tao,Xu, Zhenkai,Zhou, Lei,Qiu, Jiaqi,Wang, Maolin,Wang, Jiping
, (2019)
In this study, we demonstrate the fabrication of thermo-responsive polymer-based TEMPO nanoreactors and their application in the catalytic selective oxidation of alcohols as a highly efficient and recoverable catalyst in aqueous media. First, a diblock amphiphilic copolymer NHS-P(MMA25-b-OEGMA75) consisting of poly(methyl methacrylate) (PMMA) and poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA300) with a terminal N-hydroxysuccinimide (NHS) activated ester was synthesized utilizing reversible addition–fragmentation chain transfer polymerization (RAFT) techniques. Free radical 2,2,6,6,-tetramethyipiperidinooxy (TEMPO) was then introduced into the end of the copolymer based on activated ester functionalization to afford the temperature responsive polymer-supported catalyst TEMPO-P(MMA25-b-OEGMA75). Next, core-shell TEMPO nanoreactors were formed through self-assembly of the amphiphilic block polymers in deionized water. The morphology of the nanoreactors was well characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). The nanoreactors were then successfully applied in the selective oxidative of alcohols in water. A variety of aldehydes and ketones were achieved in excellent yields and selectivities in high reaction rates with low catalyst loading. The high efficiency in catalysis of the nanoreactors may attributed to the ideal environment where enhancing the interactions between the catalyst and the alcohol substrate, mimicking the environment of enzymes. The thermo-responsive polymer-based nanoreactors could be conveniently recovered in the temperature above the LCST of the polymer after extraction of product from the reaction mixture. This strategy provides an effective and cleaner way for the selective oxidative of alcohols in organic synthesis and industrial application.
Synthesis, characterization and theoretical and fluorescence emission microscopy studies of new Pd/Pt–cyclopropa[60]fullerene complexes: Application of Taguchi method for optimization of parameters in Suzuki–Miyaura reaction
Sabounchei, Seyyed Javad,Badpa, Khadijeh,Hashemi, Ali,Salehzadeh, Sadegh,Maleki, Farahnaz,Hosseinzadeh, Leila
, (2018)
The reactions of unsymmetric phosphorus ylides of the type [Ph2P(CH2)nPPh2?C(H)C(O)C6H4-p-CN] (n?=?1 (Y1); n?=?2 (Y2)) with C60 and M(dba)2 (M?=?Pd or Pt; dba?=?dibenzylideneacetone) are reported. Based on the various coordination modes of these ylides in complexation, the following new Pd/Pt–cyclopropa[60]fullerene complexes were obtained: P,C-coordinated [(η2-C60)Pd(κ2-Y1)] (1) and [(η2-C60)Pt(κ2-Y1)] (2) complexes and P-coordinated [(η2-C60)Pd(Y2)2] (3) and [(η2-C60)Pt(Y2)2] (4) complexes. These compounds were characterized using Fourier transform infrared, UV–visible and NMR (1H, 13C and 31P) spectroscopies and scanning electron microscopy. Furthermore, cytotoxicity studies showed that nanoparticles of these complexes can be used as non-toxic labels for cellular imaging application. Also energy decomposition analysis results revealed that the percentage contribution of ΔEelec in total interaction energy is considerably larger than that of ΔEorb. Thus, in all complexes the (η2-C60)M?(Y1) bond is considerably more electrostatic in nature than the (η2-C60)?M(Y1) bond. Finally, by application of the Taguchi method for optimization of parameters in Suzuki–Miyaura reaction, the catalytic activity of Pd complexes 1 and 3 was investigated in the cross-coupling reaction of various aryl chlorides with phenylboronic acid. According to analysis of variance results, solvent has the highest F value and it has high contribution percentage (36.75%) to the yield of Suzuki–Miyaura reaction.
Palladium(II) catalyzed Suzuki C–C coupling reactions with imino- and amino-phosphine ligands
Kemal Y?lmaz, Mustafa,?nce, Simay,Y?lmaz, Sevilay,Kele?, Mustafa
, p. 252 - 258 (2018)
A new series of bidentate PN type imino- (1–3) and amino-phosphine ligands (4–6) and their palladium(II) complexes [Pd(PN)Cl2] (1a–6a) have been synthesized and fully characterized using spectroscopic and analytical methods, including 31P, 1H, 13C NMR and FTIR spectroscopy and high resolution mass spectroscopy. The catalytic activities of the Pd(II) complexes were investigated for the Suzuki C–C coupling reactions of phenylboronic acid with aryl bromides using a substrate to catalyst ratio of 500/1. The effect of base, temperature and solvent has been investigated, and the highest reaction rates were observed at 80 °C in dimethylformamide (DMF) with K2CO3 as the base in 12 h. Under optimized reaction conditions, generally higher coupled product was obtained with substituted aryl bromides, including both electron-withdrawing (-formyl and -aceto) or -donating groups (-methyl and -methoxy) at -ortho or -para positions, except 2-bromoacetophenone which has bulkier -aceto group compared to the other aryl bromides.
Nitrogen-rich porous covalent imine network (CIN) material as an efficient catalytic support for C-C coupling reactions
Bhunia, Manas K.,Das, Swapan K.,Pachfule, Pradip,Banerjee, Rahul,Bhaumik, Asim
, p. 1304 - 1311 (2012)
In an effort to expand the realm of possibilities of nitrogen-rich porous materials that could be used in catalysis, herein we report the synthesis of a new highly nitrogen rich (ca. 45%) porous covalent imine network (CIN-1) material employing simple Schiff base chemistry and further grafting its surface with palladium. Pd-loaded CIN-1 support acts as a truly heterogeneous catalyst towards Suzuki C-C coupling reaction between aryl halides with arylboronic acids. High surface area and excellent accessibility of the catalytic sites make it very efficient for heterogeneous catalysis. The stability of the catalyst due to intimate contact between nitrogen-rich organic support and metal allows several reuses with only a minor loss in catalytic activity.
Synthesis and characterization of a supported Pd complex on volcanic pumice laminates textured by cellulose for facilitating Suzuki-Miyaura cross-coupling reactions
Soltani, Siavash Salek,Taheri-Ledari, Reza,Farnia, S. Morteza F.,Maleki, Ali,Foroumadi, Alireza
, p. 23359 - 23371 (2020)
Herein, a novel high-performance heterogeneous catalytic system made of volcanic pumice magnetic particles (VPMP), cellulose (CLS) natural polymeric texture, and palladium nanoparticles (Pd NPs) is presented. The introduced VPMP@CLS-Pd composite has been designed based on the principles of green chemistry, and suitably applied in the Suzuki-Miyaura cross-coupling reactions, as an efficient heterogeneous catalytic system. Concisely, the inherent magnetic property of VPMP (30 emu g-1) provides a great possibility for separation of the catalyst particles from the reaction mixture with great ease. In addition, high heterogeneity and high structural stability are obtained by this composition resulting in remarkable recyclability (ten times successive use). As the main catalytic sites, palladium nanoparticles (Pd NPs) are finely distributed onto the VPMP@CLS structure. To catalyze the Suzuki-Miyaura cross-coupling reactions producing biphenyl pharmaceutical derivatives, the present Pd NPs were reduced from chemical state Pd2+ to Pd0. In this regard, a plausible mechanism is submitted in the context as well. As the main result of the performed analytical methods (including FT-IR, EDX, VSM, TGA, FESEM, TEM, BTE, and XPS), it is shown that the spherical-shaped nanoscale Pd particles have been well distributed onto the surfaces of the porous laminate-shaped VPMP. However, the novel designed VPMP@CLS-Pd catalyst is used for facilitating the synthetic reactions of biphenyls, and high reaction yields (～98percent) are obtained in a short reaction time (10 min) by using a small amount of catalytic system (0.01 g), under mild conditions (room temperature).
In situ preparation of palladium / N-heterocyclic carbene complexes and use for Suzuki reaction
Oezdemir, Ismail,Goek, Yetkin,Guerbuez, Nevin,Cetinkaya, Engin,Cetinkaya, Bekir
, p. 303 - 306 (2005)
The in situ prepared three component system Pd(OAc)2, 1,3-dialkylbenzimidazolium halides (1a-e) and t-BuOK catalyses quantitatively the Suzuki cross-coupling of deactivated aryl chloride substrates. 1,3-Dialkylbenzimidazolium salts (1a-e) were
Pd(II)-Metalated and l-Proline-Decorated Multivariate UiO-67 as Bifunctional Catalyst for Asymmetric Sequential Reactions
Cheng, Lin,Cao, Liumei,Ren, Hao,Guo, Qiaoqiao,Deng, Huifang,Li, Yiming
, p. 1160 - 1169 (2022)
The construction of a multifunctional catalyst for multistep sequentialtandem reactions at the molecular level faces a formidable challenge. Multivariate (MTV)-MOFs can provide a facile and tunable platform for rationally designing such multifunctional catalysts via grafting different catalytic groups on the bridging ligands. However, the related investigations are still limited. Here, Pd(II) and l-proline are metalated and decorated to organic linkers, respectively, to build a MTV-MOF, which is then successfully applied to sequential Suzuki Coupling/asymmetric Aldol reactions with satisfied coupling performance (yields up to 99%) and good enantioselectivities (eeanti up to 98%). Inductively coupled plasma optical emission spectrometer (ICP-OES) measurements of the supernatant and hot leaching test suggest the heterogeneous nature of the catalyst. Macrosubstrate tests verify that the reaction occurs inside the pores of the MOF. The heterogeneous catalyst can maintain structural stability and catalytic activity within three cycles. Graphic Abstract: Versatile Pd(II) and l-proline were metalated and decorated, respectively, into stable UiO-67 to construct bifunctional and heterogeneous multivariate MOF catalyst, which displayed efficient and recyclable catalytic activity in sequential Suzuki Coupling/asymmetric Aldol reactions.[Figure not available: see fulltext.]
Bipyridyl palladium embedded porous organic polymer as highly efficient and reusable heterogeneous catalyst for Suzuki-Miyaura coupling reaction
Wang, Chang-An,Han, Yin-Feng,Li, Yan-Wei,Nie, Kun,Cheng, Xue-Li,Zhang, Jian-Ping
, p. 34866 - 34871 (2016)
Two robust porous organic polymers embedded with bipyridyl ligand (Bpy-POP) were obtained via a bottom-up strategy. After a simple post-treatment, a Pd(ii)-containing POP (Bpy-Pd-POP) was used as highly efficient and reusable heterogeneous catalyst for the Suzuki-Miyaura coupling reaction. It could be reused at least 15 times without significant loss of the catalytic activity (97-99% yield).
Syntheses, structural aspects, solution behavior, and catalytic utility of cyclopalladated N,N′,N″-triarylguanidines [κ2(C,N))Pd(Pyrazole)2X] (X = Br, OC(O)CF3, and PF6) in Suzuki-Miyaura coupling reactions of a
Agarwal, Pallavi,Thirupathi, Natesan,Nethaji, Munirathinam
, p. 3112 - 3123 (2016)
The reactions of six-membered cyclopalladated N,N′,N″-triarylguanidines [κ2(C,N)Pd(μ-X)]2 (3-7) with 2 equiv of pyrazole (pzH) and 3,5-dimethylpyrazole (3,5-dmpzH) in CH2Cl2 at RT for 24 h afforded a new class o
Palladium nanoparticles encapsulated in MIL-101-NH2 catalyzed one-pot reaction of Suzuki-Knoevenagel reaction
, ()
Bifunctional Cr-MOF catalysts containing palladium nanoparticles (NPs) have been prepared. Combining the high activity of Pd NPs and base sites in MIL-101-NH2, the catalysts (Pd?MIL-101-NH2) exhibited distinct catalytic activity in a
PdCuCeO-TPAB: A new catalytic system for quasi-heterogeneous Suzuki-Miyaura cross-coupling reactions under ligand-free conditions in water
Mpungose, Philani P.,Sehloko, Neo I.,Maguire, Glenn E. M.,Friedrich, Holger B.
, p. 13560 - 13566 (2017)
In this contribution, we report a simple and clean method for preparation of a single-phase Pd0.04Cu0.04Ce0.92O2-δ (PdCuCeO) solid-solution oxide and its application in quasi-heterogeneous Suzuki-Miyaura cross-coupling reactions. The catalyst was characterised fully and all the characterisation techniques strongly suggest that the Pd2+ and Cu2+ ions were successfully incorporated into the lattice of ceria. The as-prepared PdCuCeO solid-solution oxide was tested on Suzuki-Miyaura cross-coupling reactions under ligand free conditions using water as a sole solvent and tetrapropylammonium bromide (TPAB) as a phase transfer catalyst. It was discovered that TPAB acts as scavenger of Pd and the resulting material (Pd/TPAB) is able to catalyse the Suzuki-Miyaura coupling reaction. The Suzuki-Miyaura coupling of aryl iodides, bromides as well as activated aryl chlorides was efficiently performed by this PdCuCeO-TPAB catalytic system. The PdCuCeO-TPAB catalytic system also displayed good functional group tolerance and good to excellent isolated yields were obtained. Catalyst leaching and recyclability studies revealed that PdCuCeO acts as a Pd reservoir and that the reactions are essentially quasi-heterogeneous occurring over the recoverable Pd/TPAB aggregates. Only a negligible amount of palladium (0.1 ppm) was detected by ICP-OES in the product solution.
Suzuki-Miyaura reaction of unactivated aryl chlorides using benzimidazol-2-ylidene ligands
Oezdemir, Ismail,Goek, Yetkin,Guerbuez, Nevin,Cetinkaya, Engin,Cetinkaya, Bekir
, p. 4135 - 4144 (2004)
Four functionalized bis(benzimidazolium) salts (2a-d) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. A highly effective, easy to handle, and environmentally bengin process for palladium-mediated Suzuki cross-coupling was developed. The in situ prepared three-component system Pd(OAc)2/bis(benzimidazolium) bromides (2a-d) and Cs2CO3 catalyzes quantitatively the Suzuki cross-coupling of deactivated aryl chloride in aqueous media.
Generation of Polyphenylene Radical Cations and Their Cosensitization Ability in the 9,10-Dicyanoanthracene-Sensitized Photochemical Chain Reactions of 1,2-Bis(4-methoxyphenyl)cyclopropane
Tamai, Toshiyuki,Ichinose, Nobuyuki,Tanaka, Tomoko,Sasuga, Tsuneo,Hashida, Isao,Mizuno, Kazuhiko
, p. 3204 - 3212 (1998)
Cosensitization effects of polyphenylene compounds (PP) such as biphenyl (BP), terphenyls (o-, m-, p-TP), and phenanthrene (Phen) in photoinduced electron-transfer reactions were examined. The 9,10-dicyanoanthracene (DCA)-sensitized cis-trans photoisomerization of 1,2-bis(4-methoxyphenyl)-cyclopropane (CP), which proceeds in a chain reaction via free radical cation of CP (CP.+) as a chain carrier, was accelerated by adding PP, particularly by TP. A similar accelerating effect was observed in the DCA-sensitized photooxygenation of CP as another example. BP and TP were more stable under the oxygenation condition than phenanthrene and naphthalene, which also accelerate the photooxygenation CP. CP.+ is generated by the direct electron transfer from CP to the excited singlet state of DCA (1DCA*) and also by the secondary electron transfer from CP to PP.+, which is generated by the primary electron transfer from PP to 1DCA*. The laser flash photolysis study revealed that the quantum yield for the formation of free CP.+ in the direct electron transfer from CP to 1DCA* (ΦCP.+ ≈ 0.1) was smaller than that in the presence of PP. This is due to the high yield of free PP.+ generation by the primary electron transfer and the efficient secondary electron transfer from CP to PP.+. The secondary electron transfers were found to take place in nearly diffusion-controlled rates (0.9-1.5 × 1010 M-1 s-1). The high yield of PP.+ as free radical ions does not seem to be the sole factor of the cosensitization of PP for the DCA-sensitized photoreactions of CP. The ratio of the quantum yields of the photoreactions to that of the initial CP.+ formation (turnover) also increased by the addition of PP from 3 (isomerization) and 15 (oxygenation) to 32-90 for both reactions. The second-order rate constant for the decay of CP.+ in aerated acetonitrile was decreased by a factor of 0.5-0.8 by the addition of PP. We concluded that the cosensitization effect in the photoreaction involves a π-complex formation between CP.+ and PP assisting the chain reaction as well as initial CP.+ formation.
Multifunctional redox polymers: Electrochrome, polyelectrolyte, sensor, electrode modifier, nanoparticle stabilizer, and catalyst template
Deraedt, Christophe,Rapakousiou, Amalia,Wang, Yanlan,Salmon, Lionel,Bousquet, Melanie,Astruc, Didier
, p. 8445 - 8449 (2014)
Simple "click" polycondensation metallopolymers of redox-robust bis(ethynyl)biferrocene (biFc) and di(azido) poly(ethylene glycol) (PEG400 and PEG1000) were designed for multiple functions including improvement of water solubility and biocompatibility, the introduction of mixed valency and sensing capabilities, and as nanoparticle stabilizers for catalysis.
Polymeric microsphere-loaded palladium-iminodiacetic acid complex as an efficient and easily recycled catalyst for Suzuki reaction in ionic liquid
Zhang, Jianzheng,Chen, Jingshuai,Zhang, Qiuyu,Wang, Rumin,Wu, Songhua
, p. 2503 - 2514 (2019)
Core-crosslinked shelled-core microspheres of poly(styrene-co-methyl acrylic acid) (PS-co-PMAA), with cores rich in PS and the shell rich in PMAA, were synthesized by one-stage soap-free emulsion polymerization. A palladium (Pd)-iminodiacetic acid (IDA) complex catalyst is loaded on the shell of the PS-co-PMAA microsphere, which results in the advantage of high dispersion degree and, therefore, high activity. The resultant polymeric microspheres catalyst systems are then applied to catalyze the Suzuki reaction of aryl halides with phenylboronic acid in an ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]). Our catalyst systems are proved to be efficient and active for both aryl bromides and aryl iodides. Compared to traditional Pd(Ph3)4 catalyst, the PS-co-PMAA-IDA-Pd catalyst used here affords higher yield of Suzuki reaction at even lower catalyst concentration. In addition, our polymeric-microsphere based catalytic system can be easily recycled at least four times with high activity in ionic [bmim][BF4] liquid.
-
Knowles
, p. 896 (1921)
-
New strategy by a two-component heterogeneous catalytic system composed of Pd–PVP–Fe and heteropoly acid as co-catalyst for Suzuki coupling reaction
Rafiee, Ezzat,Kahrizi, Masoud,Joshaghani, Mohammad,Ghaderi-Sheikhi Abadi, Parvaneh
, p. 5573 - 5585 (2016)
We have developed a simple and efficient catalytic protocol composed of hollow palladium-poly(N-vinylpyrrolidone)-nano zero valent iron and H5PMo10V2O40 (Mo10V2) supported on Fe2O3@SiO2 core–shell nano particles, as reusable catalytic system for Suzuki coupling reaction under ligand- and base-free conditions. These reusable solid catalysts exhibited excellent activity and the methodology is applicable to diverse substrates providing good-to-excellent yields of desired products. This method has advantages of high yields, low reaction times, elimination of ligand and base, heterogeneous catalysts, and simple methodology. In order to study the role of Fe@Si–Mo10V2 in the Suzuki coupling reaction, electron transfer property of Fe@Si–Mo10V2 and Pd–PVP–Fe by means of cyclic voltammetry measurements were investigated. Moreover, this catalytic system could be recovered in a facile manner from the reaction mixture and recycled several times without any significant loss in activity. In this study, the heterogeneity of both component of our catalytic system was investigated and the content of palladium (Pd) and Mo10V2 into filtrates was evaluated quantitatively by inductively coupled plasma atomic emission spectroscopy (ICP-AES). According to the obtained results from the ICP-AES measurements, the small amount of Pd and Mo10V2 leach have been obtained.
Facilitating a high-performance photocatalyst for Suzuki reaction: Palladium nanoparticles immobilized on reduced graphene oxide-doped graphitic carbon nitride
Zhao, Xiaohua,Xie, Jiateng,Liu, Xin,Liu, Xiang
, (2019)
We prepared a non-covalently coupled hybrid of reduced graphene oxide (rGO)-doped graphitic carbon nitride (g-C3N4) by freezing-assisted assembly and calcination. Fourier transform infrared, Raman and X-ray photoelectron spectroscopies and transmission electron microscopy confirmed that rGO was incorporated into the bulk g-C3N4, which was an ideal support for loading Pd nanoparticles. The Pd nanoparticles with an average size of 4.57?nm were uniformly dispersed on the rGO-doped g-C3N4 surface. The layered structure provided large contact area of g-C3N4 with rGO, further accelerating the electron transfer rate and inhibiting electron–hole recombination. Consequently, compared with Pd/rGO/g-C3N4 and Pd/g-C3N4, the Pd/rGO-doped g-C3N4 showed a prominent catalytic activity for visible-light-driven photocatalytic Suzuki–Miyaura coupling at ambient temperature. The Pd/rGO-doped g-C3N4 exhibited very high stability after six consecutive cycles with minimal loss of catalytic activity.
Nano NiFe2O4 supported phenanthroline Cu(II) complex as a retrievable catalyst for selective and environmentally friendly oxidation of benzylic alcohols
Mehrjoyan, Forouzan,Afshari, Mozhgan
, (2021)
A new magnetically recoverable catalyst consisting of phenanthroline Cu(II) complex supported on nickel ferrite nanoparticles was prepared. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission and scanning electron microscopes, thermogravimetry, energy dispersive X-ray spectroscopy, vibrating sample magnetometry and inductively coupled plasma. Supported copper complex used for solvent free oxidation of 1- phenyl ethanol as a model. Influence of the reaction parameters (kind of oxidant, amount of the catalyst, reaction time, solvent and reaction temperature) were studied. Because of the immobilized complex has been shown to be an efficient heterogeneous catalyst for the selective oxidation of 1-phenyl ethanol to acetophenone (94% yield) by hydrogen peroxide so this green approach extended to other benzylic alcohols. The catalyst had been reused 10 times with no significant loss of catalytic activity. SEM, EDX, XRD, and ICP analysis of reused catalyst indicated that the catalyst was stable after the reaction.
Ultrafine and Highly Dispersed Pd/SiO2 for Suzuki?Miyaura Cross-coupling Reactions
Fan, Xizheng,Yang, Jingyi,Pang, Qingqing,Liu, Zhongyi,Zhang, Panke,Yang, Jing-He
, p. 2291 - 2301 (2021)
Abstract: Construction of heterogeneous Pd/SiO2 catalyst via the pollution-free strategy marked strong electrostatic adsorption has been reported for the application to Suzuki–Miyaura cross-coupling reactions. The exposed negatively charged oxygen groups, which were converted from the hydroxyl groups on the surface of silica under the alkaline atmosphere, could effectively anchor palladium species to form ultrafine Pd nanoparticles (Pd NPs) with an average particle size of 1.3?nm and high dispersion (43%). Pd/SiO2 catalyst was endowed with the excellent catalytic performance which was that the yield of the Suzuki–Miyaura reaction between bromobenzene and phenylboronic acid at 40?°C was > 99% for 30?min and the TOF was ~ 80,000?h?1. The catalyst could be easily recovered and recycled by facile procedure without a significant decrease in catalytic activity, which was able to maintain the 90% yield after repeated for 8 times. In addition, a continuous flow reaction device was designed using the Pd/SiO2 catalyst to effectively improve the production efficiency of biphenyl. Graphic Abstract: Pd/SiO2 catalyst constructed with the strategy of strong electrostatic adsorption (SEA) possesses uniformly dispersed and highly exposed Pd sites which can be easily transformed into electron-deficient Pdδ+ and strengthened stability for itself due to its strong interaction with the front surface of the carrier, and has been endowed the outstanding catalytic performance for Suzuki?Miyaura cross-coupling reaction. [Figure not available: see fulltext.]
Synthesis and catalytic application of cyclopentadienyl nickel(II) N-heterocyclic carbene complexes
Demir Atli, Deniz
, p. 1530 - 1537 (2020)
A series of ester-functionalized benzimidazolium salts 2a–c were prepared by quaternization of 1-{(ethoxycarbonyl)methyl}benzimidazole (1) with 3,5-dimethylbenzyl bromide, 2,5-dimethylbenzyl chloride and 3-methoxybenzyl chloride, respectively. Refluxing 2a–c with nickelocene in THF yielded the neutral cyclopentadienyl NHC nickel(II) complexes 3a–c. Their structures were defined by NMR, IR and elemental analysis techniques. Molecular weights of 3a–c were affirmed by MALDI-TOF mass spectrometry. Catalytic tests of 3a–c were performed in Kumada coupling of some aryl chlorides with phenylmagnesium bromide at 25 °C.
Resin-trapped gold nanoparticles: An efficient catalyst for reduction of nitro compounds and Suzuki-Miyaura coupling
Shah, Dipen,Kaur, Harjinder
, p. 70 - 76 (2014)
Gold in nanoparticle form shows good catalytic activity in contrast to bulk form and is finding applications in a variety of organic reactions. The present investigation describes direct deposition of gold nanoparticles onto commercially available resin by sorption reduction method. Uniformly dispersed nanoparticles of 3-8 nm dimensions were characterized by UV-visible spectroscopy, XRD, SEM and TEM, etc. The AuNPs were found to be remarkably stable and active catalysts for the selective reduction of nitro group under mild reaction conditions and microwave-assisted ligand-free Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acid. Calculated rate constant (2.5 × 10-2 s-1) for the reduction of 4-nitrophenol is among the best reported in the literature. The versatility of both the protocols is demonstrated by taking a number of substrates.
1,4,5,6-tetrahydropyrimidinium halides ligands for Suzuki-Miyaura cross-coupling of unactivated aryl chlorides
Alici, Buelent,Oezdemir, Ismail,Guerbuez, Nevin,Cetinkaya, Engin,Cetinkaya, Bekir
, p. 1439 - 1445 (2005)
Four functionalized bis(1,4,5,6-tetrahyropyrimidinium) salts (2a-d) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. A highly effective, easy to handle and environmentally benign process for palladium mediated Suzuki cross-coupling was developed. The in situ prepared three component system Pd(OAc)2 / bis(1,4,5,6-tetrahyropyrimidinium) bromides (2a-d) and Cs2CO 3 catalyses quantitatively the Suzuki cross-coupling of deactivated aryl chloride.
Catalytic comparison of Pd-C60 complex and its non-fullerene form bearing phosphorus ylide in C–C coupling reactions
Fatahi, Somayeh,Javad Sabounchei, Seyyed,Panahimehr, Mohammad,William Gable, Robert,Yousefi, Abed
, (2022/01/08)
The new fullerene-based Pd complex [(η2-C60) Pd(Y)2] (1) and its non-fullerene form [(Y)PdCl2] (2) bearing unsymmetrical phosphorus ylide [Ph2P(CH2)2PPh2 = C(H)C(O)Cs
A tryptophan-based copper(ii) coordination polymer: catalytic activity towards Suzuki-Miyaura cross-coupling reactions
Bhasin, K. K.,Husain, Ahmad,Kumar, Girijesh,Kumar, Rakesh,Nar, Kuldeep Kaur,Rani, Pooja,Singh, Amit Pratap
, p. 7855 - 7864 (2021/12/02)
Herein, we report the synthesis and crystal structure determination of a new Cu(ii) coordination polymer (CP) with the formula [Cu(l-tryp)(azpy)1/2(H2O)(NO3)]∝ (CP1), which exhibits an unusual tryptophan coordination mode with copper(ii) via carboxylate monodentate binding as well as chelation via Namino and Ocarbonyl groups. CP1 was prepared using the ligand l-tryptophan (l-tryp) and the co-ligand 4,4′-azopyridine (azpy), adapting the mixed-ligand approach and a solvothermal protocol. Single crystal X-ray structural analysis revealed that in CP1, Cu(ii) sites show a distorted octahedral geometry, wherein the ligand l-tryp is coordinated through the carboxylate and amine groups, whereas the co-ligand azpy is coordinated to Cu(ii) ions through the Npyridyl atom and thus maintains a distorted octahedral geometry around the Cu(ii) ions. FT-IR and EPR spectra were also recorded to corroborate the structural analysis. Finally, CP1 was employed as a heterogeneous catalyst for the Suzuki cross-coupling reaction and afforded ～98% yield under normal reaction conditions. This journal is
Facile synthesis of NC(sp3)O pincer palladium complexes and their use as efficient catalysts for Suzuki-Miyaura reaction of aryl bromides in aqueous medium
Gong, Jun-Fang,Li, Nan,Pan, Ya-Ping,Song, Mao-Ping,Yang, Jing-Jing,Zhu, Zhi-Wu
, (2020/12/15)
Two NC(sp3)O pincer palladium(II) complexes 3a-3b were readily prepared in high yields in only two steps. Of the first step, catalytic hydrophosphination of 2-alkenoylpyridines and subsequent in situ phosphine oxidation produced the NC(sp3)O pincer preligands 2a-2b. The second step is palladation of the preligands 2a-2b where PdCl2 was used as the Pd source to afford the desired Pd pincers 3a-3b via C(sp3)-H bond activation. Single crystal X-ray diffraction analysis of complex 3a unambiguously confirmed the NCO tridentate coordination mode of the complexes. The two complexes 3a-3b were applied to catalyze the Suzuki-Miyaura reaction. Complex 3b was found to be more efficient and exhibited very high activity in the Suzuki reaction of structurally diverse aryl bromides with arylboronic acids in aqueous ethanol under air. At a reaction temperature of 70 °C, a TON of up to 1.9 × 105 and a TOF of up to 9800 h?1 were achieved. At lower temperatures 3b was still very active, giving a TON of up to 9.5 × 103 and a TOF of up to 3900 h?1 at room temperature.
