一种高效可循环的有机介孔树脂负载的N-杂卡宾络合钯催化剂催化的Sonogashira反应

新型有机介孔材料FDU-15负载卡宾配体络合醋酸钯催化剂FDU-NHC/Pd(Ⅱ)的制备方法简单,通过三步反应即可制得,采用X射线衍射、N2吸附-脱附和透射电镜等手段对催化剂进行了表征,并考察了它在Sonogashira偶联反应中的催化性能.结果表明,功能化不影响FDU-15的有序介孔结构,仅其孔径、孔体积和BET比表...     

Heterogeneous Suzuki and copper-free Sonogashira cross-coupling reactions catalyzed by a reusable palladium(II) complex in water medium

A new polystyrene anchored Pd(II) azo complex has been synthesized and characterized. The present Pd(II) azo complex behaves as a very efficient heterogeneous catalyst in the Suzuki coupling and Sonogashira coupling reaction in water medium. Aryl halides, coupled with phenylboronic acids (Suzuki-Miyaura reaction) or terminal alkyne (Sonogashira reaction), smoothly afford the corresponding cross-coupling products in excellent yields (83-100% yield for Suzuki reaction and 68-96% yield for Sonogashira reaction of aryl halides) under phosphine-free reaction conditions in the presence of polystyrene anchored Pd(II) azo complex catalyst in water medium. Furthermore, the catalyst has shown good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could be easily recovered by simple filtration of the reaction mixture and reused for more than six consecutive trials without a significant loss of its catalytic activity.     

Synthesis and structural characterization of Pd(II) thiosemicarbazonato complex: Catalytic evaluation in synthesis of diaryl ketones from aryl aldehydes and arylboronic acids

A simple route to synthesize triphenylphosphinopalladium(II) thiosemicarbazonato complex has been described. Elemental analysis, spectral (IR, NMR) and single crystal X-ray diffraction techniques were employed for the complete characterization of the complex. The latter was found to be effective catalyst for carbon–carbon cross-coupling reaction of aryl- and heteroarylboronic acids with aromatic and heteroaromatic aldehydes to form the corresponding diaryl ketones. The influence of reaction parameters such as solvent, base, reaction temperature and catalyst loading was also investigated.     

A catalytic and mechanistic investigation of a PCP pincer palladium complex in the Stille reaction

In an improved procedure, the complex {2,6-bis[(diphenylphosphino)methyl]benzene}chloropalladium(II) (1) was synthesised as its THF adduct and the structure was determined by X-ray crystallography. The catalytic properties of the derivative {2,6-bis[(diphenylphosphino)methyl]benzene}(trifluoroacetato)palladium(II) (2) was investigated in the Stille reaction. Complex 2 proves to be an excellent catalyst for the C-C cross-coupling between trimethyl phenyl stannane and aryl bromides using a very low catalyst loading (0.1-0.0001%), giving high turnover numbers (TONs) up to 6.9 x 10(5). A kinetic investigation of the catalytic reaction suggests a heterogeneous colloidal palladium catalyst formed from the PCP Pd(II) pre-catalyst.     

Nanoparticles tungstophosphoric acid supported on polyamic acid: catalytic synthesis of 1,8-dioxo-decahydroacridines and bulky bis(1,8-dioxo-decahydroacridine)s

Tungstophosphoric acid nanoparticles supported on polyamic acid (TPA NPs/PAA) was prepared and employed as a catalyst for the facile selective synthesis of 1,8-dioxo-decahydroacridines and some bulky bis(1,8-dioxo-decahydroacridine)s via one-pot condensation of 5,5-dimethyl-1,3-cyclohexanedione and various aldehydes with aniline or ammonium acetate in ethanol–water solution. This catalyst was characterized by FT-IR, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), energy-dispersive X-ray analysis (EDAX), and inductively coupled plasma optical emission spectrometry (ICP-OES). The catalyst showed high thermal stability and good reusability. The products were isolated in high purity and the catalyst was easily separated in a simple workup and recycled several times without noticeable loss of activity under the described reaction conditions. The reaction is characterized by short reaction time, high efficiency, and mild reaction conditions.     

A Highly Efficient and Recyclable Solid Acid Catalyst for Synthesis of Spiro-oxindole Dihydroquinazolinones Under Ultrasound Irradiation

A simple,efficient and green procedure for the synthesis of spiro-oxindole dihyfroquinazolinones was developed by multi-component condensation of isatoic anhydride,aniline and isatin in the presence of a novel solid acid catalyst under ultrasound irradiation.The present environmentally benign protocol offers several advantages, such as shorter reaction time,a wide range of fimctional group tolerance,the use of an inexpensive heterogeneous catalyst,and a high yield of products via a simple experimental and work-up procedure.The mesoporous solid acid catalyst was directly prepared from phytic acid by microwave-sulfonation method without template.The phytic acid based solid acid was fully characterized by means of Fourier transform infrared spectroscopy(FTIR),Raman spectroscopy,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and transmission electron imcroscopy(TEM).The catalyst can be recovered and reused for at least five runs without significant impact on the product yields.     

Synthesis and Characterization of the 2‐Methylaminopyridine‐functionalized Polystyrene Resin‐supported Pd(II) Catalyst for the Mizoroki–Heck and Sonogashira Reactions in Water

A new polystyrene‐anchored Pd(II) pyridine complex is synthesized and characterized. This Pd(II) pyridine complex behaves as a very efficient heterogeneous catalyst in the Heck reaction of methyl acrylate with aryl halides and the Sonogashira reaction of terminal alkynes with aryl halides in water. Furthermore, the catalyst shows good thermal stability and recyclability. This polymer‐supported Pd(II) catalyst could easily be recovered by simple filtration of the reaction mixture and reused for more than five consecutive trials without a significant loss in its catalytic activity.     

Synthesis,characterization and heterogeneous catalytic application of a nickel(II) Schiff base complex immobilized on MWCNTs for the Hantzsch four-component condensation

A nickel(II) Schiff base complex immobilized on multi-wall carbon nanotubes (MWCNTs) surface as a highly efficient heterogeneous catalyst was synthesized and characterized by IR, X-ray diffraction patterns, scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma, elemental analysis, and thermal gravimetric analysis. Then a facile and environmentally benign procedure was developed for synthesis of polyhydroquinoline derivatives via Hantzsch one-pot condensation reaction of aromatic aldehydes, 1,3-diones, ethyl acetoacetate, and ammonium acetate in the presence of above synthesized catalyst under solvent-free conditions. This protocol has the advantages of stability, easy availability, recyclability and eco-friendly nature of catalyst, simple experimental and work-up procedure, and also high to excellent yields. Considering the solvent-free condition and also temperature, time, and yield of the model reaction, the nanocatalyst reported here is among the best catalysts reported so far for synthesis of polyhydroquinolines.     

Boehmite@SiO2@ Tris (hydroxymethyl)aminomethane-Cu(I): a novel,highly efficient and reusable nanocatalyst for the C-C bond formation and the synthesis of 5-substituted 1H-tetrazoles in green media

In this work, a versatile protocol was introduced for the preparation of a new Cu(I) supported complex on Silica supported boehmite nanoparticles (Boehmite@SiO₂@Tris-Cu(I)). The structure of the catalyst was comprehensively characterized using Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffractometer (XRD), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP), X-ray mapping, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) techniques. The catalytic activity of this catalyst was studied in the Suzuki cross-coupling reaction and synthesis of 5-substituted 1H-tetrazole derivatives in ethanol and PEG-400 respectively as green solvents. In this sense, simple preparation of the catalyst from the commercially available materials, high catalytic activity, simple operation, short reaction times, high yields and use of green solvent are some advantages of this protocol. Finally, it is worth mentioning that this nanocatalyst was easily recovered, and reused for several times without significant loss of its catalytic efficiency. In addition, stability of the catalyst after recycling was confirmed by FT-IR technique.     

Synthesis and characterization of silica-coated magnetite nanoparticles modified with bis(pyrazolyl) triazine ruthenium(II) complex and the application of these nanoparticles as a highly efficient catalyst for the hydrogen transfer reduction of ketones

We present a facile and efficient method for modifying the surface of silica-coated Fe₃O₄ magnetic nanoparticles (MNPs) with bis(pyrazolyl) triazine ruthenium(II) complex [ MNPs@BPT–Ru (II) ] . Field emission-scanning electron microscopy, thermogravimetric/derivative thermogravimetry analysis, X-ray powder diffraction, Fourier-transform infrared spectroscopy, vibrating sample magnetometry, and energy-dispersive X-ray spectrometry analyses were employed for characterizing the structure of these nanoparticles. MNPs@BPT–Ru(II) nanoparticles proved to be a magnetic, reusable, and heterogeneous catalyst for the hydrogen transfer reduction of ketone derivatives. In addition, highly pure products were obtained with excellent yields in relatively short times in the presence of this catalyst. A comparison of this catalyst with those previously used for the hydrogen transfer reactions proved the uniqueness of MNPs@BPT–Ru(II) nanoparticle which is due to its inherent magnetic properties and large surface area. The presented method also had other advantages such as simple reaction conditions, eco-friendliness, high recovery ability, easy work-up, and low cost.     

Pd-catalyzed intermolecular amidation of aryl halides: the discovery that xantphos can be trans-chelating in a palladium complex

A general method for the intermolecular coupling of aryl halides and amides using a Xantphos/Pd catalyst is described. This system displays good functional group compatibility, and the desired C-N bond forming process proceeds in good to excellent yields with 1-4 mol % of the Pd catalyst. Additionally, the arylation of sulfonamides, oxazolidinones, and ureas is reported. The efficiency of these transformations was found to be highly dependent on reaction concentrations and catalyst loadings. A Pd complex resulting from oxidative addition of 4-bromobenzonitrile, (Xantphos)Pd(4-cyanophenyl)(Br) (II), was prepared in one step from Xantphos, Pd(2)(dba)(3), and the aryl bromide. Complex II proved to be an active catalyst for the coupling between 4-bromobenzonitrile and benzamide. X-ray crystallographic analysis of II revealed a rare trans-chelating bisphosphine-Pd(II) structure with a large bite angle of 150.7 degrees.     

Preparation of core/shell/shell CoFe2O4/OCMC/Cu (BDC) nanostructure as a magnetically heterogeneous catalyst for the synthesis of substituted xanthenes,quinazolines and acridines under ultrasonic irradiation

Highly efficient synthesized magnetic cobalt ferrite nanoparticles supported on OCMC@Cu (BDC) was utilized in the preparation of biologically active heterocyclic compounds through one-pot three-component reactions between of aldehydes, dimedone, aryl amines/2-naphthol/urea under ultrasonic irradiation. This method has various advantages including excellent yields, little catalyst loading, simple procedure, facile catalyst separation, short reaction times, eco-friendly approach and simple purification. The catalyst was characterized by various spectroscopy methods such as fourier-transform infrared (FT-IR), energy-dispersive X-ray (EDX), scanning electron microscope (SEM), X-ray diffraction (XRD) and N₂ adsorption–desorption isotherm (BET). Furthermore, the heterocyclic compounds were characterized by spectral techniques. The nanocomposite was simply separated byusing an external magnet, and it can be recycled several times without significant loss of activity.     

Immobilized Pd on a NHC functionalized metal–organic framework MIL-101(Cr): an efficient heterogeneous catalyst in Suzuki−Miyaura coupling reaction in water

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.     

Immobilization of a palladium(II) bis(imidazolium) complex onto graphene oxide by noncovalent interactions: an efficient and recyclable catalyst for Suzuki–Miyaura reaction

In this research, the Suzuki–Miyaura coupling reaction catalyzed by a palladium(II) complex containing bis(imidazolium) ligand, Pd^II(BIM), immobilized on graphene oxide (GO) as heterogeneous, recyclable and active catalyst is reported. The catalyst, Pd^II(BIM)@GO, was characterized by FT-IR, diffuse reflectance UV–Vis spectroscopy, ICP, field emission scanning electron microscopy, energy-dispersive X-ray analysis, and elemental analysis. It was demonstrated that the GO-supported palladium(II) complex can act as an efficient catalyst and is reusable several times without a significant loss of their catalytic activity.     

介孔有机金属Ru(Ⅱ)非均相催化剂的制备及其催化性能的研究

采用正硅酸乙酯和有机金属Ru(II)硅烷在模板剂P123作用下共聚,合成出有序介孔Ru(II)有机金属催化剂,通过FTIR、NMR、XRD、TEM、N2吸附脱附等对催化剂进行了系统表征;将该催化剂应用于水介质中烯丙醇型异构化反应,结果表明,其具有高活性和高选择性,催化效率接近均相催化剂,且能够多次重复使用,有望在绿色化工中推广应用.     

Efficient and green synthesis of dihydropyrimido[4,5-b]quinolinetriones using MWCNTs@TEPA/Co (II) as a novel and eco-friendly catalyst

A new heterogeneous nanocatalyst [MWCNTs@TEPA/Co (II)] was successfully prepared using multiwall carbon nanotubes (MWCNTs) as a suitable and efficient support for covalent anchoring of tetraethylene pentaamine (TEPA)/Co (II). The new heterogeneous catalyst was prepared through an easy and applicable method, and characterized by various techniques such as Fourier transform-infrared, thermogravimetric analysis, energy-dispersive X-ray spectroscopy, mapping, field emission-scanning electron microscopy, inductively coupled plasma-optical emission spectrometry and Brunauer−Emmett−Teller. Synthesized catalyst was used efficiently for the preparation of dihydropyrimido [4,5-b]quinolinetrione derivatives via the four-components reaction of barbituric acid, dimedone, aryl aldehyde and amines under thermal conditions. The nanostructure catalyst was easily recovered by filtration and reused several times without noticeable loss of its catalytic activity. Low amounts of catalyst (0.005 g), short reaction times and green conditions are some merits of the presented method.     

Scope and mechanism of enantioselective Michael additions of 1,3-dicarbonyl compounds to nitroalkenes catalyzed by nickel(II)-diamine complexes

Readily prepared Ni(II)-bis[(R,R)-N,N'-dibenzylcyclohexane-1,2-diamine]Br(2) was shown to catalyze the Michael addition of 1,3-dicarbonyl compounds to nitroalkenes at room temperature in good yields with high enantioselectivities. The two diamine ligands in this system each play a distinct role: one serves as a chiral ligand to provide stereoinduction in the addition step while the other functions as a base for substrate enolization. Ligand modification within the catalyst was also investigated to facilitate the reaction of aliphatic nitroalkenes, 1,3-diketones, and beta-ketoacids. Ni(II)-bis[(R,R)-N,N'-di-p-bromo-benzylcyclohexane-1,2-diamine]Br(2) was found to be an effective catalyst in these instances. Furthermore, monodiamine complex, Ni(II)-[(R,R)-N,N'-dibenzylcyclohexane-1,2-diamine]Br(2), catalyzed the addition reaction in the presence of water. The proposed model for stereochemical induction is shown to be consistent with X-ray structure analysis.     

氧缺陷型SnO2纳米颗粒可见光催化性能的研究

由简单的水热法合成了一种可高效降解有机染料的氧缺陷型Sn O2纳米颗粒新型光催化剂,用X射线衍射、透射电镜、高分辨透射电镜和紫外-可见分光光度计等手段对其结构及性能进行了表征。结果表明,所制备的催化剂的禁带宽度最小可达2.90e V,可实现对可见光的有效吸收利用,对甲基橙的降解反应具有很高的光催化活性。将该催化剂(1g/L)分散在10mg/L的甲基橙溶液中,可见光照射下,40min内甲基橙的降解率达99%以上。由于该催化剂具有合成方法简单、高效、成本低和反应条件温和等特点,为有效解决有机染料对环境的污染问题提供了一条新的途径。     

一种结合均相和非均相催化剂优势的聚乙炔纳米颗粒负载的钯（II）催化剂

负载型的金属催化剂虽然分离方便,但在反应活性、选择性以及催化剂的结构表征方面均明显不如相应的均相催化剂。将均相催化剂通过不同的化学键固载于高比表面积载体是实现均相催化剂多相化的重要途径,这样可使催化剂兼具均相和多相催化剂的优势。然而要将均相催化剂锚定于特定载体上,通常涉及较为复杂的合成反应,对载体也有严格的要求。因而该法仅仅适用于实验室研究,难以实现规模生产。因此,提供一种简便有效地制备兼具均相和多相催化剂优势的催化剂合成方法非常必要。本文报道一种简便的制备聚乙炔纳米颗粒负载Pd(II)催化剂(NP-Pd(II))的方法,所制催化剂在水相中的Suzuki-Miyaura偶联反应中表现出极高的活性,同时具有便于分离、容易放大制备的特点。在室温下,将乙炔气通入PdCl42-的水溶液中迅速变得浑浊,静置后容器底部有棕色沉淀,同时溶液变为无色透明。固体产物使用水、乙醇等溶剂进行洗涤;干燥之后收集既得聚乙炔纳米颗粒负载的Pd(II)催化剂NP-Pd(II)。使用透射电子显微镜、红外(IR)及拉曼吸收光谱、X射线衍射(XRD)、X射线光电子能谱(XPS)以及X射线吸收光谱(EXAFS)等手段对NP-Pd(II)进行了详细表征。结果显示,在NP-Pd(II)中Pd并非以Pd纳米颗粒形式存在; XRD中没有未Pd纳米晶的特征衍射峰。 IR等表征证明乙炔在Pd的催化作用下发生聚合作用,生成了聚乙炔。 EXAFS结果表明, Pd分别和氯原子以及C=C双键进行配位;同时,没有观察到Pd–Pd键的生成,进一步证明了Pd未被还原为Pd纳米颗粒。 XPS也印证了Pd(II)的价态。形貌上, NP-Pd(II)为直径2–3nm的颗粒,其中的Pd原子均匀分散于聚乙炔纳米颗粒上,使其在反应过程中能够充分地与底物接触,从而在Suzuki-Miyaura偶联反应中表现出极高的活性。更重要的是,由于“憎水效应”, NP-Pd(II)在溶液中以微米级的聚集体形式存在,因而反应后通过离心或者静置从反应体系中分离出来。因此,在NP-Pd(II)催化剂中,每个Pd原子都是潜在的活性中心,这与典型的均相催化剂相似;同时,其独特的形貌使其具备了多相催化剂便于分离的特点。因此, NP-Pd(II)是一种兼具均相和多相催化剂优点的催化剂且其催化剂的制备方法极为简便。乙炔是常用的工业气体,溶剂采用水,制备在室温下即可完成,我们也成功地制备出克级规模的高活性、稳定性的NP-Pd(II)催化剂。     

Synthesis of 5-substituted 1H-tetrazoles and oxidation of sulfides by using boehmite nanoparticles/nickel-curcumin as a robust and extremely efficient green nanocatalyst

Nickel-anchored curcumin-functionalized boehmite nanoparticles (BNPs@Cur-Ni) as a robust and versatile nanocatalyst was synthesized and well-characterized by using Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray mapping, thermogravimetric analysis (TGA), differential thermal analysis (DTA), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The synthesis of 5-substituted 1H-tetrazoles and the oxidation of sulfides were conducted by BNPs@Cur-Ni with excellent turnover number (TON) and turnover frequency (TOF) outcomes. Also, the catalyst was reused for several sequential runs without Ni leaching or decreasing in reaction yield. Utilizing the curcumin and boehmite with a natural source as well as poly(ethylene glycol) (PEG) as a solvent in this simple protocol can be based on green chemistry rules.