Fe3O4-Lignin@Pd-NPs: A highly efficient,magnetically recoverable and recyclable catalyst for Mizoroki-Heck reaction under solvent-free conditions

Palladium nanoparticles ( Pd-NPs ) were synthesized under green conditions in water by chemical reduction of PdCl₂ with NaOH and supported by Fe ₃ O ₄ -Lignin . Fe ₃ O ₄ -Lignin is an organic–inorganic hybrid core-shell was synthesized by sonication of a mixture of Fe ₃ O ₄ -NPs (20 nm) and alkali lignin. The new materials Fe ₃ O ₄ -Lignin and Fe ₃ O ₄ -Lignin@Pd-NPs were characterized by PXRD, SEM and FT-IR spectroscopy. The Fe ₃ O ₄ -Lignin@Pd-NPs was further confirmed by UV–Visible spectroscopy, TEM, EDX, HRICP-AES and TGA/DTA. The average size of Pd-NPs determined from PXRD was 5–10 nm. The amount of palladium loaded on Fe ₃ O ₄ -Lignin obtained from EDX analysis was 26.63% by mass. The amount of Fe and Pd present in the catalyst obtained from HRICP-AES was 11.88 (wt. %) and 10.90 (wt. %) respectively per gram of lignin. The catalytic potential of Fe ₃ O ₄ -Lignin@Pd-NPs was evaluated in Mizoroki-Heck C-C coupling reaction. During the optimization studies of reaction between iodobenzene and n-butyl acrylate in various solvents and under solvent-free but aerobic conditions using various inorganic and organic bases, the product n-butyl 3-phenylprop-2-enoate ( 1a ) obtained was as high as 95% in highly polar solvents as short as in 10 min and 99% under solvent-free conditions in 3 min at 140 °C using n-Pr₃N as base. The scope of the above catalyst was investigated in the Mizoroki-Heck reaction of various aryl/heterocyclic halides and n-butyl acrylate/styrene under optimized solvent-less conditions. The corresponding products were obtained in high yields (73–99%). The catalyst recovered by magnetic decantation was reused for five times in the C-C coupling reaction between iodobenzene and n-butyl acrylate which yielded 90–95% of the desired product, 1a .     

纳米复合材料CoFe2O4/CD-SBA-15的制备与表征

为制备在磁性环境下容易分离的新型吸附材料,制备了CoFe2O4/β-CD-SBA-15纳米复合材料,采用X射线衍射(XRD)、红外光谱(FT-IR)、透射电镜(TEM)、比表面测定仪(BET)和振动样品磁强计(VSM)对纳米复合材料的结构与性能进行表征.研究表明:CoFe2O4分散在β-CD-SBA-15的骨架和孔道里...     

导电聚苯胺与磁性CoFe2O4纳米复合物的合成及其电磁性能

在利用HNO3处理CoFe2O4磁性纳米粒子使其表面离子化、分散性得到改善的基础上,采用苯胺在其表面原位聚合,制备了具有电磁功能的聚苯胺(PANI)/CoFe2O4纳米复合物.借助TEM、XRD、FT-IR、四探针电导率仪和VSM(振动样品磁强计)等分析手段研究了复合物的形貌、结构及其电磁性能.结果表明,CoFe2O4以25 nm左右的粒子分散于聚苯胺基体中,被其完全包覆,CoFe2O4与PANI之间存在化学键合作用;复合物同时具有电性能和磁性能,其导电牢随CoFe2O4含量增加而降低,饱和磁化强度随之升高,而矫顽力在所研究的范围内则先增大而后又减小,且均高于CoFe2O4的矫顽力.     

Synthesis and characterization of 1D Co/CoFe(2)O(4) composites with tunable morphologies

1D Co/CoFe(2)O(4) composites with tunable morphologies were fabricated by a facile solvothermal route in the presence of a surfactant poly(vinylpyrrolidone) (PVP); they may be very attractive for potential applications because of their outstanding soft magnetism.     

Semi-vacant Wells-Dawson anions. Synthesis of tri-tungsten-vacant derivatives and crystallographic studies of [alphabetabetaalpha-(Cu(II)OH2)2(Cu(II))2(AsW15(OH2)3(OH)O52)2]12-

The tri-tungsten-vacant polyoxometalate, [alpha-AsW15(OH)4O52]13-, derived from the semi-vacant Wells-Dawson complex [alpha-AsW18(OH)4O58]7-, reacts with the late-transition metal cations, Cu(II) or Zn(II), to form sandwich-type species; the X-ray crystal structure of [alphabetabetaalpha]-(Cu(II)OH2)2(Cu(II))2(AsW15(OH2)3(OH)O52)2]12-, prepared by the acidification of [alphabetabetaalpha]-(Cu(II)OH2)2(Cu(II))2(AsW15(OH)4O52)2]18-, reveals that the missing heteroatoms are distal to the central Cu4 unit and the vertices of the vacant tetrahedron are occupied by one OH- and three OH2 groups.     

Ferrite nanoparticles (MFe2O4 NPs) as magnetically recoverable supports for catalysis in organic synthesis

Abstract

Heterogenization of organic and metallic catalysts with a solid support is an attractive and useful strategy to solve the separation and recovery problems of catalysts. During the last decade, magnetic nanoparticles (MNPs) in general ferrite nanoparticles (MFe₂O₄ NPs) have emerged as a highly efficient support for catalysis, due to their simple fabrication, modification, and large surface area ratio. In this paper, we provide an overview of the utilization of organic and metallic molecules immobilized on magnetic ferrite nanoparticles (MFe₂O₄ NPs) as attractive and efficient catalytic systems in wide variety of in organic reactions.     

Synthesis of an open-framework copper-germanium phosphate [Cu(H2O)2(OH)]2Ge(PO4)2

A novel open-framework material [Cu(H(2)O)(2)(OH)](2)Ge(PO(4))(2), which was synthesized by a hydrothermal method, is built of GeO(6), CuO(6) octahedra and PO(4) tetrahedra, and possesses a network of interconnecting six- and eight-membered ring channels.     

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.     

Synthesis and Structure of [Cu（OH）2（H2O）2（4—C5H4N—COOH）2]

1 INTRODUCTION Supramolecular chemistry and crystal engineering of coordination compounds have attracted considerable interests nowadays owing to the fascinating structural diversity and potential applications as functional materials[1,2]. Generally, architectures of supramolecules are formed through hydrogen bonds, ?- ?stacking interaction or other weak interactions between the molecules. Recently, many supramolecular compounds containing silver(I) and copper(II) species have been re-…     

Synthesis of 1,2-disubstitued benzimidazoles using SiO2/ZnCl2

A general and easy method for the synthesis of several 1,2-disubstituted benzimidazoles using SiO₂/ZnCl₂ and solvent-free conditions is described. This efficient and improved method furnishes selectively and in good yields the corresponding 1,2-bis(organyl)-benzimidazoles starting from o-phenylenediamine and aromatic or aliphatic aldehydes. The catalytic system was re-used up three times and the use of focused microwaves accelerates the reaction.     

导电聚苯胺与磁性CoFe2O4纳米复合物的制备与表征

在利用HNO3酸化处理CoFe2O4磁性纳米粒子使其表面离子化、分散性得到改善的基础上, 采用原位聚合法制备了具有电磁功能的聚苯胺/CoFe2O4 (PANI/CoFe2O4)纳米复合物. 借助TEM, XRD, FT-IR, TG, 四探针电导率仪、VSM(振动样品磁强计)等分析手段研究了复合物的形貌、结构、热稳定性及电磁性能. 结果表明, 处理过的CoFe2O4磁性纳米粒子可形成分散均匀的PANI/CoFe2O4纳米复合物, CoFe2O4以25 nm左右的粒子分散于聚苯胺基体中; PANI与CoFe2O4之间存在化学键合作用, 正是这种作用使复合物热稳定性得以提高; 复合物同时具有导电性和磁性能, 且随CoFe2O4含量变化而变化.     

Hydrothermal Synthesis of Brucite Type Copper Hydroxide Squarate [Cu3(OH)2(C4O4)]·4H2O

Herein we report synthesis of a new brucite type copper hydroxide squarate, Cu₃(OH)₂(C₄O₄)₂·4H₂O [P2₁/c, a = 5.6437(4) Å, b = 12.8357(9) Å, c = 9.1507(6) Å, β = 95.892(1)° and Z = 2] by hydrothermal method, and its characterization by single crystal diffraction analysis as well as by IR spectroscopy. The rather wide spread of Cu–O bond lengths, can be primarily rationalised by the Jahn‐Teller effect, and secondarily by the connectivities of the CuO₆ octahedra.     

Synthesis and pharmacological activity of 2-(biphenyl-4-yl)imidazo[1,2-a]benzimidazoles

Russian Chemical Bulletin - An efficient method for the synthesis of novel 9H-imidazo[1,2-a]benzimidazole derivatives containing a biphenyl substituent at position 2 was developed. These compounds,...     

Is chrysocolla (Cu,Al)2H2Si2O5(OH)4·nH2O related to spertiniite Cu(OH)2?—A vibrational spectroscopic study

Chrysocolla (Cu, Al)₂H₂Si₂O₅(OH)₄·nH₂O is a hydrated copper hydroxy silicate and is commonly known as a semi-precious jewel. The mineral has an ill defined structure but is said to be orthorhombic, although this remains unproven. Thus, one of the few methods of studying the molecular structure of chrysocolla is to use vibrational spectroscopy. Chrysocolla may be defined as a colloidal mineral. The question arises as to whether chrysocolla is a colloidal system of spertiniite and amorphous silica. The main question addressed by this study is whether chrysocolla is (1) a mesoscopic assemblage of spertiniite, Cu(OH)₂, silica, and water, (2) represents a colloidal gel or (3) is composed of microcrystals with a distinct structure.Considerable variation in the vibrational spectra is observed between chrysocolla samples. The Raman spectrum of chrysocolla is characterised by an intense band at 3624 cm⁻¹ assigned to the OH stretching vibrations. Intense Raman bands found at 674, 931 and 1058 cm⁻¹ are assigned to SiO₃ vibrations. The Raman spectrum of spertiniite does not correspond to the spectrum of chrysocolla and it is concluded that the two minerals are not related. The spectra of chrysocolla correspond to a copper silicate colloidal gel.     

Synthesis and properties of magnetically separable Fe3O4/TiO2/Bi2O3 photocatalysts

The Fe₃O₄/TiO₂/Bi₂O₃ composites were synthesized by a sol–gel method and used as improved photocatalysts for the degradation of methyl orange (MO) under simulated sunlight at room temperature. The as-prepared Fe₃O₄/TiO₂/Bi₂O₃ composites were characterized by X-ray diffraction, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and diffuse reflectance spectroscopy (DRS). TEM analysis reveals that the composite has a core–shell structure and diameters of Fe₃O₄ core is about 200 nm. DRS results reveal that all composites showed red shift in optical absorption. TiO₂, Fe₃O₄, and Bi₂O₃ exist mainly as separate phases in the Fe₃O₄/TiO₂/Bi₂O₃ composites based on XPS analysis. The photocatalytic degradation of MO with the prepared photocatalysts was studied under simulated sunlight illumination. Photocatalytic reactivity test indicated that the removal efficiency of MO with the Fe₃O₄/TiO₂/Bi₂O₃ photocatalyst was higher than that of pure TiO₂ and Fe₃O₄/TiO₂. Recovery rate of Fe₃O₄/TiO₂/Bi₂O₃ photocatalysts achieved 80 % after five times reuse.     

Unassisted solar water splitting using a Cu2O/Ni(OH)2-ZnO/Au tandem photoelectrochemical cell

Journal of Solid State Electrochemistry - A tandem photoelectrochemical (PEC) cell consisting of a Cu2O/Ni(OH)2 photocathode and a ZnO/Au photoanode was investigated for unassisted solar water...     

Synthesis and structure of the pentacopper(II) substituted tungstosilicate [Cu5(OH)4(H2O)2(A-alpha-SiW9O33)2]10-

The dimeric, pentacopper(II) substituted tungstosilicate [Cu(5)(OH)(4)(H(2)O)(2)(A-alpha-SiW(9)O(33))(2)](10-) (1) has been synthesized in good yield using a one-pot procedure by reaction of Cu(2+) ions with the trilacunary precursor salt K(10)[A-alpha-SiW(9)O(34)]. The title polyanion represents the first polyoxotungstate substituted by 5 copper centers and the central copper-hydroxo-aqua fragment is completely unprecedented. In the course of the reaction, two [A-alpha-SiW(9)O(34)](10-) Keggin half-units have fused in an asymmetrical fashion resulting in the lacunary polyoxotungstate [Si(2)W(18)O(66)](16-). The vacancy in this species is stabilized by a magnetic cluster of five octahedrally coordinated Cu(2+) ions resulting in polyanion 1 with C(2v) symmetry.     

Polyaniline/CoFe2O4 nanocomposite inhibits the growth of Candida albicans 077 by ROS production

In recent years, polyaniline/CoFe₂O₄ nanocomposites have gained attention because of their wide utilization in optoelectronics and biomedical studies. However, very limited research has been carried out on the anticandidal activity of polyaniline/CoFe₂O₄ nanocomposite against Candida spp. Thus, the study was designed to investigate the anticandidal potential of PANI/CoFe₂O₄ nanocomposite against Candida albicans 077. PANI/CoFe₂O₄ nanocomposite (denoted as “cfPNCs”) was synthesized by polymerization of aniline in the presence of CoFe₂O₄ nanoparticles. The structural and thermal properties of the synthesized PANI/CoFe₂O₄ nanocomposite were investigated. It was noteworthy that PANI/CoFe₂O₄ nanocomposite showed promising anticandidal activity in a dose-dependent manner. Results also showed that the protection of histidine (a ROS quencher) against ROS clearly suggested the implication of ROS in anticandidal activity of PANI/CoFe₂O₄ nanocomposite. It is encouraging to conclude that PANI/CoFe₂O₄ nanocomposite bears the potential of their applications in biomedicine, especially nanotherapy for diseases caused by C. albicans.     

Synthesis and structure of asymmetric zirconium-substituted silicotungstates, [Zr6O2(OH)4(H2O)3(beta-SiW10O37)3]14- and [Zr4O2(OH)2(H2O)4(beta-SiW10O37)2]10-

The reaction of ZrCl4 with [gamma-SiW10O36]8- in a potassium acetate buffer results in two different products depending on the reactant ratios. The trimeric species [Zr6O2(OH)4(H2O)3(beta-SiW10O37)3]14- (1) consists of three beta23-SiW10O37 units linked by an unprecedented Zr6O2(OH)4(H2O)3 cluster with C1 point group symmetry. The dimeric species [Zr4O2(OH)2(H2O)4(beta-SiW10O37)2]10- (2) consists of beta22- and beta12-SiW10O37 units sandwiching a Zr4O2(OH)2(H2O)4 cluster, which also has C1 symmetry. Polyanion 1 contains more zirconium centers than any other polyoxometalate known to date.     

磁电CoFe2O4/BaTiO3纳米管的溶胶-凝胶模板法合成和表征

用溶胶-凝胶模板法合成了 CoFe2O4)/BaTiO3(CFO/BTO)复合纳米管,管的直径约为 100、200 和 300 nm,其长度约为100 μm.x射线衍射(xRD)和选区电子衍射(sAED)都显示复合纳米管中同时存在尖晶石相的CoFe2O4(CFO)和钙钛矿相的 BaTiO3(BTO),进一步的透射电子显微镜(TEM)研究证实合成的纳米复合物具有明显的管状结构.磁、电研究表明,该复合纳米管的磁性与纯 CFO 纳米管的磁性相当;而铁电性与纯BTO纳米管的铁电性相当.