Synthesis and size control of monodisperse copper nanoparticles by polyol method

We describe herein the synthesis of metallic copper nanoparticles in the presence of poly(vinylpyrrolidone), employed as a protecting agent, via a polyol method in ambient atmosphere. The obtained copper particles were confirmed by XRD to be crystalline copper with a face-centered cubic (fcc) structure. We observed monodisperse spherical copper nanoparticles with a diameter range 45+/-8 nm. The particle size and its distribution are controlled by varying the synthesis parameters such as the reducing agent concentration, reaction temperature, and precursor injection rate. The precursor injection rate plays an important role in controlling the size of the copper nanoparticles. On the basis of XPS and HRTEM results, we demonstrate that the surface of the copper is surrounded by amorphous CuO and that poly(vinylpyrrolidone) is chemisorbed on the copper surface.     

Kinetics of the dissolution of copper metal in aqueous solutions containing unsaturated organic ligands and copper(II)

The kinetics of the dissolution of copper metal in an aqueous solution containing copper(II) and an unsaturated organic ligand was followed by using an automated flow-injection analysis technique to determine the concentration of copper(I) in solution as a function of time. The results suggest that the rate of dissolution of the copper metal is dependent on electron transfer between the copper(II) and copper atoms on the surface of the copper metal, and on the stabilization of copper(I) by the unsaturated organic ligand in solution.     

Cathodic and anodic stripping determination of traces of adenine and adenosine based on accumulation of copper(I) compounds at mercury or amalgam electrodes

In the presence of adenine and adenosine, the copper(II)/copper(Hg) couple splits to the copper(II)/copper(I) and copper(I)/copper(Hg) couples. Sparingly soluble complexes of copper(I) with adenine and adenosine can be accumulated on the electrode surface either by reduction of Cu(II) ions or by oxidation of the copper amalgam electrode. The copper(I)/adenine deposit can be stripped either cathodically or anodically with detection limits of 5×10^?9 and 2×10^?8 mol dm^?3, respectively. The copper(I)/ adenosine complex yields only the cathodic stripping peak with a detection limit of 9×10^?6 mol dm^?3. The stripping peaks obtained for the copper(I)/adenine and copper(I)/ adenosine complexes are better defined and appear over a wider range of pH than the peaks related to the corresponding mercury compounds. Adenosine cannot be determined in the presence of adenine bur adenine can be determined in the presence of moderate amounts of adenosine.     

含润滑油微胶囊复合镀铜机理和镀层性能

采用水相分离法制备了以润滑油为囊心、聚乙烯醇为囊壁的微胶囊，并考察了含这种微胶囊复合镀铜层的性能.通过对这种复合镀层微观形貌的观察及耐腐蚀性、耐磨性、动摩擦系数的测定，结果表明由于复合镀铜层中含有润滑油微胶囊，其耐腐蚀性和耐磨性能都得到很大提高，并分析了这种微胶囊复合电沉积的机理和镀层的润滑、修复作用.     

Kinetics of copper dissolving in the water solution of polyacrylic acid or its copolymers with acrylonitrile and hydrogen peroxide

During the coating of metal plates by carboxyl-containing polymers from their solutions or dispersions, adsorption of the polymer onto the surface and oxidation of the metal by oxygen take place. Adsorption of polyacrylic acid and its copolymers with acrylonitrile at the copper surface and kinetics of copper dissolving in the presence of carboxyl-containing polymers and hydrogen peroxide have been investigated. The adsorption of polymers at the surface of the copper powder passes through a maximum when the content of acrylonitrile in copolymers rises. The rate at which copper dissolves increases with increased polymer concentration in solution, reaching a constant value, and does not depend on the hydrogen peroxide concentration. The rate at which copper dissolves depends on the rate of copper oxidation by hydrogen peroxide in the adsorption layer and the rate of polymer desorption. The increase of the solution pH leads to a decrease in the adsorption of polyacrylic acid at the copper surface and the rate at which copper dissolves in the presence of hydrogen peroxide.     

Preparation and properties of ligand-free methylcopper and of copper alkyls coordinated with 2,2′-bipyridyl and tricyclohexylphosphine

A series of copper alkyls (methyl, ethyl and n-propyl) with ligands (2,2′-bipyridyl and tricyclohexylphosphine) and copper methyl without ligands has been prepared by the reaction of copper(II) acetylacetonate with dialkylaluminum monoethoxides in the presence or absence of the ligand in diethyl ether under nitrogen at low temperature. The copper alkyls were characterized by elemental analysis, chemical reactions, and by IR and NMR spectra. The ligand-free methylcopper is thermally very unstable and decomposed explosively; the bipyridyl ligand showed little effect on the stability of the copper alkyl. In contrast, the tricyclohexylphosphine-coordinated complexes are thermally very stable. Various reactions of the tricyclohexylphosphine-coordinated copper alkyls toward carbon dioxide, alkyl halides and olefins have been studied.     

Interaction between congo red and copper in a binary adsorption system: Spectroscopic and kinetic studies

This study focused on the competitive adsorption of congo red (CR) and copper by chitosan hydrogel beads in a binary adsorption system. Spectroscopic analysis, including Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were integrated with kinetic studies to elucidate the interaction. It was determined that chitosan hydrogel beads show better adsorption performance towards congo red and copper in single adsorption systems. The addition of copper caused a 25% reduction in congo red adsorption capacity, while copper adsorption was enhanced slightly by the presence of congo red. The adsorption results for binary adsorption systems seem due to competition for the present amine and hydroxyl groups that may occur between congo red and copper. A congo red–copper complex was formed in binary adsorption systems. Copper attached to chitosan hydrogel beads individually or was bound by the congo red–copper complex, which resulted in an increase in adsorption capacity. Chitosan exhibited higher adsorption selectivity to the free Cu²⁺ ion than the congo red–copper complex in the binary adsorption system. Adsorption of the congo red–copper complex indicated an inhibition in the attachment of the free Cu²⁺ ion in the form of Cu(II).     

应用波长色散X荧光仪和多晶X射线衍射仪联用技术 鉴定进口铜矿和含铜物料

本文首次研究进口可利用含铜物料与进口铜矿属性的不同特性并建立鉴定方法,采用X荧光光谱法和X射线衍射光谱法联用技术建立铜矿和含铜物料属性的鉴别方法。通过X荧光光谱法对铜矿和含铜物料中元素进行定性半定量分析,再用X射线衍射光谱法对铜矿和含铜物料的特征谱峰进行扫描,与X衍射仪中标准卡片比对分析,能够确定铜矿和含铜物料的物相组成。结果显示：X荧光光谱法铜矿和含铜物料的共同特点铜的含量较高,达到冶炼铜对原料的要求,硅、铁、钠、钙和镁元素都能够检出。差异性在铅和锌元素在含铜物料中较高,在铜矿石中基本未检出;在X荧光光谱法检测出的金属元素,通过X衍射仪扫描后与标准图片比对,各元素以不同的形式存在于含铜物料中,且有规律可循。     

Solvent and steric effects on the extraction of copper(II) with pivalic acid

The solvent extraction of copper(II) with trimethylacetic acid using benzene and 1-octanol as solvents was performed at 25 degrees C and 0.1 mole. dm(-3) ionic strength in the aqueous phase. In contrast to the extraction of copper(II) with a saturated straight-chain carboxylic acid in benzene, the dimeric copper(II) trimethylacetate was observed to dissociate into the monomer, even at a moderately high concentration of copper(II) in the benzene phase. In the system using 1-octanol as a solvent, both the monomeric and dimeric copper(II) species are suggested to be solvated by some 1-octanol molecules. It has been found that the dimerization and adduct formation of copper(II) species in benzene may more effectively enhance the extractability of copper(II) than the solvation by 1-octanol molecules.     

Adsorption of anions on ultra-thin metal deposits on single-crystal electrodes: II: Voltammetric and radiochemical study of bisulfate adsorption on Pt(111) and Pt(poly) electrodes containing copper adatoms

The formation of ultra-thin metal deposits of copper on Pt(111) and polycrystalline platinum electrodes, as well as the adsorption of bisulfate on the copper-covered platinum surfaces, were studied by cyclic voltammetry and radioactive labeling. The highest charge obtained by voltammetry in the underpotential stripping range nearly corresponds to a close-packed monolayer of copper. The radioactive labeling data indicate that there are inactive and active copper adlayers toward bisulfate adsorption. The transition from inactive to active behavior is interpreted in terms of an increase in surface—bisulfate interactions at the expense of surface—perchlorate interactions. Based on recent X-ray absorption near-edge spectroscopy (XANES) analysis of copper deposition onto platinum, the site for bisulfate adsorption is most probably a Cu⁺ surface species. Combining this spectroscopic information with coulometry shows that an additional electron is confined to surface platinum atom(s) covered by the copper species. The copper film attains bulk copper properties when approximately 2.5 monolayers of copper are deposited.     

Simultaneous sorption of nonionic surfactant (alkylmonoethers) and copper(II) in a weak acid polyacrylic cation exchanger

The mutual influence of copper(II) cations and nonionic surfactant alkylmonoethers on their simultaneous sorption by the hydrogen form of Purolite C 106 polyacrylic acid functionalized cation exchanger was investigated considering the suitability for the prevention of environmental contamination. Sorption isotherms were measured and sorption equilibrium coefficients calculated. The modelling of copper(II) sorption and copper(II) carboxyl complex formation was carried out. The sorption of copper(II) proceeds predominantly by complex (ionic and coordinate) bonding followed by the change in pH, also by single coordinate bonding. The mutual action of copper(II) and alkylmonoethers leads to a decrease in the equilibrium sorption for both copper(II) and the surfactant. The sorption of copper(II) and alkylmonoethers could be applicable for the purification of sewage including copper plating rinsewater from both contaminants simultaneously for the control of copper(II) and the surfactant in sewage effluents. Received: 15 May 2000 Accepted: 9 May 2001     

Spectroscopic and density functional studies of the red copper site in nitrosocyanin: role of the protein in determining active site geometric and electronic structure

The electronic structure of the red copper site in nitrosocyanin is defined relative to that of the well understood blue copper site of plastocyanin by using low-temperature absorption, circular dichroism, magnetic circular dichroism, resonance Raman, EPR and X-ray absorption spectroscopies, combined with DFT calculations. These studies indicate that the principal electronic structure change in the red copper site is the sigma rather than the pi donor interaction of the cysteine sulfur with the Cu 3d(x2-y2) redox active molecular orbital (RAMO). Further, MCD data show that there is an increase in ligand field strength due to an increase in coordination number, whereas resonance Raman spectra indicate a weaker Cu-S bond. The latter is supported by the S K-edge data, which demonstrate a less covalent thiolate interaction with the RAMO of nitrosocyanin at 20% relative to plastocyanin at 38%. EXAFS results give a longer Cu-S(Cys) bond distance in nitrosocyanin (2.28 A) compared to plastocyanin (2.08 A) and also show a large change in structure with reduction of the red copper site. The red copper site is the only presently known blue copper-related site with an exogenous water coordinated to the copper. Density functional calculations reproduce the experimental properties and are used to determine the specific protein structure contributions to exogenous ligand binding in red copper. The relative orientation of the CuNNS and the CuSC(beta) planes (determined by the protein sequence) is found to be key in generating an exchangeable coordination position at the red copper active site. The exogenous water ligation at the red copper active site greatly increases the reorganization energy (by approximately 1.0 eV) relative to that of the blue copper protein site, making the red site unfavorable for fast outer-sphere electron transfer, while providing an exchangeable coordination position for inner-sphere electron transfer.     

The benzoyloxylation of norbornadiene and homologues by copper(III) and copper(II) benzoate complexes

Oxidation of norbornadiene and benzonorbornadiene by copper(III) and copper(II) benzoate complexes in pyridine gave the corresponding 7-benzoyloxy derivatives. The proposed mechanism suggests two single-electron oxidations by copper(III) and/or copper(II).     

Fabrication and mechanical durability of a superhydrophobic copper surface with morphological development from hydrothermal reaction

The superhydrophobic surface on copper is fabricated by using a simple hydrothermal reaction and subsequent perfluorosilane treatment. The micro‐structured and nano‐structured surface was directly obtained through the hydrothermal reaction of copper sheets with sulfur at 180 °C for 12 h, resulting in the formation of copper sulfide film on the copper substrate. The chemical composition of this film was confirmed using X‐ray photoelectron spectroscopy. After copper sulfide film is treated by perfluorosilane, the superhydrophobic surface with static water contact angle of 153 °C and a low contact angle hysteresis is achieved. The superhydrophobic surface shows strong mechanical stability and can effectively protect the copper substrate. Copyright © 2016 John Wiley & Sons, Ltd.     

Relationship between Coordination Structure and Biological Activity of Copper(II) Nicotinate

1 INTRODUCTION In 1945, Braude[1] found for the first time that adding copper (Cu) ten times the normal requisite amount into the feed can improve the production property of the animal obviously. Therefore, from then on copper has been widely applied in pig- breeding industry as an effective growth-promoting agent, especially in the process of intensive culture, which plays an important part in improving the growth of animal and the production property. However, at the same time, the high…     

Strategy for copper speciation in white wine by differential pulse anodic stripping voltammetry, potentiometry with an ion-selective electrode and kinetic photometric determination

Differential pulse anodic stripping voltammetry (DPASV), potentiometry with a copper ion-selective electrode and a kinetic photometric method were used to determine copper species in white wines. The kinetic method is based on the catalytic effect of labile copper(II) species on the oxidation of 3-hydroxybenzaldehyde azine by potassium peroxidisulfate in an ammonical medium at room temperature. The total copper concentrations were determined by flame atomic absorption spectrometry. Free copper(II) ions, labile and tightly bound copper species could be quantified in 16 non pre-treated wine samples. Received: 13 August 1996 / Revised: 28 October 1996 / Accepted: 29 November 1996     

Simultaneous adsorption of copper ions and humic acid onto an activated carbon

In this study, simultaneous adsorption of copper ions and humic acid (HA) from Aldrich onto an activated carbon is investigated. It is found that the HA adsorption in the absence of copper decreases as the pH is increased. It leads to a reduction of 34.7% in the specific surface area of carbon. There exists a critical concentration (CC) of HA for copper adsorption. At HA concentrations < CC, a decrease in copper adsorption is observed; however, the HA improves the adsorption at HA concentrations > CC. An increase in ionic strength can enhance the copper uptake; however, zinc and/or cobalt ions have an insignificant influence on copper adsorption. The adsorption is significantly increased by citric acid, whereas addition of EDTA slightly decreases the uptake. An intraparticle diffusion model is successfully used to describe the copper adsorption kinetics.     

Spectral,spatial and temporal characterization of a millisecond pulsed glow discharge: copper analyte emission and ionization

Two-dimensional maps of the spatial distributions of excited and ionized sputtered copper atoms are presented for a millisecond pulsed argon glow discharge. These maps demonstrate the temporal as well as spatial dependence of different excitation and ionization processes over the pulse cycle. Transitions from the low energy electronic states for the atom, characterized by emission such as that at 324.75 nm (3.82→0.00 eV), dominate the plateau time regime at a distance of 2.5 mm from the cathode surface. These processes originate from the electron excitation of ground state copper atoms. Transitions from high-energy electronic states, such as that characterized by emission at 368.74 nm (7.16→3.82 eV), predominate during the afterpeak time regime at a distance of 5.0–6.0 mm from the cathode surface. This observation is consistent with the relaxation of highly excited copper atoms produced by electron recombination with copper ions during the afterpeak time regime. Analyses of afterpeak and plateau intensities for a series of copper emission lines indicate an electron excitation temperature equivalent to 5.78 eV at 0.8 torr and 1.5 W. Temporal profiles exhibit copper ion emission only during the plateau time regime.     

Strategy for copper speciation in white wine by differential pulse anodic stripping voltammetry, potentiometry with an ion-selective electrode and kinetic photometric determination

Differential pulse anodic stripping voltammetry (DPASV), potentiometry with a copper ion-selective electrode and a kinetic photometric method were used to determine copper species in white wines. The kinetic method is based on the catalytic effect of labile copper(II) species on the oxidation of 3-hydroxybenzaldehyde azine by potassium peroxidisulfate in an ammonical medium at room temperature. The total copper concentrations were determined by flame atomic absorption spectrometry. Free copper(II) ions, labile and tightly bound copper species could be quantified in 16 non pre-treated wine samples. Received: 13 August 1996 / Revised: 28 October 1996 / Accepted: 29 November 1996     

Voltammetric behaviour of copper(iii) and its analytical applications

Copper(II) and copper(III) complexes with periodate or tellurate ligands are electroactive at a smooth platinum electrode, giving an anodic, cathodic or cathanodic wave in the presence of alkaline hydroxide solutions containing copper(II), copper(III), or copper(II)-copper(III) species, respectively. The corresponding limiting currents are diffusion-controlled. The following analytical applications are proposed: (a) amperometric titration of copper(III) solutions; (b) voltammetric determination of copper. Results of amperometric titrations of copper(III) were similar to those by an established procedure. Voltammetry of copper(II) allows the metal to be determined down to concentrations of 1·10^-5M, even in the presence of different ions; the procedure can be applied to such heat-transfer media for nuclear reactors as sodium and potassium metals and their hydroxides.