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1.
Methods of stripping voltammetry, quartz microgravimetry, and x-ray-fluorescence analysis are employed to explore the copper displacement process on thin electrodeposited layers of pure cobalt and nickel and on deposits of these metals with inclusions of copper. The displacement reaction proceeds at a considerable rate on cobalt in the sulfate and sulfosalicylate solutions and virtually does not proceed on nickel in both the sulfate or sulfate-chloride solutions. An estimate of the rate of the copper displacement reaction following a change in the concentration of copper ions in the solution and in the pH of the sulfosalicylate solution is given. A decrease in the contact exchange rate is facilitated by a decrease in the concentration of copper ions in solution and their participation in the formation of complexes. 相似文献
2.
Wataru Sugimoto Masashi Omoto Katsunori Yokoshima Yasushi Murakami Yoshio Takasu 《Journal of solid state chemistry》2004,177(12):4542-4545
An ion-exchangeable ruthenate with a layered structure, K0.2RuO2.1, was prepared by solid-state reactions. The interlayer cation was exchanged with H+, C2H5NH3+, and ((C4H9)4N+) through proton-exchange, ion-exchange, and guest-exchange reactions. The electrical and magnetic properties of the products were characterized by DC resistivity and susceptibility measurements. Layered K0.2RuO2.1 exhibited metallic conduction between 300 and 13 K. The products exhibited similar magnetic behavior despite the differences in the type of interlayer cation, suggesting that the ruthenate sheet in the protonated form and the intercalation compounds possesses metallic nature. 相似文献
3.
Manuela Zubitur Agurtzane Mugica Javier Areizaga Milagros Cortázar 《Colloid and polymer science》2010,288(7):809-818
Nanocomposites of poly(p-dioxanone) (PPDO) with unmodified and organically modified layered double hydroxide (LDH) have been
prepared by melt extrusion method. Dodecyl sulfate was used as organic modifier. The morphology of nanocomposites was analyzed
by X-ray diffraction and transmission electron microscopy and their thermal properties by differential scanning calorimetry
and thermogravimetric analysis. It has been found that the organic modifier decisively influences the nanocomposite morphology,
resulting in a higher level of exfoliation. In addition, the glass transition temperature of nanocomposites was slightly higher
than in case of unfilled PPDO. Moreover, the crystallization was delayed by LDH incorporation. The above behavior was ascribed
to interactions between carbonyl groups of polymer matrix and hydroxyl groups of LDH, as supported by Fourier transformed
infrared analysis. Interestingly, two different crystallization processes have been observed in the nanocomposite of PPDO
and organically modified LDH. Unmodified and organo-modified LDH, practically did not alter the final melting point of PPDO.
However, the thermal decomposition behavior was clearly influenced by the morphology exhibited by nanocomposites. 相似文献
4.
Xu J Assoud A Soheilnia N Derakhshan S Cuthbert HL Greedan JE Whangbo MH Kleinke H 《Inorganic chemistry》2005,44(14):5042-5046
A new quaternary layered transition-metal oxide, Na2Cu2TeO6, has been synthesized under air using stoichiometric (with respect to the cationic elements) mixtures of Na2CO3, CuO, and TeO2. Na2Cu2TeO6 crystallizes in the monoclinic space group C2/m with a = 5.7059(6) A, b = 8.6751(9) A, c = 5.9380(6) A, beta = 113.740(2) degrees, V = 269.05(5) A3, and Z = 2, as determined by single-crystal X-ray diffraction. The structure is composed of infinity(2)[Cu2TeO6] layers with the Na atoms located in the octahedral voids between the layers. Na2Cu2TeO6 is a green nonmetallic compound, in agreement with the electronic structure calculation and electrical resistance measurement. The magnetic susceptibility shows Curie-Weiss behavior between 300 and 600 K with an effective moment of 1.85(2) muB/Cu(II) and theta(c) = -87(6) K. A broad maximum at 160 K is interpreted as arising from short-range one-dimensional antiferromagnetic correlations. With the aid of the technique of magnetic dimers, the short-range order was analyzed in terms of an alternating chain model, with the surprising result that the stronger intrachain coupling involves a super-superexchange pathway with a Cu-Cu separation of >5 A. The J2/J1 ratio within the alternating chain refined to 0.10(1), and the spin gap is estimated to be 127 K. 相似文献
5.
One reaction system of Cu2+, dipn, and CN− with two different molar ratio sets of 1:1:5, and 2:1:8 produced two compounds 1 [CuII(dipn)][CuII(CN)4], and 2, respectively (dipn = dipropylenetriamine). Their structures were determined by X-ray crystallography. Compound 2 is built from Cu(I) and Cu(II) centers, which are bridged by cyanide groups and metal-metal bonds. The magnetic properties of 1 and 2 were investigated in 2-300 K. Compound 1 exhibits an antiferromagnetic exchange interaction between copper(II) ions mediated by cyano-bridges. 相似文献
6.
A. S. Sigeev I. P. Beletskaya P. V. Petrovskii A. S. Peregudov 《Russian Journal of Organic Chemistry》2012,48(8):1055-1058
The system Cu(I)/Cu(II)/N,N,N??,N??-tetramethylethylenediamine is a highly efficient and accessible catalyst of Sandmeyer reaction. The reaction of aryldiazonium salts with chlorides, bromides,, cyanides, and thiocyanates of alkaline metals in the presence of this catalytic system leads to the formation of the corresponding aryl halides, nitriles, and thiocyanates in high yields. 相似文献
7.
8.
O. M. Osmolovskaya V. M. Smirnov A. A. Selyutin 《Russian Journal of General Chemistry》2008,78(10):1872-1876
Vanadium(IV) oxide nanolayers on silica surface were prepared for the first time. Samples characterized by different degrees of surface coverage by vanadium(IV)-oxygen groups were studied. Samples containing only vanadium(IV) ions and both vanadium(IV) and vanadium(V) ions were obtained. The size effect on the phase transition parameters was determined by studying magnetic properties of vanadium(IV) oxide nanolayers. The phase transition temperature ranges from 140 to 220 K, depending on surface concentration of vanadium(IV) ions and their environment. 相似文献
9.
In this article, a facile l-cysteine-assisted solvothermal method is described, which is about the large-scale synthesis of Fe0.985S novel nanostructures in a mixed solution composed of ethylenediamine (EN) and distilled water. By varying process parameters, such as the molar ratio of Fe3+-to-l-cysteine (reactants), the volume ratio of water to ethylenediamine, and the reaction temperature, different kinds of architectural structures can be controllably synthesized in large quantities. At the same time, a reasonable mechanism for the growth of iron sulfide structures has been proposed. The as-prepared iron sulfide products were characterized using diverse techniques including X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM, superconducting quantum interface device (SQUID) magnetometer (Quantum Design MPMS XL). 相似文献
10.
11.
E. V. Tret’yakov O. V. Koreneva G. V. Romanenko A. S. Bogomyakov I. Ovcharenko R. Z. Sagdeev 《Journal of Structural Chemistry》2009,50(6):1193-1196
The molecular and crystal structure of Cu(II) bischelate with the deprotonated stable nitroxide radical 4,4,5,5-tetramethyl-2-(2-oxo-1-(4,4,5,5-tetramethylimidazolidine-2-ylidene)ethyl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxylom (HL) are studied. It is revealed that the complex packing is formed of separate CuL2 molecules. Oxygen atoms in >N∸O groups do not participate in Cu2+ ion coordination, and so only weak exchange interactions are observed between paramagnetic centers in CuL2. 相似文献
12.
Radhey S. Srivastava Roy Bertrand IIIAugust A. Gallo Kenneth M. Nicholas 《Tetrahedron letters》2011,52(27):3478-3480
Allylic hydrocarbons are selectively converted to the corresponding allyl amines in good to excellent yield by reaction with aryl hydroxylamines catalyzed by a 1:1 mixture of CuCl and CuCl2 (10 mol %). Under these conditions unsymmetrical olefins react highly regioselectively with N-functionalization at the less substituted vinylic carbon. Trapping experiments indicate that a free nitrosoarene is not an intermediate in these reactions. 相似文献
13.
《Electrochemistry communications》2002,4(8):605-609
The effect of ammonium chloride on the electrodeposition process and resulting magnetic properties of Co(P) alloy films was investigated. It was observed that the magnetic properties of the films varied extensively with the ammonium chloride contents in the solution. Cyclic voltammetry was employed as an electroanalytical technique to characterize the variation of interfacial polarization at different electrolyte compositions. In addition, microstructural characterization of electrodeposited Co(P) thin films by transmission electron microscopy revealed a significant increase in both grain size and preferred orientation of Co(P) grains with ammonium chloride contents. Results of characterizations indicated that the addition of ammonium chloride controlled the kinetics of electrocrystallization of Co(P) by modifying the charge transfer process and thus gave rise to increased grain size and preferred orientation in the Co(P) thin films. These microstructural features provide reasonable explanation on the variation of the magnetic properties of electrodeposited Co(P) films with the amount of ammonium chloride in the solution. 相似文献
14.
《中国化学快报》2020,31(9):2503-2506
An iron (III) cluster, namely [Fe10(μ3–O)8L8(NO3)6] (1), has been synthesized by treatment of Fe(NO3)3·9H2O with 3,5–dimethyl–1–(hydroxymethyl)–pyrazole (HL) under ambient temperature. The core skeleton of {FeIII10} can be regarded as a pear-like cage with eight triangular {FeIII3(μ3–O)} units, in which each three FeIII centers is held together by one μ3–O2− group with FeIII centers as corner-sharing triangle units. Importantly, {FeIII10} cluster is not only stable in solid state but also in solution, which is confirmed by powder X-ray diffraction (PXRD) pattern and electrospray ionization mass spectrometry (ESI-MS), respectively. Furthermore, 1 shows antiferromagnetic exchange behavior arising from the interactions between the iron(III) centers. 相似文献
15.
Biodegradable poly(propylene carbonate)/layered double hydroxide composite films with enhanced gas barrier and mechanical properties 总被引:1,自引:0,他引:1
Relatively well crystallized and high aspect ratio Mg-Al layered double hydroxides(LDHs) were prepared by coprecipitation process in aqueous solution and further rehydrated to an organic modified LDH(OLDH) in the presence of surfactant. The intercalated structure and high aspect ratio of OLDH were verified by X-ray diffraction(XRD) and scanning electron microscopy(SEM). A series of poly(propylene carbonate)(PPC)/OLDH composite films with different contents of OLDH were prepared via a melt-blending method. Their cross section morphologies, gas barrier properties and tensile strength were investigated as a function of OLDH contents. SEM results show that OLDH platelets are well dispersed within the composites and oriented parallel to the composite sheet plane. The gas barrier properties and tensile strength are obviously enhanced upon the incorporation of OLDH. Particularly, PPC/2%OLDH film exhibits the best barrier properties among all the composite films. Compared with pure PPC, the oxygen permeability coefficient(OP) and water vapor permeability coefficient(WVP) is reduced by 54% and 17% respectively with 2% OLDH addition. Furthermore, the tensile strength of PPC/2%OLDH is 83% higher than that of pure PPC with only small lose of elongation at break. Therefore, PPC/OLDH composite films show great potential application in packaging materials due to its biodegradable properties, superior oxygen and moisture barrier characteristics. 相似文献
16.
Dana Kubies Jaroslav Š?udla Rudolf Puffr Antonín Sikora Josef Baldrian Jana Ková?ová Miroslav Šlouf František Rypá?ek 《European Polymer Journal》2006,42(4):888-899
Poly(ε-caprolactone) (PCL) masterbatches with the intercalated and the exfoliated morphology were prepared by ring opening polymerization of ε-caprolactone in the presence of organomodified montmorillonite (MMT) Cloisite 30B. Poly(l-lactide) (PLLA) nanocomposites with Cloisite 30B or PCL masterbatches were prepared by melt blending. The effects of the silicate type, MMT content and the nanocomposite morphology on thermal and mechanical properties of PLLA nanocomposites were examined. The montmorillonite particles in PLLA/Cloisite 30B and PLLA/intercalated masterbatch nanocomposites were intercalated. In contrary to expectations, the exfoliated silicate layers of exfoliated masterbatch were not transferred into the PLLA matrix. Due to a low miscibility of PCL and PLLA, MMT remained in the phase-separated masterbatch domains. The stress-strain characteristics of PLLA nanocomposites, Young modulus E, yield stress σy and yield strain εy, decreased with increasing MMT concentration, which is associated with the increase in PCL content. The expected stiffening effect of MMT was low due to a low aspect ratio of its particles and was obscured by both plastifying effects of PCL and low PLLA crystallinity. Interestingly, in contrast to the neat PLLA, ductility was enhanced in all PLLA/Cloisite 30B materials and in PLLA/masterbatch nanocomposites with low MMT concentrations. 相似文献
17.
Ni0.5−xCuxZn0.5Fe2O4 (0.0≤x≤0.5) ferrite nanofibers with diameters of 80-160 nm have been prepared by electrospinning and subsequent heat treatment. Both the average grain size and lattice parameter are found to increase with the addition of copper. Fourier transform infrared spectra indicate that the portion of Fe3+ ions at the tetrahedral sites move to the octahedral sites as some of the substituted Cu2+ ions get into the tetrahedral sites. Vibrating sample magnetometer measurements show that the coercivity of these ferrite nanofibers decreases with increasing Cu concentration, whereas the specific saturation magnetization initially increases, reaches a maximum value at x=0.2 and then decreases with the Cu content further increase. Notable differences in magnetic properties at room temperature (298 K) and 77 K for the Ni0.3Cu0.2Zn0.5Fe2O4 nanofibers and corresponding powders are observed and mainly arise from the grain size and morphological variations between these two materials. 相似文献
18.
《印度化学会志》2021,98(9):100125
A new Cu(II) coordination framework {[Cu(4-abpt)(μ3-SO42-)(H2O)]·3H2O}∞ (1) based on the Cu–SO42- inorganic layer and the bent dipyridyl ligand was obtained under solvothermal conditions (4-abpt = 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole). The compound displays a three-dimensional (3D) “pillar-layer” framework, which can be simplified into a 3,5-connected gra topology. Furthermore, the magnetic properties of 1 have been investigated. As a result, compound 1 displays a weak antiferromagnetic interaction among the Cu(II) centers. 相似文献
19.
Gómez-Balderas R Raffa DF Rickard GA Brunelle P Rauk A 《The journal of physical chemistry. A》2005,109(24):5498-5508
A systematic study of the binding motifs of Cu(II) and Cu(I) to a methionine model peptide, namely, N-formylmethioninamide 1, has been carried out by quantum chemical computations. Geometries of the coordination modes obtained at the B3LYP/6-31G(d) level of theory are discussed in the context of copper coordination by the peptide backbone and the S atom of a methionine residue in peptides with special emphasis on Met35 of the amyloid-beta peptide (Abeta) of Alzheimer's disease. The relative binding free energies in the gas phase, DeltaG(g), are calculated at the B3LYP/6-311+G(2df,2p)//B3LYP/6-31G(d) level of theory, and the solvation affects are included by means of the COSMO model to obtain the relative binding energies in solution, DeltaG(aq). A free energy of binding, DeltaG(aq) = -19.4 kJ mol(-1), relative to aqueous Cu(II) and the free peptide is found for the most stable Cu(II)/Met complex, 12. The most stable Cu(I)/Met complex, 23, is bound by -15.6 kJ mol(-1) relative to the separated species. The reduction potential relative to the standard hydrogen electrode is estimated to be E degrees (12/23) = 0.41 V. On the basis of these results, the participation of Met35 as a low affinity binding site of Cu(II) in Abeta, and its role in the redox chemistry underlying Alzheimer's disease is discussed. 相似文献
20.
The electrical and magnetic properties of the tetragonal phase SmCuOSe are reported as a function of the temperature. The optical properties were studied by means of diffuse reflectance spectrum in the UV-Vis range. The electrical resistivity measurements as well as diffuse reflectance spectrum show that SmCuOSe is a semiconductor with an optical band gap (Eg) of 2.6 eV. In this phase, Cu is at its monovalent oxidation state and, as such, it does not contribute to the total magnetic moment, whereas Sm is in its 3+ oxidation state, with a large VanVleck contribution due to the admixture of the fundamental state with higher energy levels. 相似文献