Kinds Of Copper Research Articles

New insight into two penta-coordinated multinuclear copper(II) single-armed salamo-based complexes

With the reactions of a single-armed salamo-based ligand H3L and two kinds of copper(II) salts (Cu(OAc)2·H2O or CuCl2·2H2O) in mixed organic solvents, respectively, two penta-coordinated Cu(II) complexes [Cu2(L)(µ-OAc)]·MeOH (1) and [Cu4(L)2Cl2]·EtOH·CH2Cl2 (2) have been successfully constructed. The precise structures of the two Cu(II) complexes obtained by solvent evaporation method are measured by single crystal X-ray diffraction analyses. The di-nuclear complex 1 crystallizes in triclinic space group P-1, where the main structure is compose of two Cu(II) atoms, one completely deprotonated ligand (L)3− unit, one bridged μ-OAc− counter-anion and one crystallized methanol molecule. The tetra-nuclear complex 2 with an inversion center crystallizes in the same space group as 1 and contains four Cu(II) atoms, two fully deprotonated salamo-based ligand (L)3− units, two bridged Cl− counter-anions, one crystallized dichloromethane and one ethanol molecules. Compared to preceding complexes based on other single-armed salamo-based ligands, the structure of complex 2 reported in this work is unique and has never been found in previous literatures. All of Cu(II) atoms in complexes 1 and 2 are penta-coordinated with the geometries of distorted tetragonal pyramid, and the τ5 value of all Cu(II) atoms have been calculated and all results are less than 0.5. Hirshfeld surfaces analyses of complexes 1 and 2 have been established to explain the interactions of crystal structures, and the corresponding two-dimensional (2D) fingerprint plots have been carried out to quantify the intermolecular interactions. In addition, fluorescence properties of complexes 1 and 2 have been investigated.

Combustion Products of Calcium Carbide Reused by Cu-Based Catalysts for Acetylene Carbonylation.

Sustainable development is a worldwide concern. This work mainly focuses on the reuse of the combustion products of calcium carbide and the influence of different kinds of copper on the acetylene carbonylation reaction. A series of catalysts were prepared by heating the precursors under various atmospheres (air, hydrogen, and nitrogen). The X-ray diffraction and the X-ray photoelectron spectroscopy have been analyzed regarding copper species composition and content in catalysts. The result of the Cu+-promoted reaction was in good agreement with the conducted density functional theory analysis, and we speculate that Cu+ promotes the transfer of electrons in the reaction. Transmission electron microscopy and elemental mapping evaluation confirmed the difference in Cu dispersion. Characterization of catalysts using temperature programmed desorption and pyridine Fourier-transform infrared revealed differences in their acidity. Acidity was found to be favorable for acetylene carbonylation. Selectivity and yield of the CuAlZn-LDO(N) catalyst at 225 °C were 73 and 70%, respectively, and the catalyst showed good stability over two consecutive cycles of reuse.

Insight into the Improvement Mechanism of Copper Oxide/BiVO4 Heterojunction Photoanodes for Solar Water Oxidation

N-type BiVO4 films coupled with p-type copper oxide nanoparticles were investigated as photoanodes for water oxidation. Compared with the BiVO4 film, the Cu2O/BiVO4, CuO/BiVO4 and CuxO/BiVO4 films all showed significantly improved photoelectrochemical water oxidation activity and stability. As expected, the radiative recombination of charge on the three kinds of copper oxide/BiVO4 films was decreased due to the p-n junction effect between copper oxide and BiVO4. However, our investigations indicated that the electrocatalytic water oxidation on the copper oxide could be initiated when the copper oxide/BiVO4 photoanodes were irradiated by solar light; therefore, the copper oxide-coupling resulted in a more obvious improvement in the water oxidation kinetics of BiVO4 than the thermodynamic improvement in the charge separation of BiVO4. Of the three kinds of copper oxide/BiVO4 films, the CuxO/BiVO4 film comprising BiVO4 film coupled with a combination of Cu2O/CuO nanoparticles showed the best solar water oxidation performance due to the better electrocatalytic activity for water oxidation of CuxO compared with Cu2O or CuO alone. The kinetic investigations and analyses in the present work provide comprehensive insight into the mechanism of the copper oxide/BiVO4 photoanodes for solar water oxidation.

Core/shell nanocomposite for biomedicine and environmental safety

The two different routes for creation Cu(II) modified zirconia were seen. FTIR and ESR spectroscopy were investigated the influence of synthesis route on features of formation of such structure. It is shown that for both cases the interaction between copper (II) and Zr-OH and Zr=O is occurred and these centres have paramagnetic nature. When the Cu-contained polymer is used for shell formation, only one kind of paramagnetic centres of copper (II) is formed, but when the Cu-contained inorganic complex is used for shell formation two kinds of copper (II) paramagnetic centres are formed.

Synthesis, Crystal Structure, and Properties of Copper(II) Complexes with 1,4,7-Tris(2-Aminoethyl)-1,4,7-Triazacyclononane

Three kinds of copper(II) complexes with 1,4,7-tris(2-aminoethyl)-1,4,7-triazacyclononane (taetacn), [Cu(taetacn)](ClO4)2 (1), [Cu(Htaetacn)](ClO4)3 (2), and [Cu(Htaetacn)](BF4)3 (3) were synthesized and characterized by elemental analyses, IR and UV-Vis spectroscopies. The spectral features are in harmony with an octahedral geometry for 1 and a square-pyramidal coordination for 2 and 3. The crystal structure of 2 was determined by the single-crystal X-ray diffraction method at 293 K. It crystallizes in the orthorhombic space group Pnma with a = 20.605(3) A, b = 12.7944(18) A, c = 9.8972(14) A, V = 2609.2(6) A3, Dx = 1.582 g/cm 3, and Z = 4. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0723 and 0.2389, respectively, for all 3253 independent refl ections. The compound consists of squarepyramidal copper(II) cation with protonated Htaetacn and tetrahedral ClO4 – anions. The temperature dependence of magnetic susceptibilities obeyed the Curie-Weiss law with Ɵ = –2.4, –5.2 and –7.2 K for 1, 2, and 3, respectively. Cyclic voltammetry of 2 in DMF showed two quasi-reversible reduction waves (Epc = –0.98, Epc = –0.92; Epc = –1.30, Epc = –1.22 V versus Fc/Fc +).

Synthesis of UiO-66-NH2 derived heterogeneous copper (II) catalyst and study of its application in the selective aerobic oxidation of alcohols

The three-dimensional Zr-based metal-organic framework UiO-66-NH2 was functionalized with salicylaldehyde using a post-synthetic modification (PSM) strategy, and then three kinds of copper (II) salts were successfully immobilized onto the surface of the amino-functionalized Zr-MOF. The SEM and PXRD results showed that the morphology and structure of Zr-MOF were retained after multiple transformations. The obtained UiO-66-Sal-CuCl2 catalyst exhibited excellent activity for the selective aerobic oxidation of primary aromatic alcohols using molecular oxygen as the oxygen source. Furthermore, the UiO-66-Sal-CuCl2 catalyst showed a good cycle performance.

Synthesis and characterization of bis(azine) ligands and metal complexes: DNA-interaction and extraction properties for metals and dichromate anions

Two new bis(bidentate) azine ligands were prepared by linking (1Z,1'Z)-1,1'-{butane-1,4-diylbis[oxyben-zene-4,1- diyl(1Z)eth-1-yl-1-ylidene]}dihydrazine to salicylaldehyde and pyridine-2-carbaldehyde, 1,4-bis{4-{(1E)-1-((2E)-(2- hydroxybenzene--2-ylmethy-lidene)hydrazonylidene)ethyl}phenoxy}butane (H_2L^1), and 1,4-bis{4-{(1E)-1-((2E)-(pyridine--2-ylmethylidene) hydrazonylidene)ethyl}phenoxy}butane (L^2), respecti- vely. Two kinds of copper(II) and nickel(II) complexes with different ligands were prepared. Reaction of H_2L^1 with Cu(II) and Ni(II) acetate with 1:1 molar ratio gave double stranded binuclear bis(azine) complexes with stoichiometry [M(L^1)]_2 containing {M^{II}N_2O_2} centers. On the other hand, 1:1 molar ratio reaction of Cu(II) and Ni(II) chloride with L^2 yielded mononuclear metal complexes with general stoichiometry [M(L^2)Cl_2] containing {M^{II}N_2N_2} centers. The structures of both bis(azine) ligands and complexes were identified by elemental analysis, infrared spectra, UV--Vis electronic absorption spectra, magnetic susceptibility measurements, and TGA. DNA binding and DNA cleavage activities of the mononuclear complexes of L^2, [M(L^2)Cl_2] were examined by using UV-Vis titration and agarose gel electrophoresis, respectively. The results indicate that mononuclear complexes, especially [Cu(L_2)Cl_2], bind significantly calf thymus DNA and cleaves pBR322 DNA. Furthermore, the complexing properties of the bis-azine ligands toward selected transition metal cations and dichromate anions were also reported. It was found that bis(azine) ligands have high extraction ability towards dichromate anions.

ASYMMETRIC BIS(BIDENTATE) AZINE LIGAND AND TRANSITION METAL COMPLEXES: SYNTHESIS, CHARACTERIZATION, DNA-BINDING AND CLEAVAGE STUDIES AND EXTRACTION PROPERTIES FOR SELECTED METALS AND DICHROMATE ANIONS

New bis(bidentate) azine NNN’N’ donor ligand was prepared by linking (1Z,1’Z)-1,1’-{propane-1,3-diylbis[oxybenzene-4,1-diyl(1Z)eth-1-yl-1-ylidene]} dihydra-zine to pyridine-2-carbaldehyde. Two kinds of copper(II) and nickel(II) complexes with different stoichiometries were prepared. Reaction of bis(azine) ligand with Cu(II) and Ni(II) chloride with 1:1 molar ratio gave azine complexes with stoichiometry [M(L)Cl 2 ] while 2:1 molar ratio reaction of Cu(II) and Ni(II) chloride with bis(azine) composed binuclear copper complexes with general stoichiometry [M 2 (L)Cl 4 ]. The structures of both bis-azine ligand and its complexes were identified by elemental analysis, infrared spectra, UV–Vis electronic absorption spectra and magnetic susceptibility measurements, TGA and powder XRD. DNA binding and DNA cleavage activities of the synthesized metal complexes were examined by using UV-vis titration and agarose gel electrophoresis, respectively. The results indicate that all the complexes bind significantly calf thymus DNA and cleavage pBR322 DNA. Furthermore, the complexing properties of the bis-azine ligand toward selected transition metal cations and dichromate anions were also reported.

Research on the Antifouling Mechanisms of Copper and its Alloys

In this paper, the in-situ exposure tests of 15 kinds of copper and its alloys were carried out in seawater at Zhanjiang Harbor for 12 months in order to study their anti-fouling abilities and anti-corrosion properties. In the same way, the in-situ anti-fouling tests of copper and bronze were performed in Qingdao for 8 years. Successively, the anti-fouling properties were analyzed combining with the electrochemical process of copper alloy corrosion and biology process of the adhesion. The chemical, physical and biological factors influencing the fouling properties of copper alloys were also investigated. The results showed that the coppers can equip themselves with antifouling performance by producing some toxic substances during the processes of chemical and electrochemical reaction. In addition, the antifouling ability was proved to relate to the exfoliation effect, which was the result of interaction between stain layer adhesion and spalling force of the attachments.

Valence State of Active Copper in CuO x/CeO 2 Catalysts for CO Oxidation

CuO x /CeO 2 catalysts were prepared by adsorption-impregnation method. CO conversion was tested over the catalysts pretreated under different conditions for preferential CO oxidation in H 2, and the catalysts were characterized with X-ray photoelectron spectroscopy and temperature programmed reduction. Experimental results show that there are two kinds of copper, which are Cu + and Cu 2+ in calcined CuO x /CeO 2. Among them, the Cu + is the key active component for CO oxidation. The main reason is as follows: CO is activated by copper for CO oxidation over CuO x /CeO 2, while CO can not be activated by Cu 2+. Only when Cu 2+ is reduced to Cu + or Cu°, the copper may be active for CO oxidation, moreover, the experimental results show that the reduction of Cu 2+ does not lead to an increase of catalytic activity. So the active species is Cu + in CuO x /CeO 2 catalysts.

Amination and amidation of aryl iodides catalyzed by copper(I)–phenanthroline complexes

Four kinds of copper(I)–phenanthroline complexes ([Cu I(phen) 2]Cl, [Cu I(phen)Cl] 2, [Cu I(phen) 2]BF 4, and Cu I(phen)PPh 3Cl) were prepared and used as catalysts for amination and amidation of aryl iodide to investigate the influence on the yields of products due to differences of the structures. These complexes were found to work as catalysts on these reactions and showed that the differences of structures of copper(I) complexes significantly influenced the yield of aryl-nitrogen bond forming processes.

Mono, di and polynuclear Cu(II)–azido complexes incorporating N, N, N reduced schiff base: syntheses, structure and magnetic behavior

Three kinds of copper(II) azide complexes have been synthesised in excellent yields by reacting Cu(ClO 4) 2 · 6H 2O with N, N-bis(2-pyridylmethyl)amine (L 1); N-(2-pyridylmethyl)- N′, N′-dimethylethylenediamine (L 2); and N-(2-pyridylmethyl)- N′, N′-diethylethylenediamine (L 3), respectively, in the presence of slight excess of sodium azide. They are the monomeric Cu(L 1)(N 3)(ClO 4) ( 1), the end-to-end diazido-bridged Cu 2(L 2) 2(μ-1,3-N 3) 2(ClO 4) 2 ( 2) and the single azido-bridged (μ-1,3-) 1D chain [Cu(L 3)(μ-1,3-N 3)] n (ClO 4) n ( 3). The crystal and molecular structures of these complexes have been solved. The variable temperature magnetic moments of type 2 and type 3 complexes were studied. Temperature dependent susceptibility for 2 was fitted using the Bleaney–Bowers expression which led to the parameters J = −3.43 cm −1 and R = 1 × 10 −5. The magnetic data for 3 were fitted to Baker’s expression for S = 1/2 and the parameters obtained were J = 1.6 cm −1 and R = 3.2 × 10 −4. Crystal data are as follows. Cu(L 1)(N 3)(ClO 4): Chemical formula, C 12H 13ClN 6O 4Cu; crystal system, monoclinic; space group, P2 1/ c; a = 8.788(12), b = 13.045(15), c = 14.213(15) Å; β = 102.960(10)°; Z = 4. Cu(L 2)(μ-N 3)(ClO 4): Chemical formula, C 10H 17ClN 6O 4Cu: crystal system, monoclinic; space group, P2 1/ c; a = 10.790(12), b = 8.568(9), c = 16.651(17) Å; β = 102.360(10)°; Z = 4. [Cu(L 3)(μ-N 3)](ClO 4): Chemical formula, C 12H 21ClN 6O 4Cu; crystal system, monoclinic; space group, P2 1/ c; a = 12.331(14), b = 7.804(9), c = 18.64(2) Å; β = 103.405(10)°; Z = 4.

Evaluation of the copper(II) complexing ability of ultrafiltered humic acid by the solvent extraction method.

A commercial humic acid dissolved in water was fractionated to nine samples by means of ultrafiltration (UF); the nominal molecular weight used for UF membranes was 1 k-200 kDa. Concerning the nine samples, copper(II) complexing capacities (CuCC) and conditional stability constants (beta) of the formed copper(II) complexes were measured by a solvent extraction method. A total organic carbon (TOC) and the UV-VIS absorption ratio (E350 nm/E450 nm) were also measured. From a comparison of these data, it was found that a) humic acids in each fraction formed two kinds of copper(II) complexes with different stability; b) the beta values obtained from each fraction were almost the same; c) large CuCC values were observed in the molecular weight range from 10 kDa to 20 kDa and below 1 kDa; d) molecules with molecular weight higher than 50 kDa scarcely had any copper(II) complexing ability; e) the values of CuCC/TOC of each fraction were in the range from 1.7 to 3.4 x 10(-7) mol mg(-1).

Synthesis, Structure and Characterization of Two‐dimensional Network Copper Complex [Cu3(nta)2(azpy)2(H2O)2]·6H2O

AbstractThe copper(II) complex[Cu3(nta)2(azpy)2(H2O)2]·6H2O (nta = nitrilotriacetate, azpy = 4,4′‐azobispyridine) has been synthesized and characterized. The X‐ray analysis reveals that there are two kinds of copper(II) coordination environments. Cu(1) has a distorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1) is linked to Cu(2) through nta and bound to Cu(1C) by azpy, and Cu(2) is linked to Cu(2A) through azpy, which extends to two‐dimensional network with large rhombus 1.2 nm × 1.7 nm.

銅導入型および亜鉛導入型合成ハイドロタルサイトによるリン除去

We have been developing multifunctional water purifying materials using change composition hydrotalcites. Copper containing and zinc containing hydrotalcites have been synthesized for the propose of disinfection wastewater and phosphorous removal at the same time. Four kinds of copper containing hydrotalcites (Cu-HT, 1-4) and zinc containing hydrotalcites (Zn-HT, 1-4) were synthesized by a coprecipation method. Removal characteristics of phosphate ions in solution for the Cu-HT and Zn-HT have been investigated from the various standpoints.Apparent adsorption capacities of phosphate ions for the Cu-HT(1-4) and Zn-HT(1-4) were 20.9-31.9mg-P·g-1 and 14.4-21.8mg-P·g-1, respectively, near neutral pH values. Various anion selectivities for Cu-HT(4) and Zn-HT(1) were in the order of CO32->SO42->PO43->NO2->Cl->NO3-.Taking the results obtained into account, Cu-HT (4) had high and stable phosphate ion adsorption capacities with wide range of phosphorous concentrations and pH lead to the conclusion that Cu-HT (4) has the feasibility as a removal agent for phosphate ions in wastewater. Moreover, Cu-HT (4) had disinfection potency which completely sterilized 106cells·ml-1 of E.coli with the contact time at 60min previous experiment, thus, Cu-HT (4) had been expected as a multifunctional wastewater purifying materials with both phosphorous removal potency and disinfection potency.

Measurements of linear thermal expansion coefficients of copper SRM 736 and some commercially available coppers in the temperature range 20–300 K by means of an absolute interferometric dilatometer

The thermal expansivities of several grades of copper were measured in the temperature range 20–300 K by means of an absolute laser interferometric dilatometer. The present results for copper standard reference material (NIST; SRM 736) and three commercially available kinds of copper, such as a high-purity copper (99.999% purity), an oxygen-free high-conductivity copper and a tough-pitch copper, show good agreement with the NIST certified values and the CODATA recommended values within 0.09 × 10 −6K −1 over the whole temperature range.

Studies of bonding and valence states in YBa2Cu3O7−x through secondary-ion-mass spectrometry

The superconducting compound YBa2Cu3O7−x (YBCO) and oxides of copper (CuO and mixture of CuO and Cu2O) have been examined by secondary-ion-mass spectrometry (SIMS). The results support the fact that two kinds of copper (from the consideration of bonding and valence state) exist in YBCO—one in the basal planes of charge reservoir layers and the other in the conduction layers. The bonding of Cu-O in the CuO2 conduction layer unit is similar to that in CuO. No Cu+++ secondary ions could be detected in the SIMS spectrum, in agreement with electron spectroscopy for chemical analysis, extended x-ray-absorption fine structure, and electron probe microanalysis measurements reported earlier. A plausible explanation has been given for this.

Thermal decompositions of formates. Part VI. Thermal dehydration reaction of copper(II) formate dihydrate

The thermal dehydration reactions of two kinds of copper(II) formate dihydrate, which differ in origin and preparation history, have been investigated by means of TG, DTA and DSC. The kinetics of isothermal dehydration were studied by weight loss, and the difference in kinetic behavior between these two samples was related to the difference in origin and preparation history. On the whole, the dehydration mechanisms of these two samples were found to be phase boundary controlled contracting interface reactions.

Meso-Tetra[5-(8-hydroxyquinolyl)]porphine. A novel porphyrin with metal-chelating groups in the peripheral region.

meso-Tetra[5-(8-hydroxyquinolyl)]porphine was synthesized by the Rothemund method as a model of porphyrin with metal chelating groups in the peripheral region. The presence of three kinds of copper (II) complexes was demonstrated ; free base porphyrin with metal chelated 8-quinolinol groups and metalloporphyrin with metal chelated and unchelated 8-quinolinol groups. In dimethylformamide solution, reaction of the compound with excess copper (II) perchlorate occurred in two steps ; rapid metal chelation of the 8-quinolinol moiety and subsequent slow Cu (II) incorporation into the porphine moiety. Reaction with excess aluminum (III) nitrate under similar conditions gave free base porphyrin with Al (III) chelated 8-quinolinol groups.

Achromobacter cycloclastes Nitrite Reductase The Function of Copper, Amino Acid Composition, and ESR Spectra1

1. Dialysis against cyanide at pH 7 of Achromobacter cycloclastes nitrite reductase [EC 1.7.99.3] of a dissimilatory type led to the removal of about 50% of the copper from the enzyme molecule, with a concomitant decrease of the enzymatic activities. It was inferred that enzyme-bound copper atoms play an essential role in the catalytic activities of the enzyme. 2. The amino acid composition of the enzyme was determined after acid hydrolysis. 3. ESR spectra of the frozen solution and lyophilized powder of the nitrite reductase predominantly showed the presence of two kinds of copper: Type 1 Cu2+, which had narrow and sharp hyperfine splitting, and Type 2 Cu2+, which had broader hyperfine splitting. The bond between the oxidized enzyme and nitrite seems to be ionic.