Search results

1

Hydrogen bonding-based 3D supramolecular architecture of [Cu(CHA)2][TCM]·11H2O

100%

Vlassa M., Borodi G., Silvestru C., Vlassa M.

Open Chemistry

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2014

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vol. 12

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issue 1

14-24

EN

Reaction of Na4TCM (1) (H4TCM = tetra[4-(carboxyphenyl)oxamethyl]methane) with [Cu(CHA)](ClO4)2 (2)(CHA = 1,3,6,8,11,14-hexaaz atricyclo[12.2.1.1.8,11] octadecane) in a DMF-water mixture yields [Cu(CHA)]2[TCM] (3). Structural analysis of [Cu(CHA)]2[TCM]·11H2O (3·11H2O) by single crystal X-ray diffraction reveals strong copper-oxygen bonds between two complex cations and the tetraanion leading to a 3D coordination network (zwitterionic structure), consolidated through additional NH...O=C hydrogen bonding within the cation/anion association. The resulting coordination geometry around a copper atom is a distorted square pyramidal with an oxygen atom of the anionic ligand in the apical position. A 3D supramolecular network is developed in the crystal based only on NH...OC hydrogen bonds between the macrocyclic metallic tecton and the carboxylate groups of neighboring 3D coordinated (zwitterionic) moieties. The pseudotetrahedral TCM4− tetraanionic ligand induces a diamondoid architecture formed of large distorted adamantanoid cages. [...]

2

Green, purple, blue - [Cu(N-Methylimidazole)n (OOCCH3)2]m, what is in a colour

100%

Kühl O., Millinghaus S., Palm G.

Open Chemistry

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2011

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vol. 9

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issue 4

706-711

EN

Starting from the paddlewheel complex copper(II)acetate, the green N-methylimidazole adduct of copper(II)acetate is formed and transformed into the monomeric and dimeric N-methylimidazole adducts of copper(II)acetate [Cu(C4H6N2)2(CH3COO)2]n·xH2O (n = 1,2; x = 0, 6). The formation of the blue dimer or the purple monomer depends on the solvent and the presence or absence of water.

3

Optimization of analytical procedures for the simultaneous voltammetric determination of total Hg(II) in presence of Cu(II) in environmental matrices

88%

Melucci D., Montalbani S., Locatelli C.

Open Chemistry

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2012

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vol. 10

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issue 1

267-276

EN

The present work reports the critical comparison about the employment of three different supporting electrolytes (0.1 mol L−1 HClO4, 0.01 mol L−1 EDTA-Na2 + 0.06 mol L−1 NaCl + 2.0 mol L−1 HClO4 and 0.1 mol L−1 KSCN + 0.001 mol L−1 HClO4) and their instrumental and chemical optimisation for the simultaneous voltammetric determination of total mercury(II) and copper(II) in sediments and sea water at gold electrode, especially discussing the reciprocal interference problems. The differential pulse anodic stripping voltammetric (DPASV) measurements were carried out using a conventional three-electrode cell: a gold electrode (GE) as working electrode, a platinum wire and an Ag‖AgCl‖KClsat as auxiliary and reference electrodes, respectively. The analytical procedure was verified by the analysis of standard reference materials: Estuarine Sediment BCR-CRM 277, River Sediment BCR-CRM 320 and Mercury in Water NIST-SRM 1641d. Once set up on the standard reference materials, the analytical procedure was transferred and applied to sediments and sea waters sampled in a lagoon ecosystem connected with Adriatic Sea (Ravenna area, Italy).

4

Removal of cadmium and copper ions by Trichosporon cutaneum R57 cells immobilized onto polyvinyl alcohol/tetraethoxysilane hybrid matrices

88%

Bryaskova R., Georgieva N., Peshev D.

Open Chemistry

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2010

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vol. 8

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issue 5

1053-1058

EN

Polyvinyl alcohol (PVA) and tetraethoxysilane (TEOS) hybrid materials were prepared by sol-gel methods and tested as matrices for immobilization of Trichosporon cutaneum R57, capable of removing cadmium and copper ions from aqueous solutions. A kinetic model was applied and the effects of matrix TEOS content on the copper and cadmium uptake equilibria and rate constants were investigated. [...]

5

Concentrations of retinol, α-tocopherol, copper, zinc and iron in plasma of young subjects differing in their engagement in motor activities

88%

Malara M., Hübner-Woźniak E., Kurczyńska A.

Biomedical Human Kinetics

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2012

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vol. 4

1-5

EN

Study aim: To assess possible effects of gender and of the level of motor activity on the deficiencies of selected vitamins and minerals in young subjects.Material and methods: Four groups of physical education (PE) students (n = 15 each) were studied: sedentary men (SM) and women (SF), and physically active men (AM) and women (AF) engaged in endurance sports, all aged 18 - 24 years, were studied. Somatic measurements included body height and mass, and body fat content (by Durnin's method, from 4 skinfolds), the biochemical ones included concentrations of retinol, α-tocopherol, copper, zinc and iron in plasma.Results: Men had significantly higher retinol (p<0.05) and iron (p<0.01) levels than women. The AM and SF groups had significantly (p<0.05 - 0.01) higher plasma levels of copper and zinc than Group SM. Group AF had lower zinc levels than Groups AM and SF, that latter group having lower α-tocopherol compared with Group SM.Conclusions: Inasmuch the observed differences could be due to the respective intakes, the effect of motor activity and the associated increased elimination of minerals could not be ruled out.

6

Reaction of metals with benzenediazonium tetrafluoroborate in aprotic solvents

88%

Koval’chuk E., Reshetnyak O., Pereviznyk O., Marchuk I., Smetanets’kyj V., Błażejowski J.

Open Chemistry

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2010

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vol. 8

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issue 3

652-661

EN

The reaction of metals and glassy carbon with benzenediazonium tetrafluoroborate (BDFB) in aprotic solvents has been studied. During contact of Pt, Au, Ag, Pd, or V with glassy carbon in concentrated diazonium salt solution no change of color was observed. For Al, Ca, Cr, Cu, Fe, Ga, In, Mg, Li, Na, or Zn the process was accompanied by a rapid solution color change, rapid N2 release and the loss of metal sample mass. The copper metal ionization-dissolution was studied by ultraviolet and visible absorption spectroscopy, along with gravimetric and volumetric measurements. A dissolution mechanism was proposed based on kinetic, infrared, and X-ray diffraction data. The 432 nm absorption band appearing after Cu-BDFB reaction indicates formation of the mixed complex [Cu(N2C6H5·(N≡C-CH3)3]+ where the copper atom is covalently bonded to the azophenyl radical and coordinated to acetonitrile (ACN). This complex is thermodynamically unstable and decomposes slowly to a colorless crystalline and a black amorphous phase. The crystalline phase was identified as [Cu(NC-CH3)4]BF4. The amorphous phase is a mixture of products formed by azophenyl and phenyl radical condensation. [...]

7

Effect of Copper on the Crystallization Process, Microstructure and Selected Properties of CGI

88%

Gumienny G., Kacprzyk B., Gawroński J.

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8

Adsorption Capacity of Maize Biomass Parts in the Remediation of Cu2+ Ion Polluted Water

88%

Duru C. E., Duru I. A.

World News of Natural Sciences

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2017

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vol. 12

51-62

EN

We investigated the efficiency of maize biomass parts - seed chaff, stalk, cob and husk, in the remediation of Cu2+ ion polluted water in modeled solutions. The adsorption capacity of these parts followed the order of husk > stalk > cob > seed chaff, with values of 9.65 mg/g, 4.83 mg/g, 3.70 mg/g and 2.48 mg/g, respectively. Maximum adsorption capacity of each part was reached in 45 min. Herein, the husk giving the best removal efficiency of 80.80%. Characterization of the maize husk using PIXE showed that potassium is the main cation on this biomass, with concentration 5.602 g/kg. FTIR scans of the husk before and after adsorption of Cu2+ ions gave shifts in adsorption bands on -OH carrying molecules, indicating that complexation is a mechanism in the metal ion removal process. The multi porous structure of the husk, and uniform surface coverage by ions observed from SEM images before and after adsorption, shed more light on the high adsorption efficiency shown by this natural waste material.

9

Electrochemical Corrosion Evaluation of Copper-Alloyed Ductile Cast Irons

75%

Brito P., Pereira W., Santos W., Gomes H., Brito P., Pereira W., Santos W., Gomes H.

Archives of Foundry Engineering

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2020

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vol. 20

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issue 2

10

Study of Mechanical Properties and PrecipitationReactions in Low Copper Containing Al-Mg-Si Alloy

75%

Belghit H., Farh H., Ziar T., Zidani M., Guemini M.

Archives of Metallurgy and Materials

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2018

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vol. 63

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issue 4

11

Bending Strength and Fracture Investigations of Cu Based Composite Materials Strengthened with δ-Alumina Fibres

75%

Naplocha K., Kaczmar J. W., Granat K., Kurzawa A., Grodzka E., Samociuk B.

Archives of Foundry Engineering

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2013

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issue 2

12

Research on Technology of Alloyed Copper Casting

75%

Rzadkosz S., Piękoś M., Garbacz-Klempka A., Kozana J., Kranc M., Cieślak W.

Archives of Foundry Engineering

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2014

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issue 2

13

Physical Properties of Copper Based MMC Strengthened with Alumina

75%

Kaczmar J. W., Granat K., Kurzawa A., Grodzka E.

Archives of Foundry Engineering

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2014

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issue 2

14

Metallurgical Slags as Traces of a 15th century Copper Smelter

63%

Kozana J., Piękoś M., Garbacz-Klempka A., Kwak Z., Wardas-Lasoń M.

Archives of Foundry Engineering

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2017

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vol. 17

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issue 2

15

Characterization of Ca50Mg20Zn12Cu18 Alloy

63%

Hrapkowicz B., Lesz S. T.

Archives of Foundry Engineering

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2019

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vol. 19

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issue 1

16

Mechanism of Cu transport along clean Si surfaces

51%

Dolbak A., Zhachuk R., Olshanetsky B.

Open Physics

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2003

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vol. 1

|

issue 3

463-473

EN

Cu diffusion along clean Si(111), (110) and (100) surfaces are investigated by Auger electron spectroscopy and low energy electron diffraction. The effective diffusion coefficients of copper are measured in the temperature range from 500 to 650°C. It is shown that the Cu transport along silicon surface occurs by the diffusion of Cu atoms through Si bulk and the segregation of Cu atoms to the surface during the diffusion process. It is found that the segregation coefficients of Cu to silicon surface during the diffusion process depend on surface orientation.

Refine search results

Hydrogen bonding-based 3D supramolecular architecture of [Cu(CHA)2][TCM]·11H2O

Green, purple, blue - [Cu(N-Methylimidazole)n (OOCCH3)2]m, what is in a colour

Optimization of analytical procedures for the simultaneous voltammetric determination of total Hg(II) in presence of Cu(II) in environmental matrices

Removal of cadmium and copper ions by Trichosporon cutaneum R57 cells immobilized onto polyvinyl alcohol/tetraethoxysilane hybrid matrices

Concentrations of retinol, α-tocopherol, copper, zinc and iron in plasma of young subjects differing in their engagement in motor activities

Reaction of metals with benzenediazonium tetrafluoroborate in aprotic solvents

Effect of Copper on the Crystallization Process, Microstructure and Selected Properties of CGI

Adsorption Capacity of Maize Biomass Parts in the Remediation of Cu2+ Ion Polluted Water

Electrochemical Corrosion Evaluation of Copper-Alloyed Ductile Cast Irons

Study of Mechanical Properties and PrecipitationReactions in Low Copper Containing Al-Mg-Si Alloy

Bending Strength and Fracture Investigations of Cu Based Composite Materials Strengthened with δ-Alumina Fibres

Research on Technology of Alloyed Copper Casting

Physical Properties of Copper Based MMC Strengthened with Alumina

Metallurgical Slags as Traces of a 15th century Copper Smelter

Characterization of Ca50Mg20Zn12Cu18 Alloy

Mechanism of Cu transport along clean Si surfaces