• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.456-464
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• 1986

The complex formation of branched poly(ethylene imine) (BPEI) with bivalent transition metal ions, such as Fe(II), Co(II), Ni(II) and Cu(II), have been investigated in terms of visible absorption and pH titration methods in an aqueous solution in 0.1M KCl at 30${\circ}$. The stability constants for M(II)-BPEI complexes was calculated with the modified Bjerrum method. The formation curves of M(II)-BPEI complexes showed that Fe(II), Co(II), Ni(II) and Cu(II) ions formed coordination compounds with four, two, two, and two ethylene imine group, respectively. In the case of Cu(II)-BPEI complex at pH 3.4 ∼ 3.8, ${\lambda}_{max}$ was shifted to the red region with a decrease in the acidity. The overall stability constants (log $K_2$) increased as the following order, Co(II) < Cu(II) < Ni(II) < Fe(II).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.494-503
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• 1997

We investigated the initial stages of formation of the Cu/polyimide interface using another two methods by X-ray photoelectron spectroscopy. : One, in-situ measurement with increasing of Cu deposition thickness onto polyimide(PI), the other, measurement with decreasing of Cu thickness of Cu/pI film by $Ar^+$ ion etching. From these results, we find that the chemical reactions exist in Cu/PI interface. However, the measured chemical reactions were different according to experimental method.

• Analytical Science and Technology
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• v.12 no.1
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• pp.1-6
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• 1999

Copper(II) complex of piperidine dithiocarbamate (Pipdtc) was synthesized from the reaction of Cu(II) and piperidine dithiocarbamate. The possible structure of the complex was proposed on the basis of elemental analysis, molar conductivity, infrared spectroscopy, electronic absorption spectroscopy, and $^{13}C-NMR$ studies. The extraction of copper(II)-Pipdtc complex by carbon tetrachloride can be achieved in the pH range of 6.0~10. The solution of copper(II) with piperidine dithiocarbamate was bey Beer's law in the concentration up to ${\sim}8.0{\times}10^{-5}M$ at pH 9.0.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.796-800
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• 2004

The structure of [Cu(tpen)]$(ClO_4)_2$ (tpen = N,N,N',N'-tetrakis(2-pyridylmethyl)-1,2-ethanediamine) has been identified by X-ray crystallography. The copper(II) ion is surrounded by two amine N atoms and three pyridine N atoms of the ligand, making a distorted trigonal-bipyramid. Among the six potential N donor atoms (two amine N and four pyridine N atoms), only one pyridine N atom remains uncoordinated. We examined structural changes on addition of $Cl^-$ to $[Cu(tpen)]^{2+}$(1). The addition of $Cl^-$ in methanol resulted in the formation of a novel dinuclear copper(II) complex $[Cu_2Cl_2(tpen)](ClO_4)_2{\cdot}H_2O$. The structure of the dinuclear complex was verified by X-ray crystallography. Each copper(II) ion in the dinuclear complex showed a distorted square planar geometry with two pyridine N atoms, one amine N atom and one $Cl^-$ ion.

• Journal of Powder Materials
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• v.16 no.4
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• pp.291-295
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• 2009

The electromagnetic wave absorption sheets were fabricated by mixing of $Fe_{73}Si_{16}B_7Nb_3Cu_1$ nanocrystalline soft magnetic powder, charcoal powder and polymer based binder. The complex permittivity, complex permeability, and scattering parameter have been measured using a network analyzer in the frequency range of 10 MHz$\sim$10 GHz. The results showed that complex permittivity of sheets was largely dependent on the frequency and the amount of charcoal powder : The permittivity was improved up to 100 MHz, however the value was decreased above 1 GHz. The power loss of electromagnetic wave absorption data showed almost the same tendency as the results of complex permittivity. However, the complex permeability was not largely affected by the frequency, and the values were decreased with the addition of charcoal powder. Based on the results, it can be summarized that the addition of charcoal powder was very effective to improve the EM wave absorption in the frequency range of 10 MHz$\sim$1 GHz.

• Korean Journal of Environmental Agriculture
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• v.11 no.3
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• pp.243-252
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• 1992

This research was conducted to investigate the influence of kind and concentration of organic ligands such as humic (HA) or fulvic acid (FA) on the removal of Cu or Pb from the aqueous solution employing the principles in metal-ligand complexation. Increasing HA concentration enhanced the efficiency of Cu or Pb removal, but there existed upper critical concentrations capable of forming maximum HA-metal complex. which ranged 53-289 and 42-315mg/L for Cu and Pb, respectively. At these concentrations. efficiency of removal was 70 to 95 % for Pb, but 13 to 65 % for Cu. Amounts of Cu and Pb which complexed with 100mg HA were estimated to be 7.5 and 34.1mg, respectively. FA-metal complex forming reactions were fitted significantly to the empirical models of Freundlich for Cu and Langmuir for Pb. Fulvic acid precipitated nearly 100% of Pb in solution, but formed precipitates with Cu in only 13 to 29%. Comparing organic ligands. HA had a higher removal efficiency for Cu but FA had such for Pb. Metalligand complex formation was differed from kinds and concentrations of corresponding ligands and metals. Results demonstrated that this principle has a strong potential to be employed for treating heavy metals in aqueous solution.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1781-1786
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• 2007

Two copper(II) complexes, [CuL3](ClO4)2 bearing one N-CH2CH2CONH2 group as well as one N-CH2CH2CN group and [CuL4](ClO4)2 bearing two N-CH2CH2CONH2 groups, have been prepared by the selective hydrolysis of [CuL2](ClO4)2 (L2 = C-meso-1,8-bis(cyanoethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). The complex [CuL5](ClO4)2 bearing one N-CH2CH2C(=NH)OCH3 and one N-CH2CH2CN groups has been prepared as the major product from the reaction of [CuL2](ClO4)2 with methanol in the presence of triethylamine. In acidic aqueous solution, the N-CH2CH2C(=NH)OCH3 group of [CuL5](ClO4)2 undergoes hydrolysis to yield [CuL6](ClO4)2 bearing both N-CH2CH2COOCH3 and N-CH2CH2CN groups. The crystal structure of [CuL5](ClO4)2 shows that the complex has a slightly distorted square-pyramidal coordination polyhedron with an apical Cu-N (N-CH2CH2C(=NH)OCH3 group) bond. The apical Cu-N bond distance (2.269(3) A) is ca. 0.06 A longer than the apical Cu-O (N-CH2CH2CONH2 group) bond of [CuL4](ClO4)2. The pendant amide group of [CuL3](ClO4)2 is involved in coordination. The carboxylic ester group of [CuL6](ClO4)2 is also coordinated to the metal ion in various solvents but is removed from the coordination sphere in the solid state.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.715-720
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• 2014

A Cu(II) complex with an three nitrogens and one sulfur coordination environment was synthesized and characterized. Its redox potential was observed at 0.483 V vs. NHE, very similar to that of a Cu-containing fungal enzyme, galactose oxidase, which catalyzes the oxidation of alcohols to corresponding aldehydes with the concomitant reduction of molecular oxygen to water. The Cu(II) complex selectively oxidizes the benzylic alcohols using TEMPO/$O_2$ under mild reaction conditions to corresponding aldehydes without forming any over-oxidation product. Moreover, the catalyst can be recovered and reused multiple times for further oxidation reactions, thus minimizing the waste generation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.57-60
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• 1999

Geochemical study was carried out to find out soil contamination at the heaped soil, moved from bottom of the storage pond in Pohang industrial complex, in Moondug, Chemical analysis showed that contents of heavy metals in the soil were higher than those of the ordinary soil. Contents of Cu and Cd in the soil exceeded Korean standard of soil contamination. Especially content of Cu exceeded Korean standard of soil contamination(50ppm) at the six points and at one point content of Cu was 113.3ppm. Contents of Be were so higher than U.S RCRA standard(0.2ppm) that they can affect soil environment. The followed research about relation between pollutant and soil and proper measures are required to prevent soil contamination from affecting environment of Moondug.

• Bulletin of the Korean Chemical Society
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• v.7 no.5
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• pp.385-388
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• 1986

The reaction of cupric nitrate trihydrate with S-2-pyridyl thioates in acetonitrile was studied. The major products were the corresponding carboxylic acids and $[Cu(NO_3)(C_5H_4NS)(C_5H_5NS$)] (Complex A). Sometimes $[Cu(NO_3)(C_5H_4NS)(H_2O$)] was also obtained in addition to Complex A. When Complex A was recrystallized in dimethylsulfoxide, $[Cu(NO_3)(C_5H_4NS)(C_5H_5NS)$ {$(CH_3)_2SO$}$_2]{\cdot}2H_2O$ was crystallized. The structures of these copper complexes and the role of cupric nitrate in the hydrolysis of S-2-pyridyl thioates are discussed.