• Journal of the Korean Chemical Society
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• v.39 no.2
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• pp.111-113
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• 1995

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.171-177
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• 1993

In decontamination process to remove radioactive materials of reactor cooling system, the metal ions dissolved by organic acids in decontamination solution are separated by use of ion exchange resin in the column. However, organic acids in decontamination solution decrease the apparent affinity of the resin to metal ions. In light of this, some experiments were carried out on the Amberlite IRN-77 cation resin with cobalt and iron to gain a better understanding of the complexation effects on the ion exchange process. Experimental results showed that EDTA among organic acids used as chemical decontaminants predominantly caused reduction of ion exchange capacity of cobaltous ion to resin since this reagent formed the complex with the cobaltous ion stronger than that with the ferrous ion. In contrast, the effects of oxalic acid and citric acid were found to be negligible. And, single and two-component nonlinear equilibrium relationships of the metal ions were established using experimental data.

• Journal of Applied Biological Chemistry
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• v.53 no.2
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• pp.108-111
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• 2010

New salens (3) and their Cobalt complexes (4) were prepared from meso-1,2-bis(ortho-hydroxyphenyl)-1,2-diaminoethane (1) and substituted salicylic aldehydes (2). In contrast to symmetric structure of salen ligand (3), salen-Co(III) complexes (4) showed dissymmetric molecular structure due to participation of three hydroxyl groups in complex formation. One of the salens (3b) revealed decrease in Cyclin D1 expression, which represents anti-cancer property.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.1047-1052
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• 1993

The electronic spectra of enzyme-model organocobalt(Ⅲ) complexes containing completely or partially conjugated macrocyclic ligands were measured in various solvents to investigate the solvent effect on the charge transfer band for the axial cobalt-carbon bond by the extent of conjugation in the equatorial macrocyclic ring; completely conjugated, $CH_3CoL,\;C_6H_5CoL,\;CNCoL,\;CH_3CoL',\;CNCoL'$, partially conjugated $CH_3(py)Co(DH)_2, CH_3CoL＂$, unconjugated dienes, $[CH_3Co(1,4-CT)](ClO_4)_2$, and open ring, $CH_3Co(salen)$. The position of the charge transfer band which corresponds to the cobalt-carbon bond was shifted to a shorter wavelength as the polarity of solvent increased and the transition energy $(E_T)$ had a linear relationship with solvent polarity parameter, Z-value, only in the case of completely conjugated system. However, the linear correlation between $E_T$and Z was not observed for partially conjugated and open ring systems.

• Journal of the Korean Chemical Society
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• v.47 no.4
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• pp.334-338
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• 2003

The crystal structure of $[Co(phen)_2(Cl)(H_2O)] Clㆍ2H_2O$(phen=1,10-phenanthroline) has been determined by X-ray crystallography. It crystallizes in the triclinic system, space group P1, with lattice parameters a=9.662(2), b=11.445(1), c=13.037(2)${\AA}$ ${\alpha}$=64.02(1), ${\beta}$=86.364(9), ${\gamma}=78.58(2)^°$, and Z=2. The coordinated cations contain a six-coordinated cobalt atom chelated by two phen ligands and one chloride anion and one water ligand in cis arrangement. In addition to the chloride coordinated to the cobalt, there are one chloride ion and four water molecules which complete the crystal structure. In the solid state, the title compound forms three dimensional network structure through hydrogen bonds, within which exists the strongest hydrogen bond (O(3)-O(4)=2.33${\AA}$). The intermolecular hydrogen bonds connect the $[Co(phen)_2(Cl)(H_2O)]1+,\;H_2O$ moieties and chloride ion.

• Elastomers and Composites
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• v.49 no.1
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• pp.59-65
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• 2014

In this study, in order to complete curing reaction of the molding compound comprising an epoxy/anhydride at $71^{\circ}C$ for 40 hours, metal coordination complexes such as cobalt (II) acetylacetonate, potassium acetylacetonate, iron (III) acetylacetonate and chromium (III) octoate as a catalyst were applied to the epoxy/anhydride compounds respectively. The weight ratio of an epoxy part/an anhydride part was adjusted to improve the mechanical properties of the molding compound. According to the experimental results, an epoxy/anhydride compound containing chromium (III) octoate showed a high conversion at $71^{\circ}C$ for 40 hours as well as a proper processability at room temperature among the several metal coordination complexes. For the mechanical properties of the cured epoxy/anhydride compound, the compounds containing weight ratio from 0.9/1 to 0.5/1 of the epoxy part/anhydride part with chromium (III) octoate showed the high flexural strength, and higher compressive strength was shown with increasing of the hardener part.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.30-50
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• 2017

Currently, exhaust gas emitted from thermal power plants and various combustion facilities that consume large amounts of fossil fuels such as coal, oil, and natural gas contains high concentrations of $CO_2$ and is a major cause of global warming. Conventionally, as a countermeasure against this problem, research and development are being carried out from various fields, and it is considered to be one of the most promising methods for separating and recovering $CO_2$ in the exhaust gas. One of the reasons for the low use of carbon dioxide is oxidized among the carbon compounds and is present in the most stable state. From the viewpoint of $CO_2$ emissions, $CO_2$ immobilization technology, which converts $CO_2$ into chemically useful compounds, is considered to be more important.

• Journal of the Korean Chemical Society
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• v.37 no.10
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• pp.881-887
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• 1993

A cobalt(II) ion-selective carbon-paste electrode (CPE) was constructed with ${\iota}$-sparteine. Cobalt(II) ion in aqueous solution was chemically deposited through the complexation with ${\iota}$-sparteine onto the CPE. The surface of CPEs were characterized by cyclic voltammetry and differential pulse voltammetry in an acetate buffer solution, separately. Exposure of the CPEs to an acid solution could regenerate surface to reuse it for the deposition. In more than 5 deposition / measurement / regeneration cycles, the response was reproducible and linear up to $5.0{\times}10^{-6}$M with linear sweep voltammetry. The peaks at 0.17V / 0.27V were correspond to the redox of Co(II)-SP complex deposited on CPE. The anodic peak of which appeared after scan over the cathodic peak of 0.17 V to more negative scan. In case of using the differencial pulse voltammetry (DPV), we have obtained the linear response $2.0{\times}10^{-7}$M with relative standard deviation ${\pm}5.6%$. The detection limit was $1.0{times}10^{-7}$M for 20 minutes of the deposition. We have also investigated the interference effect of various metal ions, which are expected to form the complex with the ligand on the electrode.