• Current Photovoltaic Research
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• 제2권1호
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• pp.18-27
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• 2014

Dye-sensitized solar cells (DSSCs), developed two decades ago, are considered to be an attractive technology among various photovoltaic devices because of their low cost, accessible dye chemistry, ease of fabrication, high power conversion efficiency, and environmentally friendly nature. A typical DSSCs consists of a dye-coated $TiO_2$ photoanode, a redox electrolyte, and a platinum (Pt)-coated fluorine-doped tin oxide (FTO) counter electrode. Among them, redox electrolytes have proven to be extremely important in improving the performance of DSSCs. Due to many drawbacks of iodide electrolytes, many research groups have paid more attention to seeking other alternative electrolyte systems. With regard to this, one-electron outer sphere redox shuttles based on cobalt complexes have shown promising results: In 2014, porphyrin dye (SM315) with the cobalt (II/III) redox couple exhibited a power conversion efficiency of 13% in DSSCs. In this review, we will provide an overview and perspectives of cobalt redox electrolytes in DSSCs.

• 대한화학회지
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• 제22권3호
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• pp.133-137
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• 1978

새로운 네자리 아민리간드 1,10-dipropyl-5R-methyltriethylenetetramine(R-$Pr_2$metrien)이 합성되었고 이 리간드로부터 디클로로 몇 디니트로코발트(III) 착물이 합성되었다. 합성된 리간드는 트란스 이성체의 착물만을 형성할 것이 예측되었으며 예측된대로 트란스 이성체만을 형성하였다. 원소분석, 핵자기공명분광학, 흡수분광분석 및 원편광이색성분광법을 이용하여 리간드와 착물의 구조가 설명되었다.

• 대한화학회지
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• 제36권6호
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• pp.894-905
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• 1992

산소가 포화된 메탈올 용액에서 Superoxo형인 [Co(Ⅲ)(SED)(Py)$O_2$]와 [Co(III)(SOPD)(Py)$O_2$]들의 균일 산화 활성 촉매에 의한 hydrazobenzene(H2AB)의 산화 주생성물은 trans-azobenzene (t-AB)이고 반응 속도상수 k = 7.692 ${\times}$ $10^{-2}$ M/sec 및 5.076 ${\times}$ $10^{-2}$ M/sec이나 ${\mu}$-peroxo형인 [Co(III)(SED)(Py)]$_2O_2$에 의한 주생성물은 cis-azobenzene (c-AB)이 선택적으로 생성되고 반은 속도상수 k = 1.266 ${\times}$ $10^{-2}$ M/sec로 주어짐을 UV-visible 흡광도법으로 알아보았다. 이들 산화반응은 다음과 같이 균일 산소 첨가 착물촉매에 의하여 산화주생성물이 선택적으로 다르게 생성된다. $H_2$AB + Co(II)(Schiff base)$(Py)_2$ + $O_2$ ${\rightleftharpoons}_{MeOH}^K$ Co(III)(Schiff base)(Py)$O_2$${\cdot}$$H_2$AB + Py $\longrightarrow^k$ Co(II)(Schiff base)$(Py)_2$ + t-AB + $H_2O_2$(Scchiff base : SED 및 SOPD). $H_2$AB + 2Co(II)(SND)$(Py)_2$ + $O_2$ ${\rightleftharpoons}_{MeOH}^K$ [Co(III)(SND)(Py)]$_2O_2$${\cdot}$$H_2$AB + 2Py $\longrightarrow^k$ (Co(II)(SND)$(Py)_2$ + c-AB + $H_2O_2$.

• Bulletin of the Korean Chemical Society
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• 제18권10호
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• pp.1090-1093
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• 1997

The solvent effects on the isotropic NMR shifts in conformationally rigid ligands such as quinuclidine, pyridine, and 4-aminopyridine coordinated to the paramagnetic polyoxometalate, [SiW11CoⅡO39]6- (SiW11Co), are reported. For these complexes the ligand exchange is slow on the NMR time scale and pure 1H NMR signals have been observed at room temperature. The signals for the SiW11Co complexes are shifted upfield whe dimethyl sulfoxide-d6 (DMSO) is added to a D2O solution. The isotropic shifts are separated into contact and pseudocontact contributions by assuming that the contact shifts are proportional to the isotropic shifts of the same ligands coordinated to [SiW11NiⅡO39]6-. It is shown that both the contact and pseudocontact shifts decrease (the absolute values of the pseudocontact shifts increase), when D2O is replaced by DMSO. It is suggested that D2O, a strong hydrogen bond donor, withdraws electron density from [SiW11CoⅡO39]6-, increasing the acidity of the cobalt ion toward the axial ligand. When D2O is replaced by DMSO, the acidity of the cobalt ion in SiW11Co decreases, weakening the Co-N bond. Then both the contact and pseudocontact shifts are expected to decrease in agreement with the observed solvent effects.

• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1036-1042
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• 1998

The preconcentration and determination of trace elements in water samples were studied by a solvent sublation utilizing dithizonate complexation. After metal dithizonates were formed, trace amounts of cadmium, cobalt, copper and lead were floated and extracted into small volume of a water-immiscible organic solvent on the surface of sample solution and determined in the solvent directly by GF-AAS. Several experimental conditions as formation condition of metal-dithizonate complexes, pH of solution, amount of dithizone, stirring time, the type and amount of surfactants, N2 bubbling rate and so on were optimized for the complete formation and effective flotation of the complexes. And also four kinds of light solvents were compared each other to extract the floated complexes, effectively. After the pH was adjusted to 4.0 with 5 M HNO3, 8.0 mL of 0.05% acetone solution of dithizone was added to 1.00 L water sample. The dithizonate complexes were flotated and extracted into the upper methyl isobutylketone (MIBK) layer by the addition of 2.0 mL 0.2% ethanolic sodium lauryl sulfate solution and with the aid of small nitrogen gas bubbles. And this solvent sublation method was applied to the analysis of real water samples and good results of more than 85% recoveries were obtained in spiked samples.

• Macromolecular Research
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• 제16권8호
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• pp.745-748
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• 2008

• 한국세라믹학회지
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• 제53권3호
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• pp.367-375
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• 2016

A novel strategy for the synthesis of $CoSb_2$ nanoparticles is demonstrated via preparation of novel organometallic complexes. Hydrated cobalt oleate (CoOl) and non-hydrated antimony oleate (SbOl) complexes are synthesized as precursors. The $CoSb_2$ nanoparticles are prepared by hot injection, which involves thermolysis of CoOl and SbOl in a non-coordinating solvent at $320^{\circ}C$. The coordination modes and distinct thermal behaviors of the intermediate non-hydrated SbOl complexes are comparatively investigated by thermo-analytical techniques. When the reaction temperature is increased, the particle size is found to increase linearly. The crystallinity of the $CoSb_2$ nanoparticles prepared at $250^{\circ}C$ is amorphous phase without any peaks. $CoSb_2$ structural peaks start to appear at $300^{\circ}C$ and dominant peaks with high crystallinity are synthesized at $320^{\circ}C$. The potential chemical structures of non-hydrated SbOl and their reaction mechanisms by thermolysis are elucidated. The elemental composition and crystallographic structure of $CoSb_2$ nanoparticles suggest a bimodal interaction of the organic shell and the nanoparticle surface, with a chemical absorbed inner layer and physically absorbed outer layer of carboxylic acid.

• Korean Chemical Engineering Research
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• 제46권4호
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• pp.769-776
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• 2008

키랄성 말단기의 에폭사이드는 키랄중간체나 여러 출발물질로서 다양하게 이용되기 때문에 그 선택적인 합성법은 매우 유용하다. 본 연구에서는 염화코발트(II), 염화철(III) 및 질산아연(II)을 각각 함유한 키랄 코발트 살렌 촉매를 새로이 합성하고 그 특성을 평가하였다. 질량분석과 EXAF분석을 통하여 형성된 촉매 착체의 구조를 평가하였다. 합성한 촉매는 방향족 에폭사이드인 스타이렌 옥사이드와 페닐글리시딜 에테르의 속도차에 의한 비대칭 가수분해적 고리열림반응과 글리시틸부틸레이트의 합성반응에 적용하여 그 활성과 선택성을 조사하였다. 합성이 용이한 전이금속염함유 살렌착체 촉매는 물을 친핵체로 하는 라세믹 에폭사이드의 고리 열림을 통하여 99%ee 이상을 나타낼 정도의 매우 높은 광학선택성을 보였으며, 적은 양의 첨가로도 높은 활성을 보였다. 본 연구에서 적용한 촉매씨스템은 키랄 에폭사이드 및 1,2-디올 중간체의 제조에 매우 효과적이었다.

• 대한화학회지
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• 제47권4호
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• pp.334-338
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• 2003

$[Co(phen)_2(Cl)(H_2O)] Clㆍ2H_2O$(phen=1,10-phenanthroline)의 결정구조는 X-ray에 의하여 결정되었다. 그 결정은 a=9.662(2), b=11.445(1), c=13.037(2)${\AA}$ ${\alpha}$=64.02(1), ${\beta}$=86.364(9), ${\gamma}=78.58(2)^°$ 그리고 Z=2의 격자인자를 갖는 triclinic계와 space group이 P1의 구조로 결정화 되었다. 배위된 양이온은 두개의 Phen 리간드, 하나의 chloride이온과 하나의 $H_2O$ 리간드가 cis 배열로 킬레이크된 6배위 코발트 원자가 포함된다. 코발트에 배위된 chloride에 더해서, 결정구조를 이루는 하나의 chloride이온과 네개의 물분자가 있다. 고체상태에서, 제목의 화합물은 수소결합을 통하여 3차원 그물구조를 갖는다.

• 한국염색가공학회지
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• 제8권6호
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• pp.40-46
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• 1996

In order to investigate a practical application of fibrous absorbents to transition metals such as copper, nickel, cobalt, chrome, and iron, amidoximated fiber as a particular class of solid chelate agents were prepared from acrylic fibers treatment with hydroxylamine. The adsorption mechanisms of metal ions onto amidoximated acrylic fibers and their complexes were studied. Amidoximation of acrylic fiber with hydroxylamine is found to be first-order reaction, followed by the disappearance of infrared adsorption peaks due to nitrile groups of acrylic fibers. The uptake of metal ions onto amidoximated acrylic fiber is increased with temperature raising and the adsorption is also depended on pH of the soiutions. About 70% of metal ions can be recovered from aqueous solutions of Ni(II), Co(II), Cr(III), and Fe(II) on the concentration below 5x 10$^$^{-4}$ in the range of pH 2.1~10.0. Transition metals are adsorbed to form complex with amidoxime group by the ligand sites such as C=N, NH, NO, NHOH.OH.