• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.92.2-92.2
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• 2018

빠르고 정확한 글루코오스 농도 측정은 의료, 식품, 환경 등 다양한 산업에서 매우 중요하다. 글루코오스 산화효소를 기반으로 하는 현재 글루코오스 센서는 높은 감도와 선택성을 갖지만 온도변화나 다른 화학물 등 환경에 취약하다는 단점이 있다. 따라서 최근 비효소식 글루코오스 센서에 대한 연구가 활발히 진행되고 있다. 금속-유기 구조체(MOFs)는 금속이온과 유기물 리간드로 구성된 결정성 다공체로, 큰 기공 크기와 비표면적, 안정성 등을 특징으로 갖는다. 대부분의 MOFs는 전기전도도가 낮지만 금속이온의 산화/환원, 리간드의 화학적 개질을 통해 전기화학분야에서도 다양하게 연구되고 있다. 본 연구에서는 글루코오스 농도 측정을 위한 전극촉매로 다양한 금속이온과 리간드로 이루어진 MOFs를 합성했다. 표면분석을 통해 MOFs의 전기화학적 처리 전후의 구조와 성질 변화를 관찰했고 전기화학적 분석을 통해 금속이온과 리간드의 종류가 감도, 선택성 등 글루코오스 검지 성능에 주는 영향을 분석했다. 그 결과 Ni, Co 기반의 MOFs가 글루코오스에 대해 높은 감도를 보였으며 이를 통해 MOFs의 글루코오스 센서로의 응용 가능성을 확인했다.

• 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.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.590-593
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• 2011

A novel organotin(IV) complex has been prepared from $Bu_2SnCl_2$ and the N, O and S donor ligand, 5-(p-dimethylaminobenzylidene) rodanine (HL). The ligand is deprotonated in the presence of a base and the complex with the general formula $SnBuCl_2L$ is formed. This complex was fully characterized by IR, $^1H$ NMR and $^{119}Sn$ NMR and elemental analysis. Spectroscopic data indicate the ligand is coordinated through the oxygen atom to the tin and the coordination number of four is supported by $^{119}Sn$ NMR data in solution.

• Journal of the Korean Chemical Society
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• v.23 no.6
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• pp.417-419
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• 1979

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.271-282
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• 2012

We explore the effect of removal of organic ligand on the atomic configurations around oxygen in hydroxyl groups in amorphous silica gel (synthesized through hydrolysis of $SiCl_4$ in diethyl-ether) using high resolution $^{17}O$ solid state NMR spectroscopy. $^1H$ and $^{29}Si$ MAS NMR spectra for amorphous silica gel showed diverse hydrogen environments including water, hydroxyl groups (e.g., hydrogen bonded silanol, isolated silanol), and organic ligands (e.g., alkyl chain) that may interact with surface hydroxyls in the amorphous silica gel, for instance, forming silica-organic ligand complex (e.g., Si-$O{\cdots}R$). These physically and chemically adsorbed organic ligands were partly removed by ultrasonic cleaning under ethanol and distilled water for 1 hour. Whereas $^{17}O$ MAS NMR spectra with short pulse length ($0.175{\mu}s$) at 9.4 T and 14.1 T for as-synthesized amorphous silica gel showed the unresolved peak for Si-O-Si and Si-OH structures, the $^{17}O$ MAS NMR spectra with long pulse length ($2{\mu}s$) showed the additional peak at ~0 ppm. The peak at ~0 ppm may be due to Si-OH structure with very fast relaxation rate as coupled to liquid water molecules or organic ligands on the surface of amorphous silica gel. The observation of the peak at ~0 ppm in $^{17}O$ MAS NMR spectra for amorphous silica gel became more significant as the organic ligands were removed. These results indicate that the organic ligands on the surface of amorphous silica gel interact with oxygen atoms in Si-OH and provide the information about atomic structure of silanol and siloxane in amorphous silica gel. The current results could enhance the understanding of dehydration mechanism of diverse silicates, which is known as atomic scale origins of intermediate depth (approximately, 70~300 km) earthquakes in subduction zone.

• Korean Journal of Environmental Agriculture
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• v.12 no.1
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• pp.51-57
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• 1993

Objective of this research was to assess the influence of reaction time on the heavy metal-organic ligand complexation by employing kinetic models. Aqueous solutions of humic (HA) or fulvic acid (FA) were reacted with metal solutions with 1:1 ratio to form complexes. Efficiency of organic ligand on metal removal was determined by separating the precipitates from solution using $0.45\;{\mu}m$ filter paper. Complexation between Cu or Pb and HA or FA followed the first- or multiple first order kinetics, largely depending on metal concentration and kind of organic ligand. Amounts of precipitates were increased proportionally with reaction time but reached to quasiequilibrium where rate of precipitate formation was not varied with time. Copper-ligand complexation was, irrespective of ligand, fitted to the single first order kinetics at Cu concentrations lower than $300{\mu}M$, but this was fitted to the multiple first order kinetics at Cu concentrations higher than $300{\mu}M$. As increasing Cu concentrations, the precipitates formed more readily, judging from the increased rate constants (${\kappa}$). In the multiple first order kinetics, ${\kappa}$ was decreased as reaction steps proceeded. Most of Cu-ligand precipitates were formed within 15 min. FA precipitated Cu more rapidly than HA did. ${\kappa}$ for Pb-HA complexation was decreased but that for Pb-FA reaction was increased, as increasing Pb concentration. Most of Pb-organic ligand complexation occurred within 30 min. Afterwards, ${\kappa}$ values were relatively small and not affected much by time. Pb was precipitated by humic acid more readily than Cu when metal concnetrations were $200{\sim}300{\mu}M$. However, when metal concentrations were in the ranges of $400{\sim}500{\mu}M$, a reversed tendency was observed.

• Korean Journal of Environmental Agriculture
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• v.11 no.3
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• pp.235-242
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• 1992

Organic ligands in the environments are expected to play an important role in regulating the biotoxicity and fate of pesticides. Influences of dissolved humic and fulvic acids on the phytotoxicity of Paraquat were investigated using a bioassay with hydroponically grown rye as indicator species. Levels of Paraquat in water culture media were ranged from 0 to $12_{{\mu}M}$ and those of humic or fulvic acid were 1.0mM as a soluble carbon. Media were prepared in a factorial combination with pHs of 4.5, 6.5 and 8.5, Standard curves of necrosis days, fresh weight, and growth rates, as Phytotoxicity Indices, versus Paraquat concentrations were employed to evaluate the effects of organic ligands on phytotoxicity of paraquat. Organic ligand itself had little effect on rye growth, but Paraquat showed a high degree of toxicity. Paraquat started to show an intensive injury to rye at $0.4{\sim}0.6{{\mu}M}$ and upper critical phytotoxic concentration was estimated to be 11.0${{\mu}M}$ In the presence of organic ligands, times required to cause necrosis due to Paraquat were delayed upto 40%. Fresh weights and growth rates were upto 20% higher in treatments of organic ligands plus Paraquat than that of Paraquat alone. Results demonstrated that complexation of organic ligand with Paraquat reduced the bioabailability of Paraquat to rye.

• 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

• 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.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.513-522
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• 2019

Catalysts based on organic compounds, transition metal and metal-organic frameworks (MOFs) have been applied to degrade or remove organophosphorus toxic compounds (OPs). During the last 20 years, various MOFs were designed and synthesized to suit application purposes. MOFs with $Zr_6$ based metal node and organic linker were widely used as catalysts due to their tunability for the pore size, porosity, surface area, Lewis acidic sites, and thermal stability. In this review, effect on catalytic efficiency between MOFs properties according to the structure, stability, particle size, number of connected-ligand, organic functional group, and so on will be discussed.