• Mass Spectrometry Letters
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• 제1권1호
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• pp.9-12
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• 2010

Trimethylboroxine (TMB) is a six-membered ring compound containing Lewis acidic boron and Lewis basic oxygen atoms that can bind halide anion and alkali metal cation, respectively. We employed Fourier transform ion cyclotron resonance spectroscopy to study the gas-phase binding of $LiBrLi^+$ and $F^-(KF)_2$ to TMB. TMB forms association complexes with both $LiBrLi^+$ and $F^-(KF)_2$ at room temperature, providing direct evidence for the ditopic binding. Interestingly, the $TMB{\cdot}F^-(KF)_2$ anion complex is formed 33 times faster than the $TMB{\cdot}Li^+BrLi$ cation complex. To gain insight into the ditopic binding of an ion pair, we examined the structures and energetics of $TMB{\cdot}Li^+$, $TMB{\cdot}F^-$, $TMB{\cdot}LiF$ (the contact ion pair), and $Li^+{\cdot}TMB{\cdot}F^-$ (the separated ion pair) using Hartree-Fock and density functional theory. Theory suggests that $F^-$ binds more strongly to TMB than $Li^+$ and the contact ion-pair binding ($TMB{\cdot}LiF$) is more stable than the separated ion-pair binding ($Li^+{\cdot}TMB{\cdot}F^-$).

• Bulletin of the Korean Chemical Society
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• 제27권5호
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• pp.713-717
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• 2006

$S_2O$-donor macrocyclic isomers incorporating a xylyl group in o- ($L^1$), m- ($L^2$) and p-positions ($L^3$) extract no metal ions except silver(I) from aqueous to chloroform phase. And the magnitudes of %Ex for silver(I) are in the order of $L^1$ > $L^2$ > $L^3$. Taking this result into account, $L^1$-$L^3$ were utilized as membrane active components to prepare potentiometric silver(I)-selective electrodes. The proposed macrocycles-based electrodes E1 ($L^1$), E2 ($L^2$) and E3 ($L^3$) exhibited comparable results which show considerable selectivity toward silver(I) over alkali, alkali earth and other transition metal ions. Comparative NMR study on $L^1$-$L^3$ and their complexes with silver(I) in solution was also accomplished. In addition, a unique sandwich-type complex $[Ag(L^1)_2]CIO_4$ was prepared from the assembly reaction of $L^1$ with $AgClO_4$ and structurally characterized by an X-ray diffraction analysis.

• Bulletin of the Korean Chemical Society
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• 제10권2호
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• pp.155-158
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• 1989

The rates of complexation of the 18-C-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) with $K^+,\;Ca^{2+},\;Sr^{2+},\;and\;Ba^{2+}$ in methanol solution have been determined at 25$^{\circ}C$ by a pressure-jump technique. The Eigen Winkler mechanism has been applied to interprete the kinetic data. The results suggest that the rate determining step of the complexation in methanol is the rearrangement of the ligand in the outer sphere ion-dipole pair to form a stable encapsulated complex of the metal ion by the crown ether.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2786-2793
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• 2009

최근 화석에너지 고갈과 환경규제 강화로 신 재생에너지 개발 및 보급이 시급해지고 있다. 여러 가지 신재생 에너지 중 폐기물을 이용하는 방법이 에너지원의 잠재적 가치를 비교하였을 때 가장 유망한 에너지원으로 인정되고 있으며, 그 중에서도 폐기물을 고체연료로 가공하는 고형연료가 현실적이고 가장 경제적인 방법으로 인정받고 있다. 그러나 산업폐기물의 종류별 연소 시 발생되는 유해가스(HCl, Dioxin 등)와 중금속 등이 문제점으로 지적되고 있다. PVC, alkali metal chloride, alkaline earth metal chloride 등은 Cl을 발생시키는 대표적 물질이며, Cl는 열회수 장치의 부식과 같은 문제를 유발한다. 본 연구에는 두지역의 산업단지에서 고형연료의 재료가 되는 산업폐기물에 미량 존재하는 중금속 성분을 분석하였으며, Cl과 S의 농도를 분석한 결과 B산업단지의 농도가 A산업단지의 농도보다 약간 높게 나타났다. 이를 바탕으로 산업폐기물의 발생원과 연료로서의 RDF의 성능을 개선하기 위한 기초자료로 활용될 수 있을 것으로 판단된다.

• 한국염색가공학회지
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• 제14권5호
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• pp.284-293
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• 2002

Nylon 6 and polyester taffeta fabrics are dyed in aqueous medium with vat dyes such as Indanthren Red FBB, Mikethren Blue ACE and Mikethren Blue HR varying the compositions of sodium hydrosulfite and NaOH. Also nylon UMF nonwoven and polyester UMF knitted fabrics are dyed with metal complex and disperse dyes as a reference, and the wash and rubbing fastnesses for these dyes are investigated. In vat dyeing of polyester and nylon taffeta, an optimum composition of sodium hydrosulfite/NaOH is existed at a range of 1∼2wt%/0.2wt%. A good build-up property for Mikethren Blue ACE on nylon 6 UMF nonwoven fabric is shown at high temperature. Vat dyeing of polyester with Mikethren Blue Ace shows a good color shade in a higher temperature, while dyeing with Mitsui Blue HR shows low temperatures. Vat dyes In dyeing of both nylon 6 UMF nonwoven and polyester UMF knitted fabrics have a better wash fastnesses compared with metal complex or disperse dyes.

• Bulletin of the Korean Chemical Society
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• 제16권3호
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• pp.265-269
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• 1995

Complexation of ortho-xylyl-17-crown-5 (X17C5) with alkali metal ions in acetonitrile was studied by 7Li and 23Na NMR spectroscopy. The complex formation constants of X17C5 with LiI, LiSCN, NaI, and NaSCN were determined by investigating the changes in the chemical shifts as a function of the concentration ratio of X17C5 to metal ion. It was found that X17C5 forms 1:1 complex with Li+ and Na+ ions and the log Kf's for the complexation with LiI, LiSCN, NaI, and NaSCN were determined to be 2.88, 2.43, 2.53, and 2.30, respectively. In particular, the kinetics of complexation of X17C5 with Na+ was investigated by the method of 23Na NMR lineshape analysis. Activation energies were determined from Arrhenius plot of the resultant rate constant data to be 25.4 kJ/mol for NaI and 15.1 kJ/mol for NaSCN. Other kinetic parameters were also calculated by employing the Eyring equation. The decomplexation rates measured were 1.82 × 104 M-1s-1 for NaI and 1.50 × 104 M-1s-1 for NaSCN. It is concluded that the decomplexation mechanism is predominantly a bimolecular cation exchange for both cases.

• 대한화학회지
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• 제32권1호
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• pp.53-59
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• 1988

파라치환된 포타슘 페녹사이드류와 18-crown-6가 이루는 1 : 1 착물 형성상수를 전기 전도도법으로 35${\circ}C$에서 측정하여 용매와 치환기의 변화에 따른 효과를 측정하였다. 18-crown-6와 $K^+$의 착물 형성상수는 $CH_3$OH(DN=19.0) > DMF(26.6) > DMSO(29.8)의 순으로 감소되었다. 이는 전자주게 수가 클수록 $K^+$과 용매와의 상호작용이 커지므로 크라운 에테르와의 착물형성과의 서로 경쟁관계가 되어 $K_f$값이 작아진다고 추정된다. 포타슘 페녹사이드의 치환기가 p-N$O_2$ > H > p-$CH_3$ > p-O$CH_3$의 순으로 $K_f$값이 감소하는 경향을 나타내었다. 이는 전자를 당기는 기는 페녹사이드 음이온이 비편재화되어 안정해지므로 전자를 미는 기에 비해서 $K^+$를 쉽게 내어 놓을 수 있어 18-crown-6와의 착물 형성이 용이하기 때문이라고 생각된다.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1221-1227
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• 2011

Ethyl pyruvate (EP) is known as a scavenger of reactive oxygen species (ROS) in the body through its role in the donation of diketone groups to metals to form an EP-metal complex. In order to develop a method for the quantification of EP in biological media, a sensitive and specific, high-performance liquid chromatographyelectrospray ionization-mass spectrometry (HPLC-ESI/MS) method is used to determine the EP-alkali metal ion binding species. The analyte was separated on a ZORBOX SB-C8 ($3.5{\mu}m$, $30mm{\times}2.1mm$ I.D.) column and analyzed in selected ion monitoring (SIM) mode with a positive ESI interface using the m/z 255 $[2M + Na]^+$ ion. The method was validated over the concentration range of $0.5-60.0\;{\mu}g$/mL under 1/9 (v/v) of acetonitrile/methanol solvent system with flow rate 0.05 mL/min. The limit of quantification (LOQ) was $0.5{\mu}g$/mL.

• 대한방사성의약품학회지
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• 제2권1호
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• pp.17-21
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• 2016

Alkali metal fluoride sources (MFs) such as potassium fluoride (KF) have been widely used as a fluoride source in the nucleophilic displacement reaction. However, they have low solubility and nucleophilicity in most of the organic solvents. Bulky fluoride sources such as tetrabutylammonium fluoride (TBAF) were substituted for MFs to improve these properties. However, hygroscopic property of TBAF makes it less convenient for handling as well as its strong basic property can make the side-reaction occur. Recently, novel fluoride sources have been developed to solve these problems. In this paper, we would like to introduce coordinated fluoride sources as a new fluoride sources such as tetrabutylammonium tetra(t-butyl alcohol)-coordinated fluoride, crown ether metal complex fluoride, and various bulky alcohols coordinated fluoride complexes. In particular, bulky alcohol coordinated fluoride source could generated by the controlled hydrogen-bonded of fluoride with alcohols and these fluoride sources have better stability and reactivity with showing low hygroscopic property. The study of these fluoride sources will help to understand the characteristic of [$^{18}F$]fluoride for increasing the radiochemical yield in the [$^{18}F$]radiofluorination.

• 분석과학
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• 제6권3호
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• pp.247-254
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• 1993

스트론튬을 비롯한 알칼리 토금속의 전기화학적 분석의 적용은 수용액상에서 DME(Drop Mercury Electrod)에 대한 환원이 어렵기 때문에 그 연구가 많지 않다. 본 연구에서는 지금까지 UV-VIS 흡광광도법에서 스트론튬의 분석에 이용되어 온 o-Cresolphthaleoxon을 가지고 이들 사이의 착물형성에 따른 전자이동을 이용하여 전기화학적 분석에 적용시켰다. 이 때 지지전해질의 선택, Accumulation Potential 등 전기화학적 분석에 영향을 미치는 실험조건 등을 조사하여 정량범위를 결정짓고, 분석시 공존 이온의 영향을 조사하였다. UV-VIS 흡광광도법의 경우 $100{\mu}g/L$로 검출감도가 좋지 못하였으나, 전기화학적 방법을 이용할 경우 $5{\sim}30{\mu}g/L$ 범위까지의 정량이 가능하였다.