• 대한화학회지
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• 제39권4호
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• pp.288-293
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• 1995

chromotropic acid (1,8-Dihydroxynaphthalene-3,6-disulfonic acid)를 착화제로 이용한 붕소에 대한 분리 정량을 이온쌍 액체 크로마토그래피로 연구하였다. 이동상$(MeOH\; 61{\%},\;H_2O\;39{\%}$, 인산완충용액 pH=8.5)에 tetrabutylammonium bromide를 첨가하므로서 붕소-chromotropic acid 착물과 chromotropic acid를 poly(styrene-devinylbenzene) 역상컬럼(PRP-1, 15 $cm{\times}4.6$ mm i.d.) 상에서 분리할 수 있었으며, 또한 시료 용액중에 0.1 M의 tetrabutylammonium bromide를 첨가하므로 붕소와 chromotropic acid간의 착물형성을 촉진시켜 감도를 높일수가 있었다. 0.5~1000 ${\mu}g/L$ 농도범위에서 좋은 직선성을 나타내었고 검출 한계는 0.5 ${\mu}g/L$ (S/N=2)이었다. 제안된 방법으로 시판용 시약, $Na_2SO_4,\; NaOH,\; KCl$에 있는 미량의 붕소를 정량하였다.

• Archives of Pharmacal Research
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• 제29권4호
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• pp.323-327
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• 2006

The objective of this study was to examine the pharmacokinetics of organic cations in intrahepatic cholestatic rats. A pretreatment with $17{\alpha}$-ethynylestradiol was used to induce intrahepatic cholestasis, and tributylmethylammonium (TBuMA) was used as a representative model organic cation. When $[^3H]$TBuMA was intravenously administered, the AUC value for TBuMA was significantly increased by $79\%$ in cholestasis, and its total systemic clearance was consequently decreased by $46\%$. In addition, the in vivo hepatic uptake clearance of TBuMA from the plasma to the liver was decreased by $50\%$ in cholestasis. The concentration of bile salts in plasma was increased by 2.1 fold in cholestatic rats. Since TBuMA forms ion-pair complexes with anionic components such as bile salts, the decreased hepatic uptake of TBuMA in cholestasis may be due to a change in endogenous components, e.g., bile salts in the plasma. In isolated normal hepatocytes, the uptake clearance for TBuMA in the presence of cholestatic plasma was decreased by $20\%$ compared with normal plasma. Therefore, we conclude that the inhibition of the hepatic uptake process by the cholestasis may be in part due to the increased formation of ion-pair complexes of TBuMA with bile salts in the plasma.

• 약학회지
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• 제30권2호
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• pp.68-72
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• 1986

Effect of sodium taurodeoxycholate (TDC) on the pharmacokinetics of methylene blue (MB) was investigated in the rats of experimental hepatic failure induced by $CCI_4$. Intravenous infusion of TDC increased the distribution volume of central compartment ($Vd_1$) and the total body clearance ($CL_t$) of MB. Increased lipophilicity through ion-pair formation with TDC seemed to be the probable cause of increased $Vd_1$ and $CL_t$.

• 약학회지
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• 제37권1호
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• pp.30-35
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• 1993

HPLC/fluorescence detection method for the analysis of pancuronium bromide in biological fluids was developed. The method depends on the formation of insoluble red complex between pancuronium bromide and rose bengal in aqueous layer. This complex is quantitatively extracted from aqueous layer into chloroform layer. The complex is stable for 1 day in chloroform layer at room temperature. It was possible to analyze pancuronium bromide in the range of 0.05~0.5 $\mu\textrm{g}$/ml without the effect of co-prescribed drugs.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1814-1822
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• 2013

By using density functional theory calculations, we have performed a systemic study on the electronic structures and topological properties of interactions between N-butylpyridinium nitrate ($[BPY]^+[NO_3]^-$) and thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT), naphthalene (NAP). The most stable structure of $[BPY]^+[NO_3]^-$ ion pair indicates that hydrogen bonding interactions between oxygen atoms on $[NO_3]^-$ anion and C2-H2 on pyridinium ring play a dominating role in the formation of ion pair. The occurrence of hydrogen bonding, ${\pi}{\cdots}$H-C, and ${\pi}{\cdots}{\pi}$ interactions between $[BPY]^+[NO_3]^-$ and TS, BT, DBT, NAP has been corroborated at the molecular level. But hydrogen bonding and ${\pi}{\cdots}{\pi}$ interactions between $[BPY]^+[NO_3]^-$ and NAP are weak in terms of structural properties and NBO, AIM analyses. DBT is prior to adsorption on N-butylpyridinium nitrate ionic liquid.

• 대한화학회지
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• 제28권6호
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• pp.355-360
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• 1984

Methylene blue(MB$^+$)와 tetraphenylborate(TPB$^-$)이 공존하는 묽은 수용액에서 MB+만의 흡수스펙트럼보다는 장파장 쪽에서 스펙트럼의 변화를 관찰하고, 이를 나타내는 화학종에 관한 연구를 흡수분광법으로 수행하였다. 소수성이 큰 이들 두 이온의 물의 구조를 덜 깨뜨리려는 힘에 의하여 이온쌍으로 되고 더 나아가 전자밀도가 높은 TPB$^-$로 부터 전자가 옮겨진 전하이동 착물이 그것일수도 있다. 그러나 MB$^+$만의 최대 흡수 파수를 기준으로 1,000cm$^{-1}$ 만큼 높고 낮은 두 흡수띠를 보였으므로 중이온쌍, (MB-TPB)$_2$가 새로운 흡수를 보이는 주된 화학종으로 생각되었다.

• 대한화학회지
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• 제17권4호
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• pp.229-234
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• 1973

非水溶液 에틸렌디아민中에서, K-Hg,KI($C_1$) II ($C_2$)KI, Hg-K의 農談電位를 構成하여, 電位差法으로 電位差를 測定하여, Debye-Huckel型의 活性係數式으로 計算한 理論値와 比較한 결과 Marshall-Grunwald 식이 잘 適用되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.115-117
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• 2005

In this paper, we formed the shallow junction by preamorphization and low energy ion implantation. And a simulator is designed for predicting the annealing process results. Especially, if considered the applicable to single step annealing process(RTA, FA) and dual step annealing process(RTA+FA, FA+RTA). In this simulation, the ion implantation model and the boron diffusion model are used. The Monte Carlo model is used for the ion implantation. Boron diffusion model is based on pair diffusion at nonequilibrium condition. And we considered that the BI-pairs lead the diffusion and the boron activation and clustering reaction. Using the boundary condition and initial condition, the diffusion equation is solved successfully. The simulator is made ofC language and reappear the experimental data successfully.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3543-3548
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• 2010

A kinetic study on nucleophilic displacement reactions of 2-pyridyl X-substituted benzoates 1a-e with potassium ethoxide (EtOK) in anhydrous ethanol is reported. Plots of pseudo-first-order rate constants ($k_{obsd}$) vs. $[EtOK]_o$ exhibit upward curvature. The $k_{obsd}$ value at a fixed $[EtOK]_o$ decreases steeply upon addition of 18-crown-6-ether (18C6) to the reaction mixture up to [18C6]/$[EtOK]_o$ = 1 and then remains nearly constant thereafter. In contrast, $k_{obsd}$ increases sharply upon addition of LiSCN or KSCN. Dissection of $k_{obsd}$ into $k_{EtO^-}$ and $k_{EtOM}$ has revealed that ion-paired EtOK is more reactive than dissociated $EtO^-$, indicating that $K^+$ ion acts as a Lewis acid catalyst. Hammett plots for the reactions of 1a-e with dissociated $EtO^-$ and ion-paired EtOK result in excellent linear correlation with $\rho$ values of 3.01 and 2.67, respectively. The $k_{EtOK}/k_{EtO^-}$ ratio increases as the substituent X in the benzoyl moiety becomes a stronger electron-donating group. $K^+$ ion has been concluded to catalyze the current reaction by stabilizing the transition state through formation of a 6-membered cyclic complex.

• Bulletin of the Korean Chemical Society
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• 제24권4호
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• pp.431-436
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• 2003

Solvolytic rate constants at 25℃ are reported for solvolyses of cinnamyl bromide (1) in binary mixtures of water with acetone, ethanol, methanol, methanol-d, and 2,2,2-trifluoroethanol. Product selectivities are reported for solvolyses of 1 in aqueous ethanol and methanol. Rate ratios in solvents of the same $Y_{Br}$ value and different nucleophilicity provide measures of the minimum extent of nucleophilic solvent assistance (e.g. $[k_{40EW}/k_{97TFE}]$Y = 2.88, EW = ethanol-water). With use of the extended Grunwald-Winstein equation, the l and m values are similar to the values of 0.43 and 0.88 obtained for the solvolyses of 1 using the equation (see below) which includes a parameter (I) for solvation of aromatic rings. The magnitude of l and m values associated with a change of solvent composition predicts the $S_{N1}$ reaction mechanism rather than an $S_{N2}$ channel. Product selectivities (S), defined by S = [ether product]/[alcohol product]×[water]/[alcohol solvent] are related to four rate constants for reactions involving one molecule of solvent as nucleophile and another molecule of solvent as general base catalyst. A linear relationship between 1/S and molar ratio of solvent is derived theoretically and validated experimentally for solvolyses of the above substrates from water up 75% 1/S = $(k_{wa}/k_{aw})$([alcohol solvent]/[water]) + $k_{ww}/k_{aw}$ alcohol-water. The results are best explained by product formation from a “free” carbocation intermediate rather than from a solvent-separated ion pair.