• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 춘계 총회 및 학술발표회
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• pp.61-62
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• 1994

In order to prepare polyion complex membranes useful for the separation of water-alcohol by pervaporation, k-carrageenan containing artionic sulfate groups in the backbone and good hydrophilicity was selected for the polyanion membrane material and poly{1,3-bis[4-butyl pyridinium] propane. bromide}, one of the polycations synthesized in our lab and containing cationic pyridinium groups., was used. The polyion complex membranes were prepared by the ion complex formation between kcarrageenan films and poly{1,3-bis[4-butyl pyridinium] propane. bromide}. On the formation process of polyion complex membranes, the way of potyion complex formation was carefully studied. In order to study the effect of the morphology on the permeation properties of the polyion complex membranes, which is one of the important factors affecting on the permeation properties of membranes but rarely studied, the microstructure behaviors of the polyion complex mem6ranes in methanol-water mixtures with different compositions Were also studied with x-ray diffractometry and polarizing microscopy.

• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.563-567
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• 2006

The application of a synergistic solvent extraction by the formation of ternary complex with pyrocatechol violet (PV) and benzalkonium chloride (BC) was studied for determination of trace Zn(II) in water samples. The pH of sample solution and the amount of PV and BC added were optimized for the formation of the stable complex, a proper solvent was selected for the effective extraction, and the concentration of nitric acid was fixed for the back extraction of the complex from the solvent. After the ionic strength of 100 mL sample solution was adjusted to 0.1 M by adding NaCl and the pH was fixed at 9 with a carbonate buffer, 1.0 mL of 2% PV solution was added to form Zn(II)-PV complex then the Zn(II)-PV/BC ternary complex was made by adding 1.0 mL of 10% BC solution. The ternary complex was extracted into 10 mL of MIBK. And the ternary complex was back-extracted with 10 mL of 1.0 mol/L nitric acid to determine Zn(II) by a flame atomic absorption spectrophotometer (flame-AAS). The interference of concomitant ions on the extraction of Zn(II) was investigated. This procedure was applied to the analysis of three real samples such as Dalbang-dam water, laboratory tap water and Jungnajin seawater. The recoveries of Zn(II) in spiked samples were 86.58-104.1%.

• Journal of Pharmaceutical Investigation
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• 제25권4호
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• pp.283-289
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• 1995

The aim of this study is to increase the solubility and dissolution rate of clonixin by inclusion complex formation. Inclusion complexes of clonixin, a non-steroidal antiinflammatory drug, with ${\beta]-cyclodextrin$ were $2-hydrolrypropyl-{\beta]-cyclodextrin$ were prepared by freeze drying method. Inclusion complex formation of clonixin with cyclodextrins was determined by UV, IR and DSC. The apparent stability constants were calculated from the phase solubility diagrams. Dissolution rate and solubility of clonixin in water markedly increased by the complex formation.

• Journal of Pharmaceutical Investigation
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• 제14권3호
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• pp.136-143
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• 1984

Inclusion complex formation of fenbufen with ${\beta}-cyclodextrin$ in water and in solid state was comfirmed by solubility method, ultra violet absorption, circular dichroism and infra-red spectroscopies, differential thermal analysis, and X-ray diffractometry. A solid complex of fenbufen with ${\beta}-cyclodextrin$ in 1 : 1 molar ratio was prepared by the freeze-drying method, its dissolution characteristics in water and its analgesic and antiinflammatory effect in mouse or rat were examined. The apparent release of fenbufen from the inclusion complex was significantly improved, hut no significant difference in its analgesic and antiinflammatory effect was found.

• Journal of Photoscience
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• 제3권3호
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• pp.153-158
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• 1996

The effects of $\alpha$- and $\beta$-cyclodextrins (CD) on the twisted intramolecular charge transfer (TICT) behavior of p-N,N'-dimethylaminobenzoic acid (DMABA) in buffered aqueous solution have been investigated by examining formation and decay behaviors of the TICT-typical dual fluorescence. The ratio of the TICT emission to the normal emission (I$_a$/I$_b$) increases linearly $\alpha$-CD concentration increases, while in the presence of $\beta$-CD it shows nonlinear dependences on the CD concentration. The analysis of the CD-dependent changes of the I$_a$/I$_b$ and absorption spectra demonstrates formation of 1:1 inclusion complexes between DMABA and CDs. The decay time of the normal emission (ca. 700 ps) is little affected by the formation of $\alpha$-CD inclusion complex, whereas it increases upto ca. 1.6 ns upon formation of $\beta$-CD inclusion complex. The TICT emission for the $\beta$-CD inclusion complex exhibits two decay components while it shows a single component for the $\alpha$-CD inclusion complex, indicating formation of one or two types of inclusion complex in the presence of $\alpha$-CD or $\beta$-CD, respectively. These results are attributed to the CD cavity size dependence on patterns of complexation between CDs and DMABA. The CD size dependences of the TICT fluorescence properties with the orientation of the guest molecule demonstrate that the specific hydrogen bonding between the carboxylic acid group and water plays an important role in the excited-state TICT.

• 약학회지
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• 제39권2호
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• pp.175-184
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• 1995

The interaction of omeprazole(OMP) with $\gamma$-cyclodextrin($\gamma$-CyD) was investigated by solubility study and the complexation was confirmed by means of UV/VIS spectrophotometer, circular dichroism, differential scanning calorimeter, and $^{1}$H nuclear magnetic resonance spectra. The stability, dissolution rate, and partition coefficient of the complex were measured. The results present that the benzimidazole moiety and a part of pyridine ring containing sulfur atom of OMP might be included into the cavity of $\gamma$-CyD and the formation type of inclusion complex appeared to be B$_{s}$. The stoichiometric ratio of OMP to $\gamma$-CyD in the complex was found to be 1:1 and the stability constant of the complex found to be 97.1 M$^{-1}$. And the dissolution rate of OMP was markedly increased by inclusion complex formation with $\gamma$-CyD, and so it was above 90% in 5 min. from solid complex. Oil to water partition coefficient of OMP-$\gamma$-CyD complex was 60, which is significantly higher than that of OMP itself, 36.4. The degradation rate constant of OMP were greater than OMP-$\gamma$-CyD complex in aqueous solutions of various pHs, and the half lives of OMP and OMP-$\gamma$-CyD at pH 9 were 279.2 and 509.9 days, respectively, showing that the complex was more stable than OMP, therefore it was thought that OMP was stabilized by inclusion formation with $\gamma$-CyD.

• 약학회지
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• 제27권1호
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• pp.11-19
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• 1983

Rifampicin-arginine complex was prepared to increase the solubility and dissolution rate of rifampicin. Solvation method was applied to make the complex and its formation was identified by the solubility method, powder x-ray diffractometry, differential thermal analysis and spectroscopic determination. The complex was formed in the molar ratio of 1 : 1 which was proved by the slope ratio method and continuous variation method. The complex was a non-crystalline form determined by the x-ray powder diffractometric analysis. The solubility of complex in water was significantly higher than that of rifampicin itself. The stability constant and thermodynamical properties of the complex were determined to investigate the solubilization phenomena. The thermodynamic data showed that the complexation between rifampicin and arginine was an exothermic and spontaneous reaction. Simulated absorption studies carried out through the artificial lipid barrier in artificial gastric and intestinal juices. The results showed that the complex had an enhanced absorption rate of rifampicin nearly twice compared with that of rifampicin itself.

• Bulletin of the Korean Chemical Society
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• 제17권9호
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• pp.814-819
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• 1996

In search of simple host molecules for uranyl ion which form 1: 1-type complexes with high formation constants that can be used either in extraction of uranium from seawater or in catalysis of biologically important organic reactions, the uranophile activities of dihydroxyazobenzene derivative 1 were studied. Uranyl ion and 1 form a 1: 1-type complex with a very large formation constant. The formation constant was measured at pH 7-11.6 by competition experiments with carbonate ion. From the resulting pH dependence, ionization constants of the two aquo ligands coordinated to the uranium of the uranyl complex of 1 were calculated. The ionization constants were also measured by potentiometric titration of the uranyl complex of 1. Based on these results, the pKa values of the two aquo ligands were estimated as 7.1 and 11.0, respectively. At pH 7.5-9.5, therefore, the complex exists mostly as monohydroxo species. Under the conditions of seawater, 1 possesses greater affinity toward uranyl ion compared with other uranophiles such as carbonate ion, calixarene derivatives, or a macrocyclic octacarboxylate. In addition, complexation of 1 with uranyl ion is much faster than that of the calixarene or octacarboxylate uranophiles.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.222-235
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• 2017

First, in this study, the inhibition efficiencies of metal complexes with Cu(II), Ni(II) and Zn(II) of STSC ligand for corrosion control of mild steel in oilfield formation water were investigated. The IEs for a mixture of 500 ppm STSC and 5 ppm metal ion ($Cu^{+2}$, $Ni^{+2}$, $Zn^{+2}$) were found to be 88.77, 87.96 and 85.13 %, respectively. The results were obtained from the electrochemical techniques such as open circuit potential, linear and tafel polarization methods. The polarization studies have showed that all used Schiff base metal complexes are anodic inhibitors. The protective film has been analyzed by FTIR technique. Also, to detect the presence of the iron-inhibitor complex, UV-Visible spectral analysis technique was used. The inhibitive effect was attributed to the formation of insoluble complex adsorbed on the mild steel surface and the adsorption process follows Langmuir adsorption isotherm. The surface morphology has been analyzed by SEM. Secondly, the computational studies of the ligand and its metal complexes were performed using DFT (B3LYP) method with the $6-311G^{{\ast}{\ast}}$ basis set. Finally, it is found that the experimental results were closely related to theoretical ones.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.614-618
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• 2005

The complex of the composition LaL(N$O_3)_3\;(H_2O)_2$ is prepared by the reaction of La($NO_3)_3{\cdot}6H_2O$ with Nethylmorpholine in aqueous medium. The ligand is involved in the complex as a neutral species where the chelation occurs via the oxygen of the ligand moiety and the nitrate groups as bidentate ligand. The chemical structure of the studied complex is confirmed through IR, XRD, and thermal analysis data. The complexation equilibria of La(III) with N-ethylmopholine is studied in aqueous medium at ionic strength I = 0.1 mol${\cdot}dm^{-3}\;KNO_3$ and at 25, 35 and 45 ${^{\circ}C}$, respectively. The thermodynamic parameters $\Delta$G, $\Delta$H and $\Delta$S values were calculated to prove the association with the complex formation. It is clearly observed that the process is accompanied by absorption of heat, i.e. endothermic process, while the entropy does not change greatly attributed to the release of constant number of water molecules during chelate formation.