• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.131-137
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• 2001

The protonation and stability constants of complexation of Zn(II), Cd(II) and Pb(II), Hg(II) ion with sulfur-containing podand ligands such as tri(phenylthio-2-ethy1)amine (Podand N$_1$S$_3$)tetra(phenylthio-2-ethyl)ethylenediamine (Podand N$_2$S$_4$) , tris(1-benzylaminoethyl)amine (Podand N$_4$) have been determined by potentiometric titration in 95% methanol at variable temperatures, From these studies, we observed that podand N$_4$ ligand showed the largest protonation constant. Protonation constant, stability constant, enthalpy, entropy of Zn(II), Cd(II) and Pb(II), Hg(II),ions increased with the following order podand N$_1$S$_3$$_2$S$_4$$_4$.

• Bulletin of the Korean Chemical Society
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• v.17 no.12
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• pp.1109-1111
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• 1996

The Podand Ⅰ (Figure 1) has been studied as cation carrier in a bulk liquid membrane system. Ag+ and some other transition metal ions (M2+=Cu, Ni, Co, Zn, and Cd) have been transported using the podand as carrier in a bulk liquid membrane system. Studies on the transport of equimolar mixtures of two or three competing components have also been carried out with the same system. Ag+ exhibited a higher transport rate than the other M2+ in the competitive experiments. Ligand structure and the equilibrium constant for complex formation are important parameters in the transport of the metal ions.

• Journal of the Korean Chemical Society
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• v.41 no.10
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• pp.557-560
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• 1997

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.534-537
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• 1993

• Analytical Science and Technology
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• v.7 no.2
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• pp.225-232
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• 1994

The podands I-VII, acyclic polyethers, expected high extractability for $Ag^+$ against $Pb^{2+}$ were designed and synthesized with high yields. Using podands I-VII as extractants, the %extraction(%Ex) of $Ag^+$ and $Pb^{2+}$ as picrates were determined in water/chloroform systems. The stability constants(log K) for the complexation of $Ag^+$ with podands I-VII were also determined by potentiometry. %Ex($Ag^+$) were proportional to the numbers of substituted sulfur donor atoms. Podand VI(log K : 7.65) having 3 substituted sulfur and podand VII(log K : 9.15) having 4 substituted sulfur, however, exhibited almost 100% of extractability, respectively. In %Ex($Ag^+/Pb^{2+}$, oxygen-sulfur mixed donor podands(IV-VII) showed the higher values. Otherwise, the values of log K and %Ex($Ag^+$) largely depended on the variation of donor-site of sulfur. From the results of NMR experiments, it seems that it is due to the ${\pi}-{\pi}$ stacking interaction between the aromatic end-groups.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.245-256
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• 2004

The extraction of three kinds of amido podands, N,N,N'N'-tetrabutyl-3-oxa-pentanedi- amide (TBDGA), N,N,N'N'-tetra-isobutyl-3-oxa-pentanediamide(TiBDGA) and N,N,N'N'-tetra- butyl-3,6-dioxa-oct-anediam- ide(TBDOODA) on U(VI),Pu(IV), Am(III), Eu(III) and other metal ions is studied in nitric acid solutions. 40%octanol-kerosene is chosen as diluents to eliminate third phase and emulsion. TBDGA and TiBDGA show extraction selectivity to An(III) and Ln(III) much higher than to U(VI) and Pu(IV). Fe, Ru and Mo is poorly extracted by the three kinds of amid podands in 2~3mol/L $HNO_3$ solutions. Aiming to eliminate interface crude when using simulated HLLW solution in the system of 0.2mol/L TBDGA/Octanol＋kerosene, acetohydroxyamic acid was adapted. Distribution ratio of zirconium was decreased when adding acetohydroxyamic acid in aqueous solution, and interface crude disappeared as mixing extractant with HLLW. The counter-current extraction test is carried out in a set of miniature mixer-settler, with 0.2mol/L TBDGA/ 40% octanol-kerosene as extractant to separate U(VI), Pu(IV), Am(III) and Eu(III) from simulated high level liquid waste(HLLW) solution. In battery A, lanthanides and actinides are coextracted into organic phase with the recovery of 99.98% for U(Ⅵ), >99.99% for Pu(IV), and >99.99% for Am(III) and Eu(III) respectively. In battery R1, 99.99% U, 86.2% Pu and a part of Am or Eu are stripped into aqueous phase by 0.2mol/L acetohydroxyamic acid (AHA) in 0.01mol/L $HNO_3$ solution. In battery $R_2$, Am, Eu and remained Pu are completely back-extracted by 0.2mol/L AHA. This separation process contains no salt reagent, and it is not necessary to dilute HLLW feed.

• Analytical Science and Technology
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• v.12 no.2
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• pp.171-175
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• 1999

Carbon paste electrodes, modified with podands containing more than two sulfur atoms, have been employed for the voltammetric determination of Ag(I) ion from aqueous solution. The voltammetric response was characterized with respect to paste composition, preconcentration method, kind of anion, variation of pH, Ag(I) ion concentration, and possible interferences. Linear calibration curves were obtained for Ag(I) ion concentration ranging from $1.0{\times}10^{-6}$ to $9.0{\times}10^{-5}M$, and detection limit was $5.0{\times}10^{-7}M$.

• Bulletin of the Korean Chemical Society
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• v.15 no.11
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• pp.967-971
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• 1994

The stability constants, log K of the 1 : 1 complexation for IA ions, $Ag^+$, and $Tl^+$ with a series of podands having different aromatic end-groups (I-IV) have been determined conductometrically in methanol at 25.0 $^{\circ}$C. Exceptionally the equivalent conductivity, ${\lambda}_{eq}\;of\;Li^+\;and\;Na^+$ were increased by the addition of I, because the complexed ions are less mobile than solvated ions. The order of log K values for I was $Ag^+{\gg}Tl^+>K^+>Na^+>Rb^+>Cs6+>Li^+$. The log K sequence of the podands for the certain cations was I>II>III${\geq}$IV. And every podands except IV showed the maximum selectivity for $Ag^+$ among the cations. These results were discussed in terms of the aromatic end-group effects, such as hetero-donor atoms or conformational changes by ${\pi}-{\pi}$ stacking interactions. The detailed conformations of ${\pi}-{\pi}$ stacking were also discussed by the observations of upfield shifts of some aromatic protons upon complexation from $^1H$ NMR spectra.

• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.588-595
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• 1989

Log K, ${\Delta}$H and ${\Delta}$S for the complexation of $La^{3+},\;Ce^{3+}$ and $Eu^{3+}$with various multidentate ligand containing crown ether, diaza crown ether and diamine ether have been determined in methanol and acetonitril solutions at $25^{\circ}C$ by solution calorimetric titration method. The greater stability constant of $La^{3+}$-15C5 than those of 18C6 diaza [2.2] in methanol are discussed in terms of the size of metal ion and the ligand cavity and of metal ion solvation. The stabilities of $Ce^{3+}$ and $La^{3+}$ ion complexes with a various multidentate ligand in acetonitril are in the order of (diamine ether)<18C6<15C5$Ce^{3+}$, $La^{3+}$ and $Eu^{3+}$-diaza [2.2] complexes in acetonitril are increased with the following order: $Eu^{3+}$ < $La^{3+}$ < $Ce^{3+}$, that is increasing order of the optimum size and of the charge density of metal ion.

• Analytical Science and Technology
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• v.6 no.1
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• pp.29-37
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• 1993

Some new podands containing phenyl(B), benzyl(Bz), pyridine(Py), quinoline(Q) and naphthalene(Np) as end-groups, and oxygen(O) and sulfur(S) in ether chains as donor atoms have been synthesized. The univalent cation binding characteristics of these podands have been studied by NMR titration and solvent extraction. By NMR titration we have found that the most of podands form 1:1 complexes with $Ag^+$ ion. Especially, the substituted sulfur atoms in ether chains show the effects to enhance the stabilities. We also carried out the extractions of univalent cation picrates including alkaline metal, $Ag^+$, $Tl^+$ and $NH_4{^-}$ ions from aqueous to chloroform layer by using these podands. We found that the extractabilities of $Ag^+$ ion with the quinoline-containing podands such as, $Q_2O_4$, $Q_2O_5$ and $BQO_5$ were 86.8, 86.6 and 48.0% respectively, but the naphthalene-containing podands such as, $Np_2O_4$ and $Np_2O_5$ extracted quite small amount. Otherwise, in cases of $Bz_2O_3S_2$(89.4%), $B_2O_2S_2$(96.8%), $B_2O_3S_2$(58.9%), $Py_2O_2S_2$(58.8%), $Py_2O_3S_2$(42.1%), and $B_2O_4S$(15.0%), interestingly, $Bz_2O_3S_2$ which have sulfur atoms and benzyl groups showed the highest extraction selectivity for $Ag^+$ ion. This result seems due to not only the strong interaction of $Ag^+$ ion with sulfur donors according to the HSAB theory, but also the effective ${\pi}-{\pi}$ stacking interaction between two aromatic end-groups which is enhanced by the flexible methylene spacing group in benzyl groups instead of phenyl groups. The extraction coefficients gave the similar tendency as the extractabilities and the stabilities. From these results, it could be concluded that the predominant factor affected to extraction coefficients is the stabilities, which are strongly influenced by the structures of podands.