• Bulletin of the Korean Chemical Society
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• v.9 no.4
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• pp.198-202
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• 1988

Several new palladium(II) complexes of aminophosphines, $(Pd(L)X_2)$, (L = $Ph_2PNH$ ++ $NR_2$; R = $CH_3(L_1)$, $C_2H_5(L_2)$ : X = Cl, Br, I, and NCS) that contain two different donor atoms of nitrogen and phosphorus as ${\pi}$-electron acceptor, were synthesized and characterized by conductivity measurement, ir, and UV/Vis-spectra. For the dithiocyanatopalladium(II) complexes with aminophosphines, it was confirmed that the thiocyanate group trans to phosphorus is coordinated as Pd-NCS mode and the one trans to nitrogen as Pd-SCN mode, and the aminophosphines form six-membered chelate ring. The spectra of dihalogenopalladium(II) complexes with aminophosphines show that the band maxima are shifted to the short wavelengths as the concentration is decreased.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.365-368
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• 1988

Coordination chemistry of organotin(IV) dithiocarbamate complexes has been examined in terms of far infrared and $^{119}Sn$-NMR spectroscopies. Although the Sn-S stretching vibrational bands of the complex could not be correlated with the bonding nature of the dithiocarbamate ligand, $^{119}Sn$ chemical shifts were sensitive enough to distinguish clearly the coordination number of tin, and as such the bonding mode of the dithiocarbamate ligand could be indentified to be monodentate or bidentate. Thus the $^{119}Sn$-NMR study on new cyclohexyltin(IV) dithiocarbamate complexes along with the known complexes suggests that the bonding mode of the dithiocarbamate ligands and the consequent coordination number of tin are determined mainly by the inductive effects of the organic groups attached to the tin atom.

• Animal Systematics, Evolution and Diversity
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• v.37 no.3
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• pp.229-234
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• 2021

Scolelepis (Scolelepis) daphoinos is newly reported in Korean fauna. This species can be distinguished from its congeners by the following characteristics: the presence of reddish pigment patches on the posterior part of the prostomium, notopodial postchaetal lamellae that are partially fused to the branchiae, and the presence of only the bidentate hooded hooks. The morphological diagnosis and photographs of S. (S.) daphoinos are provided. The partial mitochondrial cytochrome c oxidase subunit I (COI), 16S ribosomal DNA(16S rDNA), and the nuclear 18S ribosomal DNA (18S rDNA) sequences from Korean specimens of S. (S.) daphoinos were determined. Species identification was supported by a comparison of DNA barcode sequences of COI and 16S rDNA with morphological examination from the specimens of type locality, China.

• Analytical Science and Technology
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• v.35 no.4
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• pp.143-152
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• 2022

In this review, previous studies on the synthesis and characterization of the metal Complexes with paracetamol by elemental analysis, thermal analysis, (IR, NMR and UV-Vis (spectroscopy and conductivity. In reviewing these studies, the authors found that paracetamol can be coordinated through the pair of electrons on the hydroxyl O-atom, carbonyl O-atom, and N-atom of the amide group. If the paracetamol was a monodentate ligand, it will be coordinated by one of the following atoms O-hydroxyl, O-carbonyl or N-amide. But if the paracetamol was bidentate, it is coordinated by atoms (O-carbonyl and N-amide), (O-hydroxyl and N-amide) or (O-carbonyl and O-hydroxyl). The authors also found that free paracetamol and its complexes have antimicrobial activity.

• Journal of the Korean Chemical Society
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• v.59 no.3
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• pp.209-214
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• 2015

The formation of complexes between SO₂ and acetic acid was studied theoretically. The ab initio and DFT calculations were performed with MP2 and B3LYP methods using 6-311++G(d,p), aug-cc-pVDZ and aug-cc-pVTZ basis sets. Six stable complexes were identified, and three stable bidentate complexes, C1, C2 and C3, were formed between SO₂ and syn-acetic acid, which is more stable form of acetic acid. Anti-acetic acid also form three complexes, C4, C5 and C6, with SO₂. C4 is bidentate and C5, C6 are monodentate complexes, which are less stable. The most stable complex, C1 has S⋯O=C and O⋯H-O interactions, and the S⋯O and O⋯H distances are less than the sum of van der Waals radii. The vibrational frequencies of complexes were calculated and were compared with those of monomers. The frequency shifts after formation of complex were found, and the overall pattern of frequency shifts relative to monomers is similar among the six complexes.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.444-453
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• 2011

VO(II), ZrO(II), Hf(IV), $UO_2$(II), Sn(II), V(V)$O_3$, Ru(III), Cd(II), Ho(III) and Yb(III) complexes of N'-(2-hydroxybenzyl)-2-(phenylamino)acetohydrazide ($H_2L^1$, 1) and N'-((3-hydroxy-naphthalen-2-yl)methylene)-2-(phenylamino)-acetohydrazide ($H_2L^2$, 13) have been synthesized and characterized by elemental analyses, $^1H$ NMR, IR, UV-Vis, conductance, thermal analyses (DTA and TG). The spectral data showed that the ligands behave as neutral bidentate, monobasic bidentate, monobasic tridentate or bibasic tridentate ligand bonded to the metal ions through the azomethine nitrogen atoms, phenolic hydroxyl group in protonated or deprotonated form and enolic or ketonic carbonyl group. The ligands and their metal complexes exhibit higher antifungal and antibacterial inhibitory effects than parent ligands and the solution of metal ions. Most of metal complexes exhibit higher antifungal activity than standard antifungal drug (amphotricene B). It is also clear that the ligands and their metal complexes have higher antifungal activity than antibacterial activity.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.495-500
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• 2009

Actinide sorption to the geological materials can reduce the mobility and bioavailability of radionuclides released to the environment through the development of nuclear weapons and nuclear energy. Under circumneutral pH conditions, actinide sorption can be enhanced by phosphate anions sorbed on oxide mineral surfaces as indicated by the sorption of trivalent lanthanide ions ($Ln^{3+}$), the chemical analog for trivalent actinide ions ($Ac^{3+}$). In this paper, we examined a ternary sorption system of trivalent europium ions ($Eu^{3+}$) sorbed onto boehmite (${\gamma}$-AlOOH) surfaces pre-sorbed with phosphate anions (${PO_4}^{3-}$), using extended X-ray absorption fine structure (EXAFS) spectroscopy. In the Eu-$PO_4$-boehmite ternary sorption system, $EuPO_4$ surface precipitates were formed as implicated by Eu $L_{III}$-edge EXAFS spectroscopy. Phosphorus K-edge EXAFS fingerprinting indicated a bidentate mononuclear surface complex formation of phosphate sorbed on boehmite surfaces as well as $EuPO_4$ surface precipitate formation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.4
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• pp.397-410
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• 2018

When considering the long-term safety assessment of spent-nuclear fuel management, americium is one of the most radio-toxic actinides. Although spectroscopic methods are widely used for the study of actinide chemistry, application of those methods to americium chemistry has been limited. Herein, we purified $^{241}Am$ to obtain a highly pure stock solution required for spectroscopic studies. Quantitative and qualitative analyses of purified $^{241}Am$ were carried out using liquid scintillation counting, and gamma and alpha radiation spectrometry. Highly sensitive absorption spectrometry coupled with a liquid waveguide capillary cell and time-resolved laser fluorescence spectroscopy were employed for the study of Am(III) hydrolysis and oxalate (Ox) complexation. $Am^{3+}$ ions under acidic conditions exhibit maximum absorbance at 503 nm, with a molar absorption coefficient of $424{\pm}8cm^{-1}{\cdot}M^{-1}$. $Am(OH)_3(s)$ colloidal particles formed under near neutral pH conditions were identified by monitoring the absorbance at around 506-507 nm. The formation of ${Am(Ox)_3}^{3-}$ was detected by red-shifts of the absorption and luminescence spectra of 4 and 5 nm, respectively. In addition, considerable enhancements of the luminescence intensities were observed. The luminescence lifetime of ${Am(Ox)_3}^{3-}$ increased from 23 to 56 ns, which indicates that approximately six water molecules are replaced by carboxylate ligands in the inner-sphere of the Am(III). These results suggest that ${Am(Ox)_3}^{3-}$ is formed through the bidentate coordination of the oxalate ligands.

• Journal of the Korean Chemical Society
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• v.58 no.2
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• pp.169-178
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• 2014

A new series of metal complexes of V(IV), Pd(II), Pt(IV), Ce(IV) and U(VI) with 3-[(3-chlorophenyl)-hydrazono]-pentane-2,4-dione (Cphpd) were synthesized and characterized by elemental analysis, molar conductivity, magnetic moment measurements, UV-vis, FT-IR and $^1H$ NMR as well as TG-DTG techniques. The data indicated that the Cphpd acts as a bidentate ligand through the hydrazono nitrogen and one keto oxygen. The kinetic parameters have been evaluated by using Coats Redfern (CR) and Horowitz-Metzeger (HM) methods. The thermodynamic data reflected the thermal stability for all complexes. The calculated bond length and the bond stretching force constant, F(U=O), values for $UO_2$ bond are $0.775{\AA}$ and $286.95Nm^{-1}$. The bond lengths, bond angles, dipole moment and the lowest energy model structure of the complexes have been determined with DFT calculations. The antimicrobial activity of the synthesized ligand and its complexes were screened.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2731-2736
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• 2013

We report a new tetrameric supramolecular Cu(II) complex ($Cu_4L_4$ = tetrakis(N,N'-bis(salicylidene)-2,2'-ethylenedianiline)Copper(II)) with a Schiff-base ligand ($H_2L$ = N,N'-bis (salicylaldimine)-1,2-ethylenediamine) containing two N,O-bidentate chelate groups. Though the copper sites of $Cu_4L_4$ are non-coupled, the complex exhibits a unsually high catecholase-like activity ($k_{cat}=935h^{-1}$) when the $Cu_4L_4$ solution is treated with 3,5-di-tert-butylcatechol (3,5-DTBC) at basic condition in the presence of air. Combined information obtained from UV-VIS and EPR measurements could lead the suggestion of the reaction pathway in which the substrate may bind to Cu(II) ions by anti-anti didentate bridging mode.