• 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.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.719-725
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• 1998

Tridentate Schiff base ligands were prepared by the reactions of salicylaldehyde and 2-hydroxy-1-naphthaldehyde with 2-aminophenol and 2-amino-p-cresol. And then Cu(II) complexes of those ligands were synthesized. The structures and properties of ligands and their complexes were studied by elemental analysis, $^1H$-NMR, IR, UV-visible spectra, and thermogravimetric analysis. The mole ratio of Schiff base to the metal of complexes was found to be 1:1. Cu(II) complexes were contemplated to be four-coordinated square planar configuration containing one water molecule. The redox process of ligands and complexes in DMSO solution containing 0.1 M TBAP as a supporting electrolyte was investigated by cyclic voltammetry and differential pulse voltammetry with glassy carbon electrode. The redox process of the tridentate Schiff base ligands was totally irreversible. The redox process of Cu(II) complexes was quasi-reversible and diffusion-controlled as one electron by one step process Cu(II)/Cu(I). The reduction potentials of the Cu(II) complexes shifted in the positive direction in the order of [Cu(II)(HNIPC)($H_2O$)]>[Cu(II)(HNIP)($H_2O$)]>[Cu(II)(SIP)($H_2O$)]>[Cu(II)(SIPC)($H_2O$)].

• Mycobiology
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• v.36 no.2
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• pp.93-98
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• 2008

Two Schiff base ligands $L_1\;and\;L_2$ were obtained by the condensation of glycylglycine respectively with imidazole-2-carboxaldehyde and indole-3-carboxaldehyde and their complexes with Zn(II) were prepared and characterized by microanalytical, conductivity measurement, IR, UV-Vis., XRD and SEM. The molar conductance measurement indicates that the Zn(II) complexes are 1:1 electrolytes. The IR data demonstrate the tetradentate binding of $L_1$ and tridentate binding of $L_2$. The XRD data show that Zn(II) complexes with $L_1\;and\;L_2$ have the crystallite sizes of 53 and 61 nm respectively. The surface morphology of the complexes was studied using SEM. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. A comparative study of inhibition values of the Schiff base ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium.

• Korean Journal of Crystallography
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• v.11 no.1
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• pp.28-33
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• 2000

The slow of 2,3-bis(2-pyridyl)pyarzine(bpp) with Ag(CF₃CO₂) produces crystalline product suitable for X-ray crystallography. Crystallographic characterization of the crystal (C/sub 32/H/sub 20/-F/sub 6/N/sub 8/O₄Ag₂: triclinic P1, a=8.518(5)Å, b=9.546(2)Å, c=10.632(1)Å, α=81.11(1)°, β=87.61(3)°, γ=75.66(3)°, V=827.5(5)ų, Z=1, R=0.0431) has provided that the complex is a cyclic dimer [Ag(bpp)(CF₃CO₂)]₂. Each bpp ligand connects two tetrahedral silver(I) ions in a tridentate mode (Ag-N, 2.26()-2.43(2)Å), and the trifluoroacetato anion is bonded to each silver(I) atom in a monodentate fashion (Ag-O, 2.38(1); 2.39(2) Å). The skeletal cyclic dimer is stable up to 212℃, and drastically decomposes around this temperature.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2201-2206
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• 2010

To improve the separation property and stability of metal chelate Cu(II) column, three new kinds of multidentate aminocarboxy silica columns with cation-exchange properties were synthesized using glutamic acid (Glu), glutamic acidbromoacetic acid (Glu-BAA), glutamic acid-bromosuccinic acid (Glu-BSUA) as ligands and silica gel as matrix. The standard proteins were separated with prepared chromatographic columns. The stationary phases exhibited the metal chelate property after fixing copper ion (II) on the synthesized multidentate ligand silica columns. The binding capacity of immobilized metal ion was related with the dentate number of multidentate ligands. Chromatographic behavior of proteins and the leakage of immobilized metal ion on multidentate chelate Cu(II) columns were affected by the dentate number of multidentate ligands and competitive elution system directly. The results showed that quinquedentate Glu-BSUA-Cu(II) column exhibited better chromatographic property and stability as compared with tridentate Glu-Cu(II) column, tetradentate Glu-BAA-Cu(II) column and commonly used IDA-Cu(II) column.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1189-1193
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• 2006

In order to develop radiopharmaceuticals for targeting a serotonin receptor such as $5-HT_{1A}$, histidine-$C_n$-arylpiperazines (AP) (C = alkyl, n = 2, 3, 4) were prepared in five steps with yields of 25%, 37% and 51%, respectively, and radiolabeled with the $[^{99m}Tc(CO)_3(H_2O)+3]^+$. The $^{99m}Tc(CO)_3$-Histidine-Cn-APs were prepared with a high yield (>99%) and characterized as a tridentate complex with a neutral charge to pass through the blood-brain barrier (BBB). The rhenium complexes with $Re(CO)_3$ were also synthesised and comparative experiments were achieved to evaluate the nature of the $^{99m}Tc$ complexes.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3233-3238
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• 2013

Two new Cu(II) complexes, $[Cu_2(acpy-mdtc)_2(HBA)(ClO_4)]{\cdot}H_2O$ (1) (acpy-mdtc- = 2-acetylpyridine S-methyldithiocarbamate and $HBA^-$ = benzilic acid anion) and $[Cu_2(acpy-phtsc)_2(HBA)]{\cdot}ClO_4$ (2) (acpy-$phtsc^-$ = 2-acetylpyridine 4-phenyl-3-thiosemicarbazate) have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. The X-ray analysis reveals that the structures of 1 and 2 are dinuclear copper(II) complexes bridged by two thiolate sulfur atoms of Schiff base ligand and bidentate bridging $HBA^-$ anion. For 1, each of the two copper atoms has different coordination environments. Cu1 adopts a five-coordinate square-pyramidal with a $N_2OS_2$ donor, while Cu2 exhibits a distorted octahedral geometry in a $N_2O_2S_2$ manner. For 2, two Cu(II) ions all have a five-coordinate square-pyramidal with a $N_2OS_2$ donor. In each complex, the Schiff base ligand is coordinated to copper ions as a tridentate thiol mode.

• Macromolecular Research
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• v.13 no.1
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• pp.2-7
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• 2005

A series of ethylene polymerization catalysts based on tridentate bis-imine ligands coordinated to iron and cobalt was reported. The ligands were prepared through the condensation of sterically bulky anilines with allyloxy-and benzyloxy-substituted 2,6-acetylpyridines. The pre-catalyst complexes were penta-coordinate species of the general formula $\{[(ArN=C(Me))_2(4-RO-C_5H_3N)]MCl_2\}$ (Ar=ortho dialkyl-substituted aryl ring; R=allyl, benzyl; M=Fe, Co). In the presence of ethylene and methyl alumoxane cocatalysts, these complexes were active for the polymerization of ethylene, with activities lower than those of metal complexes of the general formula $\{[(2-ArN=C(Me)_2C_5H_3N]MCl_2\}$ (Ar=ortho dialkyl-substituted aryl ring; M=Co, Fe), containing no substituents in 2,6-acetylpyridine ring. The effects of the catalyst structure and temperature on the polymerization activity, thermal properties, and molecular weight were discussed.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.923-928
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• 2000

[FeIII(BBA)DBC]ClO4 as a new functional model for catechol dioxygenases has been synthesized, where BBA is a bis(benzimidazolyl-2-methyl)amine and DBC is a 3,5-di-tert-butylcatecholate dianion.The BBA complex has a structuralfeature that iron cent er has a five-coordinate geometry similar to that of catechol dioxygenase-substrate complex.The BBA complex exhibits strong absorptionbands at 560 and 820 nm in CH3CN which are assigned to catecholate to Fe(III) charge transfer transitions. It also exhibits EPR signals at g = 9.3 and 4.3 which are typical values for the high-spin FeIII (S = 5/2) complex with rhombicsymmetry. Interestingly, the BBA complex reacts with O2 within an hour to afford intradiol cleavage (35%) and extradiol cleavage (60%) products. Surprisingly, a green color intermediate is observed during the oxygenation process of the BBA com-plex in CH3CN. This green intermediate shows a broad isotropic EPR signal at g = 2.0. Based on the variable temperature EPR study, this isotropic signalmight be originated from the [Fe(III)-peroxo-catecholate] species havinglow-spin FeIII center, not from the simple organic radical. Consequently,it allows O2 to bind to iron cen-ter forming the Fe(III)-superoxide species that converts to the Fe(III)-peroxide intermediate. These present data can lead us tosuggest that the oxygen activation mechanism take place for the oxidative cleavingcatechols of the five-coordinate model systems for catechol dioxygenases.

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1175-1179
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• 1998

The aerobic reaction of 2-(acetylpyridine)-S-methyldithiocarbazate (acpy-mdtcH) and 2-(acetylpyridine)-N-phenylthiosemicarbazate(acpy-phTscH) with manganese(Ⅱ) acetate affords Mn(acpy-mdtc)2 and Mn(acpyphTsc)2, respectively. The spectroscopic data and X-ray structure of Mn(acpy-mdtc)2 are reported. Crystal data for Mn(acpy-mdtc)2; C18H20N6S4Mn, mol wt 503.58, monoclinic crystal system(P21/c) a=12.240(5) Å, b= 10.918(l) Å, c=17.651(3) Å, β=105.93(2), and V=2268(l) Å3, Z=4, 5071 data collected with 0°< 2θ < 52.64°, 2995 data with I > 3σ(I), R= 0.046, Rw= 0.065. The ligands act as tridentate NNS donors. The two Mn-S distances are not equal, and respectively 2.512(2) Å and 2.541(2) Å. The average Mn-N (azomethine) length, 2.242(5) Å, is slightly shorter than the average Mn-N (pyridyl) length, 2.262(5) Å. The coordination environment about MN(Ⅱ) center deviates considerably from octahedral geometry. The manganese(Ⅱ)-manganese(Ⅰ) and manganese(Ⅰ)-manganese(0) reduction potentials of Mn(acpy-mdtc)2 are ∼-l.71 and ∼-l.98 V while those of Mn(acpy-phTsc)2 are ∼-l.87 and ∼-2.11 V vs. Ag/Ag+ in dimethyl sulfoxide, respectively.