• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.679-691
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• 2012

New series of metal complexes of Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and Pt(II) with 4-(p-chlorophenyl)-1-(pyridin-2-yl)thiosemicarbazide (HCPTS) have been synthesized and characterized by elemental analyses, magnetic moment, spectra (IR, UV-Vis, $^1H$ NMR, mass and ESR) and thermal studies. The IR data suggest different coordination modes for HCPTS which behaves as a monobasic bidentate with all metal ions except Cu(II) and Zn(II) which acts as a monobasic tridentate. Based on the electronic and magnetic studies, Co(II), Cu(II), Pd(II) and Pt(II) complexes have square - planner, Ni(II) has mixed stereochemistry (tetrahedral + square planar), while Zn(II) is tetrahedral. Molar conductance in DMF solution indicates the non-ionic nature of the complexes. The ESR spectra of solid copper(II) complex show $g_{\parallel}$ (2.2221) > $g_{\perp}$ (2.0899) > 2.0023 indicating square-planar structure and the presence of the unpaired electron in the $d_x2_{-y}2$ orbital with significant covalent bond character. The thermal stability and degradation kinetics of the ligand and its metal complexes were studied by TGA and DTA and the kinetic parameters were calculated using Coats-Redfern and Horowitz-Metzger methods. The complexes have more antibacterial activity against some bacteria than the free ligand. However, the ligand has high anticancer activities against HCT116 (human colon carcinoma cell line) and HEPG2 (human liver hepatocellular carcinoma cell line) compared with its complexes.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2917-2924
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• 2012

Four novel metal-organic complexes $[Cd_2(IP)_2(TBZ)_2(H_2O)_2]{\cdot}(H_2O)$ (1), $[Zn_4(IP)_4(TBZ)_4]{\cdot}2(H_2O)$ (2), $[Zn_2(BTC)(TBZ)_2(CO_2H)]$ (3), [Co(PDC)(TBZ)] (4) (where IP = isophthalate; TBZ = thiabendazole; BTC = 1,3,5-benzenetricarboxylate; PDC = pyridine-3,4-dicarboxylate) have been prepared and characterized by IR spectrum, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. X-ray structure analysis reveals that 1, 2, and 3 are one-dimensional chain polymers, while 4 is a two-dimensional network polymer. The TBZ acts as a typical chelating ligand coordinated to the metal center in all complexes. The 1D chain architecture of 1 is constructed from isophthalates and cadmium atoms. A simultaneous presence of chelating, monodentate and bidentate coordination modes of IP ligands is observed in complex 2. In complex 3, the 16-membered rings are alternately arranged forming an infinite 1D double-chain structure. The 2D skeleton of 4 is formed by cobalt ions as nodes and PDC dianions as spacers, through coordination bonds. The hydrogen bonds and ${\pi}-{\pi}$ stacking play important roles in affecting the final structure where complexes 1 and 3 have 2D supramolecular networks, while complexes 2 and 4 have 3D supramolecular architectures.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1157-1161
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• 2008

2,6-Dinitrophenol (2,6-DNP) complexes with lanthanide series including yttrium (except Pm, Tm, and Lu) have been synthesized and their crystal structures have been analyzed by X-ray diffraction methods. Singlecrystal X-ray structure determinations have been performed at 296 K on the Ce$\rightarrow$Yb species and shown them to be isomorphous, triclinic, P1, a = 8.6558(2)$\rightarrow$8.5605(3) $\AA$, b = 11.8813(3)$\rightarrow$11.6611(4) $\AA$, c = 13.9650(3) $\rightarrow$13.8341(5) $\AA$, $\alpha$ = 73.785(1)$\rightarrow$73.531(2)o, $\beta$ = 74.730(1)→74.903(2)${^{\circ}}$, $\gamma$ = 69.124(1)→ 69.670 $(2){^{\circ}}$, V = 1266.86(5)→1221.53(7) $$\AA^{3}$$, Z = 2. In Ln(III) complexes, three 2,6-DNP ligands coordinate directly to the metal ion in the bidentate fashion. The nine coordinated Ln(III) ion forms slightly distorted tri-capped trigonal prism. There are no water molecules in the crystal lattice. The dependences of metal to ligand bond lengths are discussed on the atomic number of lanthanide elements. The thermal properties of lanthanide complexes of 2,6- DNP have also studied by TG-DTG and DSC thermal analysis methods.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.355-355
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• 2016

There has been an explosive development of nanocrystal (NC) synthesis and application due to their composition-dependent specific properties. Despite the composition, shape, and size of NCs foremost determine their physicochemical properties, the surface state and molecule conjugation also drastically change their characteristics. To make practical use of NCs, it is a prerequisite to understand the NC surface state and the degree to which they have been modified because the reaction occurs on the interface between the NCs and the surrounding medium. We report in here an analysis method to identify conjugated ligands and their binding states on semiconductor nanocrystals based on their molecular information. Surface science techniques, such as time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and FT-IR spectroscopy, are adopted based on the micro-aggregated sampling method. Typical trioctylphosphine oxide-based synthesis methods of CdSe/ZnS quantum dots (QDs) have been criticized because of the peculiar effects of impurities on the synthesis processes. Since the ToF-SIMS technique provides molecular composition evidence on the existence of certain ligands, we were able to clearly identify the n-octylphosphonic acid (OPA) as a surface ligand on CdSe/ZnS QDs. Furthermore, the complementary use of the ToF-SIMS technique with the FT-IR technique could reveals the OPA ligands' binding state as bidentate complexes.

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.661-668
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• 1992

The polymeric compound [{Mo(NO)_2Cl_2}n] was prepared by reductive nitrosylation of NaNO_2 and acidified FeSO_4 with MoCl_5. The reactions of [{Mo(NO)_2Cl_2}n] with unidentate and bidentate ligands afforded neutral monomeric $[Mo(NO)_2Cl_2L_2(or L-L)] in high yield (80∼90%). 3,5-Lutidine, {\gamma}-Cyanopyridine, 1,2-Phenylenediamine, 1,10-Phenanthroline, sym-Diphenylethylenediamine, 9,10-Phenanthrenequinone, 1,3-Bis(diphenylphosphino)propane and 8-Hydroxyquinoline were used as coordinating ligands. The preparation and characterization of these dinitrosylmolybdenum complexes by elemental analysis, 1H NMR, infrared, and UV-Visible spectroscopy are reported. The infrared spectra indicate that in all of the compounds prepared, the NO groups occupy cis-positions in the octahedral group of ligands.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.46-52
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• 1992

$TiO_2/SO_4{^{2-}}$ was prepared by precipitation from the mixed solution of titanium chloride and hydrochloric acid followed by modification with sulfuric acid. The characterization of prepared catalyst was performed by using IR, XPS, XRD and DT-TGA. Infrared spectra of $TiO_2/SO_4{^{2-}}$ showed bidentate sulfate ion coordinated to the surface of $TiO_2$. The acid strength of modified catalyst was at least $H_0{\leq}-14.52$, showing the superacidic properties which are attributed to the double bond nature of S=O of the complex formed by the interaction of $TiO_2$ with sulfate ion. For $TiO_2/SO_4{^{2-}}$, the specific surface area increased and the transition from the amorphous to anatase phase occurred at a higher temperature, as compared with pure $TiO_2$.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.212-217
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• 1992

The thermodynamic parameters for the formation of gadolinium benzoate have been determined in the ionic medium of 0.1 M $NaClO_4$ at $25^{\circ}C$ in aqueous solution. The thermodynamic results indicate that the complex is stabilized by the excess entropy effect caused by the dehydration of reacting ions. The especially high stability of Gd(III)-benzoate compared to the monodentate ligand complexes might be ascribed to the conjugation effect of the benzene ring in the benzoate ligand. IR spectra show that benzoate anion acts as a bidentate ligand toward $Gd^{3+}$ to form a chelate ring in solid state. Magnetic susceptibility data of the compound were also obtained and well described by Curie-Weiss law in the temperature range 80${\sim}$300K.

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.692-697
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• 1995

The chemical compositions and possible structure for the complex of B15C5 with Nd(Ⅲ) have been determined by NMR spectrophotometry in acetone-d6. On the stepwise additions of Nd(Ⅲ) to B15C5 solution of constant concentration, all the resonances shifted to downfield and the mole ratio of B15C5 to Nd(Ⅲ) was found to be 1 : 1. From the line broadening of proton peaks of NMR spectra, it was found that oxygen atoms in B15C5 interact with Nd(Ⅲ) ion. And in IR spectra of Nd(Ⅲ)-B15C5 complex, the band of asymmetric C-C-O stretching vibration shifted to a lower frequency region upon complexation. We have proposed the possible structure of the Nd(Ⅲ)-B15C5 coordinated with the five ether oxygen atoms and with the three bidentate nitrato groups.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.49-52
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• 2011

A dinuclear copper(II) complex of [$Cu_2(aceace)_4$(dipyph)] [aceace = acetylacetone, dipyph = 1,4-di(4-pyridylethene-2-yl-)benzene] has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction. It crystallizes in the monoclinic system, space group P21/c, with lattice parameters a = 7.9584(16) $\AA$, b = 18.594(4) $\AA$, c = 15.063(4) $\AA$ $\beta=120.97(2)^o$ and $M_r$ = 807.85 ($C_{40}H_{44}Cu_2N_2O_8$), Z = 2. Each of the $Cu^{2+}$ ion adopts a square pyramid geometry and coordinates with four oxygen atoms from two aceace ligands and one nitrogen atom from dipyph bidentate ligand. Magnetic measurement shows that the Weiss constant and Curie constant for the title compound are -0.22 K and 0.1154 emu K/mol, respectively. Thermal stability data indicate that the title complex undergoes two steps decomposition and the residue is $Cu_2O_4$. In the potential range of -1.5 ~ 0.8 V, the title complex represents an irreversible electrochemical process.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1197-1202
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• 2005

The Ln(III) complexes with picrate ligand, $[Sm(Pic)_2(H_2O)_6]Pic{\cdot}6H_2O$, 1, and $[Ho(Pic)(H_2O)_7](Pic)_2{\cdot}3H_2O$, 2, have been synthesized and their crystal structures are analyzed by X-ray diffraction methods. Complex 1, crystallizes in the monoclinic $P2_1/n$ space group and complex 2 in the triclinic P-1 space group. In complex 1, two picrate ligands coordinate to the Sm(III) ion, one of them in the bidentate fashion. There are one picrate anion and six water molecules in the crystal lattice. The nine-coordinated Sm(III) ion forms a slightly distorted tricapped trigonal prism. In complex 2, only one picrate ligand coordinates to the metal ion as a monodentate. There are two picrate anions and three water molecules in the crystal lattice. The eight-coordinated Ho(III) ion forms a distorted bicapped trigonal prism. Based on the results of the TG-DTG and DSC thermal analysis, it was analyzed that the lanthanide picrate complexes 1 and 2 are thermally decomposed in three distinctive stages, the dehydration, the picrate decomposition, and the formation of the metal oxide.