• Journal of the Korean Chemical Society
• /
• v.39 no.3
• /
• pp.191-197
• /
• 1995

The reactions of [${Mo(NO)_2Cl_2}_n$] with unidentate ligands in $CH_2Cl_2$ solvent afforded monomeric complexes [$Mo(NO)_2L_2Cl_2$]. $[Mo(NO)_2L_4](ClO_4)_2$ was obtained by reaction of unidentate with $[Mo(NO)_2L_2Cl_2]$ in aceton solvent. 4-Dimethylaminopyridine(dmap), pyridine(py), and isoquinoline(isoq) were used as coordinating ligands. These dinitrosylmolybdenum complexes are prepared and characterized by elemental analysis, $^1H$ NMR, infrared, and UV-Visible spectroscopy. The infrared spectra indicate that the NO groups occupy cis-positions of the octahedral.

• Journal of the Korean Chemical Society
• /
• v.38 no.4
• /
• pp.319-327
• /
• 1994

The novel Schiff base hexadentate ligand, bis-(salicylaldehyde)-triethylentetramine (BSTT) and heptadentate ligand, bis-(salicylaldehyde)-tetraethylenpentamine(BSTP) were synthesized by the reaction of salicylaldehydes with triethylenetetramine and tetraethylenepentamine, having four and five nitrogen atoms, respectively. These liquid Schiff base ligands were become in form of the pale-yellow crystals in the specific pH 4.0 by adding acetic acid concentrated hydrochloric acid. The Cu(Ⅱ) complexes of the Schiff bases were synthesized by reaction of the Schiff base with Cu(Ⅱ) ion and their possible structures were proposed by several analytical data, and physical and chemical properties.

• Polymer(Korea)
• /
• v.29 no.4
• /
• pp.321-330
• /
• 2005

In 1990's the Korean polyolefin industry boomed up through the development of magnificient polymerization catalysts. To understand the general situation of polymerization catalyst R & D, the various experimental results had been summarized for the investigation of not only the supported Ziegler-Natta catalyst used presently in polyolefin industry but also the metallocene catalysts applied for the preparation of special grade of polyolefin. In addition, it had been shown that the new polymeric materials were prepared by new developed catalyst, and the polymer in-situ nanocomposites could be obtained with the application of catalyst heterogenization procedures.

• Journal of the Korean Chemical Society
• /
• v.47 no.6
• /
• pp.553-558
• /
• 2003

The crystal structure of $[n-Bu_4N]_2[Mo_6O_{19}]$(TBAM) (n-Bu4N=tetrabutylammonium) has been determined by X-ray crystallography. It crystallizes in the monoclinic system, space group C2/c, with lattice parameters ${\alpha}$=16.314(5), b=17.288(5), c=17.776(4)${\AA}$ ${\beta}$=101.47(3), and Z=4. In $[Mo_6O{19}]^{2-}$ anion, Mo atoms occupy six vertices of octahedron and each Mo atom is coordinated by six oxygen atoms to adopt distorted octahedral coordination geometry. The average bond distance of Mo-Ot (terminal), Mo-Ob (bridged) and Mo-Oc (central) are 1.680 ${\AA}$, 1.931 ${\AA}$ and 2.325 ${\AA}$ respectively. In $[n-Bu_4N]^+$ cation, the N atom possesses a slightly distorted tetrahedral geometry. There are some potential extensive C-H ${\cdots}$ O hydrogen bonds in the lattice, by which connecte molecules and stabilize the crystal structure. Thermogravimetric analysis suggests that thermal decomposition of the title compound includes two transitions and it loses weight at 356.0 and 803.5 $^{\circ}$, respectively, and the residue presumable be $Mo_2O_2$. Accordingly, the title compound has high thermal stability.

• Journal of the Korean Chemical Society
• /
• v.55 no.4
• /
• pp.603-611
• /
• 2011

Ethoxylacetyl oxime ligands [HL, (1) and $H_2L^1$, (3)] react with copper(II) acetate monohydrate yield octahedral and square planar complexes, respectively. The complexes have been postulated due to elemental analyses, IR, UVVis. spectra, magnetic susceptibility, conductivity and ESR spectra. Molar conductance of the complexes in DMF indicates a non-ionic character. The ESR spectra of [$(L)_2Cu(H_2O)_2$], (2) complex at room temperature and 77K are characteristic of an axial symmetry ($d_{x2-y2}$) with covalent bond character and have a large line width typical of dipolar interactions. However, [$(L^1)Cu$], (4) complex in the solid state showed spectra of marked broadening and loss of hyperfine splitting confirming spinexchange interactions between the copper(II) sites. The spectrum of the doped copper(II) complex at room temperature showed super-hyperfine splitting from coordinated nitrogen atoms and it has an axial type ($d_{x2-y2}$) with covalent bond character and an essentially square-planar arrangement around the copper(II) ion. The spectrum of [$(L^1)Cu$], (4) in frozen methanol at 77K was characteristic of the triplet state of a dimer species and the distance found between the two copper(II) centers was calculated and is equal to 4.8 ${\AA}$.

• Korean Journal of Crystallography
• /
• v.16 no.2
• /
• pp.75-80
• /
• 2005

[ $LiK_{1-x}Rb_{x}SO_{4}(x=0.1,\;0.2)$ ] crystals were grown by means of aqueous solution growth technique at 313 K. Structure analysis of them was carried out with space group $P6_{3}(#173)$ by X-ray diffraction. In these compounds, the Li and $SO_{4}^{2-}$ ions lying on the three-fold axes formed infinite three-dimensional network and K and Rb atoms located on the six-fold axes are coordinated by twelve and fifteen O atoms respectively. The most suitable stabilization was achieved when the occupancy factors of K and Rb atoms are (0.91 : 0.09), (0.77 : 0.23) respectively.

• Applied Biological Chemistry
• /
• v.17 no.2
• /
• pp.143-148
• /
• 1974

The interaction of the carcinogenic mycotoxin, Aflatoxin $B_1$, with the electron-donating molecule, benzene, was studied spectrophotometrically. The formation of charge-transfer complex between Aflatoxin $B_1$ and benzene in the presence of zinc chloride was observed and the apparent equilibrium constant of this charge-transfer complex was found to be 0.198 (liter $mole^{-1}$). It is assumed that, as the result of this study, some charge-transfer complexes could be formed between the weak electron-accepting Aflatoxin $B_1$ and strong electron-donating molecules, and the spectral changes occurred in the binding of Aflatoxin $B_1$ with proteins or DNA is attributed to the existence of charge-transfer type interaction.

• Journal of the Korean Electrochemical Society
• /
• v.10 no.2
• /
• pp.150-154
• /
• 2007

Redox complexes to transport electrodes from biomaterial to electrodes are very important part in commercial biosensor industry. A novel osmium redox complex was synthesized by the coordinating pyridine group with osmium metal. A novel osmium complex is described as $[Os(dme-bpy)_2(ap-im)Cl]^{+/2+}$. We have been studied the electrochemical characteristics of this osmium complex with electrochemical techniques such as cyclic voltammetry and chronoamperommetry. In order to immobilize osmium redox complexes on the electrode, we deposited gold nano-particles on screen printed carbon electrode(SPE). The electrical signal converts the osmium redox films into an electrocatalyst for glucose oxidation. The catalytic currents were monitored that the catalytic currents were linearly increased from 1 mM to 5 mM concentrations of glucose.

• Applied Chemistry for Engineering
• /
• v.26 no.6
• /
• pp.631-639
• /
• 2015

Extraction/separation of cobalt by solvent extraction is reviewed. Separation of cobalt using various reagents and also cobalt recovery from scrap using commercial extractant were analyzed. The separation ability for cobalt followed the order of phosphinic > phosphonic > phosphoric acid due to the increasing stabilization of tetrahedral coordination of cobalt complexes with the extractant in the organic phase. Depending upon the solution composition, commercial extractants like Cyanex 272, D2EPHA and PC 88A should primarily be used for commercial extraction processes and also the efficient management of their combination could address various separation issues associated with cobalt bearing scrap.

• Journal of the Korean Chemical Society
• /
• v.37 no.10
• /
• pp.903-909
• /
• 1993

Reaction mechanism of palladium(0, II)-phosphines complexes catalyzed cyclocarbonylation for unsaturated carboxylic acid such as crotonic acid, methacrylic acid and 3-butenoic acid has been investigated by product analysis, molecular mechanics and extended Huckel molecular orbital method. Reaction of 3-butenoic acid with palladium(0, II)-phosphines catalyst gives palladium containing cycloester through intermediate palladium-olefin ${\pi}$ -complex in the catalytic carbonylation. Palladium(0, II)-phosphines complexes catalyze the cyclocarbonylation of 3-butenoic acid to give 3-methylsuccinic anhydride and glutaric anhydride. But ${\pi}$ -complexes with palladium(0, II)-phosphines and unsaturated carboxylic acids such as crotonic acid and methacrylic acid are not effective the catalytic cyclocarbonylation.