• Journal of the Korean Chemical Society
• /
• v.57 no.5
• /
• pp.574-590
• /
• 2013

A new solid complexes of Ti(IV), Y(III) and Ce(IV) have been synthesized with ofloxacin. The formulae and structure of the complexes have been proposed in the light of analytical, spectral ($^1H$ NMR, IR and UV-Visible), magnetic, molar conductivities and thermal studies. The complexes are soluble in DMSO-$d_6$ and DMF. The measured molar conductance values indicate that, the three complexes are electrolyte in nature. The results support the formation of the complexes and indicated that ofloxacin reacts as a bidentate ligand chelate to the metal ion through the pyridone oxygen and one carboxylato oxygen. The kinetic parameters of thermogravimetric and its differential have been evaluated by using Coats Redfern (CR) and Horowitz-Metzeger (HM) methods. The thermodynamic data reflect the thermal stability for all complexes. The metal- ligand binding of the Ti(IV), Y(III) and Ce(IV) complexes is predicted using density funcational theory at the B3LYP-CEP-31G level of theory and total energy, dipole moment estimation of different Ti(IV), Y(III) and Ce(IV) ofloxacin structures. The biological activities of the ofloxacin, inorganic salts and their metal complexes were assayed against different bacterial species.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.10
• /
• pp.1050-1052
• /
• 1997

The complexes M(CO)4-1,2-(PPh2)2-1,2-C2B10H10 (M=Cr 2a, Mo 2b, W 2c) have been prepared in good yields from readily available bis-diphenylphosphino-o-carboranyl ligand, closo-1,2-(PPh2)2-1,2-C2B10H10 (1), by direct reaction with Group Ⅵ metal carbonyls. The infrared spectra of the complexes indicate that there is an octahedral disposition of chelate bis-diphenylphosphino-o-carboranyl ligand around the metal atom. The crystal structure of 2a was determined by X-ray diffraction. Complex 2a crystallizes in the monoclinic space group P21/n with cell parameters a = 12.2360(7), b = 17.156(1), c = 16.2040(6) Å, V = 3354.1(3) Å3, and Z =4. Of the reflections measured a total of 2514 unique reflections with F2 > 3σ(F2) was used during subsequent structure refinement. Refinement converged to R1 = 0.066 and R2 = 0.071. Structural studies showed that the chromium atom had a slightly distorted pseudo-octahedral configuration about the metal center with two phosphine groups of o-carborane occupying the equatorial plane cis-orientation to each other. These metal carbonyl complexes are rapidly converted to the corresponding metal carbene complexes, [(CO)3M=C(OCH3)(CH3)]-1,2-(PPh2)2-1,2-C2B10H10 (M= Cr 3a, Mo 3b, W 3c), via alkylation with methyllithium followed by O-methylation with CF3SO3CH3.

• Journal of the Korean Chemical Society
• /
• v.33 no.5
• /
• pp.510-515
• /
• 1989

New nickel(II) and coppr(II) complexes of a saturated pentaaza macrobicyclic ligand $[Ni(D)]^{2+},\;[Cu(D)]^{2+},\;and\;[Cu(D)Cl]^+$, where D is 1,3,6,9,12-pentaazabicyclo[10,2,l]pentadecane, have been prepared by the template condensation reaction of tetraethylenepentamine and formaldehyde in the presence of the metal ion. The complexes contain one imidazolidine ring in the macrobicyclic ligand, D. The complexes $[Ni(D)]^{2+}\;and\;[Cu(D)]^{2+}$ have square planar geometry with 5-5-5-6 chelate ring sequence. The electronic spectra of $[Cu(D)Cl]^+$indicate that the complex has square pyramidal geometry. Synthesis, charactrization, and the spectroscopic and chemical properties of the macrobicyclic nickel(II) and copper(II) complexes are described.

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

• Bulletin of the Korean Chemical Society
• /
• v.24 no.2
• /
• pp.225-228
• /
• 2003

• Journal of Environmental Health Sciences
• /
• v.18 no.2
• /
• pp.106-116
• /
• 1992

In order to examine the influences of diluent, DVB, and ligand content, in the adsorption velocities and capacities of chelating resins to heaw metal ions, the chelating resins containing the PO$_3$H, amide, and PO$_3$H+amide were prepared from AN-STR-DVB copolymer. The adsorption capacities of chelating resins were measured by ICP-AES. The major results of the studies are as follows: The optimized compositions of the chelating resins having the highest adsorptivity for the heavy metal ions were found to be DVB=7 wt%, toluene= 100 vol%. The adsorption rate of the chelating resins to the heaw metal ions was PO$_3$H > PO$_3$H+Amide > Amide in order.

• Journal of the Korean Chemical Society
• /
• v.12 no.3
• /
• pp.81-84
• /
• 1968

Stabilities of chelates of 7-nitroso-8-hydroxyquinoline-5-sulfonate have been determined for divalent transition metal ions, Mn(Ⅱ), Fe(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) by means of the Calvin-Bjerrum technique. Comparison of these stability constants with those obtained for 8-hydroxyquinoline, and 8-hydroxyquinoline-5-sulfonate shows that the observed differences are essentially the results of the lower basicity of the sulfonated group and different metal-ligand bond. The divalent metal chelate stability sequence is not in agreement with the reported metal orders for other chelating agents. The stabilities were found to follow the order Mn(Ⅱ) < Fe(Ⅱ) ${\approx}$ Co(Ⅱ) > Ni(Ⅱ) < Cu(Ⅱ) > Zn(Ⅱ).

• Journal of the Korean Applied Science and Technology
• /
• v.22 no.4
• /
• pp.299-305
• /
• 2005

In this study, we designed color of tunable and high efficient organic materials using the quantum dynamics and the semi-empirical calculation, and applied this results to the fabrication of organic light-emitting diodes. Also we optimized the molecular structure of phosphorescent materials and the energy transfer from a host to a dye which makes organic light-emitting diodes improve. Using quantum dynamics method, the molecular structures of ligand only and the whole metal chelate were optimized, and these energy levels were calculated. From this test results, we could understand the emission mechanism of phosphors with various ligands as well as design the proper ligands reducing the T-T annihilation and the carrier lifetime. We also could design ligands with various colors using this test method.

• Analytical Science and Technology
• /
• v.13 no.6
• /
• pp.810-814
• /
• 2000

The open-chain hexadentate $N_4$, $O_2$ ligands 1, 15-bis(2-hydroxybenzyl)-2, 6, 10, 14-tetraazapentadecane (BSATPD. 4HCl) has been synthesized as its tetrahydro-chloride salt and characterized by EA, IR, NMR, and Mass spectrum. Its protonation constants ($logK_n{^H}$) and stability constants ($logK_{ML}$) for $Cu^{2+}$, $Ni^{2+}$, $Co^{2+}$ and $Zn^{2+}$ ions were determined in aqueous solution by potentiometry and compared with those of analogous $N_4$, $O_2$ ligands contain ethtylenic spacers or propylenic spacers, which make six-membered chelate rings between the aliphatic nitrogen atoms.

• Bulletin of the Korean Chemical Society
• /
• v.17 no.8
• /
• pp.688-693
• /
• 1996

Tetradentate Schiff base ligands derived from 2-hydroxy-1-naphthaldehyde and aliphatic diamine have been synthesized. Cu(Ⅱ) complexes of Schiff base ligands have been synthesized from the free ligands and copper acetate. The mole ratio of ligand to copper was identified to be 1:1 by the result of elemental analysis and Cu(Ⅱ) complexes were in a four-coordinated configuration. The electrochemical redox process of Cu(Ⅱ) complexes in a DMF solution has been investigated by cyclic voltammetry, chronoamperometry, differential pulse voltammetry, and controlled potential coulometry. The redox process of Cu(Ⅱ) complexes is one electron transfer process in quasi-reversible and diffusion-controlled reaction. The electrochemical redox potentials and the kinetic parameters of Cu(Ⅱ) complexes are affected by the chelate ring of Schiff base ligands.