• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.440-447
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• 2012

Heteroleptic complexes of zirconium (IV) derived from bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic ${\beta}$-diketones of the general formula ZrLL' (where $LH_2=RCNH(C_6H_4)SC:C(OH)N(C_6H_5)N:CCH_3$, $R=-C_6H_5$, $-C_6H_4Cl(p)$ and $L^{\prime}H_2=R^{\prime}C:(NOH)C:C(OH)N(C_6H_5)N:CCH_3$, $R^{\prime}=-CH_2CH_3$, $-C_6H_5$, $-C_6H_4Cl(p)$ were prepared by the reactions of zirconium tetrachloride with disodium salts of Schiff bases ($L\;Na_2$) and oximes of heterocyclic ${\beta}$-diketones ($L^{\prime}\;Na_2$) in 1:1:1 molar ratio in dry refluxing THF. The structures of these monomeric zirconium (IV) complexes were elucidated with the help of elemental analysis, molecular weight measurements, spectroscopic (IR, NMR and mass) studies. A distorted trigonal bipyramidal geometry may be suggested for these heteroleptic zirconium (IV) complexes. The ligands (bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic ${\beta}$-diketones) and their heteroleptic complexes of zirconium (IV) were screened against A. flavus, P. aeruginesa and E. coli.

• Journal of the Korean Chemical Society
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• v.57 no.1
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• pp.52-62
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• 2013

The interaction of titanium (IV), yttrium (III), zirconium (IV), palladium (II) and cerium (IV) with deprotonated enrofloxacin leads to the formation of the neutral or cationic mononuclear complexes. The isolated solid complexes have been characterized with physicochemical and spectroscopic techniques and thermogravimeteric analyses. The spectroscopic data indicate that the enrofloxacin ligand is on the deprotonated mode acting as bidentate ligand coordinated to the metal ions through the ketone oxygen and a carboxylato oxygen and the metal ions completed the coordination number with water molecules. The thermal decomposition mechanisms proposed for enrofloxacin and their metal complexes were discussed. The activation energies, $E^*$, enthalpies, ${\Delta}H^*$, entropies, ${\Delta}S^*$ and Gibbs free energies, ${\Delta}G^*$, of the thermal decomposition reactions have been derived from thermogravimetric (TG) and differential thermogravimetric (DTG) curves, using Coats-Redfern (CR) and Horowitz-Metzeger (HM) methods. The antimicrobial activity has been evaluated against six different microorganisms.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.94-98
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• 2008

A fundamental study was developed concerning the novel solvent extraction of the tetravalent metal ions; zirconium(IV), hafnium(IV) and thorium(IV). Their extraction behavior in toluene was investigated with a recently synthesized naphthol-derivative Schiff base, 1-({[4-(4-{[(E)-1-(2-hydroxy-1-naphthyl)methyliden]amino}phenoxy) phenyl]imino}methyl)-2-naphthol (HAPMN). The spectrophotometrical examination of the complex formation between HAPMN and the Zr(IV), Hf(IV) and Th(IV) ions in acetonitrile revealed the formation of stable 1:1 complexes in the solution. After the thorium extraction in toluene, it was found that [Th(OH)3HA] was the respective deriving substance. While, in the case of zirconium and hafnium extraction, the extracted adduct was found to be [M4(OH)8(H2O)16Cl62HA]. The stoichiometric coefficients of these extracted species were determined by the slope analysis method. The extraction reaction followed a cation exchange mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.303.2-303.2
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• 2014

The oxides of group IV transition metals such as titanium, zirconium, hafnium have many important current and future application, including protective coatings, sensors and dielectric layers in thin film electroluminescent (TFEL) devices. Recently, group IV transition metal oxide films have been intensively investigated as replacements for SiO2. Due to high permittivities (k~14-25) compared with SiO2 (k~3.9), large band-gaps, large band offsets and high thermodynamic stability on silicon. Herein, we report the synthesis of new group IV transition metal complexes as useful precursors to deposit their oxide thin films using chemical vapor deposition technique. The complexes were characterized by FT-IR, 1H NMR, 13C NMR and thermogravimetric analysis (TGA). Newly synthesised compounds show high volatility and thermal stability, so we are trying to deposit metal oxide thin films using the complexes by Atomic Layer Deposition (ALD).