• Journal of the Korean Chemical Society
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• v.46 no.3
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• pp.194-204
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• 2002

Aseries of novel salen-type complexes {[Mn(III)($L_{acn}$)CI]: n=1~11} containing CI- ion were obtained by reactions of the Mn(CH$_3$COO)$_2$· 4H$_2$O with the potentially tetradentate compartmental ligand {$H$_2$L_{acn}$} prepared by condensation the of one mole of diamine {ethylenediamine, 1,3-propnediamine, o-phenylenediamine and 2,2-dimethyl-1,3-propanediamine} with two moles of aldehyde {alicylaldehyde, 5-chloro-salicylaldehyde, 3,5-dichlorosalicylaldethyde, and 3,5-di-tert-butyl-2-hydroxy-benzaldehyde} in a methanol solution. The resulting salen-type lignds and their Mn(III) complexes were identified and characterized by elemental analysis, conductivity, themogravimetry and UV-VIS, IR and NMR spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1661-1666
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• 2004

The reaction of titanium tetraisopropoxide with 2 equiv of N,N-diethyl acetoacetamide affords Ti($O^iPr)_2(CH_3COCHCONEt_2)_2$ (1) as colorless crystals in 80% yield. Compound 1 is characterized by spectroscopic (Mass and $^1H/^{13}C$ NMR) and microanalytical data. Molecular structure of 1 has been determined by a single crystal X-ray diffraction study, which reveals that it is a monomeric, cis-diisopropoxide and contains a six coordinate Ti(IV) atom with a cis($CONEt_2$), trans($COCH_3$) configuration (1a) in a distorted octahedral environment. Variable-temperature $^1H$ NMR spectra of 1 indicate that it exists as an equilibrium mixture of cis, trans (1a) and cis, cis (1b) isomers in a 0.57 : 0.43 ratio at -20$^{\circ}C$ in toluene-$d_8$ solution. Thermal properties of 1 as a MOCVD precursor for titanium dioxide films have been evaluated by thermal gravimetric analysis and vapor pressure measurement. Thin films of pure anatase titanium dioxide (after annealing above 500$^{\circ}C$ under oxygen) have been grown on Si(100) with precursor 1 in the substrate temperature range of 350- 500$^{\circ}$ using a bubbler-based MOCVD method.

• Journal of the Korean Chemical Society
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• v.30 no.3
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• pp.282-288
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• 1986

Kinetic studies were carried out for the substitution of $H-2$O for $Cl^-$ ligand of chloropentaamminecobalt(III) in the presence of $Hg^{2+}$ catalyst by UV spectrophotometer. It has been found that $Hg^{2+}$ ion appears first order dependence and the overall reaction is second order. The reaction system can be believed to occur via $S_N2$ reaction, because the calculated rate equation for our presumed $S_N2$ mechanism is in agreement with the observed one.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.673-675
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• 2004

The tetranuclear copper(II) cluster compound $[Cu_4OCl_6(C_{14}H_{12}N_2)_4]$ has been synthesized by hydrothermal reaction and studied by X-ray diffraction. The four copper(II) atoms locate four capsheaves of a tetrahedral skeletal structure and a oxygen atom as interstitial atom occupies the center position of the same tetrahedron, and each edge of the Cu-Cu tetrahedron is bridged by one ${\mu}_2$-Cl anion. The copper atom possesses slightly distorted trigonal bipyramidal geometry with three ${\mu}_2$-Cl atoms in equatorial position and the interstitial O atom and one N atom from 3-benzyl-benzimidazole ligand occupying axial position. The Cu-Cu distances are in the range of 3.0986-3.1162 ${\AA}$. The EPR spectrum suggested that the copper(II) ground state $d_{x2-y2}$ and the coordination geometry was trigonal bipyramidal.

• Bulletin of the Korean Chemical Society
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• v.19 no.6
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• pp.671-676
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• 1998

The formation and dissociation rates of $Ce^{3+}$ Complexes of the 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-NN', N",N"'-tetraacetic acid (1), 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-N,N',N",N"'-tetramethylacetic acid (2), and 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-N,N',N",N"'-tetrapropionic acid (3) have been measured by the use of stopped-flow spectrophotometry. Observations were made at 25.0±0.1 ℃ and at an ionic strength of 0.10 M $NaClO_4$. The complexation of $Ce^{3+}$ ion with 1 and 2 proceeds through the formation of an intermediate complex $(CeH_3L^{2+})^*$ in which the $Ce^{3+}$ ion is incompletely coordinated. This may then lead to be a final product in the rate-determining step. Between pH 4.76 and 5.76, the diprotonated $(H_2L^{2-})$ from is revealed to be a kinetically active species despite of its low concentration. The stability constants $(logK(CeH_3L^{2+}))$ and specific water-assisted rate constants $(k_{OH})$ of intermediate complexes have been determined from the kinetic data. The dissociation reactions of $Ce^{3+}$ complexes of 1, 2, and 3 were investigated with $Cu^{2+}$, ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid-catalyzed contributions. The effect of buffer and $Cu^{2+}$ concentration on the dissociation rate has also been investigated. The ligand effect on the dissociation rate of $Ce^{3+}$ complexes is discussed in terms of the side-pendant arms and the chelate ring sizes of the ligands.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.612-619
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• 2011

Lanthanide(III) complexes of 1,2-diphenyl-4-butyl-3,5-pyrazolidinedione(phenylbutazone, PB) have been synthesized and characterized by elemental analyses, molar conductance measurements, IR, UV-Vis. and NMR spectra. The spectral data reveal that the PB acts as a bidentate and mono-ionic ligand coordinating through both the carbonyl oxygens of the pyrazolidinedione ring. The molar conductance data suggest that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied by TG and DTG in air atmosphere and the results provide information about dehydration, thermal stability and thermal decomposition. The final products are found to be the corresponding metal oxides. The thermodynamic parameters and kinetic parameters were evaluated for the dehydration and decomposition stages. The negative entropy values of the decomposition stages indicate that the activated complexes have a more ordered structure than the reactants and that the reactions are slower than normal. Based on these studies, the complexes have been formulated as $[Ln(PB)_3]{\cdot}5H_2O$(Ln=La and Ce) and $[Ln(PB)_3(H_2O)_2]{\cdot}2H_2O$(Ln=Pr, Nd and Sm).

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1583-1587
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• 2009

The four dentate $N_2O_2$ Schiff base ligand of bis(2-hydroxyacetophenone)-1,2-propanediimine (BHAPN) and its manganese (III) complex were synthesized and identified by microanalysis, spectral data ($^1H$ NMR, MS, FT-IR and UV-Visible) and molar conductivity measurement. The mild and efficient homogeneous oxidative decarboxylation of some carboxylic acids by catalytic amount of this manganese (III) complex, using tetrabutylamonium periodate as a mild oxidant in chloroform at room temperature is reported. The catalyst used in this study showed good activity for the decarboxylation of the titled compounds.

• Journal of the Korean Chemical Society
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• v.57 no.1
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• pp.63-72
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• 2013

Some vanadyl complexes were synthesized by treating a methanolic solution of the appropriate Schiff base ligand and one equivalent of $VO(SO_4)_2$ to yield [($VOL_2^{1-14}$)](L=Salicylaldehyde's derivatives, Schemes 1, 2). These oxovanadium (IV) complexes were characterized based on their FT-IR, UV-Vis spectroscopy and elemental analysis. The IR spectra suggest that coordination takes place through azomethine nitrogen and phenolate oxygen. In addition, the formation constants of the oxovanadium (IV) binary complexes were determined in methanolic medium. The ab initio calculations were also carried out to determine the structural and the geometrical properties of one of the complexes and its calculated vibrational frequencies were investigated.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.75-80
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• 1997

Preparation and properties of Eu(hfa)3·L (Hhfa = hexafluoroacetylacetone, L = bis(2-methoxyethyl)ether, diglyme, and 2, 2':6', 2"-terpyridine, tpy), which are potential CVD precursors for europium, were investigated. The reaction of the Eu2O3 with Hhfa in the presence of tridentate neutral ligand yielded the nine-coordinated Eu(hfa)3·L. Eu(hfa)3·diglyme is air- and moisture-stable and most importantly has good volatility and thermal stability. Eu(hfa)3·tpy shows no sublime intact. The complex Eu(hfa)3·diglyme has been characterized by an X-ray structure determination; monoclinic P21/n, a=10.252(1), b=16.051(6), c=19.392(8) Å, β=96.10(2)°, V=3173(2) Å3. The europium atom in Eu(hfa)3·diglyme adopts a square-antiprismatic geometry with the ninth coordinating oxygen atom capping one of the square faces. All the adducts have been characterized by IR, TGA/DTA.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.518-523
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• 1995

New square planar nickel(Ⅱ) complexes with various 1-alkyl (4a-4c) and 1-hydroxyalkyl (4d-4f) derivatives of the 14-membered pentaaza macrocycle 8-ethyl-8-nitro-1,3,6,10,13-pentaazacyclotetradecane have been synthesized by two-step metal template condensation reactions of ethylenediamine, nitroethane, formaldehyde, and appropriate primary amines. The nitro group and/or hydroxyl group of 4a-4f are not directly involved in the coordination. The nickel(Ⅱ) complexes exist in coordinating solvents such as MeCN, Me2SO, and H2O as equilibrium mixtures of the square planar [Ni(L)]2+(L=4a-4f) and octahedral species [Ni(L)S2]2+(S=solvent molecule). Although the ligand field strength and redox potentials of the complexes are not affected by the nature of the substituents, the formation of octahedral species for 4d-4f in MeCN is strongly restricted by the hydroxyl group. Synthesis, characterization, and solution behaviors of the nickel(Ⅱ) complexes are described.