• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.594-602
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• 2011

The effect of ${\alpha}$-, ${\beta}$- and ${\gamma}$-picolines on the stereochemistry of the coordination compounds of lanthanide(III) nitrates derived from 4[N-(furfural)amino]antipyrine semicarbazone (FFAAPS) has been studied. The general composition of the present coordination compounds is [Ln(FFAAPS)$(NO_3)_3$Pic] (Ln=La, Pr, Nd, Sm, Gd, Tb, Dy or Ho and Pic=${\alpha}$-, ${\beta}$- or ${\gamma}$-picolines). All these coordination compounds have been characterized by elemental analyses, molecular weight, molar conductance, magnetic susceptibility, infrared and electronic spectra. The infrared studies suggest that the FFAAPS behaves as a neutral tridentate ligand with N, N, O donor while ${\alpha}$-, ${\beta}$- or ${\gamma}$-picoline is coordinated to the lanthanide(III) ions via heterocyclic N-atom. Nitrates are bicovalently bonded in these compounds. From the electronic spectral data, nephelauxetic effect (${\beta}$), covalence factor ($b^{1/2}$), Sinha parameter (${\delta}%$) and the covalence angular overlap parameter (${\eta}$) have been calculated. Thermal stabilities of these complexes have been studied by thermogravimetric analysis. The coordination number of lanthanide(III) ions in the present compound is found to be ten. The antibacterial studies screening of the primary ligand FFAAPS and the complexes showed that the present complexes have moderate antibacterial activities.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.184-189
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• 1998

Tris(pentafluorophenyl)indium acetonitrile complexes have been prepared from the reaction of Indium trihalides (halogen=Cl, Br) and bis(pentafluorophenyl)cadmium in acetonitrile, and characterized by elementary analysis, $^13C{^1H}-,\; ^1H-\;and\; ^{19}F-NMR$ spectroscopy and mass spectrometry. The Indium (III) compounds were formed stable 1:1 adducts with acetonitrile. $In(C_6F_5)_3{\cdot}DMAP$ has been prepared from the ligand exchange reaction of In$(C_6F_5)_3 {\cdot} CH_3CN$ with DMAP in $CH_2Cl_2 {\cdot} DMAP$ has higher donating character and replaced the $CH_3CN$ through the ligand transfer reaction.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.294-301
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• 1999

Geminal bisphosphonates have been well known to be effective inhibitors of various calciumrelated disorders such as Paget's disease, hypercalcemia of malignancy, and osteoporosis. To synthesize bisphosphonates, we have used the pentacovalent oxaphospholene prepared from methyl vinyl ketone and triethyl-phosphite. Υ-Ketobisphosphonates are obtained by bromination, applied Westheimer reaction, and hydrolysis of synthesized oxaphospholene. This compound was converted to the N-alkylated Υ-aminobisphosphonates by the reductive amination. Conversion of the resulting secondary amine to the tertiary one, followed by introduction of the second alkyl group on the nitrogen, was led to the synthesis of new N,N'-dialkylated Υ-aminobisphosphonates.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.151-151
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• 2010

본 연구에서는 배위자로 공액계 벤젠고리로 연결된 중심금속이 이리듐인 착물화합물과 합성하여 인광재료로서의 가능성을 실험하였다. 새로운 이리듐착물화합물의 화학적 구조를 알아보기 위해 $^1H$-NMR, $^{13}C$-NMR, UV-vis, spectrophotometer를 사용하였으며, 광 물리학적, 전기화학적 특성에 대한 측정은 spectrofluorometer, cyclic voltammetry를 통하여 측정하였다. 이리듐 단핵 및 이핵착체는 589~598nm의 영역에서 발광파장이 확인되었으며, DMSO[$5{\times}10^{-5}$]용액에서 양자효율이 단핵 착물화합물의 경우 0.1, 이핵착물화합물의 경우 0.13으로 나타났다. 이핵 이리듐착물화합물의 전기화학적 특성은 energy gap은 2.45eV, optical band gap은 2.58eV로 계산되었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.152-152
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• 2010

본 연구에서는 인광 효과가 큰 heavy metal 인 이핵 Iridium 착체가 합성된 구조적, 광학적 및 전기적 특성을 배경으로 하였다. 가교제로는 카본 conjugated 된 리간드 bipyridine계 배위자를 사용하여 단핵 및 이핵 Platinum 착물 화합물을 합성 하였다. 합성 되어진 이핵 Platinum 착물 화합물의 화학적 구조를 결정하기 위해 $^1H(^{13}C)$-NMR, UV-vis, Spectro Photometer, MALDI TOF-MS 등을 사용하였으며, 광 물리적, 전기화학적 측정을 Spectrofluoromete, Cyclic Voltammetry를 통해 관찰 하였다.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.431-441
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• 1993

The structure and reactivity of ${\pi}$-and metallacycle form in the bis(trimethylphosphine) palladium(0) complexes with acrylic acid, methacrylic acid, crotonic acid(A group) and 3-butenoic acid, 4-pentenoic acid(B group) have been investigated by Molecular Mechanics and Extended Huckel Molecular Orbital method. The calculation shows that A groups with large value of frontier electron density of HOMO and LUMO produce $\pi-complexes$ instead of metallacycle. But B groups with small value of frontier electron density of LUMO, especially 3-butenoic acid, form stable metallacycle. Moreover the methyl-substituted five-membered compared with the six-membered metallacycle is energetically stable conformation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.25 no.3
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• pp.67-80
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• 2020

Zinc (Zn) is known as an essential micronutrient for phytoplankton in the ocean. In surface waters, most of total dissolved Zn presents as organic complexes, and organic complexation dominates the speciation of Zn in seawater. Organic complexation reduces the bioavailable fraction of Zn, the free metal ion (Zn²⁺), which present less than 5% in surface waters. In this paper, a brief introduction on chemical speciation of dissolved Zn in seawater and analytical method for chemical speciation measurement is provided. Some representative studies were also introduced to describe the importance of chemical speciation of Zn (or other trace metals) on bioavailability and biogeochemistry in the ocean.

• Analytical Science and Technology
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• v.28 no.3
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• pp.204-211
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• 2015

Lanthanide complexes have attracted much attention because of their unique light emitting property. The light-emitting efficiencies of europium β-diketonate complexes were compared with those of complexes coordinated by the ligands of amines or phosphine oxides. The results demonstrated that the complexes that were coordinated by phosphine oxides had higher light-conversion performance than those coordinated by amines. The highest light-emitting efficiency was observed when the ligand of trioctylphosphine oxide was coordinated. In order to determine the coordination equivalency of trioctylphosphine oxide in the above complexes, 31P-NMR and their photoluminescence spectra were measured. The findings showed that the europium β-diketonate complex had one or two coordination equivalencies of trioctylphosphine oxide according to the steric hindrance of its original ligand.

• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.213-218
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• 2001

The reaction of peroxo vanadium(V) complexes, $VO(O_2)_2(pic)^{2-}$, $VO(O_2)(nta)^{2-}$, and $VO(O_2)(dipic)^-$ with thiolato-cobalt(III), $(en)_2Co(SCH_2CH_2NH_2)^{2+}$ resulted in an oxygen-atom transfer in aqueous solutions. Rate constants ($M^{-1}S^{-1}$) for these reactions were (35$\pm$1), $(4.8{\pm}0.4){\times}10^{-2}$ , and $(8.6{\pm}0.5){\times}10^{-4}$, respectively. The coordinate peroxide was activated in the oxygen-atom-transfer reaction of $VO(O_2)_2(pic)^{2-}$, but it is not the case for VO(O$_2$) $(nta)^{2-}$ and VO(O$_2$) $(dipic)^-$. In this paper, we proposed that the direct attack of an electrophilic peroxide to a nucleophilic substrate occurs in the oxygen-atom transfer pathway of peroxo vanadium(V) complexes.

• Journal of the Korean Chemical Society
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• v.51 no.3
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• pp.240-243
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• 2007

The eight coordinated yttrium(III) complex Y(tpb)3(H2O)2 (Htpb=4,4,4-Trifluoro-1-phenyl-1,3-butanedione) has been synthesized and structurally characterized by X-ray diffraction method. The coordination polyhedron of Y(tpb)3(H2O)2 has a dodecahedron. The angle between two trapezia, Y-O2-O1-O5-O6 and Y-O4-O3-O8-O7, is 89.59°. The O1-O5 and O3-O8 distances are 2.965 and 2.995 A whereas the O2-O6 and O4-O7 distances are 4.256 and 4.403 A.