• Bulletin of the Korean Chemical Society
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• 제18권1호
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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.

• 분석과학
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• 제28권3호
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• pp.204-211
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• 2015

란탄족 착물은 독특한 발광 특성으로 인하여 많은 연구가 되고 있는 물질이다. 유로피움(III) β-디케토네이트 착물에 아민계열 또는 포스핀옥사이드계열 리간드를 추가로 배위 결합시켜 발광 효율을 비교하였으며, 아민계열 배위보다는 발광 효율 증진에는 포스핀옥사이드 계열이 더 좋은 추가 리간드임을 확인하였다. 그 중에서도 트리옥틸포스핀 옥사이드를 배위시켰을 때 가장 높은 발광효율이 관찰되었다. 추가로 배위될 수 있는 트리옥틸포스핀 옥사이드의 당량을 확인하기 위해서 ³¹P-NMR과 photoluminescence를 분석하였다. 유로피움(III) β-디케토네이트 화합물은 리간드의 입체장애에 따라 트리옥틸포스핀 옥사이드의 배위 당량은 1 개 또는 2 개가 가능함을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제22권2호
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• pp.199-204
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• 2001

A Cryptate (221) having a short alcohol pendant (2) was metallated with europium(Ⅲ) in anhydrous condition, and its hydrolytic activity for phosphate esters at neutral pH was examined. While the activity for the phosphate diester and monoester is comparable to that of the parent metal complex [1Eu]3+, its hydrolytic activity towards a phosphate triester is significantly suppressed. Potentiometric titration and luminescence spectroscopic studies for the equilibrium behavior of the complex in solution suggest that a dimer formation through the metal hydroxides as well as the pendant alcohol is likely to happen. The low hydrolytic activity for the triester seems to be associated with the dimer formation.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.3055-3060
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• 2012

A simple, rapid and sensitive spectrofluorometric method was developed for the determination of folic acid (FA), based on its quenching effect on the fluorescence intensity of enoxacin (ENX)-europium ($Eu^{3+}$) complex as a fluorescent probe. Fluorometric interaction between ENX-$Eu^{3+}$ complex and FA was studied using UV-visible and fluorescence spectroscopy. The quenched fluorescence intensity at an emission wavelength of 614 nm was proportional to the concentration of FA. Optimum conditions for the determination of FA were investigated. Under optimal conditions, the reduced fluorescence intensity at 614 nm was responded linearly with the concentration of FA. The linearity was maintained in the range of $1.25{\times}10^{-9}$ to $1.50{\times}10^{-7}$ M (R = 0.9986) with the limit of detection ($3S_b/m$) (where $S_b$ is the standard deviation of blank and m is the slop of linear calibration curve) of $6.94{\times}10^{-10}$ M. The relative standard deviation (RSD) for 9 repeated measurements of $1.0{\times}10^{-9}$ M FA was 1.42%. This method was simple, cost effective, and relatively free of interference from coexisting substances. Successful determinations of FA in pharmaceutical formulation and biological samples with the developed method were demonstrated.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4145-4149
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• 2012

A novel and simple method of luminescence enhancement effect for the determination of trace amounts of bile acid was proposed. The procedure was based on the luminescence intensity of the balofloxacin-europium(III) complex that could be strongly enhanced by bile acid in the presence of sodium dodecyl benzene sulfonate (SDBS). Under the optimum conditions, the enhanced luminescence intensity of the system exhibited a good linear relationship with the bile acid concentration in the range $5.0{\times}10^{-9}-7.0{\times}10^{-7}\;mol\;L^{-1}$ with a detection limit of $1.3{\times}10^{-9}\;mol\;L^{-1}$ ($3{\sigma}$). The relative standard deviation (RSD) was 1.7% (n = 11) for $5.0{\times}10^{-8}\;mol\;L^{-1}$ bile acid. The applicability of the method to the determination of bile acid was demonstrated by investigating the effect of potential interferences and by analyzing human serum and urine samples. The possible enhancement mechanism of luminescence intensity in balofloxacin-europium(III)-bile acid-SDBS system was also discussed briefly.

• 한국응용과학기술학회지
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• 제18권1호
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• pp.12-19
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• 2001

Eu(III) exhibits one electron-transfer reduction at $E_{1/2}$ = -0.564 V(vs. Ag/AgCl) and the hypersensitive peak at 615 ㎚ corresponding to $^{5}D_{0}{\rightarrow}^{7}F_{2}$ transition in 0.1 M $LiClO_{4}$ aqueous solution. Upon the addition of 2,6-pyridine dicarboxylic acid(PDA) to the Eu(III) aqueous soultion, the reduction potential shifts negatively and the PDA, and the Eu(III)-PDA complex emits great fluorescence than free-Eu(III) ion at 615 nm. The results are interpreted in term of the electrochemical and spectrofluorometric studies.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.529-532
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• 1999

본 연구에서는 유기 전기 발광 소자에서 녹색 발광층으로 사용되는 terbium(Tb) complexes와 europium(Eu) complex, 정공 수송층으로 사용되는 TPD (N, N\`-diphenyl-N,\`(3-methylphenyl)-1, 1\`biphenyl-4, 4\`-diamine), 그리고 전자 수송층으로 사용되는 Alq$_{3}$ (trois(8-hydroxyquinolino)aluminum), Bebq$_2$들의 Uv/Vis. 홉광도와 PL 스펙 트럼과 같은 광학적 특성을 조사하였으며 또한 이러한 물질들을 이용하여 다양한 종류의 유기 전기 발광 소자를 제작하고 제작된 소자들의 전류밀도-전압-조도 등의 전기 . 광학적 특성을 조사하였으며, 그 결과 다 음과 같은 결곤을 얻을 수 있었다. 다양한 ligand를 갖는 Tb complex들의 경우에도 EL 스펙트럼의 파장대 (wavelength)는 546nm~548nm의 녹색 발광을 하는 것을 알 수 있었고, 제작된 소자 중에서 Tb(ACAC)$_3$(Phen) 을 발광충으로 하고, TPD, 그리고 Bebq$_2$를 각각 정공 수송층, 전자 수송 층으로 한 소자가 가장 낮은 구동 전압을 갖는다는 것을 확인하였으며 logJ-logV 특성에서도 모든 전계 구간에서 이러한 구조의 소자가 가장 높은 전류밀도를 나타냈으며 저 전계 구간에서 전류밀도 타이가 가장 컸다. 소자의 전류밀도와 휘도의 관계에 있어서는 제작된 네 종류의 소자 중 Tb(ACAC)3(Cl-Phen)를 발광층으로 하고 TPD, 그리고 Bebq2를 각각 정공 수송층, 전자 수송 층으로 한 소자가 가장 휘도가 우수한 것을 알 수 있었다. 또한 red (europium complex), green (terbium complex), 그리고 blue (TPD) 색깔을 나타내는 유기 재료를 사용하여 한 소자에서 백색 소자를 제작하여 cyclic voltametric방법을 이용하여 각 유기 물질들의 에너지 준위를 조사하여, 각각의 소자들을 에너지 밴드 다이어그램(energy band diagram)으로 자세히 설명하였다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.447-452
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• 2003

산화물 핵연료의 리튬환원공정에서 생성되는 $Li_2O$와 희토류원소 산화물($RE_2O_3$)의 화학적 반응을 밝혔다. 스칸듐, 이트륨, 프라세오디뮴, 네오디뮴, 사마륨, 유러퓸, 가돌리늄, 이테르븀 및 루테튬의 산화물은 각각 어떤 $Li_2O$의 임계농도 이상에서 $Li_2O$와 반응하여 복합산화물($LiREO_2$)을 형성하고, 이들 산화물이 복합산화물을 형성하는 각각의 $Li_2O$ 임계농도는 0.1 wt%, 1.9 wt%, 5.3 wt%, 5.0 wt%, 3.0 wt%, 3.9 wt%, 2.9 wt%, 2.6 wt% 및 0.3 wt%로 나타났다. $CeO_2$ 및 란타늄 산화물은 $Li_2O$와 반응하지 않는 것으로 나타났다. 실험에서 얻은 이들 희토류원소 복합산화물의 LiCl 용융염에 대한 용해도는 매우 작았다.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1057-1064
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• 2005

Photoluminescence (PL) spectra of Eu(III) and Tb(III) complexes with mixed oxydiacetate (ODA) and 1,10-phenanthroline (phen) ligands and with homoleptic ODA reveal characteristic line-splitting at 10 K, depending on the site-symmetry of the lanthanide ion in the complex. The energy-level schemes of the $^7F_J$ states and the emitting levels for Eu(III) and Tb(III) ions have been proposed by simulating the line splitting in the framework of crystal-field Hamiltonian. The sets of refined crystal-field parameters for the experimentally determined sitesymmetry satisfactorily reproduce the experimental energy-level schemes. In addition, the PL quantum yield and the decay time were determined at room temperature. The PL quantum yields of [$Eu(ODA){\cdot}(phen){\cdot}4H_2O]^+$ and [Tb$(ODA){\cdot}(phen){\cdot}4H_2O]^+$ in the crystalline state (Q = 17.7 and Q = 56.6%, respectively) are much greater than those of [Eu($ODA)_3]^{3-}and\;[Tb(ODA)_3]^{3-}$(Q = 1.1 and Q = 1.3, respectively), due to the energy transfer from phen to the lanthanide ion. In the aqueous state, the relaxation of the phen moiety due to the solvent results in the reduction of the quantum yield and the shortening of the lifetime.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.317-320
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• 1998

Electroluminescent(EL) devices based on organic materials have been of great interest due to their possible applications for large-area flat-panel displays, where they are attractive because of their capability of multicolor emission, and low operation voltage. In this study, glass substrate/ITO/Eu(TTA)$_3$(Phen)/Al(A), glass substrate/ITO/TPD/Eu(TTA)$_3$(phen)/Al(B) aNd glass substrate/ITO/TPD/Eu(TTA)$_3$(Phen)/A1Q$_3$/Al (C) structures were fabricated by vacuum evaporation method, where aromatic diamine(TPD) was used as a hole transporting material, Eu(TTA)$_3$(phen) as an emitting material, and tris(8-hydroxyquinoline) Aluminum (AlQ$_3$) as an electron transporting layer. Etectroluminescent(EL) and I-V characteristics of Eu(TTA)$_3$(phen) with a various thickness were investigated. This structure shows the red EL spectrum, which is almost the same as the PL spectrum of Eu(TTA)$_3$(phen). I-V characteristics of this structure show that turn-on voltage was 9V and current density was 0.01A/㎤ at a dc operation voltage of 9V. Electrical transporting phenomena of these structures was explained using the trapped-charge-limited current model with I-V characteristics.