• Bulletin of the Korean Chemical Society
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• 제23권4호
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• pp.623-625
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• 2002

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2213-2216
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• 2009

A novel carbazole functionalized bis-$\beta$-diketone type organic ligand, 1,1′-(2,6-bispyridyl)bis-3-(9-ethylcarbazole- 3-yl)-1,3-propanedione ($H_2L$) and its corresponding lanthanide complexes $Eu_2(L)_3\;and\;Tb_2(L)_3$ were successfully prepared. The ligand and complexes were characterized in detail based on FT-IR spectra, $^1H$ NMR and elemental analysis. The observed UV-Vis absorption and photoluminescence properties of the complexes were investigated, it shows that the Eu(III) and Tb(III) ions can be sensitized efficiently by the ligand ($H_2L$) to some extent, in particular, the complex $Tb_2(L)_3$ exhibits a more excellent luminescence property than the Eu(III) complex. Meanwhile, the introduction of the carbazole moiety can enlarge the $\Pi$-conjugated system of the ligand and enhance the luminescent intensity of the complexes. The results show that the complexes would be used as excellent luminescent materials.

• 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.

• Bulletin of the Korean Chemical Society
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• 제16권7호
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• pp.654-657
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• 1995

A series of excitation spectra (7Fo→5Do transition) of Eu(Ⅲ) ion in aqueous solution ([Eu(Ⅲ)]=1.12 × 10-2 mol L-1; pH 1.0 to 7.0) were obtained under CO2 free atmosphere using a pulsed tunable dye laser system. The broad and low intensity spectra (peak maximum: 578.89 nm) showed that the trivalent ion (Eu3+) underwent a low degree of hydrolysis at pH below 6.0. Eu(Ⅲ) hydroxo complex formation seemed more significant at pH above 6.0, shown by the occurrence of intense new peak at 578.63 nm. The spectra of those solutions prepared in N2 atmosphere showed no signs of the presence of interfering carbonate species. The Eu(Ⅲ) hydroxo complex formation was not observed when complexation studies between Eu(Ⅲ) ion and weak organic acids (e.g. glutarate and diglycolate) were conducted at pH 6.0 or below.

• Rapid Communication in Photoscience
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• 제2권1호
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• pp.34-37
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• 2013

Two novel antenna complexes of $Eu^{III}$ with 1-naphthoic acid (NA) as primary ligand and two aromatic N-donor ligands namely N-hexyl-N-(pyridin-2-yl) pyridin-2-amine (1) and 4-((dipyridin-2-ylamino)methyl)benzoic acid (2) have been synthesized and characterized by various spectroscopic techniques. The room-temperature (298 K) photoluminescence spectrum of $Eu^{III}$ complexes composed of typical line like emissions, assigned to transitions between the first excited state $^5D_0$ to the $^7F_J$ (J = 0-4), resulting in red emission along with the residual emission from the 1-naphthoic acid moiety in the blue region. The determined CIE color coordinate value for the complex 2 is (x = 0.36, y = 0.34), which is in white region.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1745-1747
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• 2011

• 대한화학회지
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• 제38권1호
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• pp.50-54
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• 1994

흐름주입법에 의하여 분광광도법으로 몇 가지 가벼운 란탄족 원소를 정량하였다. Chromeazurol S는 양이온 계면활성제인 DTAB존재하에서 란탄족 이온과 착물을 형성한다. Tris 완충용액(pH 10.5)에서 이 착물의 최대흡수파장은 650 nm 에서 655 nm범위이고 몰흡광계수는 약 $1.8{\times}10^5\;L mol^{-1}cm^{-1}$였다. FIA에 의한 Nd(III), Eu(III) 및 Sm(III)의 검정곡선은 0.1 ~ 0.6 ppm에서 직선관계를 보였고, 이 검정곡선의 상관계수(${\gamma}$)는 0.9993이였다. 검출한계(S/N)는 Nd(III)과 Eu(III)에 대하여는 10 ppb이고, Sm(III)에 대하여는 20 ppb였다. 상대표준편차는 시료 0.4 ppm에 대하여 약 ${\pm}$1.2%이고, 시료의 분석 속도는 약 $50hr^{-1}$였다.

• 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.

• Bulletin of the Korean Chemical Society
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• 제19권1호
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• pp.83-86
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• 1998

The luminescence spectra of Eu(Ⅲ) complexes have been measured as a function of molar metal-to-ligand ratio and pH. The ligands used in this study are tridentate iminodiacetate (IDA) and methyliminodiacetate (MIDA). The 620 nm emission band, attributed to the $^5D_0{\to}^7F_2$ transition, is monitored to investigate the optimum condition for $EuL_3^{3-}$ complex formation in aqueous state. In addition, the sensitivity of the 465 nm absorption band, attributed to the $^7F_0{\to}^5D_2$ transition, to the ligand environment has been also investigated.

• 자원환경지질
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• 제42권5호
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• pp.495-500
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• 2009

액티나이드(actinide)의 지질물질로의 수착은 핵에너지와 핵무기 개발로 인하여 인위적으로 자연환경에 노출된 핵종 원소의 이동성과 생물이용가능성을 낮추어 줄 수 있을 것으로 기대된다. 3가의 액티나이드 이온은 3가의 란타나이드(lanthanide) 이온과 유사한 화학적 성질을 띠므로, 3가 액티나이드의 산화광물 표면수착량은, 중성 또는 약한 산성의 pH 상태에서 3가의 란타나이드처럼, 인산염 이온(${PO_4}^{3-}$) 이 수착된 상태에서 크게 증가될 것으로 사료된다. 본 연구에서는 3가액티나이드 이온의 화학적 동족체인 3가 유로피움 이온($Eu^{3+}$)이 인산염이 수착된 상태의 뵈마이트 (${\gamma}$-AlOOH; boehmite) 표면에 수착되는 삼성분 수착계를 X선 흡수분석(EXAFS)을 통하여 관찰하였다. Eu X-선 흡수분석은 Eu-$PO_4$-뵈마이트 삼성분 수착계에서 뵈마이트 표면에 $EuPO_4$ 표면침전물이 형성되는 것을 지시하여 준다. 인산염이 뵈마이트 표면에서 $EuPO_4$ 표면침전물을 형성할 뿐 아니라 두자리 단핵 표면착물을 형성한 것을 P X-선 흡수분석을 통하여 확인하였다.