• 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.

• Korean Journal of Materials Research
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• v.32 no.4
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• pp.193-199
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• 2022

In this study, lenses are fabricated using various nanomaterials as additives to a silicone polymer made with an optimum mixing ratio and short polymerization time. In addition, PVP is added at a ratio of 1 % to investigate the physical properties according to the degree of dispersion, and the compatibility with hydrophobic silicone and the possibility of application as a functional lens material are confirmed. The main materials are SIU as a silicone monomer, DMA, a hydrophilic copolymer, EGDMA as a crosslinking agent, and 2H2M as a photoinitiator. Holmium (III) oxide, Europium (III) oxide, aluminum oxide, and PVP are used. When Holmium (III) oxide and Europium (III) oxide are added based on the Ref sample, the characteristics of the lens tend to be similar overall, and the aluminum oxide shows a tendency slightly different from the previous two oxides. This material can be used as a silicone lens material with various nano oxides and polyvinylpyrrolidone (PVP) acting as a dispersant.

• Journal of the Korean Chemical Society
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• v.39 no.6
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• pp.477-480
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• 1995

• 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.38 no.9
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• pp.653-659
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• 1994

The fluorescence intensities of europium and samarium can be greatly enhanced in the presence 2-thenoyltrifluoroacetone(TTA), n-octanol and Triton X-100 in aqueous solution of pH 7. It was also found that the fluorescence intensity can be greatly increased by the addition of excess of $La^{3+}$. The excitation and emission wavelengths of europium and samarium were 345 nm, 380 nm and 617 nm, 567 nm, respectively. The fluorescence intensity was a linear function of the concentration of europium and samarium in the range TEX>$1{\times}10^{-7}∼1{\tiems}10^{-9}\;M,\;1{\tiems}10^{-5}∼1{\times}10^{-7}\;M$, respectively, and the detection limits were 1$1{\times}10^{-11}\;M$ for europium and $1{\times}10^{-8}\;M$ for samarium and the luminescence mechanism of the system is discussed.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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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.

• Analytical Science and Technology
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• v.16 no.3
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• pp.206-211
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• 2003

The DC polarograms of some rare earth elements have been investigated in various pH solution and electrolytes. Samarium ion has two well-defined reduction waves at -1.75 V and -1.95 V in 0.1 M NaCl solution and those are a diffusion controlled in nature. Europium and ytterbium ions give also two step reduction waves at -0.75 V and -1.95 V for europium and -1.45 V and -2.00 V for ytterium in $(C_2H_5)_4NCl$ solution. On the other hand, lantanium and neodium ions show a single reduction wave at -1.75 V. The differences of half wave potentials between europium, ytterium and samarium ions make it possible to determine each ions in the mixed solution sponteniously. In case of europium ion, the stability constants for the complexs of $Eu^{3+}$-EDTA and $Eu^{3+}$-DTPA are evaluated.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1747-1749
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• 1999

Organic electroluminescent devices (OLEDs) have received a great deal of attention due to their potential application as full-color displays. Europium complexes are known as excellent red color-emitting materials for OLEDs since they show intense photoluminescence at around 610 nm with a sharp spectral bandwidth. In this study, triple-layer and multiple quantum-well structures consisting of Eu$(TTA)_3$(bpy) complex well layer sandwiched triphenyldiamine derivative (TPD) layers were fabricated and their photoluminescent characteristics were investigated. Sharp emission at the wavelength of 615 nm has been observed from the triple-layer and multiple quantum-well structures containing Eu complex. Details on the electrical properties of these structures will be also discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1020-1024
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• 2006

Europium$(Eu^{2+}\;or\;Eu^{3+})$-activated calcium aluminium silicate phosphors were synthesized for the first time and the structures and luminescence characteristics of these phosphors were investigated. The phosphors in this study emitted blue, green, and even red light depending on the starting milterials and annealing conditions for synthesis. In addition, the structure was also changed when the different starting materials were used. When $CaCO_3$ was used as a starting material, tetragonal $Ca_2Al_2SiO_7$ was formed. However, pure green light was emitted when the annealing was conducted in reduced atmosphere and red one was emitted by annealing in air. In the case of $CaSiO_3$ as a starting material, triclinic $CaAl_2Si_2O_8$ was formed and only pure blue emission was observed. Moreover, this blue phosphor exhibited higher intensity than that of commercial YAG:Ce phosphor, which showed the possibility of application on the phosphor for new light source such as a UV-LED.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.204-208
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• 2012

A novel chemiluminescence (CL) flow injection method for the determination of balofloxacin is described. The method is based on the weak CL signal arising from the reaction of $KBrO_3$ with $Na_2S_2O_4$ in acidic medium being significantly enhanced by balofloxacin in the presence of europium (III) ion and sodium dodecyl benzene sulfonate (SDBS). The experimental conditions that affected CL intensity were carefully optimized and the CL reaction mechanism was briefly discussed. Under the optimum conditions, the relative CL intensity was proportional to the concentration of balofloxacin in the range of $7.0{\times}10^{-11}$ to $3.0{\times}10^{-7}g\;mL^{-1}$. The detection limit was $2.7{\times}10^{-11}g\;mL^{-1}$ and the relative standard deviation was 2.1% for $7.0{\times}10^{-10}g\;mL^{-1}$ balofloxacin (n = 13). The proposed method was successfully applied to the determination of balofloxacin in pharmaceutical formulations and biological fluids.