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101.
We report upconversion multicolor tuning based on uniform β-NaYF4:Yb/Tm/Er nanoparticles. The as-synthesized nanoparticles with an average diameter of 25 nm are well dispersed in a wide range of nonpolar solvents including hexane, cyclohexane, dichloromethane, and toluene. These nanoparticles show intense upconversion emissions and the color output can be precisely modulated by adjusting activator ratios of Tm3+ to Er3+. Dopant-concentration dependent emission properties of the triply doped particle system are also investigated. In addition, we demonstrate that these nanoparticles can be readily transferred to polar solvents such as ethanol and water by growing a thin silica layer (10 nm) around the particles, providing potential applications in biological labeling and imaging. 相似文献
102.
Summary A sensitive and selective laser-induced luminescence detection scheme for orotic acid in urine, separated by micellar electrokinetic capillary chromatography (MEKC) has been developed. The 325 nm line from a helium cadmium laser is used to excite orotic acid, which transfers its energy to terbium. Resultant luminescence of terbium is linear with orotic acid concentration over more than 2.5 orders of magnitude. This novel and practical system enables the detection of 50 nm orotic acid in urine in less than 1.5 minutes while using only nanoliters of sample. The significant decrease in analysis time over traditional methods (spectrophotometric and chromatographic) comes from the high efficiency of MEKC. A dramatic improvement in sensitivity and selectivity over UV detection in capillary electrophoresis is achieved through the use of laser-induced lanthanide ion energy transfer luminescence detection. Finally, no sample pretreatment is needed and the method is free from any known interferences in urine. 相似文献
103.
Cristina Mas Ana Mantecn Angels Serra Xavier Ramis Josep Maria Salla 《Journal of polymer science. Part A, Polymer chemistry》2005,43(11):2337-2347
3,4‐Epoxycyclohexylmethyl 3,4‐epoxycyclohexane carboxylate was cured with different proportions of γ‐butyrolactone with lanthanum, samarium, and ytterbium triflates as catalysts. The curing was studied with differential scanning calorimetry (DSC) and Fourier transform infrared in the attenuated‐total‐reflection mode (FTIR/ATR). FTIR/ATR was used to monitor the competitive reactive processes and to quantify the evolution of the epoxide, lactone, and intermediate spiroorthoester groups. The glass‐transition temperature of the crosslinked materials was high and increased when the proportion of lactone decreased. The kinetics were studied with DSC experiments and were analyzed with isoconversional procedures. The differences in the reactivities of the systems were related to the Lewis acidity of the lanthanide salt used as the initiator. An increase in the proportion of lactone produced an increase in the reaction rate. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2337‐2347, 2005 相似文献
104.
The optical absorption spectra of EuCl3 in aqueous and acidic solutions were measured in the visible anduv regions of the spectrum. The concentration as well as the temperature of the solutions were varied to establish an accurate
free-ion energy level scheme of Eu3+. The energy levels were assigned on the basis of a correlation between the calculated and the experimentally observed transition
energies and associated band intensities. 相似文献
105.
利用N-succinopyridine(HL)配体,成功合成了2个同构型镧系化合物[Ln(HL)2(H2O)4]Cl3(Ln=Pr(1),Eu(2))并对其进行了结构表征。1和2均由羧酸配体双桥联金属离子形成1D链结构,再通过氢键进一步相互连接构成了3D超分子结构。变温磁化率测试表明1中Pr(Ⅲ)离子之间存在反铁磁相互作用,而在2中,Eu(Ⅲ)离子之间则表现出弱铁磁相互作用。固态发光测试观察到2可以发出很强的红光,但由于Pr(Ⅲ)离子的能隙较大,未观察到1的特征峰。 相似文献
106.
Chatphorn Theppitak Suwadee Jiajaroen Nucharee Chongboriboon Songwuit Chanthee Filip Kielar Winya Dungkaew Mongkol Sukwattanasinitt Kittipong Chainok 《Molecules (Basel, Switzerland)》2021,26(15)
Two new lanthanide-based coordination polymers, [Sm2(bzz)(ben)6(H2O)3]·0.5H2O (1) and [Eu(bbz)(ben)3] (2), were synthesized and characterized. The described products were formed from in situ-generated benzoate (ben) and N’-benzoylbenzohydrazide (bbz) ligands, which were the products of transformation of originally added benzhydrazide (bzz) under hydrothermal conditions. Compound 1 exhibits a one-dimensional (1D) double-chain structure built up from the connection of the central Sm3+ ions with a mixture of bzz and ben ligands. On the other hand, 2 features a 3D network with a 4-connected (66) dia topology constructed from dinuclear [Eu2(ben)6] secondary building units and bbz linkers. High-pressure CO2 sorption studies of activated 1 show that maximum uptake increases to exceptionally high values of 376.7 cm3 g−1 (42.5 wt%) under a pressure of 50 bar at 298 K with good recyclability. Meanwhile, 2 shows a typical red emission in the solid state at room temperature with the decay lifetime of 1.2 ms. 相似文献
107.
Nagwa Abo El-Maali Asmaa Y. Wahman Aref A.M. Aly Ahmed Y. Nassar Douaa M. Sayed 《应用有机金属化学》2020,34(6):e5594
Lanthanide complexes are of increasing importance in cancer diagnosis and therapy. In the present study 1:1 and 1:3 solid complexes of La (III)–5-FU (5-fluorouracil) were prepared and characterized. In solution, the formation of 1:1 La (III) and Eu (III) complexes enabled the enhancement of 5-FU's effectiveness. Binding constants of the 1:1 complexes of both metals were estimated using spectrophotometry and HPLC with fluorescence detection methods. The thermodynamic parameters ΔG ° , ΔH ° and ΔS ° were calculated using differential scanning calorimetry. Evaluation of the cytotoxic activity of the 1:1 La (III)- and Eu (III)–5-FU complexes was performed through two methodologies, trypan blue for cell viability where La (III)- and Eu (III)–5-FU complexes were found to have 52,000 and 80,000 dead cells, respectively, and via flow cytometric analysis to measure the apoptotic values, which were found to be 59.87 and 86.86% respectively. 相似文献
108.
The mass spectral analysis of metal salts, especially lanthanide and transition metal salts, can be challenging. Although getting information on the metal present is usually straightforward, obtaining information on the correct oxidation state and anion composition is challenging. Many ionisation techniques have some redox component to the ionisation process, which commonly results in changing the oxidation state of the metal and the associated loss of ligand and anion information. We present here a simple method for negative ion matrix‐assisted laser desorption/ionisation mass spectrometry using the non‐acidic flavonoid flavone as a novel matrix. This results in reliable information on the oxidation state of the metal as spectra are dominated by anion adduct ions with very little (typically no) redox processes occurring. 相似文献
109.
110.
以2,5-噻吩二甲酸和稀土盐为原料,通过水热反应,合成了3个稀土金属配位聚合物{[La(OH)(SO4)]}n(1),{[La2(TDC)2(SUC)]}n(2)和{[Gd2(TDC)2(ox)(H_2O)4]·2H_2O}n(3)(H_2TDC=2,5-噻吩二甲酸,SUC=丁二酸,ox=草酸),分别用X射线单晶衍射、元素分析、红外光谱对配合物2和3进行了表征。实验结果表明:配合物2和3均呈现三维网络结构,其中配合物2属于正交晶系,空间群为Pbca,a=1.372 8(4)nm,b=0.704 0(2)nm,c=2.136 2(6)nm,Z=8;配合物3属于单斜晶系,空间群为C2/c,a=1.934 3(4)nm,b=0.990 5(2)nm,c=1.252 8(3)nm,β=107.463(4)°,Z=4。 相似文献