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71.
This work reports on the synthesis and characterization of the ligand 3-hexadecylpentane-2,4-dione (Hhdacac) and its Eu3+ complexes Eu(hdacac)6·2H2O, Eu(hdacac)6·phen and Eu(hdacac)6·tta, where phen and tta denote 1,10-phenanthroline and thenoyltrifluoroacetone, respectively. These new compounds present long carbon chains and their expected miscibility into non-polar ambients is confirmed by the emission spectra of Eu(hdacac)6·tta in hexane. Moreover, the amphiphilic properties of Eu(hdacac)6 complexes allow the obtainment of thin luminescent films by the Langmuir-Blodgett technique. In both cases (solids and films), the typical antenna effect of β-diketonates is observed. The alluring characteristics of these compounds raise great interest in many fields of Materials Science, like photo- and electro-luminescent materials (mainly thin “organic” films), metal catalysts or probes in non-polar solutions, and Langmuir-Blodgett films of several compositions. For the characterization of these products, nuclear magnetic resonance spectroscopy (1H NMR), thermogravimetric analysis, elementary analyses (C, H), scanning electron microscopy (energy dispersive X-ray spectroscopy), absorption (UV-vis/FT-IR) and photoluminescence spectroscopies were used. 相似文献
72.
Guang Yang Hui-An Chen Zhong-Yuan Zhou Xiao-Ming Chen 《Journal of chemical crystallography》1999,29(3):309-316
Three dimeric lanthanide(III) complexes, [Eu2(bet)8(H2O)4](CIO4)6
(1), [Tb2(bet)8(H2O)4](ClO4)6
(2), and [Eu2(bet)4(H2O)8] Cl6·6H2O (3) (bet = Me3N+CH2COO–, trimethyl-aminoacetate), have been prepared and structurally characterized by X-ray crystallography. Complex 1 crystallizes in the monoclinic space group P21/c, with a = 11.7807(8), b = 27.757(5), c = 11.7980(8) Å, = 99.500(4)°, V = 3805.1(8) Å3, and Z = 2. Complex 2 is isomorphous to complex 1, crystallizing in the monoclinic space group P21/c, with a = 11.7769(14), b = 27.725(3), c = 11.795(5) Å, = 99.668(14)°, V = 3797(2) Å3, and Z = 2. Complex 3 crystallizes in the orthorhombic space group Pbca, with a = 12.5664(8), b = 17.8645(9), c = 22.2573(8) Å, V = 4996.6(4) Å3 and Z = 4. Both complexes 1 and 2 comprise quadruply carboxylate-O,O-bridged [M2(bet)4]6+ dimeric cores (M = Eu, Tb), and each metal ion is further coordinated by two terminal aqua ligands and two monodentate bet carboxylates to form a distorted square-antiprismatic coordination geometry. Complex 3 also has a [Eu2(bet)4]6+ core, in which two bet ligands act in the 1:1:2 bridging fashion, and the other two bet ligands in the less common 2:1:2 bridging fashion, namely bridging-chelate mode. Each europium(III) ion in complex 3 is further coordinated by four water molecules to complete a monocapped square antiprism. 相似文献
73.
Roos PH Venkatachalam A Manz A Waentig L Koehler CU Jakubowski N 《Analytical and bioanalytical chemistry》2008,392(6):1135-1147
Numerous structurally and enzymatically similar cytochromes P450 (CYPs) are involved in the metabolism of xenobiotics and
are present in different amounts and with different enzyme profiles in human tissues and cells. Analysis of their adaptively
regulated and individually variable patterns is a peculiar analytical challenge. We developed a laser ablation inductively
coupled plasma mass spectrometry (LA-ICP-MS) based method for concomitant detection and semiquantitative determination of
electrophoretically separated and blotted CYPs. The first results are given here for the two enzymes CYP1A1 and CYP2E1. Specific
monoclonal antibodies directed against the enzymes were differentially labelled with europium via a covalently linked chelator
and with iodine, respectively. Analysis of the modified antibodies shows that both europium and iodine are coupled to the
heavy and the light chains of the antibodies. Also, the antibodies maintained their antigen-binding properties after labelling
as demonstrated by LA-ICP-MS-analysed immunoblots. The method allowed us to detect specifically and concomitantly both CYP
enzymes in complex biological samples, i.e. microsomes of rat liver and minipig duodenum, which are characterized by different
levels and proportions of the two CYP enzymes. A strong CYP1A1 signal is found in liver microsomes of 3-methylcholanthrene-treated
rats, while it is (nearly) absent in liver microsomes of rats treated with isonocotinic acid hydrazide (isoniazid). The constitutively
expressed CYP2E1 is found in microsomes of both treatment groups. Duodenal microsomes of minipigs orally exposed to polycyclic
aromatic hydrocarbons show a clear CYP1A1 signal. Low levels of CYP2E1 can also be detected in these microsomes. The LA-ICP-MS
method allows concomitant determination of CYPs, thereby exhibiting sensitivity similar to that of conventional chemoluminescence
detection via peroxidase-labelled secondary antibodies. The latter method allows readout of a single CYP protein in a 1D separation.
Although the results presented here are only for labelling by use of the elements iodine and europium, the same strategy can
be applied also for other lanthanide elements in combination with chelating compounds, so LA-ICP-MS of western blots offers
a new capability to be applied for highly multiplexed CYP determinations via labelled antibodies. 相似文献
74.
Y.Q. Li 《Journal of solid state chemistry》2008,181(3):515-524
The influence of the replacement of Sr by Ca on structural and luminescence properties of Eu2+-doped Sr2Si5N8 is reported. The Rietveld refinement of the powder X-ray diffraction data shows that the Ca2+ ion preferentially occupies the larger Sr site in Sr2Si5N8:Eu2+. Although the excitation spectrum is hardly modified, the position of the emission band of Eu2+ can be tailored through partial replacement of Sr by Ca in Sr2Si5N8:Eu2+, resulting in red-emission shifting from 620 to 643 nm. Furthermore, (Sr, Ca)2Si5N8:Eu2+ shows high potential as a conversion phosphor for white-light LED applications due to similar absorption, conversion efficiency and thermal quenching behaviour for 465 nm excitation after the introduction of the Ca ion. 相似文献
75.
Synthesis and photophysical properties of novel organic–inorganic hybrid materials covalently linked to a europium complex 总被引:2,自引:0,他引:2
Xianmin Guo Huadong Guo Lianshe Fu Hongjie Zhang L.D. Carlos Ruiping Deng Jiangbo Yu 《Journal of photochemistry and photobiology. A, Chemistry》2008,200(2-3):318-324
A novel sol–gel derived hybrid material (classed as Eu-DBM-Si) covalently grafted with Eu(DBM-OH)3·2H2O (where DBM-OH = o-hydroxydibenzoylmethane) was prepared through the primary β-diketone ligand DBM-OH. All the synthesized ligands were characterized by 1H NMR, elemental analyses and Fourier transform infrared spectra (FTIR). The resultant Eu-DBM-Si material exhibited good transparent and homogenous property. Compared to the Eu-DBM hybrid prepared by physically doped silicon dioxide with Eu(DBM-OH)3·2H2O, the Eu-DBM-Si hybrid presented more efficient ligand-to-Eu3+ energy transfer and a significant improvement in the measured emission quantum yield. Furthermore, the photophysical properties of these hybrid materials, such as the photoluminescence (PL) spectra, PL intensities, symmetry properties, lifetime decays, and Judd-Ofelt parameters were also investigated in detail. 相似文献
76.
Optical spectra (absorption, emission, excitation, decay) and dielectric relaxation were measured for divalent europium and partially for ytterbium in lanthanum fluoride crystals. Optical absorption of LaF3–Eu2+ contains not only asymmetric weakly structured band at 245 nm but also less intense bands at 330, 380 nm. Broadband Eu2+ emission at 600 nm appeared below 80 K with decay time 2.2 μs at 7.5 K. Emission at 600 nm is attributed to so-called anomalous luminescence. Bulk conductivity is directly proportional to absorption coefficient of Eu2+ bands. Dielectric relaxation peak of LaF3–EuF3 is attributed to rotation of dipoles Eu2+-anion vacancy. The long-wavelength absorption at 300–400 nm region are assigned to transitions from 4f7Eu2+ ground state to states of neighbouring fluorine vacancy. 相似文献
77.
Stanimirov SS Hadjichristov GB Petkov IK 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(5):1326-1332
Diamine derivatives of tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanediono]europium were synthesized and characterized by NMR, IR and UV-vis spectroscopy. The emission efficiency and decay times of the produced Eu(III) coordination complexes in acetone solutions were measured upon ligand excitation. The effect of the amine ligands was studied and the relation between the emission and the structure of the synthesized compounds was discussed. 相似文献
78.
Lanthanide chelates are excellent labels in ligand binding assays due to their long lifetime fluorescence, which enables efficient background reduction using time-resolved measurement. In separation-free homogeneous assays, however, some compounds in the sample may cause quenching of the lanthanide fluorescence and extra steps are required before these samples can be measured. In this study we have evaluated whether europium chelates packed inside a polystyrene nanoparticle are better protected from the environment than individual Eu(III)-chelates, and do these particles have higher tolerance against known interfering compounds (bivalent metal ions and variation of pH). We also tested whether metal ions had any effect on a fluorescence resonance energy transfer (FRET) based detection of a bioaffinity binding reaction. The presence of metal ions or variation of pH did not affect the fluorescence of the Eu(III)-chelate dyed nanoparticles, while significant decrease of the fluorescence was detected with a 9-dentate Eu(III)-chelate. Metal ions also decreased the fluorescence lifetime of the 9-dentate Eu(III)-chelate from 0.960 to 0.050 ms. Coloured metal ions caused a minor decrease in sensitised emission generated by FRET when Eu(III)-chelate dyed nanoparticles were used as donor labels. The decreased signal was due to the absorption of the sensitised emission by the coloured metal ions, since the metal ions had no effect on the lifetime of the sensitised emission. Thus the Eu(III)-chelate dyed nanoparticles are preferred labels in homogeneous bioaffinity assays, when interfering compounds are known to be present. 相似文献
79.
以含RE2O3(RE=Eu, Yb)为起始物, 在空气中成功地合成了MBPO5:RE(2+)(M=Ca, Sr, Ba;RE(2+)=Eu(2+), Yb(2+))荧光体, 测定了它们的激发和发射光谱峰位以及发射半高宽. 相似文献
80.