铕(Ⅲ)-锌(Ⅱ)双核配合物的合成和表征

Two new Eu(Ⅲ)-Zn(Ⅱ) binuclear complexes Zn(Salen)EuL₃ have been synthesized, where Salen=Shiff base of bissalicylaldehyde with ethlenediamine and L=acetylacetone (for complex Ⅰ) or trifluoroacetylacetone (for compelx Ⅱ). Analytical experimetal such as IR, UV and elemental analysis suggest the possible component and structure, the fluorescence spectrum of the complex Ⅱ suggests the M^*→M fluorescence mechanism.     

Eu(BA)3phen的晶体结构和荧光光谱

标题配合物晶体属三斜晶系，Ｐ１空间群，晶胞参数ａ＝１０７９２（２）ｎｍ，ｂ＝１１８９６（２）ｎｍ，ｃ＝１２４４６ｎｍ，α＝１０５１２（３）°，β＝９３７６（３）°，γ＝１１３１９（３）°，Ｖ＝１３９２（１）ｎｍ－３，Ｚ＝２，Ｄｘ＝１６５９ｇ·ｃｍ－３。配合物晶体由双核分子组成，两个中心Ｅｕ３＋通过羧基桥联，它们的化学环境相同。Ｅｕ３＋的配位数为８，其配位多面体为一畸变的四方反棱柱体。在７７Ｋ配合物的荧光光谱说明配合物中仅存在一种Ｅｕ３＋格位。     

Eu(DMBM)2(2,2′-bipy)NO3的合成与荧光光谱

本工作首次合成了Eu(DMBM)₂(2,2′-bipy)NO₃(DMBM=二对甲氧基苯甲酰甲烷,2,2′-bipy-2,2′-联吡啶)。通过元素分析、热谱、电导率、红外和拉曼光谱、质子核磁共振谱对所合成化合物进行了表征。在77K测定了固体配合物的激发光谱和发光光谱。光谱数据说明配合物含有两种Eu(Ⅲ)格位。配合物中三种配体在Eu(Ⅲ)周围的分布情况略有不同,显示出不同的晶体场效应。光谱数据表明,配合物中Eu(Ⅲ)格位属于非中心对称的点群C₁或C₃或C₂。     

Eu2(3,4-DMBA)6(PHEN)2的晶体结构及HRS研究

合成了铕（Ⅲ）与３,４－二甲基苯甲酸（３,４－ＨＤＭＢＡ）、邻菲咯啉（ＰＨＥＮ）形成的晶体配合物Ｅｕ２（３,４－ＤＭＢＡ）６（ＰＨＥＮ）２．测定其分子量Ｍ＝１５５９．３５,晶体属三斜晶系,Ｐ１空间群,ａ＝１．２６６５（４）ｎｍ,ｂ＝１．３５６７（４）ｎｍ,ｃ＝１．０７５５（４）ｎｍ,α＝９８．８７（３）°,β＝１０８．２５（３）°,γ＝８７．９８（２）°,Ｚ＝１,最终的偏离因子Ｒ＝０．０３１．以Ｅｕ（Ⅲ）离子为荧光探针,在７７Ｋ下测定了配合物的高分辨光谱（ＨＲＳ）．铕配合物的激发光谱、发光光谱、时间分辨光谱和发光寿命测定结果表明,该配合物中存在两种化学环境不同的Ｅｕ（Ⅲ）离子格位     

Eu(DBM)_3(2,2′-bipy)的晶体结构和荧光光谱

Eu(C_(15)H_(12)O_2)3(C_(10)H_3N_2).分子量M=1103.03.空间群P2_1/c,a=1.3309(4)nm.b=2.2473(5)nm,c=1.6231(1)nm,β=109.68(1)°,V=4.571(2)nm~3,Z=4,D_x=1.43 g·cm~(-3).用5590个可观察衍射点对64个非氢原子坐标和各向异性温度因子进行全矩阵最小二乘法精修。最终的偏离因子R=0.046.中心离子Eu(Ⅲ)由DBM配体的6个氧原子和2,2′-bipy的2个氮原子螫合配位,配位多面体为畸变的四方反棱柱体.利用标题化合物能发生较强荧光的特性,以Eu(Ⅲ)离子为荧光探针,77K下测定了配合物的高分辨激光激发和发射光谱.结果表明,配合物中Eu(Ⅲ)离子仅有一种晶格格位,~5Do→~7F_j(J=0～2)跃迁光谱和晶体结构表明中心离子具有C_1格位对称性。     

Eu(DBM)_3TPPO的晶体结构和荧光光谱

C_(63)H_(51)O_7PEu,三斜晶系,空间群,a=12.336(3),b=18.729(5),c=11.502(3),α=95.86(2),β=103.14(2),γ=87.89(2)°,Z=2,D_x=1.39gcm~(-3)。用6989个I>3σ(I)的可观察衍射数据对72个非氢原子的原子坐标和各向异性温度因子进行全矩阵最小二乘精修,最终的偏离因子R=0.055。中心离子Eu(Ⅲ)由七个氧原子配位,配位多面体为畸变的单帽三棱柱体,帽位由TPPO的氧原子占据,Eu—O原子间距在2.305(4)—2.367(4)之间。77K下测定了配合物的高分辨激光激发和发射光谱,结果表明配合物中Eu(Ⅲ)离子有两种格位,一具C_(2v)点对称性,另一具C_s点对称性。具有较低对称性C_s的物种在配合物中占绝对优势。77K下还记录了掺1％铕的配合物Gd(DBM)_3TPPO的发射光谱,结果表明Gd(Ⅲ)离子具有与标题化合物中Eu(Ⅲ)离子相同的格位。     

[Eu2(o-ClC6H4OCH2COO)6(C12H8N2)2(H2O)2]·(CH3)2SO的晶体结构和荧光光谱

标题配合物Ｍ＝１８９２．０１,单斜晶系,空间群Ｐ２１／ｃ,ａ＝１．２９７５（３）ｎｍ,ｂ＝２．６５９１（９）ｎｍ,ｃ＝１．２１１８（３）ｎｍ,β＝９６．９５（１）°,Ｚ＝２,Ｄｃ＝１．５７７ｇ／ｃｍ３,Ｔ＝２９３（２）Ｋ。最终的偏离因子Ｒ＝０．０５８３。该配合物以二聚体形式存在,通过其中的桥联羧基形成了双核分子。该分子中羧基具有桥联双齿、桥联三齿和单齿三种配位模式,Ｅｕ－Ｅｕ之间的距离为０．４０１９（１）ｎｍ。在７７Ｋ下测得配合物中Ｅｕ（Ⅲ）离子仅有一种格位。５Ｄ０→７ＦＪ（Ｊ＝０～２）跃迁光谱说明Ｅｕ（Ⅲ）离子格位具有Ｃ２对称性。     

含稀土铕(Ⅲ)配位聚合物的研究

将铕的有机配合物NaEu(TTA)4与聚（苯乙烯-丙烯酸）（PSAA）反应制备了铕配位聚合物[Eu(Ⅲ）-TTA-PSAA]，用电导、DTA-TGA、荧光光谱等对其进行了表征。由于配合物中存在着Eu^3 分别与TTA^-和PSAA分子中羧基的配位作用，并进一步交联，因此配合物样品均不溶于大部分有机溶剂，只能溶于N，N-二甲基甲酰胺和丙三醇/异丙醇的混合溶剂，且耐热性得到提高。配合物为褐色固体，在常温、紫外光下发出红光，主要是由于Eu^3 离子的^5D0→^7F2跃进。讨论了pH值对配合物荧光强度的影响，当pH=10时，合成的配合物具有最好的荧光性。     

以Eu（Ⅲ）作荧光探针时间分辨荧光法测定吡哌酸

建立了一种以Eu(Ⅲ)作为荧光探针,时间分辨荧光法测定吡哌酸的新方法。吡哌酸和Eu(Ⅲ)配合后在受到紫外光激发时发生分子内能量转移,配合物发射铕离子的特征荧光。以荧光强度进行条件优化,结果表明,在pH 8.2的缓冲溶液中,加入适量阴离子表面活性剂十二烷基硫酸钠(SDS)后,体系荧光强度大大增强。方法的检出限(3σ)为2×10-8mol/L,测定精度RSD为0.62%(2×10-6mol/L,n=11)。吡哌酸溶液在5×10-8~5×10-6mol/L范围内线性关系良好。该方法可用于吡哌酸片剂及尿液中痕量吡哌酸的测定,药片测定结果与药典方法基本一致。     

Ca2+、La3+及Eu3+对NaDC胶团的作用

在水溶液中将脱氧胆酸钠（ＮａＤＣ）分别与ＣａＣＬ２、ＥｕＣｌ３及ＬａＣｌ３反应,改变反应物浓度和配比,合成了系列脱氧胆酸络全物。利用红外光谱（ＦＴＩＲ）、元素分析、ＩＣＰ分析及Ｘ身材线粉末衍射谱,对它们的组成和结构进行了研究。结果表明：水溶液中ＣａＣｌ２与ＮａＤＣ的反应不是简单离子间的反应,改变其反应物浓度和配比,生成组成和结构不同的络合物;而ＬｎＣｌ３与ＮａＤＣ反应时,反应物浓度和配比的改变不影     

Spectral and temporal luminescent properties of Eu(III) in humic substance solutions from different origins

Although a high heterogeneity of composition is awaited for humic substances, their complexation properties do not seem to greatly depend on their origins. The information on the difference in the structure of these complexes is scarce. To participate in the filling of this lack, a study of the spectral and temporal evolution of the Eu(III) luminescence implied in humic substance (HS) complexes is presented. Seven different extracts, namely Suwannee River fulvic acid (SRFA) and humic acid (SRHA), and Leonardite HA (LHA) from the International Humic Substances Society (USA), humic acid from Gorleben (GohyHA), and from the Kleiner Kranichsee bog (KFA, KHA) from Germany, and purified commercial Aldrich HA (PAHA), were made to contact with Eu(III). Eu(III)-HS time-resolved luminescence properties were compared with aqueous Eu³⁺ at pH 5. Using an excitation wavelength of 394 nm, the typical bi-exponential luminescence decay for Eu(III)-HS complexes is common to all the samples. The components τ₁ and τ₂ are in the same order of magnitude for all the samples, i.e., 40 ≤ τ₁ (μs) ≤ 60, and 145 ≤ τ₂ (μs) ≤ 190, but significantly different. It is shown that different spectra are obtained from the different groups of samples. Terrestrial extract on the one hand, i.e. LHA/GohyHA, plus PAHA, and purely aquatic extracts on the other hand, i.e., SRFA/SRHA/KFA/KHA, induce inner coherent luminescent properties of Eu(III) within each group. The ⁵D₀ → ⁷F₂ transition exhibits the most striking differences. A slight blue shift is observed compared to aqueous Eu³⁺ (λ_max = 615.4 nm), and the humic samples share almost the same λ_max ≈ 614.5 nm. The main differences between the samples reside in a shoulder around λ ≈ 612.5 nm, modelled by a mixed Gaussian–Lorentzian band around λ ≈ 612 nm. SRFA shows the most intense shoulder with an intensity ratio of I_612.5/I_614.7 = 1.1, KFA/KHA/SRHA share almost the same ratio I_612.5/I_614.7 = 1.2–1.3, whilst the LHA/GohyHA/PAHA group has a I_612.5/I_614.5 = 1.5–1.6. This shows that for the two groups of complexes, despite comparable complexing properties, slightly different symmetries are awaited.     

The effect of calcium substitution on the afterglow of Eu2+/Dy3+ doped Sr4Al14O25

The effect of calcium substitution on the afterglow of tetrastrontium aluminate phosphors (Sr₄Al₁₄O₂₅:Eu²⁺, Dy³⁺) was investigated. A series of (Sr₁-_xCa_x)O⊎nAl₂O₃:Eu²⁺(1%), Dy³⁺(0.5%), with variation of calcium content (x = 0 − 1), were synthesized by a high temperature solid state reaction in a reducing atmosphere. The photoluminescence, persistent luminescence (afterglow), and lumen equivalents of these materials were studied and compared. It turned out that the afterglow properties of the phosphors were strongly dependent on the Sr/Ca ratio. As the Ca content increased, a phase transition and blue shift in emission spectra were observed.      

Fluorescence enhancement of the Eu-Tb-benzoylacetone-phenanthroline system

The Eu-benzoylacetone-phenanthroline system, which has strong fluorescence intensity, was studied. It was found that the fluorescence intensity can be greatly increased by La, Gd, Tb, Lu and Y, Tb giving the greatest enhancement (ca. two orders of magnitude). The maximum fluorescence intensity was obtained at pH 8.0. Beer's law was obeyed from 1.0 × 10^?9 to 2.0 × 10^?7 M Eu. The detection limit for europium was 2.0 × 10^?11 M.     

KZnF3中Ce3+→Eu2+的能量传递

研究了KZnF3中Ce3+和Eu2+的光谱特性,在共掺Ce3+和Eu2+的体系中,观察到了Ce3+对Eu2+的能量传递过程.计算了能量传递的量子效率,探讨了能量传递机理.研究发现,Ce3+的存在有利于Eu2+的f-f跃迁线状发射.     

Eu3＋和Ho3＋对乙醇在Pt-TiO2/C电极上氧化的助催化作用

报道了用循环伏安法研究Eu3＋和Ho3＋吸附的碳载Pt-TiO2(Pt-TiO2/C)催化剂对乙醇电化学氧化的助催化作用.发现无论在中性溶液中还是在酸性溶液中,当Pt-TiO2/C催化剂吸附Eu3＋或Ho3＋后,都可以使乙醇的电催化氧化电流密度明显增加,其原因主要是Eu3＋或Ho3＋都能促进吸附的CO的电氧化.     

Resonance light scattering properties of Eu3+ in gold colloid

Gold colloidal containing rare-earth ions Eu3+ were prepared at room temperature. Fluorescence spectra and resonance light scattering (RLS) spectra of Eu3+ ions and gold colloid containing Eu3+ were measured. For solution containing Eu3+, RLS features show two peaks at the edges of the visible light wavelength region. The short wavelength peak takes place at about 400 nm and the longer wavelength peak is the corresponding 1/2 fraction frequency RLS peak, which takes place at about 780 nm. When gold colloids were added to the solution containing Eu3+, both these two RLS peaks were enhanced. We believe that the energies, which are absorbed by the surface plasmon resonance in the gold nanoparticles, are efficiently transferred into the Eu3+ ions to cause the increased scattering.     

Synthesis and fluorescence properties of rare earth (Eu3+ and Gd3+) complexes with alpha-naphthylacetic acid and 1,10-phenanthroline

Rare earth binary complex Eu(NNA)3 (NNA, alpha-naphthylacetic acid), ternary complex Eu(NNA)3.phen (phen, 1,10-phenanthroline) and a series of dinuclear complexes with different mole ratios of Eu3+ to Gd3+ were synthesized. Many advanced approaches, such as element analysis, FTIR spectra, TG and DTA analysis, were used to determine the composition and structure of binary and ternary complex. Moreover, their fluorescence properties were studied by fluorescent spectra and lifetimes. The fluorescence spectra and decay curves of dinuclear complexes indicated that the fluorescence emission intensity was enhanced and the fluorescence lifetime was prolonged by Gd3+. The dinuclear complexes show the best properties when the mole ratio of Eu3+ to Gd3+ is 6:4. A new parameter Y, which was used to evaluate the effect of Gd3+, was introduced. In addition, the relationship of Y value and mole fraction of Gd3+ was analyzed by mathematical software. The results showed that Y value decreased by single exponential mode when the content of Gd3+ decreased.