聚合物稀土配合物发光材料的合成与性能研究

聚合物稀土配合物兼具稀土离子独特的发光特性和聚合物易加工成型等优点,在平面显示和信息通讯等领域具有巨大的应用潜力,研究开发新型大分子配体以及稀土含量高且荧光强的聚合物稀土配合物材料具有重要意义。本文重点对聚合物稀土配合物发光材料结构设计和合成方法的研究进展进行了综述,并从大分子配体和高分子稀土配合物的结构与发光性能关系...     

新型La2CuMnO6和LaMnO3催化剂的甲烷燃烧催化性能比较

采用溶胶-凝胶法在空气气氛下于1100 ℃焙烧3 h后制备了一种新型单相稀土双层钙钛矿催化材料La2CuMnO6, 测试了其甲烷催化燃烧反应性能. 该化合物对甲烷催化燃烧反应表现出较好的催化活性, 起燃温度(T10)和完全转化温度(T90)分别为437.5和649.2 ℃, 在相同条件下与稀土单层钙钛矿型催化剂LaMnO3相比, 其T10和T90分别降低了53.1和116.5 ℃. XPS结果显示, La2CuMnO6氧空位浓度相对较大, 此外, La2CuMnO6与LaMnO3相比, 其TPR谱、SEM、TEM和磁性明显不同, 并与其甲烷催化燃烧活性有一定的对应关系.     

Exchange couplings in one-dimensionally arrayed 4f-3d heterometallic [Ln2Cu2]n compounds: A chemical trend of the coupling parameter

Heterometallic polymeric coordination compounds [{Ln(hfac)₂(CH₃OH)}₂{Cu(dmg)(Hdmg)}₂]_n (abbreviated as [Ln₂Cu₂]_n) involving light lanthanoid ions, Pr, Nd, Sm, and Eu, were synthesized, where H₂dmg and Hhfac stand for dimethylglyoxime and 1,1,1,5,5,5-hexafluoropentane-2,4-dione, respectively. The X-ray crystallographic analysis shows that their structures are isomorphous to those of the known heavy lanthanoid analogs. The exchange couplings were evaluated by high-frequency electron paramagnetic resonance and pulsed-field magnetization studies, giving ferromagnetic exchange parameters: J_Pr-Cu/k_B = 0.039(1) K, J_Nd-Cu/k_B = 0.38(1) K, J_Sm-Cu/k_B = 0.95(2) K, and no interaction between Eu and Cu ions. A significant trend is found in the order of the periodic table. The ferro- and antiferromagnetic 4f-3d couplings were characterized for the light and heavy lanthanoid derivatives, respectively. The magnitude of J_Ln-Cu decreases with a decrease of the 4f-spin portion, i.e., the number of unpaired electrons, whether the coupling is ferro- or antiferromagnetic.     

Catalytic asymmetric hydroxylation of α-alkoxycarbonyl amides with a Pr(OPr)3/amide-based ligand catalyst

A catalytic asymmetric hydroxylation of N-nonsubstituted α-alkoxycarbonyl amides is described. A new effective catalyst comprising Pr(OⁱPr)₃ and a fluoro-substituted amide-based ligand was identified using oxaziridine as the oxidizing reagent. The catalyst components were in dynamic equilibrium in the reaction mixture, which assembled to form the associated transition state through metal coordination and hydrogen bonding.     

Determination of relative rate of spectral events by novel modification of two-dimensional correlation spectroscopy

Sign of two-dimensional (2D) correlation peaks provides information on sequence of spectral events. This information is related to molecular mechanism of changes in a given system. Recently, few papers addressing the problems with interpretation of the sign of 2D correlation peaks have been published. To overcome these problems, a modification of the generalized 2D correlation method has been proposed. This method compares variations in the dynamic spectrum with a linear change at a reference point. The rates of spectral responses at individual wavenumbers are proportional to magnitudes of the peaks in the slice of asynchronous spectrum at the reference point. This way, analysis of complex 2D contour plots is replaced by a simple examination of one-dimensional (1D) slice spectrum. In spite of reduced ability of the resolution enhancement, in special cases the proposed method provides information not accessible from the classical 2D correlation analysis. At first, the principles of this method are shown with the synthetic data. Next, the influence of spectral separation, band width and position changes on the slice spectrum is evaluated. Finally, the proposed approach is applied to the experimental spectra of two hydrogen-bonded systems.     

RE（NO_3）_3·（GLy）_3·nH_2O配合物的合成和表征

本文在水溶液中合成了镧、镨、钐和钆四种稀土硝酸盐与甘氨酸的固态配合物。化学分析表明，它们的化学组成分别是Ｌａ（ＮＯ＿３）＿３·（ＧＬｙ）＿３·Ｈ＿２Ｏ、Ｐｒ（ＮＯ＿３）＿３·（ＧＬｙ）＿３·Ｈ＿２Ｏ、Ｓｍ（ＮＯ＿３）＿３·（ＣＬｙ）＿３·３Ｈ＿２Ｏ和Ｇｄ（ＮＯ＿３）·（ＧＬｙ）＿３·３Ｈ＿２Ｏ。用红外光谱法和Ｘ射线衍射法测定了配合物的结构特征，表明它们是一类完全不同于稀土硝酸盐和甘氨酸的新化合物。同时，考察了配合物在几种常见溶剂中的溶解性。     

高效毛细管区带电泳检测稀土元素

本文使用背景电解质为含有吸收作用的肌酸酐和作为配合对离子的羟基异丁酸，肜高效毛区带电泳（ＣＺＥ）间接紫外光度法测定稀土元素。探讨了背景电解质酸度，吸光共存离子和配合对离子浓度对稀土电泳分离的影响；提出用背景电解质预，沉积法克服毛细管壁的强烈吸附干扰。９种稀土元素混合物１１ｍｉｎ内完成分离检测。应用内标法对稀土钢样中单个稀土含进行了定量分析。     

ICP-MS测定高纯氧化铒中稀土杂质的研究

从同位素的选择、基体效应,内标元素的选择及仪器工作等方面对实验参数进行了优化,重点研究了等离子体功率及仪器分辩率的改变对铒基体所形成的氢化物多原子离子干扰的影响。通过提高等离子体功率、改变仪器分辨率及数学方程校正等方法,减小和剔除了ErH对Ho和Tm测定的干扰。实验中选取Cs为内标元素,测定了不同含量的高纯氧化铒样品。分析结果与标准加入法结果进行了比较,之间无显著性差异。     

Nitric oxide and singlet oxygen photo-generation by light irradiation in the phototherapeutic window of a nitrosyl ruthenium conjugated with a phthalocyanine rare earth complex

The photochemical, photophysical and photobiological studies of a mixture containing cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] (H₂-dcbpy = 4,4′-dicarboxy-2,2′-bipyridine) and Na₄[Tb(TsPc)(acac)] (TsPc = tetrasulfonated phthalocyanines; acac = acetylacetone), a system capable of improving photodynamic therapy (PDT), were accomplished. cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] was obtained from cis-[Ru(H₂-dcbpy)₂Cl₂]·2H₂O, whereas Na₄[Tb(TsPc)(acac)] was obtained by reacting phthalocyanine with terbium acetylacetonate. The UV–Vis spectrum of cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] displays a band in the region of 305 nm (λ_max in 0.1 mol L⁻¹ HCl)(π–π*) and a shoulder at 323 nm (MLCT), while the UV–Vis spectrum of Na₄[Tb(TsPc)(acac)] presents the typical phthalocyanine bands at 342 nm (Soret λ_max in H₂O) and 642, 682 (Q bands). The cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] FTIR spectrum displays a band at 1932 cm⁻¹ (Ru–NO⁺). The cyclic voltammogram of the cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] complex in aqueous solution presented peaks at E = 0.10 V (NO^+/0) and E = −0.50 V (NO^0/−) versus Ag/AgCl. The NO concentration and ¹O₂ quantum yield for light irradiation in the λ > 550 nm region were measured as [NO] = 1.21 ± 0.14 μmol L⁻¹ and ø_OS = 0.41, respectively. The amount of released NO seems to be dependent on oxygen concentration, once the NO concentration measured in aerated condition was 1.51 ± 0.11 μmol L⁻¹ The photochemical pathway of the cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)]/Na₄[Tb(TsPc)(acac)] mixture could be attributed to a photoinduced electron transfer process. The cytotoxic assays of cis-[Ru(H-dcbpy^-)₂(Cl)(NO)] and of the mixture carried out with B16F10 cells show a decrease in cell viability to 80% in the dark and to 20% under light irradiation. Our results document that the simultaneous production of NO and ¹O₂ could improve PDT and be useful in cancer treatment.     

Syntheses, crystal structures and spectroscopic properties of KEu[AsS4], K3Dy[AsS4]2 and Rb4Nd0.67[AsS4]2

Three rare earth compounds, KEu[AsS₄] (1), K₃Dy[AsS₄]₂ (2), and Rb₄Nd_0.67[AsS₄]₂ (3) have been synthesized employing the molten flux method. The reactions of A₂S₃ (A = K, Rb), Ln (Ln = Eu, Dy, Nd), As₂S₃, S were accomplished at 600 °C for 96 h in evacuated fused silica ampoules. Crystal data for these compounds are: 1, monoclinic, space group P2₁/m (no. 11), a = 6.7276(7) Å, b = 6.7190(5) Å, c = 8.6947(9) Å, β = 107.287(12)°, Z = 2; 2, monoclinic, space group C2/c (no. 15), a = 10.3381(7) Å, b = 18.7439(12) Å, c = 8.8185(6) Å, β = 117.060(7)°, Z = 4; 3, orthorhombic, space group Ibam (no. 72), a = 18.7333(15) Å, b = 9.1461(5) Å, c = 10.2060(6) Å, Z = 4. 1 is a two-dimensional structure with ²_∞[Eu(AsS₄)]⁻ layers separated by potassium cations. Within each layer, distorted bicapped trigonal [EuS₈] prisms are linked through distorted [AsS₄]³⁻ tetrahedra. Each Eu²⁺ cation is coordinated by two [AsS₄]³⁻ units by edge-sharing and bonded to further two [AsS₄]³⁻ units by corner-sharing. Compound 2 contains a one-dimensional structure with ¹_∞[Dy(AsS₄)₂]³⁻ chains separated by potassium cations. Within each chain, distorted bicapped trigonal prisms of [DyS₈] are linked by slightly distorted [AsS₄]³⁻ tetrahedra. Each Dy³⁺ ion is surrounded by four [AsS₄]³⁻ moieties in an edge-sharing fashion. For compound 3 also a one-dimensional structure with ¹_∞[Nd₀.₆₇(AsS₄)₂]⁴⁻ chains is observed. But the Nd position is only partially occupied and overall every third Nd atom is missing along the chain. This cuts the infinite chains into short dimers containing two bridging [As₄]³⁻ units and four terminal [AsS₄]³⁻ groups. 1 is characterized with UV/vis diffuse reflectance spectroscopy, IR, and Raman spectra.