铕与β-丙氨酸配合物的合成及晶体结构

随着稀土在农业、医学及生物分子研究中的广泛应用，稀土进入生物生存的环境，并通过多种途径进入生物体内，因此研究稀土氨基酸配合物的组成和结构，对了解金属离子的生物效应及蛋白质的构效关系有重要意义，有关稀土与α-丙氨酸配合物的单晶结构已有不少报道，而对稀土     

稀土单分子磁体

单分子磁体因其磁性双稳态和慢弛豫机制而在超高密度存储材料、自旋电子器件等领域具有潜在的应用. 稀土单分子磁体因为具有较大的磁矩和磁各向异性而成为近年来研究的热点话题. 目前有关稀土单分子磁体的综述都主要集中在它们的合成、结构及磁性能, 而在其它性质方面缺少深入而系统的研究. 因此, 本论文结合现有的研究成果, 围绕稀土单分子磁体的高翻转能垒、复杂的多弛豫机制、可调控的磁性以及多功能材料的四个特点进行了综述, 旨在更好的理解稀土单分子磁体的物理、化学本质, 为稀土单分子磁体的设计与调控提供思路.     

稀土离子配合物与磷脂双分子膜的作用研究

利用一维和二维Ｈ核磁共振方法研究了柠檬酸稀土、稀土－ＤＴＰＡ配合物与磷脂双分子膜的作用，结果表明Ｌ在近生理条件下（ＰＨ＝７．４）及 柠檬酸配体的磷脂双分子膜体系中，稀土离子首先与柠檬酸体作用，形成的配合物对磷脂双分子膜的结构影响较小，稀土－ＤＴＰＡ配合物对磷脂双分子膜的结构没有影响这些结果为科学地评价稀土离子进行体内的毒性提供了实验依据。     

蒽醌与稀土离子间的能量转移研究

分子间或分子内的电子激发态能量转移是重要的初级光化学过程，很多体系电子激发态能量转移过程已经报导[1-3]，对稀土离子和谈基化合物的研究发现，用光激发配体时，激发了的配体可将能量转移给稀土离子，使稀土离子激发到发光能级，可观察到稀土的特征荧光，若稀土离子和谈基     

稀土单分子磁体的研究进展

在信息存储和量子计算方面具有广阔应用前景的单分子磁体及相关研究中,应用各向异性显著的稀土离子以期提高单分子磁体自旋翻转能垒的研究倍受关注。本文综述了稀土单分子磁体的研究进展,并着重介绍了单核、三核及四核镝配合物单分子磁体的磁学性质。     

冠醚取代蒽醌超分子体系的设计与合成及分子内能量转移的研究

大环冠醚由于其自组装性能及分子识别能力而引起人们广泛的重视.近来,冠醚又成为在超分子体系中用于建构主体分子的一种重要的建造单元[1～4].Costa[5]等曾报道苯并冠醚与被识别的稀土离子铕(Ⅲ)与铽(Ⅲ)之间的能量传递过程,选择性激发冠醚主体观察到稀土离子的发光.由于二氮杂冠醚与稀土离子能形成更稳定的配合物[6].我们利用了冠醚分子的分子识别能力及蒽醌分子的光敏性,设计合成了一种新的氮杂冠醚取代蒽醌分子(图1)(以下文中用代号AQ-CW表示),并以该分子作为主体分子,以稀土离子作为客体构成超分子体系,研究超分子体系内的能量转移过程.     

尖吻蝮蛇毒抗凝血因子Ⅱ的稀土离子荧光探针研究

尖吻蝮蛇毒抗凝血因子Ⅱ（ACFⅡ）分子中有两个钙离子结合位点,钙离子对ACFⅡ的内源荧光有增强作用,稀土离子（Nd^3 ,Sm^3 ,Eu^3 ,Gd^3 和Tb^3 ）能取代ACFⅡ分子中的钙离子,并对ACFⅡ的内源荧光有不同程度的猝灭作用,其中Tb^3 接受ACFⅡ分子中Trp残基传递的能量后,特征荧光增强。稀土离子与ACFⅡ荧光滴定表明,ACFⅡ分子中有两个稀土离子结合位点,稀土离子和钙离子在ACFⅡ分子中两个结合部痊是共同的竞争结合部位。ACFⅡ与不同稀土离子之间有相近的表观结合常数K1或K2。Tb^3 与RE^3 （RE=Nd,Sm,Eu或Gd)间线性自由能关系表明,稀土离子与ACFⅡ结合时,没有明显的空间效应。ACFⅡ分子中的两个结合位点在结构上都有较大的柔性,这种结构柔性为钙离子在ACFⅡ与活化凝血因子X的结合反应中起到的促进作用提供了结构基础。     

磷光寿命法研究稀土配合物的跨膜传输

从分子水平研究细胞与稀土离子及其配合物的作用机制和跨膜行为以及在细胞内作用的靶分子是阐明稀土生物效应的基础理论问题，研究这一问题对指导稀土的应用意义重大．要实现解决这一科学家梦寐以求的本质问题，关键是要寻求切实可行的有效的研究方法．室温磷光光谱分子探针技术在研究动物组织和细胞方面的应用发展非常迅速，由于氧在各种组织中分布的差异，因而对探针分子的磷光碎灭影响不同．曾经有人用把外吩配合物为磷光探针研究了细胞组织的病变行为’‘－‘’．本文选用的探针为稀土钦离子，通过测定稀土钦离子的磷光寿命，可以观察稀…     

稀土与细胞,器官,组织的作用及其生理效应

稀土与细胞、器官、组织的作用及其生理效应杨频，魏春英（山西大学分子科学研究所，太原，０３０００６）我国稀土贮量占世界第一位，稀土微肥已被大面积使用，稀土已进入植物，如在玉米大豆中，稀土含量为１０（－８）～１０（－１０）ｇ／ｇ［１］。随着稀土的广泛应用...     

稀土生物功能-植物＆微生物篇

稀土及其化合物早已被广泛应用于农业和医药业等生产实践中，多年的稀土生物无机化学研究表明：稀土元素能够增强植物光合作用，促进根系吸收，调节激素和氮代谢，抑制细菌繁殖等。稀土能够选择生物代谢中关键的生物分子的靶位点进行结合或取代反应，调控生物分子的功能和行为。从而在植物和微生物体内发挥了重要的生物学功能。然而，过量的稀土会对机体的生长带来不利的影响，为了在生产实践中更加科学和安全地应用稀土的生物功能，稀土最适剂量的探究及其在生物体内积累效应的研究将会是下个阶段的研究重点。     

稀土在机动车尾气催化净化中的应用与研究进展

随着我国机动车尾气排放法规日趋严格,对机动车尾气净化催化剂性能提出了更高的要求.稀土元素由于独特的4f电子层结构和储放氧性能等特性,在机动车尾气催化剂中得到广泛应用.本文综述了稀土元素在机动车尾气催化剂中的应用及相关机理研究现状,并依据京V排放法规要求探讨了最新排放限值对尾气净化催化剂性能的要求,分析了稀土在开发高性能催化剂中的作用,并对稀土在机动车尾气净化催化剂中的应用前景进行了展望.     

Amperometry with Two Polarizable Electrodes. Chelometric Determination of Rare Earths

Abstract

The method of determining rare earths by chelometric EDTA titration with biamperometric end-point indication using two stationary platinum electrodes was studied. The convenient pH range for the determination of lanthanum is 5.0 – 8.0, for yttrium 3.5 – 8.0 and for ytterbium 3.0 – 8.0. Rare earths have been determined in the presence of iron and thorium. Iron and thorium can be titrated at pH 1.5 – 2.0 and rare earths of the lanthanum group can be determined by successive titration at pH 5.0. Large amounts of rare earths of the yttrium group interfere with the determination of iron and thorium.     

The determination of sc,y, nd,ce and la in silicate rocks by a combined cation exchange-spectrochemical method

The combined use of cation exchange enrichment and spectrochemical analysis for the determination of rare earths in common silicate rocks is described. Rare earth elements are more strongly adsorbed by cation exchange resins than the abundant elements, hence the latter can be eluted with a concentration of acid which does not desorb the rare earths. The rare earths are then eluted by stronger hydrochloric acid and the effluent is evaporated to an amount of material sufficiently small to are spectrographically. This procedure allowed the determination of Sc, Y, Nd, Ce and La. in 13 South African'granite rocks and Y, Nd, Cu and La in 6 South African basic rocks.     

Activation analysis of rare-earth elements in opium and cannabis samples

Rare earth concentrations in 65 Opium, Cannabis and Cannabis resin samples seized from various parts of world were determined by destructive NAA. Great variations in absolute element concentrations, but only small significant differences of rare earth concentration ratios were found, indicating inconsiderable biogeochemical fractionation. The mean values of these ratios correspond with the relative abundances of the rare earths in the upper continental earth's crust.     

Spectrophotometric determination of cerium subgroup rare earths in nickel-base alloys in the presence of yttrium with p-acetylchlorophosphonazo and mixed surfactants

Rare earth elements react with p-acetylchlorophosphonazo (CPApA) to form colour complexes. In the presence of emulsifier OP and cetylpyridinium chloride (CPC), the yttrium complex is not formed because of micellar masking, while the cerium subgroup rare earths give more sensitive reactions with CPApA(epsilon(Ce) = 1.16 x 10(5) 1 . mol(-1) . cm(-1)) due to micellar sensitization. Most foreign ions can be tolerated in considerable amounts. The optimum conditions of the complex formation reaction and the composition of the Ce-CPApA complex are described. A simple method is proposed for the determination of cerium subgroup rare earths in nickel-base alloys with satisfactory results.     

Group separation of rare earth elements by liquid-liquid extraction for the neutron activation analysis of silicate rocks

Rare earth elements are isolated as a group from neutron activated rock samples by a new radiochemical procedure based on extraction with thenoyltrifluoracetone/phenanthroline in CHCl₃. The procedure consists of three extraction steps, obviates the use of anactive carriers and gives practically quantitative chemical yields, thereby avoiding fractionation of the individual rare earths. Details of the dissolution, chemical separations and counting procedure are given togther with an analysis of BCR-1.     

Sol-Gel Preparation of Selective Emitters for Thermophotovoltaic Conversion

Selective emitters are materials characterized by a high temperature emissivity significantly changing in different spectral regions. One of the crucial steps for the development of Thermophotovoltaic (TPV) generators is given by an optimal matching of the spectral emissivity of an IR radiation source with the spectral region where is maximum the efficiency of photovoltaic cells. The emitters should retain good structural properties at the working temperature above 1300°C and they can be either an external coating for the a burner or, as a structural material, a burner and emitter at once.In this work, oxide glass and ceramics containing rare earths have been prepared and characterized as selective emitters candidates. Different approaches and materials have been attempted all based on a colloidal route. Rare earths oxides (erbium and holmium) have been incorporated in transparent silica glass and in polycrystalline alumina and zirconia using their hydrated salts as oxide precursors. Rare earth modified silica glass were obtained by sintering silica xerogel containing fumed silica and hydrolysed ortholisicate. Rare earth modified alumina and mixed alumina-zirconia ceramics were obtained from slurries containing alumina colloidal particles and milled ceramic fibres. Functional properties i.e. the high temperature spectral emissivities have been measured by means of a specially designed apparatus where the working conditions of the selective emitters can be reproduced and monitored.     

稀土金属在离子液体中催化甲苯的选择性硝化反应

摘 要 将稀土金属盐负载在己内酰胺类离子液体上组成稀土金属盐和离子液体的复合物作为催化剂和溶剂,用于催化甲苯与等摩尔67%硝酸的硝化反应,利用核磁共振对离子液体的结构进行了表征。考察了不同的反应温度、反应时间及催化剂的种类和用量等因素对甲苯硝化反应的产率和对位选择性的影响。得出反应的最佳反应条件为：反应温度55℃,反应时间24h,苯磺酸镱（Yb）和苯磺酸离子液体（CPBSO）用量分别占甲苯的摩尔分数为5%和10%。产物硝基甲苯中邻、对位异构体质量比o/p=1.1,较硝硫混酸硝化(o/p=1.6)显著降低,产率达46.5 %。离子液体重复使用4次均表现出较好的催化活性及对位选择性。     

Complexation between rare earth metals and 1, 5-di(2-hydroxy-5-sulfophenyl)-3-cyanoformazan occurring on cetyltrimethylammonium bromide micelle

The microsurface adsorption-spectral correction technique (MSASC) has been applied to investigation of the ternary interaction of 1,5-di(2-hydroxy-5-sulfophenyl)-3-cyanoformazan (DHSPCF) with cetyltrimethylammonium bromide (CTAB) and rare earths Y, Eu, Dy and Yb. The CTAB micelle enriched DHSPCF molecules on its microsurface in monolayers and then sensitized the complexation between rare earths and DHSPCF. The binary aggregate and the ternary complex both were characterized.     

Reaction between rare earth elements and HFNO2 solution

Rare earth elements react with HFNO₂ solution to produce nitrosylium fluorometallates (NO)_xLnF_x+3. The value of x is 1.0 or 1.5 for light rare earth elements and 0.5 or 1.0 for heavy rare earths. Nitrosylium fluorometallates of rare earth elements can be decomposed into the simple fluoride and nitrosyl fluoride at low temperatures (46–68°C).