Volume and compressibility effects in the formation of metal-EDTA complexes

We used precise measurements of ultrasonic velocity and density to study the complexation of ethylendiaminetetraacetic acid (EDTA) with Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺ at 25‡C and pH 12. From these measurements we obtained the changes in the molar concentration increment of the ultrasonic velocity δA, the apparent molar adiabatic compressibility δK_sΦ, and the apparent molar volume δV_Φ of complex formation. The hydration contributions δ(AV_h) to the volume effect of binding range from 39.6 to 46.6 cm³-mol^-1 while the hydration contribution to the adiabatic compressibility change in the binding, δ(δK_h), ranges from 103.9X 10^-4 to 131.1 X 10^-4 cm³-mol^-1-bar^-1. These data are interpreted in terms of dehydration of interacting molecules,i.e., transfer of water molecules from the hydration shells of cations and EDTA into the bulk water. The ratio δ(δV_h)/ δ(δV_h) is in the range 0.35 to 0.38 bar, indicating a dominant contribution from the dehydration of charged atomic groups in the volume and the compressibility effects of complex formation.     

聚合物载体-稀土金属络合物的表征及其催化聚合共轭双烯的活性

本文采用含一定量功能团的直链碳氢共聚物作为载体,如苯乙烯-丙烯酸共聚物(SAAC),苯乙烯-2-(甲基亚硫酰基)乙基甲基丙烯酸酯共聚物(SMC)。介绍了这类聚合物载体-稀土金属络合物的合成方法,讨论了它们的红外光谱。聚合物载体-钕络合物催化剂具有很高的催化活性和定向效应.SAAC·Nd 三元体系的催化效率高达170kg聚丁二烯/gNd·小时,SMC·NdCl_3 二元体系的催化效率是小分子氯化钕二甲基亚砜络合物 NdCl_3·4DMSO的 2—3倍。聚丁二烯顺式-1,4结构含量在 98％以上。体系也适用于异戊二烯的聚合,产物顺式-1,4含量在95％左右。     

Solvent extraction of lanthanide ions with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP), III: Extraction of gadolinium(III), terbium(III), dysprosium(III), holimum(III), and thulium(III) byHPMBP from aqueous solutions

Summary The solvent extraction behaviour of Gd(III), Tb(III), Dy(III), Ho(III), and Tm(III) has been investigated using 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP or HL) in carbon tetrachloride as the extractant. Depending on the concentration ofHPMBP in the organic phase the chelatesLnL ₃ [Ln(III)=Gd, Tb, Dy, Ho, Tm] and adductsLnL ₃ · HL [Ln(III)=Gd, Tb, Dy, Ho] were extracted. The extraction equilibrium constants (K _ex3 orK _ex4) for the formation ofLnL ₃ orLnL ₃ · HL and the two-phase stability constants of the chelates or adducts ( ₃ ^x , ₄ ^x ) have been evaluated.

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Extraktion von Seltenerdmetall-Ionen mit 1-Phenyl-3-methyl-4-benzoyl-prazolon-5(HPMBP), 3. Mitt.: Extraktion von Gd(III), Tb(III), Dy(III), Ho(III), und Tm(III) aus wäßrigen Lösungen

Zusammenfassung Die Extraktion von Gd(III), Tb(III), Dy(III), Ho(III), und Tm(III) mittels 1-Phenyl-3-methyl-4-benzoyl-pyrazolon-5 (HPMBP oderHL) in Kohlenstofftetrachlorid wurde untersucht. In Abhängigkeit von der Konzentration anHPMBP in der organischen Phase bildeten sich Chelate vom TypLnL ₃ [Ln(III)=Gd, Tb, Dy, Ho, Tm] and Addukte vom TypLnL ₃ · HL [Ln(III)=Gd, Tb, Dy, Ho]. Die Werte der Extraktions-Gleichgewichtskonstanten (K _ex3 oderK _ex4) fürLnL ₃ oderLnL ₃ · HL, sowie die Zweiphasen-Beständigkeitskonstanten ( ₃ ^x , ₄ ^x ) der Chelate oder Addukte wurden berechnet.

     

稀土矿石成分分析标准物质的研制

介绍两种稀土矿石成分分析标准物质的研制过程。采用X射线荧光光谱法检验标准物质的均匀性和稳定性，标准物质的均匀性和稳定性良好。由8家具有权威性的测试单位协同定值及对数据进行数理统计，确定了该标准物质的标准值及标准偏差。     

（NH_4）_n［LaSb_9W_（21）O_（86）M_3］·xH_2O杂多配

合成了（ＮＨ４）ｎ［ＬａＳｂ９Ｗ２１Ｏ８６Ｍ３］·ｘＨ２Ｏ（Ｍ＝Ｍｎ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｃｒ，Ｆｅ），通过元素分析、１８３ＷＮＭＲ核磁共振谱、可见光谱、电化学测定对其进行了表征。     

LnHal2Hn ? Neue Phasen in den ternären Systemen Ln/Hal/H. I. Strukturen

LnHal₂H_n — New Phases in the Ternary System Ln/Hal/H. I. Structures Rare earth hydride halides of the compositions LaBr₂(H,D)_0.90, CeBr₂H_0.87, Cel₂H_0.90, Cel₂D_0.96, and GdI₂H_0.97 have been synthesised by heating either the dihalides, LnHal₂, or mixtures of LnHal₃ and LnH_x at 700°C ?800°C in hydrogen atmosphere. The heavy atom partial structures, as determined by X-ray scattering, correspond to the various sequences found in MoS₂ and NbS₂. From neutron scattering experiments the hydrogen atoms were located in the positions centering the anionic prisms and the cationic triangles.     

高效毛细管电泳测定混合氯化稀土中的稀土元素

研究了在以含有紫外吸收的咪唑为背影电解质和以α－羟基异丁酸为络合剂的缓冲液体系中，用毛细管电泳间接外法检测和然土离子的方法，讨论了各操作条件对稀土离子分离泊影响。     

叶绿素-希土的光谱与酸度影响

以希土空白作对比，改变不同试液的酸度，发现不管溶液中是否存在希土离子，叶绿素吸收峰的改变只在溶液pH小于1.5时出现，pH大于等于1.5时不发生，说明叶绿素紫外可见吸收谱峰的改变是由酸度引起，而希土离子的作用与此无关。     

Rare‐Earth Metal Alkyl Complexes with 3‐Arylamido‐Functionalized Indolyl Ligands: Synthesis,Characterization and Reactivity†

A series of dinuclear rare‐earth metal alkyl complexes {[μ‐η²:η¹:η¹‐3‐( L NCH)(CH₂SiMe₃)Ind]RE(CH₂SiMe₃)(THF)}₂ ( L ¹ = 2‐^tBuC₆H₄, RE = Y, Gd, Dy, Er, Yb; L ² = 2,4,6‐Me₃C₆H₂, RE = Dy, Er; Ind = indolyl) and {[μ‐η²:η¹:η¹‐3‐( L NCH₂)Ind]RE(CH₂SiMe₃)(THF)}₂ ( L ¹, RE = Y, Dy, Er, Yb; L ², RE = Er, Yb) bearing 3‐arylamido functionalized indolyl ligands having diverse bonding modes with metal ions were synthesized either by the insertion reaction of the imino group to the RE—C bond or by the alkane elimination reaction. In the preparation of above complexes, rare‐earth metal alkyl complexes [μ‐η⁵:η¹:η¹‐3‐( L ²NCH)(CH₂SiMe₃)Ind]Gd(CH₂SiMe₃)(THF)}₂ with a μ‐η⁵:η¹:η¹ coordination mode to the gadolinium ion and {[μ‐η³:η¹:η¹‐3‐( L ²NCH₂)Ind]Dy(CH₂SiMe₃)(THF)}₂ with a μ‐η³:η¹:η¹ coordination mode to the dysprosium ion were unexpectedly isolated. The reactions of 3‐( L ²N=CH)Ind with Er(CH₂SiMe₃)₃(THF)₂ at room temperature, generated a tetranuclear imino‐indolyl erbium intermediate {[μ‐η¹:η¹‐3‐( L ²N=CH)Ind]Er(CH₂SiMe₃)₂(THF)}₄, which can transform into the amido functionalized indolyl erbium complex in hot toluene. Moreover, the reactivities of the newly synthesized ytterbium complex with N‐heterocyclic compounds were investigated, affording the corresponding products of the mixed pyridyl‐indolyl, imidazolyl‐indolyl, and ortho‐metalated complexes. The yttrium complexes showed a high regioselectivity and steroselectivity for the isoprene polymerization with 1,4‐trans selectivity up to 91.7% and 1,4‐cis selectivity up to 96.1% in the presence of cocatalysts, respectively.     

Aspartic and Glutamic Acid as Ligands to Alkali and Alkaline-Earth Metals: Structural Chemistry as Related to Magnesium Therapy

Magnesium and other alkaline-earth and alkali metals play an important role in the biochemistry of virtually all living organisms. In contrast to “trace elements” these “common metals” are distributed in most cells and tissues, often in considerable concentrations, and a constant supply is indispensable for unrestricted performance of biological functions. In contemporary medicine, various forms of magnesium therapy are recommended in order to compensate for magnesium deficiency due to certain dysfunctions as well as to loss from excessive transpiration. In addition, there are numerous indications for prophylaxis. Magnesium is usually administered orally in the form of “complexes” with “natural” anions derived from I -aspartic, L -glutamic, L -pyroglutamic (pidolic), citric, and orotic acid. Analytical, electrochemical, and spectroscopic investigations of aqueous solutions of these Pharmaceuticals, together with X-ray diffraction studies of crystalline samples, have given a detailed knowledge of these coordination compounds. Only certain combinations can be addressed as magnesium complexes, whereas others are only present as aquo complexes both in aqueous solutions and in the solid state. Thus, a delicate balance of metal complexation and hydrogen bonding exists for the components of the drugs, which is relevant for the metal carrier functions of the organic ligands. Compared with the more flexible stereochemistry of Ca, Sr, Ba, Mn^II , Zn, Li, Na, and K complexes, which have coordination numbers between 4 and 9, octahedral hexacoordination is found exclusively for magnesium, the most stereoselective of these metals.