542 resultados para YB-III

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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A series of novel, colorless, and transparent sot-gel derived hybrid materials Ln-DBM-Si covalently grafted with Ln(DBM-OH)(3)center dot 2H(2)O (where DBM-OH = o-hydroxydibenzoylmethane, Ln = Nd, Er, Yb, and Sin) were prepared through the primary beta-diketone ligand DBM-OH. The structures and optical properties of Ln-DBM-Si were studied in detail. The investigation results revealed that the lanthanide complexes were successfully in situ grafted into the corresponding hybrids Ln-DBM-Si. Upon excitation at the maximum absorption of ligands, the resultant materials displayed excellent near-infrared luminescence.

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A beta-diketone ligand 4,4,5,5,5-pentafluoro-1-(2-naphthyl)-1,3-butanedione (Hpfnp), which contains a pentafluoroalkyl chain, was synthesized as the main sensitizer for synthesizing new near-infrared (NIR) luminescent Ln(pfnp)(3)phen (phen = 1,10-phenanthroline) (Ln = Er, Nd, Yb, Sm) complexes. At the same time, a series of lanthanide complexes covalently bonded to xerogels by the ligand 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline (phen-Si) were synthesized in situ via a sol-gel process. [The obtained materials are denoted as xerogel-bonded Ln complexes (Ln = Er, Nd, Yb, Sm).] The single crystal structures of the Ln(pfnp) 3phen complexes were determined.

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New near-infrared-luminescent mesoporous materials were prepared by linking ternary lanthanide (Er3+, Nd3+, Yb3+, Sm3+, Pr3+) complexes to the ordered mesoporous MCM-41 through a functionalized 1,10-phenanthroline (phen) group 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline. The resulting materials (denoted as Ln(hfth)(3)phen-M41 and Pr(tfnb)(3)phen-M41; Ln=Er, Yb, Nd, Sm; hfth = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dionate; tfnb = 4,4,4-trifluoro-1-(2-naphthyl)- 1, 3-butanedionate) were characterized by powder X-ray diffraction, N-2 adsorption/desorption, and elemental analysis. Luminescence spectra of these lanthanide-complex functionalized materials were recorded, and the luminescence decay times were measured. Upon excitation at the absorption of the organic ligands, all these materials show the characteristic NIR luminescence of the corresponding lanthanide (Er3+, Nd3+, Yb3+, Sm3+, Pr3+) ions by sensitization from the organic ligands moiety. The good luminescent performances enable these NIR-luminescent mesoporous materials to have possible applications in optical amplification (operating at 1300 or 1500 nm), laser systems, or medical diagnostics.

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The ligand Hhfth [4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dione], which contains a heptafluoropropyl group, has been used to synthesize several new ternary lanthanide complexes (Ln = Er, Ho, Yb, Nd) in which the synergistic ligand is 1,10-phenanthroline (phen) or 2,2'-bipyridine (bipy). The two series of complexes are [Ln(hfth)(3)phen] [abbreviated as (Ln)1, where Ln = Er, Ho, Yb] and [Ln(hfth)(3)bipy] [abbreviated as (Ln)2, where Ln = Er, Ho, Yb, Nd]. Members of the two series have been structurally characterized. The growth morphology, diffuse reflectance (DR) spectra, thermogravimetric analyses, and photophysical studies of these complexes are described in detail. After ligand-mediated excitation of the complexes, they all show the characteristic near-infrared (NIR) luminescence of the corresponding Ln(3+) ions (Ln = Er, Ho, Yb, Nd). This is attributed to efficient energy transfer from the ligands to the central Ln(3+) ions, i.e. an antenna effect. The heptafluorinated substituent in the main hfth sensitizer serves to reduce the degree of vibrational quenching. With these NIR-luminescent lanthanide complexes, the luminescent spectral region from 1300 to 1600 nm, which is of particular interest for telecommunication applications, can be covered completely.

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The ytterbium(III) extraction kinetics and mechanism with mixtures of bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex272) and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) dissolved in heptane have been investigated by constant interfacial cell with laminar flow. The effects of the stirring rate, temperature, extractant concentration, and pH on the extraction with mixtures of Cyanex272 and P507 have been studied. The results are compared with those of the system with Cyanex272 or P507 alone. It is concluded that the Yb(III) extraction rate is enhanced with mixtures extractant of Cyanex272 and P507 according to their values of the extraction rate constant, which is due to decreasing the activation energy of the mixtures. At the same time, the mixtures exhibits no synergistic effects for Y(III), which provides better possibilities for Yb(III) and Y(III) separations at a proper conditions than anyone alone. Moreover, thermodynamic extraction separation Yb(III) and Y(III) by the mixtures has been discussed, which agrees with kinetics results. Extraction rate equations have also been obtained, and through the approximate solutions of the flux equation, diffusion parameters and thickness of the diffusion film have been calculated.

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本文分另研究了H[DEHP]从不同酸性介质中萃取稀土(III)(Sc、Y、Ho、Er、yb、Lu)及Fe(III)、Zn(II)的机理及性能。一、H[DEHP]从 H_2SO_4介质中萃取Sc(III)的机理 1. H[DEHP]萃取H_2SO_4及其机理 2. H[DEHP]萃取Sc(III)的机理,用斜率法和饱和法确定了H[DEHP]的正庚烷溶液从H_2SO_4溶液中萃取Sc_2(SO_4)_3的机理及萃合物组成。研究表明,H[DEHP]萃取Sc(III)在高、低两种酸度范围内存在着两种不同的萃取机理。二、H[DEHP]从HCl介质中萃取Ln(III)和Fe(III)的性能及H[DEHP]萃取Ln(III)的机理研究了H[DEHP]的正庚烷溶液从HCl介质中萃取稀土(III)(Sc、Y、Ho、Er、Yb、Lu)和Fe(III)的性能,得出H[DEHP]在相同条件下萃取以上各金属离子的顺序是:Sc(III)>Fe(III)>Lu(III)>Yb(III)>Er(III)>Y(III)>Ho(III), 并计算了各金属离子之间的分离因素(β)。文中还讨论了Sc(III)、Fe(III)、Lu(III)之间的分离以及重稀土离子间的萃取分离,同时与相同实验条件下HEH[EHP]的萃取性能进行了比较,为新的萃取体系提供了一些参数。三、H[DEHP]从不同介质中萃取Fe(III)的机理,研究了H[DEHP]的正率烷溶液从Hcl介质中和H[DEHP]的正庚烷溶液从H_2SO_4介质中萃取Fe(III)的平衡规律;用斜率法、饱和法以及IR和NMR谱等讨论了低酸度下的萃取机理。四、H[DEHP]萃取Zn(II)的机理,研究了H[DEHP]的正率烷溶液从Hcl介中萃取Zn(II)的平衡,利用斜率法、饱和法及SR、NMR谱等讨论了低Hcl浓度下的萃取机理。

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The separation of Sc(III) from Y(III), La(III) and Yb(III) in [C(8)mim][PF6] containing Cyanex 925 has been investigated, and is reported in this paper. A cation exchange mechanism of Sc(III) in [C(8)mim][PF6] and Cyanex 925 is proposed by study of the influence of anionic and cationic species on the extraction. The coefficient of the equilibrium equation of Sc(III) was confirmed by slope analysis of log D-Sc vs log [Cyanex 925], and the loading capacity also confirmed the stoichiometry of Cyanex 925 to Sc(III) was close to 3:1. Infrared data for Cyanex 925 saturated with Sc(III) in [C(8)mim][PF6] indicated strong interaction between P=O of Cyanex 925 and Sc(III). In addition, the relationship between log D-Sc and temperature showed that temperature had little influence on the extraction process, and the resulting thermodynamic parameters indicated that an exothermic process was involved.

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The extraction and stripping of ytterbium (III) from sulfuric acid medium using Cyanex 923 in heptane solution was investigated. The effects of extractant concentration, pH and sulfate ion as well as stripping agents, acidity and temperature on the extraction and stripping were studied. The equilibrium constants and thermodynamic parameters, such as Delta H (10.76 kJ(.)mol(-1)), Delta G (-79.26 kJ(.)mol(-1)) and Delta S (292.41 J(.)K(-1.)mol(-1)), were calculated. The extraction mechanism and the complex species extracted were determined by slope analysis and FrIR spectra. Furthermore, it was found that the extraction of Yb (III) from sulfuric acid medium by Cyanex 923 increased with pH, concentration of SO42-, HSO4-, and extractant concentration, and approximately a quantitative extraction of Yb (III) was achieved at an equilibrium pH near 3.0, and the extracted complex was YbSO4(HSO4)(.)2Cyanex923((o)).

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Extraction resins, of the type of;levextrel, (which is a collective term for styrene/divinylbenzene based copolymers of predominantly macroporous structure that contain a selective extractant) are important for the recovery and separation of metal ions, as they combine features of solvent extraction and ion exchange resins. This paper presents the results of the adsorption of heavy rare earth ions (Ho(III), Er(III), Tm(III), Yb(III), Lu(III) and Y(III)) from hydrochloric acid solutions at 0.2 mol/L ionic strength and 50 degrees C by the extraction resin containing di (2,4,4-trimethyl pentyl) phosphinic acid (Cyanex 272) and the chromatographic separation of (Er(III), Tm(III) and Yb(III)). Technological separation products, with purity and yield of Tm2O3 >99.97%, >80%, Er2O3 >99.9%, >94% and Yb2O3 >99.8%, >80% respectively, have been obtained from a feed having the composition Tm2O3 60%, Er2O3 10%, and Yb2O3 3%, the others 27%. The distribution coefficients, extraction equilibrium constants and separation factors have been determined as a function of acidity, loading of the resin and rare earths, flow rates and column ratios. The resolutions and efficiencies of separation of Er/Tm/Yb each other have been calculated. The stoichiometry of the extraction of rare earth ions has been suggested as well.

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本文研究了中性萃取剂三烷基氧化膦(Cyanex 923)从硫酸介质中萃取与反萃三价稀土Yb(III)的热力学和动力学机理,对该萃取剂的界面活性进行了深入的研究,并详细探讨了其从硫酸介质中萃取Ce(IV)时液/液界面的吸附参数及萃合物的聚集。此外,还考察了一种羧酸类萃取剂仲辛基苯氧基取代乙酸(CA-12)所组成的萃取有机相中W/O微乳液的热力学稳定性与结构参数。 1. 研究了Cyanex 923从硫酸介质中萃取与反萃Yb(III)的热力学。考察了一些影响萃取与反萃的条件,如:酸度、盐析剂、温度、反萃剂种类等,得出了萃取机理与热力学函数,为分离Yb(III)与其它稀土元素提供了有用的参数。 2. 研究了Cyanex 923 从硫酸体系中萃取Yb(III)的动力学,通过考察搅拌强度、比界面积、温度、反应物浓度等各种因素对萃取速率的影响,确定其对Yb(III) 的萃取动力学为扩散控制过程,反应主要在液/液界面进行,控制步骤为反应物种通过界面凝滞膜的界面扩散过程,并推导出了萃取速率经验式。 3. 考察了温度、离子强度、酸度、添加剂和不同稀释剂对萃取剂Cyanex 923在Cyanex 923-稀释剂/Na2SO4-H2SO4界面的界面活性的影响,得到了Cyanex 923在不同条件下的界面吸附参数,对萃取剂界面活性与萃取动力学的关系进行了讨论。 4.考察了Cyanex 923-正庚烷/Ce(IV)-H2SO4 萃取体系在液/液界面的吸附参数,重点研究了体系的界面活性物种、萃合物聚集造成的界面现象及其对溶剂萃取过程的影响,详细地研究了Ce(IV)和H2SO4的萃取对萃取体系一些物化性质的影响,观测到了萃取体系中反胶束的存在。 5. 研究了皂化CA-12—添加剂组成的萃取有机相中W/O微乳液的热力学稳定性,考察了皂化率、电解质本性与浓度、pH值、温度对体系最大加溶水量的的影响,并考查了不同添加剂与含水量时微乳液形成的热力学函数及结构参数。

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生物小分子配体的二、三元及多元体系中稀土的化学形态研究是考察稀土在体内的分布、代谢和生物效应的关键,对阐明稀土对环境和人体健康的影响及其作用机理具有十分重要的意义。1. 稀土与生物小分子溶液体系的研究 (1)在模拟生理条件下研究了Yb(III)分别与组氨酸、苏氨酸、脯氨酸以及Zn(II)分别与脯氨酸、色氨酸组成的五个新二元溶液体系。经计算机程序优化得到体系中生成的物种类型及各物种的稳定常数。所有体系均有1100型物种生成,Yb(III)-组氨酸体系还有1102型物种生成。(2)在模拟生理条件下研究了Pr(III)、Gd(III)、Tb(III)、Yb(III)四种稀土离子和Ca(II)、Zn(II)两种生命金属离子与组氨酸、色氨酸、苏氨酸及脯氨酸组合成的五个新三元体系。发现五个双氨基酸体系中均有三元配合物物种生成。除稀土(/Zn)-Pro-Thr体系外,三元配合物均广泛存在并有很高含量。总体来看,稀土的配位行为相近,其中Gd(III)和Tb的尤为相似。在包括组氨酸的体系中,Ca(II)和Zn(II)的三元配合物明显比稀土物种稳定。而在其它体系中,Ca(II)、Zn(II)三元配合物的稳定性接近或小于稀土的相应物种。2. 金属离子与生物分子多元体系的数学模型法研究 (1)对稀土离子(钆)、生命金属离子(钙或锌)与两种氨基酸配体共存的五个新四元体系,利用已有的二、三元配合物稳定常数,经程序进行了模拟计算,对各金属物种的分布变化进行了分析。结果表明,在组氨酸参与配位的两个体系中,稀土Gd(III)对Ca(II)或Zn(II)的物种分布影响较小。而在其它三个体系中,与三元体系相比,金属的三元物种含量均降低,自由离子和二元配合物的含量升高,这说明稀土在生物配体体系中对Ca(II)或Zn(II)具有竞争取代作用。(2)首次建立多相模型用数学模型法研究了人体血浆中二十二种配体(包括磷酸根、碳酸根、蛋白质生物大分子及生物小分子)同时存在的条件下Gd(III)、Ca(II)、Zn(II)的分布情况及Gd(III)的存在对Ca(II)、Zn(II)物种分布的影响。结果表明,进入血浆中的稀土绝大部分以磷酸盐和碳酸盐沉淀形式存在。可溶态稀土主要分布于与运铁蛋白、草酸、免疫球蛋白、柠檬酸、天冬氨酸等生成的物种及含羟基物种之间,并且可溶态稀土的分布受稀土总浓度和pH值的影响。稀土的浓度高于血浆中本底值时将对Ca(II)、Zn(II)的物种分布产生影响。以上工作取得的新成果不仅丰富了稀土的生物无机化学,而且为阐明稀土生物效应和评估稀土农用安全性提供了科学数据。

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属离子与生物分子作用的研究是生物无机化学研究热点之一。研究稀土、钙和锌离子与生物小分子的作用及其在体液中的物种分布对于考察稀土在体内的运输、代谢、生物效应及其对生物金属离子钙、锌生物功能的影响具有十分重要的意义。亦可为阐明稀土对人体健康的影响提供科学依据。本论文从以下几个方面开展了新工作并取得重要的新研究结果。1.在模拟生理条件下用PH电位法对Yb,Zn两种金属离子与甘氨酸、丙氨酸、撷氨酸、半肤氨酸、天冬酰胺和谷氨酰胺六种小分子配体组成的二元体系进行了研究,通过SCOGsZ程序确定了体系中存在的物种并测定其稳定常数。通过对比得到配合物稳定性的一些重要规律。2.在模拟生理条件下研究了四种稀土离子(Pr(111)、Gd(111)、Tb(111)、Yb(111))和两种生物金属离子(Ca(II)、Zn(II))与以柠檬酸作为第一配体,七种小分子生物配体(甘氨酸、丙氨酸、撷氨酸、丁二酸、半胧氨酸、天冬酞胺、谷氨酞胺)为第二配体的三元体系。通过SCOGSZ程序确定了各体系中合理的物种类型并测得其稳定常数。运用COMICS程序,对各体系中金属离子随酸度变化的物种分布进行了深入的研究。上述工作发现三元配合物是一类重要的物种。也发现稀土与钙、锌三元配合物稳定性相近,这表明稀土可与钙、锌竞争生物配体。3.运用COMICS程序,以金属离子与生物小分子二元和三元体系的数据为基础,模拟计算得到Gd(III)与ca(II)/Zn(ll)共存的以柠檬酸作为第一配体,甘氨酸、丙氨酸、撷氨酸、丁二酸、半胧氨酸作为第二配体的四元体系中稀土离子对钙、锌离子物种的影响。发现稀土可明显影响钙的物种分布,而对锌的略有影响。4.合成了Gd(III)与丙氨酸、Sm(III)与异亮氨以及Yb(III)、Zn(II)与亮氨酸配合物单晶,并测定其晶体结构。上述配合物分别具有双核二聚体结构以及氢键组装 的Zn(II)四面体和Yb刀4立方烷结构。研究发现无多齿经基配位和稀土与配体卜2的摩尔比利于二聚体结构生成;高pH和多齿OH-配位利于生成立方烷结构5.在HF/LANL2DZ水平,研究了La(III)与半耽氨酸的配位作用。得到了它们的优化结构、体系能量、能隙及电荷分布,取得了与实验相一致的结果。6.运用数学模型法研究了人体液中Gd(III)、Ca(II)和Zn(II)的物种分布,并考察了外源性Gd(III)对Ca(II)和zn(II)物种分布的影响。发现不可溶的物种是Gd(III)的重要物种。也发现Gd(III)对Ca(Il)、Zn(II)物种分布有不同程度的影响,这可能引起了Ca(II)、Zn(II)的生物功能某种变化。

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本文通过酸性磷(膦)类萃取剂二(2,4,4一三甲基戊基)磷酸(Cyanex272)与2一乙基己基嶙酸一单一2一乙基己基醋(P507)协同萃取的手段对萃取体系进行改善,系统研究了Cyanex272与P507体系的热力学和传质动力学规律及其界面的性质,为该萃取体系在工业上的应用提供丰富的基础数据,具体的研究内容如下:1.研究了Cyanex272与PSO7组成的双溶剂体系(HDP)及其单独体系萃取Yb(III)的热力学性质,得出了协同萃取机理,获得了萃取平衡方程式以及协萃物的组成,对金属离子在萃取过程中离解和配位的热量变化规律作出了解释。研究发现HDP协萃体系对Y(III)和Yb(III)的分离效果要高于其单独萃取体系,且HDP负载稀土的反萃性能以及萃取重稀土的选择性都优于P507。2.用层流恒界面池法研究了Cyanex272萃取Y(III),Yb(III)以及从Cyanex272-Y负载中反萃取Y(III)的传质动力学,考察了各种因素对反应速率的影响,获得了萃取速率方程,推测了动力学机理,并找出了正萃与反萃取的内在联系。3.研究了HDP萃取Y(III),Yb(III)以及从HDP-Y负载中反萃取Y(III)的传质动力学,获得了萃取速率方程,推测了动力学机理,发现PSO7的加入降低了萃取和反萃取的活化能,与Cyanex272相比萃取速率得到了提高,与PSO7相比反萃取速率也得到了增强。热力学的结果和动力学的结果相互得到了印证。4.考察了不同稀释剂、水相酸度、水相离子强度以及温度对Cyanex272以及HDP体系界面活性的影响,并得出在相同的条件下HDP的界面活性要高于Cyanex272的界面活性。在研究界面吸附与萃取动力学之间的关系中发现,cyanex272和HDP的界面性质能定性的反映其萃取动力学机理。

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本文研究了酸性磷(膦)酸酯对稀土及相关元素的萃取(包括协同萃取)机理,利用核磁共振(NMR)测试手段对HEH/EHP(III)、BTMPPA-Yb(III)的萃合物结构进行了~1H、~(13)C、~31P NMR谱的测定,获得了一些新的结构信息。

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The tertiary lanthanide complexes [Ln(hfth)(3)phen] (Ln=Er, Nd, Yb, Sm) and [Pr(tfnb)(3)phen] have been Successfully covalently attached in the ordered SBA-15 mesoporous materials via a functionalized 1,10-phenanthroline group 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline (Phen-Si). The derivative materials [denoted as Ln(hfth)(3)phen-S15 and Pr(tfnb)(3)phen-S15; Ln=Er, Yb, Nd, Sm; hfth=4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dionate; tfnb=4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedionate] were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and N-2 adsorption/desorption.