稀土丙酸盐的红外光谱研究

本文研究了La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y十三种稀土丙酸盐的FT-IR光谱, 对1800-100cm^-^1的主要红外吸收谱带进行了归属, 指认316-349cm^-^1的强吸收带为Ln-O键的伸缩振动带. 稀土丙酸盐红外光谱表明存在两种不同的羧基配位形式. 从La到Tm以及Y等十一种丙酸配合物的配位羧基具有对称的螯合双齿形式, 而对稀土Yb和Lu, 与中心离子配位的三个羧基中, 至少有一个羧基具有螯合桥式三齿配位形式. 结果还表明稀土丙酸盐Ln-O键基本上是离子键.     

交流电弧中共存稀土元素对光谱线强度影响的研究

本工作较系统地研究了在交流电弧中不同量的共存稀土元素镝、钬，饵，铥和镱对某些被测稀土元素光谱线强度的影响。用交流电弧激发溶液干渣样品，其样品是在固定量的被测元素溶液中各自分别加入不同量的共存元素镝、钬、铒、铥和镱，摄谱后测量各被测元素的光谱线强度对共存元素在溶液中各个不同浓度作关系曲线。     

化学气相传输法分离二元混合重稀土氧化物

稀土气态配合物;化学气相传输法分离二元混合重稀土氧化物     

萃取色谱分离-原子发射光谱测定超高纯氧化铥、氧化镱和氧化镥中痕量稀土杂质

用２－乙基己基膦酸单２－乙基己酯萃取色谱分离－原子发射光谱测定超高纯Ｔｍ２Ｏ３、Ｙｂ２Ｏ３、Ｌｕ２Ｏ３中痕量稀土杂质，可用于纯度为９９．９９９９％～９９．９９９９９％（不含非稀土杂质）Ｔｍ２Ｏ３、Ｙｂ２Ｏ３、Ｌｕ２Ｏ３的纯度分析，１４个稀土杂质的回收率在６７％～１３３％之间；相对标准偏差 ５．１％～２３．２％；分离周期 １０～１３ ｈ。     

二价稀土(Sm,Eu,Yb)与3-苯基-5-(呋喃-2)吡唑啉二硫代甲酸固态配合物的制备

本文首次制得了二价稀土与含硫有机配体的固态配合物RE(SSCNC₁₃H₁₁NO)₂·xH₂O(RE=Sm,Eu,Yb,x=3,4),研究了它们的性质,并对二价及相应的三价稀土配合物在物理化学性质上的差异进行了探讨。     

Blue,green,red upconversion luminescence and optical characteristics of rare earth doped rare earth oxide and oxysulfide

The cold isostatic press pretreatment process was adopted to prepare fine rare earth oxysulfide up-conversion phosphors with spherical shape, narrow size distribution and high luminescence efficiency. The upconversion optical characteristics and brightness of the blue (Y2O2SYb,Tm), green (Y2O2S: Yb,Er), red (Y2O3Yb,Er) emitter were also investigated, and a novel method was successfully developed for the brightness measurement of upconversion luminescence (UPL). It is shown that a white color can be obtained by the appropriate mixture of these primary blue, green and red emissions components. The Er3 ions exhibit different upconversion mechanism in Y2O2S and Y2O3 host materials. The rare earth oxysulfide is an efficient upconversion matrix. The UPL brightness of Y2O2S: Yb,Er is 6.5 times higher than that of Y2O3: Yb,Er, and Y2O2S: Yb,Er shows UPL brightness of 1100 cd/m2 under 5.56 W/cm2 power density using a 980 nm laser diode.     

基于MCM-41分子筛表面的镱离子印迹聚合物的制备及其性能

运用离子印迹技术,以3-氯丙基三乙氧基硅烷为锚定剂,将功能单体直链聚乙烯亚胺(PEI)接枝在MCM-41分子筛表面,选择镱离子作为模板离子,以环氧氯丙烷交联制备出基于MCM-41表面的镱离子印迹聚合物Yb(Ⅲ)-IIP-PEI/MCM-41,并以同样的方法制备非离子印迹聚合物(NIP-PEI/MCM-41)。 利用傅里叶变换红外光谱仪和扫描电子显微镜等技术手段对Yb³⁺印迹聚合物进行表征,采用静态吸附法确定了Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺的最佳吸附条件及选择性吸附性能。 结果表明,Yb(Ⅲ)-IIP-PEI/MCM-41和NIP-PEI/MCM-41的最大吸附量分别为229.93和99.27 mg/g;印迹材料对Yb³⁺的吸附符合Langmuir模型;吸附平衡在40 min的时候基本可以达到,可以利用准二级动力学模型来描述其吸附过程;Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺具有较强的选择性,同时也具有很好的重复使用性能。 成功地将MCM-41和离子印迹聚合物的优点结合起来,制备出一种对稀土Yb离子既有高吸附量又有高选择性的吸附材料,为进一步将其应用在处理实际废水,分离回收低浓度稀土废水中的稀土元素等方面打下了基础。     

Determination of rare earth elements in soils and sediments by inductively coupled plasma atomic emission spectrometry after cation-exchange separation

The influence of matrix elements such as Ba, Ca, Fe, K, Na and Ti, on the inductively coupled plasma atomic emission spectrometry determination of the rare earth elements in soils and sediments is investigated and analytical lines with minimal interferences are chosen. The analysis of certified reference materials by two calibration methods (pure rare earth solutions and IAEA-Soil 5) and after cation-exchange proved that calibrations with IAEA-Soil 5 increase the number of accurately determined rare earth elements (REE), permitting the instrumental determination of Ce, Eu, La, Nd, Tb, Yb and Y in soils and some sediments. The cation-exchange procedure permits the determination of 12 REE with very good accuracy (below 10%) and detection limits varying between 0.05 (Eu, Tb, Yb) and 0.5 (Er) mg kg(-1).     

The solubilities and anion-exchange behavior of rare earth elements in potassium carbonate solutions

The solubilities of rare earth elements (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,Tm, Yb,Lu andY) in potassium carbonate solution, and the distribution coefficients of the rare earth ions between the carbonate solution and Dowex I resin were measured. The values obtained show a variation that depends on the concentration of potassium carbonate and atomic number. There is a clearly different tendency in these values between La-Ho and Er-Lu.     

Enhancing the Value of Free Metals in the Synthesis of Lanthanoid Formamidinates: Is a Co‐oxidant Needed?

Treatment of N,N′‐bis(aryl)formamidines (ArFormH), N,N′‐bis(2,6‐difluorophenyl)formamidine (DFFormH) or N,N′‐bis(2,6‐diisopropylphenyl)formamidine (DippFormH), with europium metal in CH₃CN is an efficient synthesis of the divalent complexes: [{Eu(DFForm)₂(CH₃CN)₂}₂] ( Eu1 ) or [Eu(DippForm)₂(CH₃CN)₄] ( Eu2 ). The synthetic method was extended to ytterbium, but the metal required activation by addition of Hg⁰. With DFFormH in CH₃CN, [{Yb(DFForm)₂(CH₃CN)}₂] ( Yb1 ) was obtained in good yield, and [Yb(DFForm)₂(thf)₃] ( Yb3 ) was obtained from a synthesis in CH₃CN/THF. Thus, this synthetic method completely circumvents the use of either salt metathesis, or redox transmetallation/protolysis (RTP) protocols to prepare divalent rare‐earth formamidinates. Heating Yb1 in PhMe/C₆D₆ resulted in decomposition to trivalent products, including one from a CH₃CN activation process. For a synthetic comparison, divalent ytterbium DFForm and DippForm complexes were synthesised by RTP reactions between Yb⁰, Hg(R)₂ (R=Ph, C₆F₅), and ArFormH in THF, leading to the isolation of either [Yb(DFForm)₂(thf)₃] ( Yb3 ), or the first five coordinate rare‐earth formamidinate complex [Yb(DippForm)₂(thf)] ( Yb4 b ), and, from adjustment of the stoichiometry, trivalent [Yb(DFForm)₃(thf)] ( Yb6 ). Oxidation of Yb3 with benzophenone (bp), or halogenating agents (TiCl₄(thf)₂, Ph₃CCl, C₂Cl₆) gave [Yb(DFForm)₃(bp)] or [Yb(DFForm)₂Cl(thf)₂], respectively. Furthermore, the structural chemistry of divalent ArForm complexes has been substantially broadened. Not only have the highest and lowest coordination numbers for divalent rare‐earth ArForm complexes been achieved in Eu2 and Yb4 b , respectively, but also dimeric Eu1 and Yb1 have highly unusual ArForm bridging coordination modes, either perpendicular μ‐1κ(N:N′):2κ(N:N′) in Eu1 , or the twisted μ‐1κ(N:N′):2κ(N′:F′) DFForm coordination in Yb1 , both unprecedented in divalent rare‐earth ArForm chemistry and in the wider divalent rare‐earth amidinate field.     

Synthesis and rare earth metal ion-sensing properties of aza-crown derivative incorporating with diaryl-1,3,4-oxadiazole

A new fluorescent chemosensor (A18C6-Ox) in which a monoaza-18-crown-6 is linked to a diaryl-1,3,4-oxadiazole fluorophore by a methylene spacer has been synthesized to evaluate binding interaction with the rare earth ions by means of absorption and emission spectrophotometry. Absorption spectra of A18C6-Ox showed a broad band at 289nm and there was no significant change in the presence of Sc3+, La3+, Pr3+, Sm3+, Gd3+, Tb3+, Yb3+ and Lu3+ except for Ce3+ and Eu3+. From the emission spectral change of A18C6-Ox, interaction of the rare earth ions with A18C6-Ox is very strong. The formation of A18C6-Ox complexing with Sc3+, La3+, Pr3+, Sm3+, Gd3+, Tb3+, Yb3+ and Lu3+ leads to an increase in fluorescence intensity of A18C6-Ox, while Ce3+ and Eu3+ ions interact strongly causing fluorescence quenching of A18C6-Ox. In addition, the optimal complexation stoichiometry of the rare earth ions with A18C6-Ox was investigated by the fluorescent titration.     

A rapid carrier-free separation method for divalent rare earths

A separation of carrier-free divalent rare earths by electrolytic reduction and amalgamation is described. The separation is carried out in a water-jacketed cell, 1 cm diameter by 10 cm long, fitted with a stopcock at the bottom. The cell utilizes a Pt anode and Hg cathode. The electrolyte used is potassium citrate-rare earth acetate at a concentration of 10 mg rare earth oxide per ml. The decontamination factor observed for Lu in a typical separation for Yb is ≥10⁴. Sm, Eu, and Yb are all amalgamated if present in the sample. For the present study, the parameters have been evaluated primarily for the case of Yb. A current of 100 mA is applied to 0.5 ml of electrolyte containing 1–1000 μg of Yb(III) for 5 min. The amalgam is decomposed and the Yb recovered by shaking for 1 min with 6M HCl. The overall time required is about 10 min and the yield is reproducible at 84–85%. Under these conditions, the electrolyte may contain up to 3.5 mg of Yb although at 2 mg the yield begins to decrease. The effects of current time, density and electrolyte concentration are discussed. This method has the advantage of being rapid and carrier-free, and the separated rare earth is in a form suitable for further chemical separation if required. Based on work performed under the auspices of the U.S. Atomic Energy Commission.     

Negative thermal expansion in rare earth molybdates

Negative thermal expansion in rare earth molybdates of A₂Mo₃O₁₂ family (A=Y, Er, Yb and Lu) is measured by high temperature X-ray diffraction and dilatometry. Rare earth molybdates which are isostructural with the corresponding rare earth tungstates, also exhibit this phenomena attributed to transverse acoustic vibrations. The rare earth molybdates of A₂M₃O₁₂ family with an orthorhombic structure (A=Y, Er, Yb and Lu) are highly hygroscopic and exhibit negative thermal expansion after the complete removal of water molecules. Axial thermal expansion co-efficient calculated from high temperature X-ray diffraction (RT-1073K) shows rare earth size effect. As the ‘A’ cation decreases in size, the thermal expansion co-efficient along ‘b’ axis and the linear thermal expansion co-efficient become less negative. The thermal expansion behaviour of the tetragonal La₂Mo₃O₁₂ is also reported to demonstrate the effect of crystal structure.     

纳米TiO2基质掺杂稀土离子Er3+和Yb3+的上转换发光特性

采用溶胶-凝胶法制备了掺杂稀土离子Er3 及Er3 /Yb3 的TiO2纳米晶体,考察了样品在980 nm激发光源作用下,不同的稀土离子掺杂量、不同的焙烧温度、不同的激发温度等对其上转换发光特性的影响,并对Er3 /Yb3 共掺杂的上转换发光机制进行了探讨.     

超声作用下稀土离子对纳米TiO2与牛血清白蛋白相互作用的影响

在模拟人体生理条件下,采用紫外光谱法、荧光光谱法和聚丙烯酰胺凝胶电泳(SDS-PAGE)研究了超声作用下三种稀土离子(La3+、Gd3+、Yb3+)存在的不同体系中,纳米TiO2与牛血清白蛋白(BSA)的相互作用.结果表明:在超声作用下,不同体系中纳米TiO2均导致BSA的内源荧光猝灭,其猝灭机制主要为静态猝灭和非辐射能量转移;凝胶电泳结果表明,不同体系中的纳米TiO2均未对BSA的结构造成明显的损伤,由热力学数据确定其作用力主要为氢键和范德华力.稀土离子的存在使纳米TiO2与BSA的结合常数、结合距离和热力学参数发生改变,但结合位点数和作用力类型基本不变.稀土离子对纳米TiO2与BSA的结合产生明显的"四分组效应",它们分别以"离子架桥"和"同位取代"方式参与纳米TiO2与BSA的结合过程.     

三氟甲烷磺酸稀土盐对聚丙烯热稳定性的影响及机理

通过熔融共混将三氟甲烷磺酸镱[Yb(OTf)₃]和三氟甲烷磺酸镧[La(OTf)₃]添加至聚丙烯(PP)中, 制得PP/Yb和PP/La材料, 并对其热稳定性进行表征. 热失重分析(TGA)和差示扫描量热分析(DSC)结果显示, Yb(OTf)₃和La(OTf)₃均可以显著提高聚丙烯的热稳定性. 当Yb(OTf)₃添加量仅为1%(质量分数)时, PP的起始分解温度从275 ℃提高至305 ℃, 最大分解温度从384 ℃提高至405 ℃, 160 ℃下的氧化诱导时间从12.1 min延长至43.0 min, 热焓从1907 J/g降低至483 J/g; 而PP/La1的起始分解温度、 最大分解温度、 160 ℃下的氧化诱导时间和热焓分别为300 ℃, 409 ℃, 18.6 min和633 J/g. 结果表明, La(OTf)₃对聚丙烯热稳定性的改善作用弱于Yb(OTf)₃, 对2种稀土盐产生不同实验结果的原因进行分析并提出机制. 由于阴离子和阳离子的共同作用, Yb(OTf)₃和La(OTf)₃均可提高PP的热氧稳定性. La(OTf)₃中三氟甲烷磺酸根的自由基捕捉能力和稀土离子的配位能力发挥主要作用, 而Yb(OTf)₃中的稀土离子的高反应活性也起到关键作用.     

Synthesis,characterization, and bonding properties of polymeric fullerides AC70.nNH3 (A = Ca,Sr, Ba,Eu, Yb)

Reduction of C70 with alkaline earth and rare earth metals dissolved in liquid ammonia results in metal fulleride solvates AC70.nNH3 (A = Ca, Sr, Ba, Eu, Yb) containing linear polymeric, anionic chains infinity 1 [C70(2-)]. The compounds were characterised by means of Raman spectroscopy and single-crystal structure determination. The accurate crystal structure of [Sr(NH3)8]C70.3NH3, determined with atomic resolution, allowed for a comparison with results of quantum chemical calculations. The nature of the C-C bonds in the fulleride is analysed in detail leading to a model explaining the unexpected polymerisation of C70(2-).     

Preparation et caracterisation de complexes [cis-4,4′-dinitrodibenzo-18-couronne-6, LnCl3, 3CH3CN]

Some new complexes between thecis-4,4′-dinitrodibenzo-18-crown-6 and rare earth chlorides LnCl₃ (Ln=Nd, Gd, Yb) were synthesized in acetonitrile. Ligandcis-4,4′-dinitrodibenzo-18-crown-6 and its complexes were identified by infrared spectroscopy, X-ray diffraction and thermal analysis (TG and DTA). Acis-trans isomerisation of the complexed ligand is observed about 148°C when heating the rare earth complex.

     

稀土取代的复合氧化物Eu_（0．5）RE_（0．5）Fe_（0．5）Mn_（0．

利用固相反应合成了稀土取代的复合氧化物Ｅｕ_（０．５）ＲＥ_（０．５）Ｆｅ_（０．５）Ｍｎ_（０．５）Ｏ_３（ＲＥ＝Ｌａ，Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ）．测量了这些化合物的ＸＲＤ和ＸＰＳ谱。在ＸＰＳ研究中发现，稀土取代而使稀土元素本身的结合能相对于其倍半氧化物中的有所降低；在取代的复合氧化物中，随着ＲＥ离子半径的减小，Ｆｅ、Ｍｎ的结合能随之增加。