Optical analysis and separation of trivalent lanthanides in deep eutectic solvents

Deep eutectic solvents(DESs) were used for luminescence measurements in quantitative analysis of trivalent lanthanide ions and as solvents for light rare earth elements(LREE) in solid-liquid separation.The spectroscopic characteristics of lanthanide chlorides LnCl_3(Ln=Eu,Tb),respectively their aquo complexes,are described in a comprehensive study that demonstrates the significant enhancement of the phosphorescence emission intensity in DESs as polar and weakly coordinating solvent.Several DESs stabilize the lanthanide ion luminescence against changes in temperature and moisture,which is advantageous compared with the use of ionic liquids.Small amounts of water lead in certain eutectic systems even to a further increase in phosphorescence emission intensity.By investigating the solubility of lanthanide sesquioxides Ln_2 O_3(Ln=La,Nd,Sm,Eu,Gd,Tb,Dy) in DESs,selectivities are identified that may be of use for the separation of LREE.     

Studies on some lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine

Seven new lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine were synthesized. These complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, FT-IR, electronic and 1HNMR spectra, X-ray powder diffraction, and thermogravimetric studies. The ligand, 4-hydroxyantipyrine （hap）, contained carbonyl oxygen and hydroxyl oxygen as potential donor sites. On coordination, deprotonation occurred and as a result, hap acted as a monobasic bidentate ligand. A coordination number 6 was assigned to the lanthanide（Ⅲ） ions in these complexes with orthorhombic structure. All the complexes were thermally stable-150℃ and underwent decomposition in three stages with the formation of Ln2O3 as the final residues.     

Structure and Bonding in Some Gd（Ⅲ） Metal Complexes Studied by Three-Dimensional X-Ray Analysis and ^155Gd Mossbauer Spectroscopy

Some functional lanthanide metal complexes, such as acetylacetonato complexes, ethylenediaminetetraacetato complexes, were successfully applied for diagnostic technique. The authors are interested in investigating the structure and bonding in lanthanide and actinide metal complexes using 166Er, t55Gd, and 237Np Mtissbauer spectroscopies in connection with single-crystal and/or powder X-ray diffraction, making clear the differences on their structures as well as the differences in the participation of 4f and 5f orbitals in the chemical bonds. In this article, the crystal structures of two novel Gd（Ⅲ） acetylacetonato complexes, Gd（pta）3 · 2H2O （pta = 1,1,1 -trifluoro-5,5-dimethy 1-2,4-hexanedione） and Gd（bfa）3 · 2H2O （bfa = 1, 1, 1 -trifluoro-4-phenyl-2-4-butanedione） were reported. Though both of them were dihydrate and had distorted square antiprismatical structure, Gd（pta）3 · 2H2O crystallizes in the P 2 1/n （#14） monoclinic space group and its lattice parameters are a = 1.4141（6） nm, b = 1.0708（3） nm, c =2.2344（4） nm, β =952.4（2）°, and Gd（bfa）3· 2H2O crystallizes in P 212121 orthorhombic space group and its lattice parameters were a = 1.322 （1） nm, b = 2.295 （1） nm, c = 1. 0786（8） nm. In the meantime, the authors had finished a systematic investigation on the ^155Gd Mossbauer isomer shift （δ） of various Gd（Ⅲ） metal complexes having a different coordination number （C.N.） and different ratios coordinating oxygen to nitrogen. A tendency for the 6 value to decrease with an increase in the C.N, and the number of the nitrogen atom coordinating to Gd was confirmed. This indicated that the Gd-O and/or Gd-N bond in the investigated Gd（Ⅲ） metal complexes had a small covalent contribution, which was possible to be deduced from the O and/or N atoms of the lisands donating electrons to 6s, 5d, and 4f orbitals of Gd.     

Synthesis and Characterization of Some Lanthanide（Ⅲ） Complexes with 4- [N-（2-methoxy benzylinine）formy1]-2, 3-dimethyl-1-phenyl-3-pyazolin-5-one

A series of seven novel lanthanide（Ⅲ ） nitrato complexes with 4-[ N-（2-methoxybenzylimine）formyl] 1-2, 3- dimethyl-1-phenyl-3-pyazolin-5-one （2mbfa）, were synthesized. These complexes were characterized by elemental analysis, molecular mass determination, conductance and magnetic moment measurements, IR, UV-visible, and ^13CNMR spectral studies, In these complexes, the Schiff base, 2mbfa, acts as neutral bidentate ligand by utilizing the carbonyl oxygen and azomethine nitrogen as donor sites. All the three nitrate ions are also coordinated unidentately with 7 coordination for the lanthanide（Ⅲ） ions with a tentative monocapped octahedral geometry for the complexes. All the seven lanthanide（Ⅲ） complexes have a general formula, [ Ln（2mbfa）：（NO3）3 ].     

Crystal Structure and Luminescence Property of Lanthanide Complexes with 2-Fluorobenzoic Acid and 2,2''-Bipyridine

The two compounds of [Ln(2-FBA)3·2,2'-bpy]2 (2-FBA=2-fluorobenzoato, 2,2'-bpy=2,2'-bipyridine, Ln=Eu(1), Dy(2)) were synthesized and their structures were determined by X-ray diffraction method. Crystallized complexes 1 and 2 are isomorphous, monoclinic system with P21/n space group. The two complexes are binuclear molecule with an inversion center. The two lanthanide ions are linked by four bridged 2-FBA ligands and each lanthanide ion is further bonded to one chelated bidentate 2-FBA ligand and one 2,2'-bipyridine molecule. The coordination number of metal ion is eight. The europium complex exhibits strong red fluorescence. 5D0→7Fj (j= 1～4) transition emission of Eu3 ion was observed.     

Studies on NaLn(WO_4)_2 Single Crystals(Ln=La,Pr,Nd)

The crystals of NaLn(WO4)_2(Ln=La,Pr,Nd)are grown from a melt of LiCl-Na_2WO_4 flux by slowcooling method.The chemical analysis data show that the crystals are NaLa(WO_4)_2,NaPr(WO4)_2 andNaNd(WO_4)_2 respectively.The structures of the crystals are ascertained that they belong to scheelite structureof the tetragonal system with a space group of 14_1/a.The lattice parameters of the crystals have beencalculated.It is found that the cell volume of NaLn(WO_4)_2 crystals decrease with a decrease of Ln~(3 )radius.The bond distances and their angles in NaLa(WO_4)_2 and NaNd(WO_4)_2 are given.It is found that inaccordance with the decrease of ionic radii of Ln~(3 )due to increase of atomic number,the bond distances betweenLn-O,Ln-Ln and W-O decrease regularly.The infrared spectra of NaLn(WO_4)_2 are measured.Thetetrahedra characteristic absorptions of WO_4~(2-)are shown.The sensitization of host lattice is observed from theexcitation and fluorescent spectra of NaLa(WO_4)_2 and NaPr(WO_4)_2.     

Hydrothermal synthesis of 3D porous architectures

A novel porous lanthanide-organic coordination polymer, [Nd(H2O)(HnicO)(TP)]·2H2O (1) (H2nicO=2-hydroxynieotinic acid, TP= terephthalate), was prepared under hydrothermai condition and characterized by single-crystal X-ray diffraction, thermogravimetrie analysis and infrared spectroscopy. Compound 1 exhibited a flexible coordination geometry of lanthanide ions, which possessed a three-dimensional (3D) open framework with one-dimensional (1D) channels containing lattice water molecules. This framework structure exhibited a high stability up to 330 ℃ after removing free water molecules. A homometallic supramolecular framework (Zn(HnicO)2(H2O)2 (2)) was obtained due to the competitive reaction between organic ligands, Nd3+ and Zn2+ ions. The results showed that on the basis of the soft-hard/acid-base principle the coordination selection between metal ions and organic ligands played an essential role in the smart construc-tion of lanthanide architectures.     

A series of 3D lanthanide complexes based on H bond and halogen-halogen interactions:Synthesis,structure, spectroscopic and thermal properties

Four lanthanide coordination complexes, namely, [Ln(2,3-DClBA)_3(5,5'-dmebipy)(H_2O)]_2(Ln=Sm(1), Eu(2), Dy(3), Ho(4)); 2,3-DClBA=2,3-dichlorobenzoate; 5,5'-dmebipy=5,5'-dmethylbipyridine) were synthesized and characterized by elemental analysis, infrared spectroscopy and single crystal X-ray diffraction. Findings indicated that complex 3 was a dinuclear molecule, and the center Dy~(3+) was eight-coordinated. Each dinuclear units could be connected by H bond and halogen-halogen interactions. Luminescent property of complex 2 suggested the typical intense emissions of Eu~(3+) ions. Thermal analysis showed that the complexes decomposed in three steps: the coordination water was lost firstly then the neutral ligand 5,5'dmebipy was lost and lastly the 2,3-DClBA ligand was lost.     

Pr（Ⅲ） and Nd（Ⅲ） Absorption Spectroscopic Probe to Investigate Interaction with Lysozyme （HEW）

Pr（ Ⅲ ） and Nd（ Ⅲ ） can be utilized as absorption spectroscopic probes to investigate the interaction of biomolecules like Lysozyme （HEW） with Ca（ Ⅱ ） in-vitro ; the most abundant metal ion in the human body system. The spectroscopic techniques involving comparative absorption, absorption difference, and quantitative intensity analysis using 4f-4f transitions are utilized for changes in the inner sphere coordination pattern of Pr（ Ⅲ ） and Nd（Ⅲ ） in solution as well as in solid state. The present study deals with an important biomolecule in human metabolism, that is, Lysozyme （HEW）. The absorption er-Condon the probab spectral parameters such as the oscillator strength （P）, the Judd-Ofelt （Tλ） intensity parameters, and the Slatinter electronic parameters are calculated using chi square methods. The obtained results are used to determine le geometry of the complex in the solution, the nature of the bond between Pr（Ⅲ）/Nd（Ⅲ） with lysozyme, and the inner sphere coordination environment of f-f transitions. The results obtained from various experimental conditions are utilized to investigate the coordination changes in the Pr（Ⅲ）/Nd（Ⅲ） complexes caused by different coordinating sites of lysozyme, normalized bite, denticity, the solvent nature, the coordination number, the nature of bond and other parameters to mimic the interaction of the Ca（ Ⅱ ） ion with such biomolecule.     

Highly luminescent europium and terbium complexes based on succinimide and N-hydroxysuccinimide

The preparation of two highly luminescent europium(III) and terbium(III) complexes with succinimide(SI) and N-hydroxysuccinimide(NHSI) were reported,which were further investigated through elemental chemical analysis,thermal analysis,FT-IR,powder X-ray diffraction,SEM and fluorescence spectroscopy.Data collected through these analysis revealed the formation of the Eu(III) and Tb(III) complexes with the above mentioned ligands at a metal to ligand(M:L) molar ratio of 1:3.Interesting conclusions regarding the efficient sensitization through the coordination site of the lanthanide luminescent centers were retained from the photoluminescent spectra investigation.Strong luminescence emission was observed in case of Eu(III)-SI and Tb(III)-NHSI complexes while the corresponding Eu(III)-NHSI and Tb(III)-SI complexes exhibited no photo luminescent properties.Newly obtained luminescent lanthanide complexes may be of particular interest for various applications in optoelectronics.     

Determination of Coordination Configuration of Rare Earth Ionswith Aminoacids in Solutions with Cooperative Vibronic Spectroscopy

Rare earth ions have similar physical andchemical properties to Ca2 , Mg2 and canchemically substitute the positions of Ca2 ,Mg' in biological systems['j. Understandingthe coordination configuration of RE ions, including the ligand types and ligand numbers inbiological systems, can provide useful information. As biological bodies contain large quantity of water, it is very important to understandthe coordinations of RE ions with watermolecules and other biological molecules inaqueous solu…     

The ~(13)C-NMR Study of the Conformation of L-Arginine in Aqueous Solution by Lanthanide Probes

The heavy lanthanide ions(Dy,Ho,Er,Tm and Yb)were used to probe the conformation of L-arginine inaqueous solution.The results showed that the contact contribution to the observed~(13)C paramagnetic shift is verysmall for nuclei four or more bonds away from the bound lanthanide ion and it is significant for those in closeproximity to the lanthanide ion.The overall conformation of L-arginine was established by fitting the calculatedgeometric factors for the corresponding experimental data.In the lanthanide-L-arginine complex,the wholebackbone of the ligand is located outsite the zero-dipolar shift cone of the lanthanide ion with the carboxyl groupselectively coordinated to the metal.The calculated RE-O distance is 0.21 nm for the bidentate coordinationmode and the ligand is in an extended conformation in the solution with the molecular backbone corresponding tothe trans form.     

稀土有机框架材料（Ln-MOFs）的合成及应用

稀土有机框架材料 (Ln-MOFs) 因镧系离子存在特殊的电子排布[Xe]4fn (n = 0～14)而具有独特的发光性和磁性,且具有不饱和配位的金属位和大的比表面积,在化学工业中具有广阔的应用前景而备受关注. 研究表明,Ln-MOFs具有特殊的拓扑结构以及特定尺寸和形状的孔道,是一种新型多功能结晶材料,涉及了无机化学、有机化学以及配位化学等多学科,然而,通过简单的设计直接合成得到精确的Ln-MOFs是比较困难的,且有机配体和镧系金属单元具有无穷组合,故Ln-MOFs的合成与应用依然是今后研究的重点. 文中以设计合成稀土有机框架材料(Ln-MOFs)的配体类型为主线,综述了Ln-MOFs的合成与结构,重点阐述了其在催化剂、热稳定性、气体吸附、发光材料、磁性材料等方面的应用.      

Progress on Study of Luminescence of Rare Earth Organic Chelates

Ｓｉｎｃｅｒａｒｅｅａｒｔｈｃｈｅｌａｔｅｓｗｅｒｅｆｏｕｎｄｔｏｅｍｉｔｌａｓｅｒｉｎｔｈｅｂｅｇｉｎｎｉｎｇｏｆ 1 96 0ｓ ,ｔｈｅｆｌｕｏ ｒｅｓｃｅｎｃｅｐｒｏｐｅｒｔｉｅｓ ,ｅｆｆｉｃｉｅｎｃｙａｎｄｌｉｆｅｔｉｍｅｆｏｒｒａｒｅｅａｒｔｈｏｒｇａｎｉｃｃｈｅｌａｔｅｓｗｅｒｅｅｘｔｅｎｓｉｖｅｌｙｓｔｕｄｉｅｄ .Ｔｈｅｃｈｅｌａｔｅｓｗｅｒｅｐｒｏｖｅｄｎｏｔｔｏｂｅｓｕｉｔａｂｌｅｆｏｒｌａｓｅｒｍａｔｅｒｉａｌｓｉｎｔｈｅｅｎｄｏｆ1 970ｓ .Ｓｏｉｎｉｓｕｇｇｅｓｔｅｄｔｏｕｓｅｒａ…     

镧系元素高氯酸盐苯丁基亚砜配合物的合成与表征

本文以稀土高氯酸盐ＲＥ（ＣｌＯ_４）_３ｎＨ_２Ｏ（ＲＥ＝Ｌａ~（３＋）、Ｃｅ~（３＋）、Ｐｒ~（３＋）、Ｎｄ~（３－）、Ｓｍ~（３－）、Ｅｕ（３＋），ｎ＝６～７）与苯丁基亚砜ＰＢＳＯ（Ｃ_６Ｈ_５Ｃ_４Ｈ_９）在无水乙醇体系中合成出六个新配合物，并对配合物进行了元素分析，稀土离子含量测定，配体ＰＢＳＯ含量测定ＣｌＯ_４~－含量测定、ＩＲ谱、导电、ＴＧ－ＤＴＡ分析及Ｘ－射线粉末衍射。确定了配合物的组成为［ＲＥ（ＢＰＳＯ）_７（ＣｌＯ_４）］（ＣｌＯ_４）_２，配位数为８，电解质类型为１：２。     

Thermochemical Properties of Ternary Complexes of RE Perchlorate withGlycine and Imidazole

Ｒａｒｅｅａｒｔｈｉｏｎｓｐｏｓｅｓｓｏｍｅｓｐｅｃｉａｌｆｕｎｃｔｉｏｎｓｉｎｂｉｏｌｏｇｉｃａｌｂｏｄｙ．Ａｍｉｎｏａｃｉｄｓａｒｅｔｈｅｓｔｒｕｃｔｕｒｅｕｎｉｔｏｆｐｒｏｔｅｉｎｓ．Ｉｍｉｄａｚｏｌｅｉｓｈｅｔｅｒｏｃｌｙｃｌｉｃｃｏｍｐ...     

Raman spectra of RE2O3 （RE=Eu,Gd, Dy,Ho, Er,Tm, Yb,Lu, Sc and Y）：laser-excited luminescence and trace impurity analysis

Raman spectra of a series of cubic rare earth sesquioxides RE2O3 （RE=Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc and Y） were investigated by Raman spectroscopy with both 532 and 785 nm laser lines. Abundant additional bands due to laser-excited lumines-cence were observed. For Eu2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3 and Yb2O3, the luminescence mainly came from the intrinsic trivalent lanthanide ions, while for Gd2O3, Lu2O3, Sc2O3 and Y2O3, their luminescence were attributed to the trace impurities of other lumines-cent lanthanide ions such as Eu3＋, Nd3＋and Er3＋. This investigation confirmed Raman spectroscopy as a useful tool for detecting trace luminescent lanthanide impurities.     

Theoretical elucidation of rare earth extraction and separation by diglycolamides from crystal structures and DFT simulations

Diglycolamides(DGAs) show excellent application prospects for the extraction and separation of rare earth metals from highly radioactive liquid wastes and rare earth ores.The extraction ability of DGAs for rare earth ions in nitrate or chloride media increases with increasing atomic number of the rare earth metal.To understand the origin of this phenomenon,three binuclear crystals [Ln(TEDGA)3][Ln(NO_3)_6] of N,N,N',N'-tetraethyldiglycolamide(TEDGA) with rare earth ions La(Ⅲ),Pr(Ⅲ) and Eu(III) were prepared and characterized crystallographically.The three complexes belong to the triclinic crystal system,P-1 space group.The bond lengths of Ln-O_(amide) are significantly shorter than those of Ln-O_(ether) in the same crystal.The Ln-O_(amide) and Ln-O_(enher) bond lengths gradually decrease with increasing atomic number of the rare earth ion.The dihedral angle formed by TEDGA and metal ions through the tridentate coordination gradually increases with increasing metal ion atomic number,tending toward the formation of sizeable planar coordination structures for the most massive rare earth ions.The structures of the compounds formed by the extractant and metal ion were optimized by means of DFT simulations.We find that the interaction between TEDGA and the rare earth ion is dominated by electrostatic interaction by analyzing binding energy,WBIs,Mulliken charge,natural electron configurations,and molecular orbital interaction.The covalent component of the Ln-O bonds of the complexes increases with increasing metal atomic number.The observed increase in extraction and separation capacity of diglycolamides for rare earth ions with increasing atomic number might be due to the formation of two fivemember rings by one tridentate ligand.The rare earth ions with large atomic numbers tend to form planar structures with large dihedral angles with DGA ligands.     

Study of Properties of Intermetallic Compounds of Rare Earth Metals by Artificial Neural Networks

ＹａｎＬｕ－Ｍｉｎｇ；（严六明）；ＺｈａｎＱｉａｎ－Ｂａｏ；（詹千宝）；ＱｉｎＰｅｉ；（钦佩）；ＣｈｅｎＮｉａｎ－Ｙｉ；（陈念贻）（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＭｅｔａｌｌｕｒｇｙ，ＡｃａｄｅｍｉａＳｉｎｉｃａ，Ｓｈａｎｇｈａｉ２０００５０...     

Hydraulic Conductivity and Swelling of Nonprehydrated GCLs Permeated with Single-Species Salt Solutions

The influence of single-species salt solutions of various concentration, cation valence, and pH on swelling and hydraulic conductivity of nonprehydrated GCLs was examined. At similar concentration, swell was largest with NaCl, KCl, and LiCl solutions (monovalent cations Na+, K+, and Li+) and smallest with LaCl3 solutions (trivalent cation La3+). Intermediate swell volumes were obtained with divalent solutions (CaCl2, MgCl2, ZnCl2, and CuCl2). Analogous results were obtained from hydraulic conductivity tests. GCL specimens permeated with solutions containing divalent or trivalent cations had higher hydraulic conductivity than GCLs permeated with monovalent solutions or deionized water, unless the divalent or trivalent solutions were very dilute (≤0.01 M). Hydraulic conductivity increased as the concentration increased, and at high concentration (1 M) only small differences existed between hydraulic conductivities measured with all solutions. Swelling and hydraulic conductivity were related to size of the hydrated cation for monovalent cations, but no relationship was observed for different species of divalent and trivalent cations provided that the valence was the same. However, pH only influenced swelling and hydraulic conductivity when the pH was very low (<3) or very high (>12).