Cationic networks in the structures of rare earth germanates and borogermanates: Typology of cationic networks in the structures of rare earth compounds

The cationic networks in the structure of binary and mixed-anion compounds forming in the Ln₂O₃-B₂O₃-GeO₂ systems have been studied. The collection of the known cationic networks consisting of two dominating pure forms, anisotropic and isotropic, as well as of the combined anisotropic-isotropic and multivector variety of anisotropic cationic networks, was enlarged by two new types of isotropic cationic networks, namely, combined isotropic-isotropic (in the Nd₄GeO₈ structure) and imperfect isotropic (in the structure of borogermanates Ln₁₄ (BO₆)₆ (GeO₄)2O(₈).     

Anisotropic distribution of cations in the structures of rare earth compounds

Anisotropic cationic networks, which constitute the left-hand side of the binary opposition with isotropic cationic networks, are topologically identical in the structures of quite different rare earth compounds.     

Ordered ternary compounds of the rare earth sesquisulfides

Intermediate compositions were investigated in eight Ln₂S₃-Ln₂′S₃ systems and reaction products characterized by Raman spectroscopy. Raman spectra are reported for the ordered structures reported in earlier literature. Based on the Raman spectra, LaLuS₃ previously reported as isostructural with LaDyS₃ (the I-type structure) is actually a new ordered compound. It was indexed on an orthorhombic cell with a=7.304, b=6.659 and . A second previously unreported compound, Dy₃ScS₆, was identified by its Raman spectrum. Sharp Raman lines with a unique arrangement for each structure-type indicate that the ternary rare earth sulfides are well-ordered structures.     

Self-assemblies of luminescent rare earth compounds in capsules and multilayers

This review addresses luminescent rare earth compounds assembled in microcapsules as well as in planar films fabricated by the layer-by-layer (LbL) technique, the Langmuir–Blodgett (LB) method and in self-assembled monolayers. Chemical precipitation, electrostatic, van der Waals interactions and covalent bonds are involved in the assembly of these compounds. Self-organized ring patterns of rare earth complexes in Langmuir monolayers and on planar surfaces with stripe patterns, as well as fluorescence enhancement due to donor–acceptor pairs, microcavities, enrichment of rare earth compounds, and shell protection against water are described. Recent information on the tuning of luminescence intensity and multicolors by the excitation wavelength and the ratio of rare earth ions, respectively, are also reviewed. Potential applications of luminescent rare earth complex assemblies serving as biological probes, temperature and gas sensors are pointed out.     

稀土在电沉积镍-钴合金中的作用

由于稀土元素具有独特的电子层结构和化学性能,使稀土及其化合物在材料科学领域中的应用越来越广泛,尤其是稀土在电沉积过程中的研究及应用正日趋深入。这是因为在电镀溶液中加入少量的稀土化合物后,可以改善镀液的分散能力和深镀能力,提高电镀的电流效率,增加镀层的硬度和耐蚀性等[1 4],但有关稀土在电沉积镍 钴合金中的作用的研究还未见报道。本文研究了在硫酸盐体系镍 钴合金电镀液中加入少量的稀土化合物后对电沉积过程、合金电极的催化性能、合金镀层的形貌和成分的影响。1　实验方法基础镀液成分(g/L)为NiSO4·7H2O200,CoSO4…     

Perfluorinated rare earth metals catalyzed nitration of aromatic compounds

The nitration of aromatic compounds can be carried out in the presence of perfluorinated rare earth metal catalyst without halogenated organic solvent.     

Catalytic properties of rare earth manganites and related compounds

Perovskite-type oxides REMnO₃ (RE=La-Dy) and PrMn_1–xNi_xO₃ (x=0–0.8) have been prepared. The catalytic activity and the reducibility of these oxides were investigated. The effect of RE, Ni ions on catalytic property, and the relation between catalytic activity and reducibility are discussed.

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, , REMnO₃ (RE=La, Pr, Nd, Sm, Eu, Gd, Dy) PrMn_1–xNi_xO₃ (x=00,8). . RE Ni , .

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Project Supported by the Science Fund of the Chinese Academy of Sciences     

Novel cationic rare earth metal alkyl catalysts for precise olefin polymerization

This mini‐review provides recent progress in the synthesis of rare earth metal dialkyl complexes and their application as highly efficient and regio‐/stereoselective catalysts in the coordination‐insertion (co)polymerization of olefins such as styrene, isoprene, 1,3‐cyclohexadiene, and ocimene. Through modifying the coordination atom, the ligand skeleton, and the substitutent on the skeleton of the chelating ligand, tuning the electron density and the steric environment around the rare earth metal center, the precise control of the activity and regio‐/stereoselectivity of the (co)polymerization as well as the comonomer incorporation and sequence distribution of the resulting copolymers are achieved. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2271–2280     

Reversal of coupling in intermetallic compounds containing two rare earth elements

The reversal in coupling (from antiferromagnetic to ferromagnetic order with increasing x) in Eu_xLa_1−xAl₂ ternaries is successfully analyzed in terms of the RKKY formalism. The Fermi wavevector k required to account for the behavior of these ternaries is k = 0.94 k₀, which is in close agreement with the k-value previously obtained for GdAl₂ and GdAl₂-based ternaries from NMR work. The similarity of behavior of Gd_0.1La_0.9Al₂ and Eu_0.1La_0.9Al₂ and their observed Curie temperatures can also be understood using the same theoretical framework and approximately the same k-values.     

稀土冠醚配合物的研究XV. 稀土硝酸盐与臂型冠醚配合物的合成 和性质研究

本工作以6-羟基-2,3,9,10-二苯并-1,4,8,11,14-五氧杂-环十六-2,9-二烯(1)及其衍生物(2,3和4)为配体,在乙腈中合成了十八种新的稀土硝酸盐配合物。其中羧酸冠醚4与稀土硝酸盐[Ln(NO~3)~3]分别形成2:1型(Ln=La,Ce,Pr,Nd)、4:3型(Ln=Sm)和3:4型(Ln=Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y)配合物;冠醚1与La(NO~3)~3形成1:1型配合物;冠醚2,3与La(NO~3)~3均形成2:1型配合物。对所得配合物进行了元素分析、紫外光谱、红外光谱、^1H核磁共振、X射线光电子能谱等性质研究。对臂型冠醚中边臂的配位作用进行了初步讨论。     

Ordered bimetallic coordination networks featuring rare earth and silver cations

Three lanthanide complexes of the ditopic ligand 3-cyanopentane-2,4-dionate (acacCN) have been synthesized and structurally characterized. Longer intermolecular contacts result in ninefold coordination of the cation in Ce(acacCN)(3)(H(2)O)(2), whereas mononuclear complexes of the same stoichiometry with coordination number eight are obtained for the smaller Eu(III) and Yb(III) cations. Reaction of these labile compounds with AgPF(6) leads to re-organization of the coordination sphere of the rare earth cations: neutral extended structures are formed in which the peripheric -CN moieties of Ln(acacCN)(4) anions coordinate to silver cations. The initially formed heterometallic networks show additional coordination of water or inclusion of solvent molecules; three different structure types, two of them as isomorphous pairs, have been characterized. In the case of Eu(III) and Yb(III), these solids are instable when stored in their mother liquor and undergo a slow aging process, finally resulting in phase pure stable and solvent-free 3D networks Ln(acacCN)(4)Ag.     

NMR study of extracted compounds of trioctylalkylammonium with rare earth nitrates

¹H and ¹³C NMR was used to investigate the structure of ion pairs formed by trioctylalkylammonium (alkyl = CH₃-C₈H₁₇) cation and rare earth-containing anions in nitrobenzene. The cation-anion distance in the investigated compounds increases from trioctylmethyl to trioctylbutylammonium salt, remaining constant with further growth of the n-alkyl chain. The ion pair formation changes the conformation equilibrium of the cation alkyl radicals to make easier the cation-counter-ion contact.     

稀土冠醚配合物的研究 XI: 稀土(III)硝酸盐与戊二酰双(苯并-15-冠-5)配合物的合成和性质研究

本工作合成了十五个新的镧系、钇的硝酸盐和戊二酰双(苯并-15-冠-5)的配合物,并进行了元素分析、紫外光谱、红外光谱、激光拉曼光谱、差热和热重等性质研究, 对这一系列稀土配合物的性质作了比较。     

Crystal structures, phase-transition, and photoluminescence of rare earth carbodiimides

Rare earth carbodiimides with the general formula RE 2(CN 2) 3 crystallize with two modifications. A monoclinic( C2/m) modification is obtained for RE = Y, Ce-Tm and a rhombohedral ( R3 c) modification for RE = Tm-Lu. The space group R3 c is confirmed by single-crystal structure determination on Lu 2(CN 2) 3 and indexed powder patterns of RE = Tm, Yb and Lu. The use of diverse chemical syntheses conditions for Tm 2(CN 2) 3 revealed the dimorphic character of this compound. In addition, pressure experiments on Tm 2(CN 2) 3 have induced a phase-transition from rhombohedral to monoclinic. This transformation comprises an increase of the coordination number of Tm from 6 to 7, and a unit-cell volume reduction in the order of 20 %. The photoluminescence behavior of lanthanide doped Gd 2(CN 2) 3:Ln samples is presented with different activators (Ln = Ce, Tb) revealing a broad band emission of Gd 2(CN 2) 3:Ce, quite similar to that of the well-known YAG:Ce.     

稀土配合物的研究 IV: 稀土元素与4-酰代双吡唑啉酮BPMPPD及1,10-二氮杂菲三元配合物的合成和性质的研究

4-酰代双吡唑啉酮是一类新型β双酮多啮金属离子螯合剂和萃取剂, 其性能优于单吡唑啉酮, 本文继合成1,5-双(1'-萃基-3'-甲基-5'-氧代吡唑-4')-1,5-戊二酮(BPMPPD, H2A)后, 又合成了它和1,10-二氮杂菲(Phen, P)与稀土元素形成的三元固态配合物, 并对这些新配合物的性质进行了研究。