Synthesis and single-crystal x-ray diffraction examination of a structurally homologous series of tetracoordinate heteroleptic anionic lanthanide complexes: Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(L)3 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb; (L)3 =(THF)3, (Et2O)3, (THF)2(Et2O)

Anhydrous lanthanide(III) chlorides (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) react with 3 equiv of lithium 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentanide, Li[N[Si(CH3)2CH2Ch2Si(CH3)2]], in THF or Et(2)O to afford the monomeric four-coordinate heteroleptic ate complexes Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(THF/Et2O)3 (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Tm (8), Yb (9)), whose solid-state structures were determined by the single-crystal X-ray diffraction technique. All complexes additionally were characterized by melting point determination, elemental analyses, and mass spectrometry.     

用非等温DSC曲线确定Ln(NCS)3-·4C3H5CH2NH2的热分解反应机理函数及热分解反应动力学参数

本文利用非等温DSC曲线对十二种镧系元素异硫氰酸盐与苄胺形成的配合物Ln(NCS)3·4C6H5CH2NH2(Ln=La、Pr、Nd、Sm、Eu、Ge、Tb、Dy、Ho、Er、Tm、Yb)进行了非等温动力学研究, 并运用积分法和微分法进行了分析, 推断了它们的热分解反应机理函数。     

1,5-双(1'-苯基-3'-甲基-5'-吡唑啉酮-4')-戊二酮-[1,5]和十六烷基吡啶盐的稀土配合物的合成及表征

合成了13种1,5-双(1′-苯基-3′-甲基-5′-吡唑啉酮-4′)-戊二酮-[1,5](BPMPPD)和溴化十六烷基吡啶盐(CPB)的稀土配合物.研究了配合物的红外光谱、紫外可见光谱、差热-热重谱、荧光光谱、核磁共振谱及摩尔电导等性质,发现配合物属离子型缔合物CP⁺[Ln(BPMPPD)₂]^-.Pr、Nd、Ho、Er、Tm配合物发生超灵敏跃迁.配合物的热分解温度具有"四分组"效应,Sm、Eu、Tb、Oy为线性荧光。     

Coordination polymers based on inorganic lanthanide(II) sulfate skeletons and an organic isonicotinate N-oxide connector: segregation into three structural types by the lanthanide contraction effect

Fourteen three-dimensional coordination polymers of general formula [Ln(lNO)(H2O)(SO4)]n, where Ln = La, 1.La; Ce, 2.Ce; Pr, 3.Pr; Nd, 4.Nd; Sm, 5.Sm; Eu, 6.Eu; Gd, 7.Gd; Tb, 8.Tb; Dy, 9.Dy; Ho, 10.Ho; Er. 11.Er; Tm, 12.Tm; Yb, 13.Yb; and Lu, 14.Lu; INO = isonicotinate-N-oxide, have been synthesized by hydrothermal reactions of Ln3+, MnCO3, MnSO4 x H2O, and isonicotinic acid N-oxide (HINO) at 155 degrees C and characterized by single-crystal X-ray diffraction, IR, thermal analysis, luminescence spectroscopy, and the magnetic measurement. The structures are formed by connection of layer, chain, or dimer of Ln-SO4 by the organic connector, INO. They belong to three structural types that are governed exclusively by the size of the ions: type I for the large ions, La, Ce, and Pr; type II for the medium ions, Nd, Sm, Eu, Gd, and Tb; and type III for the small ions, Dy, Ho, Er, Tm, Yb, and Lu. Type I consists of two-dimensional undulate Ln-sulfate layers pillared by INO to form a three-dimensional network. Type II has a 2-fold interpenetration of "3D herringbone" networks, in which the catenation is sustained by extensive pi-pi interactions and O-H...O and C-H...O hydrogen bonds. Type III comprises one-dimensional chains that are connected by INO bridges, resulting in an alpha-Po network. The progressive structural change is due to the metal coordination number decreasing from nine for the large ions via eight to seven for the small ions, demonstrating clearly the effect of lanthanide contraction. The sulfate ion acts as a micro4- or micro3-bridge, connecting two, three, or four metals, and is both mono- and bidentate. The INO ligand acts as a micro3- or micro2-bridge with carboxylate group in syn-syn bridging or bidentate chelating mode. The materials show considerably high thermal stability. The magnetic properties of 4.Nd, 6.Eu, 7.Gd, and 13.Yb and the luminescence properties of 6.Eu and 8.Tb are also investigated.     

Synthesis and characterization of heterodinuclear Ln(3+)-Fe3+ and Ln(3+)-Co3+ complexes,bridged by cyanide ligand (Ln3+ = lanthanide ions). Nature of the magnetic interaction in the Ln(3+)-Fe3+ complexes

The reaction of Ln(NO3)3.aq with K3[Fe(CN)6] or K3[Co(CN)6] in N,N'-dimethylformamide (DMF) led to 25 heterodinuclear [Ln(DMF)4(H2O)3(mu-CN)Fe(CN)5].nH2O and [Ln(DMF)4(H2O)3(mu-CN)Co(CN)5].nH2O complexes (with Ln = all the lanthanide(III) ions, except promethium and lutetium). Five complexes (Pr(3+)-Fe3+), (Tm(3+)-Fe3+), (Ce(3+)-Co3+), (Sm(3+)-Co3+), and (Yb(3+)-Co3+) have been structurally characterized; they crystallize in the equivalent monoclinic space groups P21/c or P21/n. Structural studies of these two families show that they are isomorphous. This relationship in conjunction with the diamagnetism of the Co3+ allows an approximation to the nature of coupling between the iron(III) and the lanthanide(III) ions in the [Ln(DMF)4(H2O)3(mu-CN)Fe(CN)5].nH2O complexes. The Ln(3+)-Fe3+ interaction is antiferromagnetic for Ln = Ce, Nd, Gd, and Dy and ferromagnetic for Ln = Tb, Ho, and Tm. For Ln = Pr, Eu, Er, Sm, and Yb, there is no sign of any significant interaction. The isotropic nature of Gd3+ helps to evaluate the value of the exchange interaction.     

钼和稀土的二乙基二硫代甲酸盐配合物的电化学研究

研究了N,N-二乙基二硫代甲酸根(dtc)作配体的双核配位化合物[Mo(dtc)₄][Ln(dtc)₄](Ln=La,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho和Er)的氧化还原性质及其在电极过程中的电化学特性.     

La0.5R0.5Ba2Cu3O7,Pr0.5R0.5Ba2Cu3O7以及RBa2Cu3o7（R=稀土）的键共价性计

使用复杂晶体化学键理论计算了Ｌａ０．５Ｒ０．５Ｂａ２Ｃｕ３Ｏ７（Ｒ＝Ｐｒ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ,Ｄｙ,Ｙ,Ｈｏ,Ｅｒ,Ｔｍ,Ｙｂ,Ｌｕ）（Ｌａ－Ｒ１２３）,Ｐｒ０．５Ｒ０．５Ｂａ２Ｃｕ３Ｏ７（Ｒ＝Ｌａ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ,Ｄｙ,Ｈｏ,Ｙ,Ｅｒ,Ｔｍ,Ｙｂ,Ｌｕ）（Ｐｒ－Ｒ１２３）以及ＲＢａ２Ｃｕ３Ｏ７（Ｒ＝Ｌａ,Ｐｒ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ,Ｄｙ,Ｈｏ,Ｙ,Ｅｒ,Ｔｍ）（Ｒ１２３）中Ｃｕ－Ｏ键的键共价性,结果表明Ｐｒ－Ｒ１２３,Ｌａ－Ｒ１２３,以及Ｒ１２３都应具有超导性,而实验结果是Ｌａ０．５Ｐｒ０．５Ｂａ２Ｃｕ０７,Ｒ０．５,Ｐｒ０．５Ｂａ２Ｃｕ３Ｏ７（Ｒ＝Ｌａ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ）无超导性,产生这种矛盾的原因尚不明确,需要做进一步的研究。     

乙酰丙酮-5,10,15,20-四-(对氯苯基)卟啉稀土配合物的制备和性质

用丙酸做溶剂,吡咯与对氯笨甲醛反应制备5,10,15,20-四-(对氯苯基)卟啉(p-Cl)Tpp;后者与稀土乙酰丙酮配合物Ln(acac)₃·3H₂O在1,2,4-三氯苯中反应制得乙酰丙酮-5,10,15,20-四-(对氯苯基)卟啉稀土配合物Ln(p-Cl)Tppacac;并做了元素分析、UV、IR和PMR等性质的研究。     

Synthesis, structure, and thermally stable luminescence of Eu(2+)-doped Ba2Ln(BO3)2Cl (Ln = Y, Gd and Lu) host compounds

A new family of chloroborate compounds, which was investigated from the viewpoint of rare earth ion activated phosphor materials, have been synthesized by a conventional high temperature solid-state reaction. The crystal structure and thermally stable luminescence of chloroborate phosphors Ba(2)Ln(BO(3))(2)Cl:Eu(2+) (Ln = Y, Gd, and Lu) have been reported in this paper. X-ray diffraction studies verify the successful isomorphic substitution for Ln(3+) sites in Ba(2)Ln(BO(3))(2)Cl by other smaller trivalent rare earth ions, such as Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb. The detailed structure information for Ba(2)Ln(BO(3))(2)Cl (Ln = Y, Gd, and Lu) by Rietveld analysis reveals that they all crystallize in a monoclinic P2(1)/m space group. These compounds display interesting and tunable photoluminescence (PL) properties after Eu(2+)-doping. Ba(2)Ln(BO(3))(2)Cl:Eu(2+) phosphors exhibit bluish-green/greenish-yellow light with peak wavelengths at 526, 548, and 511 nm under 365 UV light excitation for Ba(2)Y(BO(3))(2)Cl:Eu(2+), Ba(2)Gd(BO(3))(2)Cl:Eu(2+), and Ba(2)Lu(BO(3))(2)Cl:Eu(2+), respectively. Furthermore, they possess a high thermal quenching temperature. With the increase of temperature, the emission bands show blue shifts with broadening bandwidths and slightly decreasing emission intensities. It is expected that this series of chloroborate phosphors can be used in white-light UV-LEDs as a good wavelength-conversion phosphor.     

Determination of dissociation constants for some pyrogallol azo derivatives and stability constants of their complexes with rare-earth metals

The dissociation constants of some haloazo derivatives of pyrogallol and the stability constants of their complexes with rare-earth metals (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) are determined by potentiometric titration in aqueous ethanol (3: 7). A correlation between the dissociation constants of the reagents and the stability constants of their complexes is found.     

Molar enthalpies of formation of LnAl2 compounds

The enthalpy of solution of Eu in Al and the standard molar enthalpy of formation of LnAl₂ (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) were determined by dissolution calorimetry, using a calorimeter based on liquid aluminium. Experimental results are compared with model predictions.     

Syntheses and crystal structures of anhydrous Ln(hfac)3(monoglyme). Ln = La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Er, Tm

The crystal structures of a broad series of anhydrous Ln(hfac)(3)(monoglyme) complexes, prepared in moderate to high yield, are presented: hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-; Ln = La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Er, Tm. This study contradicts the general assumption that monoglyme is too small a polyether to act as a partitioning agent displacing coordinated water on the larger lanthanide(III) ions. The structures of an intermediate La(hfac)(3)(monoglyme)(2) species and the hydrated Ce(hfac)(3)(monoglyme)(H(2)O) species are also included. The crystallographic evidence presented herein is supplemented by other characterization techniques (melting point, IR, etc.) and trends are delineated.     

Determination of rare earths and thorium in apatites by thermal and epithermal neutron-activation analysis

A procedure is described for the non-destructive determination of Na, Mn, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu and Th in apatites by thermal and epithermal neutron-activation of independent portions of the material. The method was applied to three apatites with different contents. The precision obtained was better than +/-5% for La, Ce, Sm, Eu, Gd, Tb and Dy and +/-20% for Yb, Nd, Ho, Er and Lu for an apatite with a total rare-earth oxide content of the order of 1%. Determination of Ce, Tb and Yb could only be carried out with thermal neutron-activation analysis, while Gd, Ho and Er could only be determined after irradiation with epithermal neutrons.     

Luminescence tuning of imidazole-based lanthanide(III) complexes [Ln = Sm, Eu, Gd, Tb, Dy

To tune the lanthanide luminescence in related molecular structures, we synthesized and characterized a series of lanthanide complexes with imidazole-based ligands: two tripodal ligands, tris{[2-{(1-methylimidazol-2-yl)methylidene}amino]ethyl}amine (Me(3)L), and tris{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(3)L), and the dipodal ligand bis{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(2)L). The general formulas are [Ln(Me(3)L)(H(2)O)(2)](NO(3))(3)·3H(2)O (Ln = 3+ lanthanide ion: Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)), [Ln(H(3)L)(NO(3))](NO(3))(2)·MeOH (Ln(3+) = Sm (6), Eu (7), Gd (8), Tb (9), and Dy (10)), and [Ln(H(2)L)(NO(3))(2)(MeOH)](NO(3))·MeOH (Ln(3+) = Sm (11), Eu (12), Gd (13), Tb (14), and Dy (15)). Each lanthanide ion is 9-coordinate in the complexes with the Me(3)L and H(3)L ligands and 10-coordinate in the complexes with the H(2)L ligand, in which counter anion and solvent molecules are also coordinated. The complexes show a screw arrangement of ligands around the lanthanide ions, and their enantiomorphs form racemate crystals. Luminescence studies have been carried out on the solid and solution-state samples. The triplet energy levels of Me(3)L, H(3)L, and H(2)L are 21?000, 22?700, and 23?000 cm(-1), respectively, which were determined from the phosphorescence spectra of their Gd(3+) complexes. The Me(3)L ligand is an effective sensitizer for Sm(3+) and Eu(3+) ions. Efficient luminescence of Sm(3+), Eu(3+), Tb(3+), and Dy(3+) ions was observed in complexes with the H(3)L and H(2)L ligands. Ligand modification by changing imidazole groups alters their triplet energy, and results in different sensitizing ability towards lanthanide ions.     

Heptanuclear heterometallic [Cu6Ln] clusters: trapping lanthanides into copper cages with artificial amino acids

Employment of the artificial amino acid 2-amino-isobutyric acid, aibH, in Cu(II) and Cu(II)/Ln(III) chemistry led to the isolation and characterization of 12 new heterometallic heptanuclear [Cu(6)Ln(aib)(6)(OH)(3)(OAc)(3)(NO(3))(3)] complexes consisting of trivalent lanthanide centers within a hexanuclear copper trigonal prism (aibH = 2-amino-butyric acid; Ln = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), and Yb (12)). Direct curent magnetic susceptibility studies have been carried out in the 5-300 K range for all complexes, revealing the different nature of the magnetic interactions between the 3d-4f metallic pairs: dominant antiferromagnetic interactions for the majority of the pairs and dominant ferromagnetic interactions for when the lanthanide center is Gd(III) and Dy(III). Furthermore, alternating current magnetic susceptibility studies reveal the possibility of single-molecule magnetism behavior for complexes 7 and 8. Finally, complexes 2, 5-8, 10, and 12 were analyzed using positive ion electrospray mass spectrometry (ES-MS), establishing the structural integrity of the heterometallic heptanuclear cage structure in acetonitrile.     

Syntheses, structure, some band gaps, and electronic structures of CsLnZnTe3 (Ln=La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y)

Eleven new quaternary rare-earth tellurides, CsLnZnTe3 (Ln=La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Y), were prepared from solid-state reactions at 1123 K. These isostructural materials crystallize in the layered KZrCuS3 structure type in the orthorhombic space group Cmcm. The structure is composed of LnTe6 octahedra and ZnTe4 tetrahedra that share edges to form [LnZnTe3] layers. These layers stack perpendicular to [010] and are separated by layers of face- and edge-sharing CsTe8 bicapped trigonal prisms. There are no Te-Te bonds in the structure of these CsLnZnTe3 compounds so the formal oxidation states of Cs/Ln/Zn/Te are 1+/3+/2+/2-. Optical band gaps of 2.13 eV for CsGdZnTe3 and 2.12 eV for CsTbZnTe3 were deduced from single-crystal optical absorption measurements. A first-principles calculation of the density of states and the frequency-dependent optical properties was performed on CsGdZnTe3. The calculated band gap of 2.1 eV is in good agreement with the experimental value. A quadratic fit for the lanthanide contraction of the Ln-Te distance is superior to a linear one if the closed-shell atom is included.     

Structural,electrical, and magnetic properties of a series of molecular conductors based on BDT-TTP and lanthanoid nitrate complex anions (BDT-TTP = 2,5-Bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene)

The platelike crystals of a series of novel molecular conductors, which are based on the pi-donor molecules BDT-TTP (2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) with a tetrathiapentalene skeleton and lanthanide nitrate complex anions [Ln(NO3)x](3-x)(Ln = La, Ce, (Pr), Tb, Dy, Ho, Er, Tm, Yb, Lu) with localized 4f magnetic moments, were synthesized. Except for the Ce complex, the salts were composed of (BDT-TTP)(5)[Ln(NO(3))(5)] and were isostructural. Even though the Ce crystal had a different composition, (BDT-TTP)(6)[Ce(NO(3))(6)](C(2)H(5)OH)(x)() (x approximately 3), the crystals all had the space group P(-)1. Although the X-ray examination of the Pr salts was insufficient, the existence of two modifications was suggested in these systems by preliminary X-ray examination. Previously, we reported the crystal structures and unique magnetic properties of (BDT-TTP)(5)[Ln(NO(3))(5)] (Ln = Sm, Eu, Nd, Gd). Thus, by combining the results of this work with previous one, we for the first time succeeded in obtaining a complete set of organic conductors composed of the identical pi-donors (BDT-TTP in this case) and all the lanthanide nitrate complex anions (except the complex with Pm(3+)). The crystals were all metallic down to 2 K. Electronic band structure calculations resulted in two-dimensional Fermi surfaces, which was consistent with their stable metallic states. Except for the Lu complex, which lacked paramagnetic moments, the magnetic susceptibilities were measured on the six heavy lanthanide ion complex salts by a SQUID magnetometer (Ln = Tb, Dy, Ho, Er, Tm, Yb). The large paramagnetic susceptibilities, which were caused by the paramagnetic moments of the rare-earth ions, were obtained. The Curie-Weiss law fairly accurately reproduced the temperature dependence of the magnetic susceptibilities of (BDT-TTP)(5)[Ho(NO(3))(5)] in the experimental temperature range (2-300 K) and a comparatively large Weiss temperature (|THETAV;|) was obtained (THETAV;(Ho) = -15 K). A Weiss temperature (THETAV;(Tm) = -8 K) was also obtained for Tm. The |THETAV;| values of other (BDT-TTP)(5)[Ln(NO(3))(5)] salts and (BDT-TTP)(6)[Ce(NO(3))(6)](C(2)H(5)OH)x(x approximately 3) were as follows: |THETAV;|/K = 4 (Er), < or =2 (Ce, Tb, Dy, Yb). The comparatively strong intermolecular magnetic interaction between Ho(3+) ions, which was suggested by the |THETAV;| value, is inconsistent with the traditional image of strongly localized 4f orbitals shielded by the electrons in the outer 5s and 5p orbitals. The dipole interactions between Ln(3+) ions causing the Curie-Weiss behavior and the comparatively large THETAV; value of (BDT-TTP)(5)[Ho(NO(3))(5)] is inconsistent with the data, since the complexes exhibit isostructural properties and there is not a clear relationship between the magnitudes of THETAV; values and those of magnetic moments. Therefore, it is possible that the 4f orbitals of Ho atom are sensitive to the ligand field, which will have an effect on the orbital moment of the Ho(3+) ion and/or produce a small amount of mixing between 4f and ligand orbitals to give rise to "real" intermolecular antiferromagnetic interaction through intermolecular overlapping between pi (BDT-TTP) and ligand orbitals of lanthanide nitrate complex anions.     

Two- and three-dimensional lanthanide complexes: synthesis, crystal structures, and properties

3,5-pyrazoledicarboxylic acid (H3L) reacts with nitrate salts of lanthanide(III) (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er) under hydrothermal conditions to form a series of lanthanide polymers 1-9. These nine polymers have the same crystal system of monoclinic, but they exhibit three different kinds of metal-organic framework structures. The complexes {[Ln2(HL)3(H2O)4].2H2O}n (Ln=Pr (1), Nd (2), and Sm (3)) were isostructural and exhibited porous 3D frameworks with a Cc space group. The complexes {[Ln2(HL)3(H2O)3].3H2O}n (Ln=Eu (4), Gd (5), and Tb (6)) were isostructural and built 2D double-decker (2DD) frameworks with a P21/c space group. The complexes {[Ln(HL)(H2L)(H2O)2]}n ((Ln=Dy (7), Ho (8), and Er (9)) were also isostructural and formed 2D monolayer (2DM) frameworks with a P21/n space group. The structure variation from the 3D porous framework to the 2D double-decker to the 2D monolayer is attributed to the lanthanide contraction effect. Notably, six new coordination modes of 3,5-pyrazoledicarboxylic acid were observed, which proved that 3,5-pyrazoledicarboxylic acid may be used as an effective bridging ligand to assemble lanthanide-based coordination polymers. The photophysical and magnetic properties have also been investigated.     

Extraction of rare-earth nitrates by phosphoryl podands

The distribution of trace amounts of rare-earth nitrates between aqueous solutions of NH₄NO₃ and organic solutions of phosphoryl podands is studied for Ln = La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y. The stoichiometry of the extraction complexes is determined. The effect of the structure of the extractant and the nature of the organic solvent on the efficiency of rare-earth recovery to the organic phase is considered.     

镧系三氟化物的SCF-Xα-SW研究

对10个镧系元素(Ln)三氟化物进行了非相对论和相对论SCF-Xα-SW计算, 通过能级、轨道、结合能及布居数对比, 讨论化学键本质: 共价键中4f轨道的作用及相对论效应,结果表明, LnF3中Ln原子轨道参与成键的次序是: 轻稀土d>f>p>s, 而重稀土则有f>d>p>s。相对效应使Ln4f能级上移, 扩大了与F2p能级的距离, 减弱成键。原子序数增大, Ln4f能级下移, F2p能级距离缩小, 使重稀土氟化物中成键增强, 结合能计算值与实验值定性趋势一致, 重稀土氟化物电离能的计算表明, 相对论方案是获得定量符合所应该采用的。