水合稀土三氯醋酸盐的合成及脱水热焓的测定

本文合成了稀土三氯醋酸盐,用化学分析、热重法和五氧化二磷真空干燥脱水法对其组成进行了测定。除三水合三氯醋酸镧外,其它皆为未见报道的新水合物Ln(CCl_3COO)_3·XH_2O(Ln=Eu,x=2.5; Ln=Ce、Nd、Sm、Gd,x=2; Ln=Pr,x=1.5)。用X射线粉末衍射法测定了化合物的衍射数据。用TG、DTG和DTA热分析研究了水合盐的脱水过程,并用DSC法测定了水合盐在各脱水阶段的脱水热焓值.     

水合稀土二氯醋酸盐的合成及热分解研究

合成了La,Ce,Nd,Sm,Eu,Gd二氯醋酸盐,经化学分析,热重法和五氧化二磷真空千燥脱水法确定组成为Ln(CHCl2COO)3.nH2O(n=2,Ln=La,Ce,Nd;n=1.5,Ln=Sm;n=1.25,Ln=Eu;n=1,Ln=Gd),它们均属新水合物.用DTA-TG-DTG并用技术并辅以化学分析和红外光谱技术研究了其热分解机理,实验证明,由室温至600℃范围内,它们均发生三步主要反应:水合盐脱水变为无水盐;无水盐分解为中间产物,Ln2(OH)Cl5.3H2O[Eu盐分解为Eu2(OH)Cl5.2H2O];中间产物进一步分解为LnOCl[Ce盐为CeO2].并观察到无水盐和氯氧化物形成温度皆与原子序数呈现镧系"双一双效应".     

间硝基苯甲酸稀土配合物的热分解

用TG-DTA,高温X-射线衍射研究了稀土间硝基苯甲酸配合物LnL_3·nH_2O(n=2,Ln=La→Lu+Y;n=0,Ln=Sc,HL=间硝基苯甲酸)的热分解行为,DSC测定其脱水相变过程中的热力学函数,同时用透射电镜观察了热分解产物的超微性。     

稀土乙酸盐水合物热分解机理的研究

采用TG—DTG和DSC法,在空气气氛下对14种稀土乙酸盐水合物(Ln(Ac)_3·nH_2O,Ln=La～Lu+Y,除Ce、Pm,n=4或5]的热分解机理进行研究。热分解机理在钕、钆处发生转折。无水盐的形成温度随原子序数的增加而降低。采用Freemen-Carroll和Kissinger法计算了稀土乙酸盐脱水、分解过程的活化能,以脱水过程的活化能对原子序数作图呈“斜W效应”。用DSC测定了稀土乙酸盐脱水、分解过程的焓变。     

四甲基双硅桥联环戊二烯基稀土金属有机配合物的合成及[Me4Si2(C5H4)2Sm(μ-Cl)(THF)]2的晶体结构研究

四甲基双硅桥联环戊二烯基钠与无水三氯化稀土在THF溶剂中反应合成了标题配合物Me₄Si₂(C₅H₄)₂LnCl[Ln:3Nd,4Sm,5Gd,6Y]和配合物Me₄Si₂(C₅H₄):Ln(C₅H₅)(THF)n[Ln:1La,n=1;2Pr,n=0].通过元素分析、¹HNMR、13CNMR和MS确证了配合物的结构,在THF溶液中重结晶获得配合物4的单晶,x射线衍射证明晶体结构为二聚体,4为单斜晶系,空间群为P2₁/c,晶体学数据a=1.2982(3)nm,b=1.2269(3)nm,c=1.3681(2)nm,β=96.79(2)°,V=2.162(1)nm³,Z=2,D_x=1.53g/cm³,偏差因子R=0.068.     

稀土氨基酸络合物的研究(Ⅰ)——一氯化三甘氨酸二水合谱的晶体结构

在水溶液中培养了甘氨酸镨、钕的针状晶体,元素分析结果表明可用Ln(Gly)₃Cl₃·3H₂O表示(Ln为Pr,Nd;Gly为甘氨酸)。用X射线衍射方法测定了Pr(Gly)₃Cl₃·3H₂O的单晶结构,其结构式为{[Pr(Gly)₃·(H₂O)₂]·Cl₃·H₂O}_n,属正交晶系,空间群P2₁2₁2₁,每一晶胞中有4个络合单元,形成一维链式聚合物·晶胞参数如下:α=4.779(1)Å,b=12.052(3)Å,c=30.953(11)Å。络合单元中镨为九配位,其配位多面体为畸变的三冠三角棱柱体。     

稀土复合硫化物Ln6MSi2S14(M=Co、Ni)的合成

用气固相反应合成出一系列Ln₆MSi₂S₁₄(Ln=La·Dy,M=Co、Ni)化合物,给出了X射线粉末衍射数据和晶胞参数。     

稀土吲哚-3-乙酸和吲哚-3-丁酸配合物的合成、表征及成键特性研究

在乙醇水溶液体系中合成了8种新的稀土吲哚-3-乙酸和吲哚-3-丁酸配合物,其通式为Ln(lA)₃·2H₂O和Ln(IB)₃·2H₂O(Ln=La,Nd,Sm,Er;IA=C₁₀H₈NO₂;IB=C₁₂H₁₂NO₂)。用元素分析、电导测定、电子吸收光谱、红外光谱、X光电子能谱和热重-差热分析确定了配合物的组成和成键特性。     

基于席夫碱配体构筑的LnⅢ2配合物的结构、荧光性质及生物活性

以多齿席夫碱配体H₂L(H₂L=(E)-N′-(3-乙氧基-2-羟基亚苄基)-3-羟基吡啶甲酰肼)为配体,与Ln(acac)₃·2H₂O(Ln=Tb、Ho、Er;acac^-=乙酰丙酮根)反应,通过溶剂热法,成功得到了3例新的双核稀土配合物[Ln₂(acac)₂(L)₂(C₂H₅OH)₂](Ln=Tb((1)、Ho((2)、Er(3))。单晶X射线衍射分析表明：配合物1～3的结构主要由2个Ln^Ⅲ离子、2个乙酰丙酮根(acac^-)、2个L^2-及2个C₂H₅OH组成,中心Ln^Ⅲ离子通过2个μ₂-O原子相互连接,形成一个平行四边形的Ln₂O₂核心。固体荧光实验测...     

镧系元素-锑-硫三元体系的研究(Ⅳ)——CeSbOS2的合成及晶胞参数的测定

作为无机新材料的开发,近年来,我们系统地研究了Ln-Sb-S三元体系,先后合成了Ln₈Sb₈S₂₁(Ln=La,Ce)、Ln₃Sb₃S₁₀(Ln=La,Ce)、Ln_3-xSb_xS₄(Ln=La,Ce,Sm)、Ln_1-xSb_xS₂(Ln=Nd)和Ln₃SbS₆(Ln=Pr,Nd)等十余种新化合物的单晶。同时也注意到法国M.Pardo等人在报导LnOBiS₂(Ln=La,Ce,Pr)型化合物时,曾提及LnOSbS₂型化合物的存在,并给出了NdOSbS₂的部分数据。     

Preparation and Characterization of Heteropoly-complex K_11[La(GaW_11O_39H_2)_2]· xH_2O

Heteropoly complexes K11[Ln(CaW 11O39H2)21 · x H2O(Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy ) have been prepared and analysed. Some properties such as thermal behavior, IK and UV spectra, X-ray powder diffraction, magnetic susceptibility and X-ray photoelectron spectrum have been investigated.     

Solution enthalpies of hydrates LnCl3·xH2O (Ln=Ce–Lu)

Trichlorides of the lanthanide elements Ln=Ce–Lu form: (a) isotypic hexahydrates LnCl₃·6H₂O with a coordination number (CN) 8 for the Ln³⁺ ions. (b) Two isotypic groups of trihydrates LnCl₃·3H₂O, in the first group Ln=Ce-Dy the CN is 8; the structure of the second group Ln=Er–Lu is unknown. With Ho no trihydrate exists; a dihydrate is formed. (c) Two isotypic groups of monohydrates LnCl₃·H₂O with unknown structure – Ln=Ce–Dy and Ln=Ho–Lu. For all compounds and for anhydrous chlorides LnCl₃ solution enthalpies were measured with an isoperibolic calorimeter. The Δ_solH⁰ values do not depend only on the difference (lattice enthalpies/hydration enthalpies), but also on the state in solution. According to Spedding the CN of the Ln³⁺ ions against water changes from 9 to 8 between Nd and Sm, causing minima in the series of solution enthalpies. Dihydrates LnCl₃·2H₂O are found for Ln=Ce, Pr, Nd, Sm and presumably for Eu and Gd. They are not yet well characterised.     

Thermochemical properties of Ln(Gly)4Im(ClO4)3·nH2O (Ln = Gd, Tb, Dy, Y)

The enthalpies of dissolution in water of new ternary complexes of four late trivalent lanthanide ions Ln(Gly)₄Im(ClO₄)₃·nH₂O (Ln=Gd, Tb, Dy, Y; Gly: glycine; Im: imidazole and n=1 or 2) were measured by means of a Calvet microcalorimeter. Empirical formulae for the calculation of the enthalpies of dissolution (Δ_dissH), relative apparent molar enthalpies (Δ_dissH (app)), relative partial molar enthalpies (Δ_dissH (partial)) and enthalpies of dilution (Δ_dilH_1,2) were obtained from the experimental data of the enthalpies of dissolution of these complexes. The plot of Δ_dissH_m^Θ, Δ_dissH (app) and Δ_dissH (partial) versus the values of the ionic radius of the lanthanide element (r) showed a grouping effect of the lanthanide elements, indicating that the coordinated bond between the lanthanide ions and the ligands has some covalent character. The unknown value of the standard enthalpy of dissolution for the similar complex: Ho(Gly)₄Im(ClO₄)₃·H₂O was estimated according to the plot of Δ_dissH_m^Θ versus r.     

Self-assembly of lanthanide mixed-carboxylates coordination polymers

Two new mixed-ligands lanthanide coordination polymers, [Ln(Ac)(ip)(H₂O)₂]·0.5H₂O (Ln=La (1); Ln=Eu (2); Ac=acetate; ip=isophthalate) have been synthesized under hydrothermal condition. Single-crystal X-ray analyses show that complexes 1 and 2 are three-dimensional structure in which lanthanide ions are bridged by monocarboxylate ligand, acetate or dicarboxylate ligand, isophthalate. And the central lanthanide ions, La³⁺ and Eu³⁺, are both nine-coordinate with oxygen atoms. The thermogravimetric analysis was carried out to examine the thermal stability of the title complexes. And the photoluminescence property of complex 2 was also investigated.     

Large cluster formation through multiple substitution with lanthanide cations (La, Ce, Nd, Sm, Eu, and Gd) of the polyoxoanion

Several new large polyoxotungstates have been synthesized by reaction of lanthanide cations with the well-known "As(4)W(40)" anion, [(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)](28-) (1). The heteropolyanions [(H(2)O)(11)Ln(III)(Ln(III)(2)OH)(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)](20)(-) (Ln = Ce, Nd, Sm, Gd) (2-4) (Ln(3)As(4)W(40)) and [M(m)()(H(2)O)(10)(Ln(III)(2)OH)(2)(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)]((18-m)(-)) (Ln = La, Ce, Gd and M = Ba, K, none) (5-7) (Ln(4)As(4)W(40)) have been isolated as alkali metal and ammonium salts, respectively, and characterized by single-crystal X-ray analysis, elemental analysis, and IR and (183)W-NMR spectroscopy. The X-ray analyses revealed interanionic W-O-Ln bonds between adjacent Ln(x)()As(4)W(40) units forming a "dimer" for x = 3 and chains for x = 4. Upon dissolving in water these bonds hydrolyze and the monomeric species form. The straightforward syntheses which require the use of concentrated NaCl solutions (1-4 M) and the addition of stoichiometric amounts of Ba(2+) or K(+) reemphasize the importance of the presence of appropriate countercations for the assembly of large polyoxometalate structures.     

氯灭酸与消炎痛稀土盐类的研究

在醋酸钠-甲醇溶液中,制备了两种非甾体抗炎药——氯灭酸、消炎痛的稀土盐类三十一个.研究了它们的溶解性,测定了它们的UV、IR、X射线粉末衍射、热谱和电导.确定化合物的组成为Ln(Ch)_3·nH_2O,Ce(Ch)_4·H_2O和Ln(Ind)_3·mH_2O(Ln=各种稀土离子;Ch=氯灭酸酸根;Ind=消炎痛酸根,n=1～2,m=3～5).动物试验表明,它们的毒性比相应的氯化物为小.     

Formation of nanocrystalline structures in the Ln<Subscript>2</Subscript>O<Subscript>3</Subscript>-MO<Subscript>2</Subscript> systems (Ln = Gd,Dy; M = Zr,Hf)

The formation of (Ln³⁺)₂(M⁴⁺)₂O₇ (Ln = Gd, Dy; M = Zr, Hf) nanocrystallites obtained by annealing mixed hydroxides LnM(OH)₇ · nH₂O (precursors) synthesized by coprecipitation has been studied by synchronous thermal analysis, X-ray diffraction (normal and anomalous diffraction of synchrotron radiation), and EXAFS. In the systems under consideration, heat treatment of the X-ray amorphous precursors leads to their dehydration, and at 600–700°C, nanocrystallites with an fcc structure of disordered fluorite start forming. A further increase in temperature is accompanied by crystallite growth (CDD) and considerable change in the local structure of the heat-treated compounds. The crystallization enthalpies and activation energies have been determined.     

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.     

Lanthanide(III)-cobalt(II) heterometallic coordination polymers with radical adsorption properties

Two new coordination polymers {[Ln(2)(PDA)(6)Co(3)(H(2)O)(6)] x xH(2)O}(n) [Ln = Nd, x = 7 (1); Ln = Gd, x = 3.25 (2); H(2)PDA = pyridine-2,6-dicarboxylic acid] have been prepared under hydrothermal conditions with Ln(NO(3))(3) x 6H(2)O, CoO, and H(2)PDA in a molar ratio of 2:3:6. X-ray crystallographic analyses reveal that they crystallize in the hexagonal group P6/mcc and exhibit a nanotubular 3D framework. The adsorption experiment shows that 1 and 2 can adsorb radicals, which is proven by electron paramagnetic resonance spectra with the characteristic bands of the radicals at g = 2.006 and 2.005, respectively.