Binuclear Lanthanide Complexes Containing SodiumSyntheses and Crystal Structure of (C_5Me_5)_2Nd(μ-Cl)_2Na(DME)_2 and (C_5Me_5)_2Nd(μ-OCH_3)_2Na(DME)_2

The reaction of NdCl_3 with NaC_5Me_5 generates a novel complex (C_5Me_5)_2Nd(μ-Cl)_2Na(DME)_2 (1).Then (1) reacts with 1 mol ratio Na and a little methyl-naphthalene generating another novel complex(C_5Me_5)_2Nd(μ-OCH_3)_2Na(DME)_2 (2).Complex (1) belongs to orthorhombic crystal system,space groupPbn2_1 with a=1.2635(3) nm,b=1.6127(5) nm,c=1.6543(4J nm,V=3.371(2) nm~3,D_c=1.36 gcm~(-3) andZ=4.The central metal Nd is coordinated by two C_5Me5 ring centroids and two μ-chlorine atoms forming adistorted tetrahedron.The crystal of complex (2) is monoclinic,space group C2/n with a=1.7482(5) nm,b=1.3260(4) nm,c=1.6406(7) nm,β=109.39(3)°,V=3.5874(1) nm~3,D_c=1.26 gcm~(-3) and Z=4,Twofive-membered ring centroids and two p-oxygens of OCH_3 form a distorted tetrahedron around the centralneodymium ion.     

Synthesis and Crystal Structure of a Novel Ion-pair Complex of [Li(THF)_4Nd(C_8H_8)_2]·2THF

The reaction of NdCl_3 with lithium methylnaphthalene in 1:2 mole ratio in THF generates black powder.The powder reacts with cyclooctatetraene(COT)in THF to form the title complex.[Li(THF)_4Nd(C_8H_8)_2]·2THF crystallizes in the monoclinic space group P2/c with unit-cell dimensions a=1.7858(7)nm,h=1.3243(4)nm,c=1.8086(6)nm.β=106.52(4)°,V=4.10 nm~3 and D_c=1.268 g/cm~3 for Z=4.F(000)=1660,R=0.0774,R_n=0.0733.The complex consists of discrete ion-pair and two THF moleculesadduct.In the anion,the neodymium atom is coordinated by two COT rings.The structure of the cation showsthat the lithium atom is attached with THF molecules only.     

Reaction of (C_5H_5)_2NdCl·2LiCl with n-Butyllithium: Formation and Crystal Structure of [Li(DME)_3][(C_5H_5)_3Nd(μ-H)Nd(C_5H_5)_3]

Reaction of (C_5H_5)_2NdCl·2LiCl with n-Butyllithium: Formation and Crystal Structure of [Li(DME)_3][(C_5H_5)_3Nd(μ-H)Nd(C_5H_5)_3]     

Synthesis,Characterization and Crystal Structure of Ln(CCl_3COO)_3·(phen)_2·2H_2O

Coordination compounds of lanthanide trichloroacetates with 1,10-phenanthroline weresynthesized and characterized as Ln(CCl_3COO)_3·(phen)_2·2H_2O(phen=1,10-phenanthroline,Ln=Tb～Lu)by chemical analysis,IR spectra,thermal analysis and crystal X-ray structural analysis.The crystal ofEr(CCl_3COO)_3·(phen)_2·2H_2O belongs to monoclinic system,with space group P2_1/c,a=1.6969(6)nm,b=1.3776(5)nm,c=1.7563(9)nm,β=114.79(9)°,V=3.727(1)nm~3,Z=4.     

Crystal Structure of a Heteronuclear Complex of Erbium-Yttrium and Glycine [ErY(GIy)_6(H_2O)_4] (ClO_4)_6·5H_2O

The title complex [ErY(Gly)_6(H_2O)4](ClO_4)_6·51H_2O has been synthesized.Its crystal structure has beendetermined by X-ray diffraction method.The crystal is triclinic with space group P.The unit cell parametersare as follows:a=1.1518(4) nm,b=1.4105(7) nm,c=1.5530(6) nm,α=96.61(3)°,β=102.74(3)°,γ=105.70(3)°,V=2.3277(17) nm~3,Z=2,D_(calc)=2.091 g/cm~3.The structure has been refined to a final R of0.0785.The crystal-is an infinite chain complex,in which four carboxyl groups from glycine molecules bridge theEr~(3+) and Y~(3+) ions,and the other two carboxyl groups bridge two adjacent Er~(3+) or Y~(3+) ions.     

Crystal Structure of{[(μ_2-Cl)(C_5H_5)Sm(μ_2-Cl)]_2(μ_3-Cl)(μ_4-O)Sm(μ_2-Cl)·THF}_2~(2-)·[Li(DME)_2·Li(THF)_2·DME]~(2 )·DME

The crystal structure of title complex has been determined by the method of X-ray single crystaldiffraction.The crystal belongs to monoclinic space group C_(2/c)with the unit parameters a=2.8907(7),b=2.0431(5),c=1.5723(3)nm;β=115.67(2)°.The unit volume V is 8.36924(348)nm~3;Z=8,Dc=1,82g·cm~(-3),μ(MoK_α)=46.4cn~(-1); F(000)=4416.The final R is 0.083,Rw 0.088.The title complex con-sists of two univalent cations and one divalent anion.The anion has a cluster structure including six Sm~(3 ).Coordination numbers of all six Sm~(3 )are eight,but their surroundings are different from each other.Two ofthem are decahedral array,and the others are octahedral array f the centroid of each pentacyclodienyl ring istaken as one point.     

Synthesis of the Early Lanthanide Complexes[Li(DME)_3][MeCpLn(NPh_2)_3](Ln=La,Pr,Nd)and X-Ray Crystal Structure of La Complex

The reaction of MeCpLnCl·2LiCl·nTHF with 2 equivalent of LiNPh_2 in THF,hexane andtoluene mixture solution gives the new complex[Li(DME)_2][(η~5-MeCp)Ln(NPh_2)_3](Ln=La,Pr,Nd)byextraction with DME.They have been characterized by elemental analysis,IR and NMR.The La complexcrystallizes in the monoclinic space group P2_1/c with α=1.8335(6)nm,b=1.6576(5)nm,c=1.7461(6)nm,β=96.04°,V=5.277 nm~2,Z=4,D_c=1.26g·cm~(-3),R=0.057 and R_w=0.048(1≥2.5σ(I_o))for 3378 reflec-tions.The complex consists of a pair of a cation and an anion.La~(3+) is coordinated by onemethylcyclopentadienyl and three diphenylamidos to form six-coordinate pseudotetrahedron with the meanLn-N and La-C(ring)distances of 0.2459(8)and 0.2843(11)nm,respectively.     

Crystal and Molecular Structure of Triboluminescent Complex Eu(NO_3)(TTA)_2(TPPO)_2

Eu(NO_3)(TTA)_2(TPPO)_2 (TTA=thenoyltrifluoroacetone,TPPO=triphenylphosphine oxide),M=1212.90,triclinic P1,a=1.1081(2)nm,b=1.1857(2)nm,c=1.2580(2)nm,α=65.54(1)°,β=77.91(1)°,γ=61.99(1)°;Z=1,V=1.3281(4)nm~3,D_c=1.47g/cm~3,μ_(MoK_α)=14.1 cm~(-1).The crystal desplaystriboluminescence upon fracture.Structure study shows that the crystal is noncentrosymmetric and no disor-der is found.It is concluded that the polarity of crystals is necessary for the observation of triboluminescence.     

Synthesis,photoluminescence properties and thermal investigation by TG-MS of RE(DAS)_3·xH_2O(RE=Eu~(3+),Tb~(3+))

Rare earth(Ⅲ) diphenyl-4-amine sulfonates(RE(DAS)_3·xH_2O,RE=Eu~(3+),Tb~(3+))phosphors were synthesized by precursor method from barium diphenyl-4-amine sulfonate and rare earth sulfates.FTIR,TG/DSC coupled to mass spectrometry(TG/DSC/MS),X-ray powder diffraction(XPD),scanning electron microscopy(SEM) and photo luminesce nce(PL) spectroscopy were utilized to structurally and morphologically characterize the samples.Thermal decomposition of Eu(DAS)_3·7H_2O and Tb(DAS)_3·2H_2O at 973 K under dynamic air atmosphere results in crystalline Eu_2O_2SO_4 and Tb_2O_2SO_4 materials,respectively.Accordingly,MS spectra reveal the liberation of thermal decomposition products of precursors,largely as CO_2,NO_2 and SO_2 gases.The diphenyl-4-amine sulfonate(DAS) ligand demonstrats a good stabilizing property for Eu~(3+) and Tb~(3+) ions.The Eu(DAS)_3·7H_2O and Tb(DAS)_3·2H_2O compounds display efficient red and green emissions,under UV excitation,arising from the ~5D_0→~7F_J(J=0-4) and ~5D_4→~7F_J(J=0-6) transitions of the Eu~(3+) and Tb~(3+) ions,respectively.     

Synthesis of two lanthanide clusters Ln_4~Ⅲ(Gd_4 and Dy_4) with [2×2] square grid shape:Magnetocaloric effect and slow magnetic relaxation behaviors

Two isostructural tetranuclear lanthanide clusters named [Ln_4(L)_4(CH_3 O)4]·CH_3 OH(Ln=Gd(Ⅲ) for 1,Dy(Ⅲ) for 2,H_2 L=N'-(2-hydroxy-3-methoxybenzylidene)-6-(hydroxymethyl) picolinohydrazide) were successfully isolated by using a polydentate Schiff based ligand and Ln(Ⅲ) nitrate salts.The structures of 1 and 2 were characterized by X-ray structural analyses,they are held by four double deprotonated ligands L~(2-).In them all the lanthanide ions are eight-coordinated and distributed over four vertices of a parallelogram,presenting a Ln4 cluster with a strict [2 × 2] square grid pattern.The details of magnetic analysis show that 1 displays weak anti-ferromagnetic exchange between neighboring Gd(Ⅲ) ions through carboxylate oxygen and methanol oxygen ligand atoms.Furthermore,1 exhibits significant magnetocaloric effect with the maximum entropy change-ΔS_m value of 28.5 J/(kg K) for ΔH=7.0 T at 2.0 K.For compound 2,remarkable slow magnetic relaxation behaviors are observed in the presence of zero magnetic field with τ_0=1.02 × 10~(-6) s and energy barrier ΔE/k_B=43.24 K.     

STUDIES ON RARE EARTH COMPLEXES WITH CROWN ETHERS ⅩⅧ——Synthesis,Characterization and Crystal Structure of[Sc(NO_3)_3(H_2O)_2]·(15-Crown-5)

The single crystal of the complex [Sc(NO_3)_3(H_2O)_2]·(15C5) has been prepared in acetonitrile.Thenew complex has been characterized by elemental analysis,IR spectra,solubility and molar conductancemeasurements.The structure of the complex is determined by single crystal X-ray diffraction analysis.     

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.     

[Ir(F_2ppy)_2(Br_2bpy)]~+PF~-_6配合物的合成、晶体结构及光物理性能测试

采用氯桥二聚体(F_2ppy)_2Ir(μ-Cl_2)Ir(dfppy)_2、辅助配体4,4′-二溴-2,2′-联吡啶(Br_2bpy)和阴离子六氟磷酸根(PF~-_6)合成了一种阳离子型铱配合物[Ir(F_2ppy)_2(Br_2bpy)]~+PF~-_6,并通过元素分析、核磁共振谱(NMR)、红外光谱(FT-IR)及质谱(MS)分析确定了配合物的分子结构,并且首次测定了其晶体结构。结果表明,该配合物结晶于单斜晶系,P2_1/n空间群,a=0.98612(9) nm,b=2.2240(2) nm,c=1.47121(14) nm,α=90°,β=98.574(2)°,γ=90°,V=3.1905(5) nm~3, C_(32)H_(18)Br_2F_(10)IrN_4P,分子量M_r=1031.49,密度D_c=2.147 mg·m~(-3),μ(Mo Kα)=6.831 mm~(-1),F(000)=1960,横型拟合性GOF=1.029,Z=4,可观测衍射点的残差因子R值:R_1=0.0321和wR_2=0.0741且I2σ(I)。阳离子型铱配合物[Ir(F_2ppy)_2(Br_2bpy)]~+PF~-_6为电中性八面体配合物, Ir-C键的平均长度为0.2018(3) nm,而Ir-N(C^N配体)键的平均长度为0.2052(3) nm, Ir-N(N^N配体)键的平均长度为0.2138(3) nm。该铱配合物的紫外可见吸收光谱和光致发光光谱的研究表明,其常温最大发射位于551 nm处,显示发射强烈的黄绿光,初步推测该磷光发射可能来自金属到环金属配体和辅助配体的电荷转移(MLCT)跃迁。     

INFLUENCE OF Pr_6O_(11) ON THE GAS SENSING CHARACTERISTICS OF SnO_2 SEMICONDUCTOR

This paper is to discuss the sensing characteristics of SnO_2 semiconductor components in whichPr_6O_(11) is added.When experimenting under 11 gases of CH_3COCH_3,C_2H_5OH.C_6H_5CH_3,H_2,NH_3,CO,CO_2 CH_4,C_4H_10,n—C_6H_(14)and n—C_7H_(16),we find that the components have selectivity to CH_3COCH_3,C_2H_5OH and that the ideal amount of Pr_6O_(11) in the components is about I.Owt%.The experiments also showthat with the increase of the amount of Pr_6O_(11),the ideal working temperature,the response and restorationtime decrease.     

Synthesis and thermal behavior of [Li(thf)_3(μ-Cl)La{N(SiMe_3)_2}_3] and its investigation as spin-coating precursor for lanthanum-based layer formation

The lanthanum(Ⅲ) complex [Li(thf)_3(μ-CI)La{N(SiMe_3)_2}_3](3) was obtained by the reaction of LaCl_3 with three equiv of Li[N(SiMe_3)_2]_3 in a tetrahydrofuran solution. The molecular structure of 3 in the solid state was characterized by a tetracoordinated anionic lanthanide(Ⅲ) amide in form of an adduct with LiCl(thf)_3 as evidenced by single crystal X-ray structure analysis. In order to study the suitability of 3 as a precursor for the deposition of La_2O_3/LiLaSiO4 by thin layer deposition techniques,its thermal behavior was investigated by thermogravimetry(TG) and TG-MS-coupled studies. TG studies show a two-step decomposition process, whereby volatile decomposition products can be detected during the second decomposition step. TG measurements under an atmosphere of oxygen produced La_2O_3, Calcination processes of 3 under ambient atmosphere for 10 h at 1000 ℃ gave La_2O_3 and LiLaSiO_4,which was confirmed by PXRD studies. Metal-organic 3 was applied as spin-coating precursor for La_2O_3 thin film formation giving the as-deposited layers nearly crack-free.     

Syntheses aod Crystal Structures of Rare Earth Complexes with Adamantanecarboxylic Acid, [LnL_3(HL)(H_2O)]_2·2EtOH·2H_2O (Ln=Nd (1), La (2))

Syntheses aod Crystal Structures of Rare Earth Complexes with Adamantanecarboxylic Acid, [LnL_3(HL)(H_2O)]_2·2EtOH·2H_2O (Ln=Nd (1), La (2))     

尺寸形貌可控Y(NH_4)(C_2O_4)_2·H_2O和Y_2O_3的制备及其形成机制

以硝酸、氨水、硝酸铵、商业氧化钇及草酸为初始原料,加入分散剂聚乙二醇(PEG2000)及表面活性剂十二烷基苯磺酸钠(SDBS),采用改进的草酸沉淀工艺成功制备氧化钇前驱体Y(NH_4)(C_2O_4)_2·H_2O及经随后的焙烧工艺获得最终产品Y_2O_3粉体。具体工艺中,将一定浓度的小体积Y(NO_3)_3溶液滴入大体积氨水-硝酸铵混合溶液中形成Y(OH)_3溶胶,整个滴入过程体系pH值保持稳定,然后将85℃温度下的饱和草酸溶液滴加入上述制备的Y(OH)_3溶胶中,进行沉淀转化以制备钇草酸盐前驱体Y(NH_4)(C_2O_4)_2·H_2O,继而经焙烧工艺成功制备Y_2O_3粉体。X射线衍射技术(XRD)和扫描电子显微镜(SEM)表征表明:前驱体Y(NH_4)(C_2O_4)_2·H_2O具有立方晶体结构,有轻微的团聚,经950℃焙烧2 h后,尽管失去了O,C和H,立方相Y_2O_3产品完整地保留了前驱体的形貌特征。进一步,主要通过调整表面活性剂SDBS/分散剂PEG2000质量比及改变草酸沉淀转化终点pH值来考察其对Y_2O_3产品尺寸及形貌的影响。不同条件下制备的Y_2O_3粉体扫描电子显微镜(SEM)表征表明:精确控制实验条件,特别是控制草酸沉淀转化过程终点pH值,可制备出形貌和尺寸可控的Y_2O_3粉体,当草酸沉淀转化过程中终点pH值小于1.8时,制备的Y_2O_3粉体粒径在1μm以下。另外,基于前驱体Y(NH_4)(C_2O_4)_2·H_2O在空气气氛下的差示-热重(TG-DSC)分析结果,其热分解过程应为:Y(NH_4)(C_2O_4)_2·H_2O→Y(NH_4)(C_2O_4)_2→Y_2O_2CO_3→Y_2O_3。     

Rare Earth Complexes of Aminopolycarboxylic Acid Ⅱ.Synthesis and Structure of Lanthanum Complex of Dipicolinic Acid

Complexes of the general formula,(Me_4N)_2[(Ln(HDPA)_2(DPA)]·Cl,have been synthesized,whereLn=La,Ce,Pr,Nd,Sm and H_2DPA=dipicolinic acid.Among them,the crystal structure of the La complexhas been determined by a four-circle X-ray diffractometer to a final R value of 0.080.The crystal isorthorhombic,space group Pccn with a=1.0321(1),b=1.4951(2),c=2.0766(6)nm,V=3.2044(9)nm~3,andZ=4.The rare earth ion is nine coordinated to forming a tortuous tricapped trigonal prism.     

Influence of reaction parameters on the luminescence properties of monodisperse NaGd(1−x−y)(WO4)2:xEu3+,yTb3+ phosphor by molten salt synthesis

Eu~(3+) activated and Eu~(3+), Tb~(3+) co-activated monodisperse sodium double tungstates NaGd(WO4)2 phosphors were prepared by molten salt method at 750 ℃ for 10 h using NaCl as a flux. The crystal structure and morphology of the as-synthesized phosphors were measured by XRD and SEM, respectively. The photoluminescence properties were characterized by PL spectra, decay lifetime and CIE. The presence of NaCl plays an important role in the morphology and luminescence properties. In this work,NaCl and one of the raw material Na_2 CO_3 in a certain proportion will form a low eutectic salt to decrease the reaction temperature and benefit the formation of monodisperse NaGd(WO_4)_2 crystals. The color of Eu~(3+) and Tb~(3+) co-doped NaGd(WO_4)_2 phosphors can be tuned from creamy white to orange, red and green by adjusting the doping concentration of rare earth ions, since the emission contain the broad blue-green emission origin from NaGd(WO_4)_2 host and characteristic red and green emission origin from Eu~(3+) and Tb~(3+) ions. The electroluminescent spectra and CIE measurement shows that the LED device with NaGd_((1-x))(WO_4)_2:xEu~(3+)(x = 0.24) phosphor can be excited by 365 nm and 380 nm LED chip, and their CIE coordinate is(x = 0.45, y = 0.45) and(x = 0.36, y = 0.37), Ra is 80.3 and 86.3, T_c is 3196 and4556 K, respectively. As a single-component phosphor, NaGd(WO_4)_2:Eu~(3+),Tb~(3+) have potential application in UV-pumped WLEDs.     

配位聚合物{[Nd_2(C_2O_4)_3(H_2O)_6]·3CH_3OH}_n的合成及晶体结构

采用水热法合成了稀土配位聚合物{[Nd2(C2O4)3(H2O)6].3CH3OH}n(1),得到该配合物的粉红色块状晶体,并对其进行了元素分析。用单晶x射线衍射法测得其晶体结构,属单斜晶系,空间群为P21/c,晶胞参数为:a=1.1200(2)nm,b=0.96325(17)nm,c=1.02580(18)nm,α=90°,β=114.278(3)°,γ=90°,Z=4,V=1.0088(3)nm3。配合物中钕离子为九配位,与配体结合生成蜂窝状二维层,通过氢键的连接形成了三维超分子配合物。