二丁基硫醚的合成及其萃取分离钯、铂的研究

用Na₂S·9H₂O和1-溴丁烷合成了二丁基硫醚(简写为M)。以二丁基硫醚为萃取剂进行了钯、铂萃取分离的研究,并采用正交实验,得出了钯、铂分离的最佳条件为c_M=0.344 mol·L^-1,O/A=1∶1,t=6 min,c_H⁺=2 mol·L^-1。测得二丁基硫醚萃取钯的容量大于17 g·L^{-1相似文献}   

三足七齿Schiff碱铈(Ⅲ)双核配合物的晶体结构和性质研究

制备了Schiff碱型三足体配体H₃Brapi,通过溶剂热方法合成了Ce(Ⅲ)的双核配合物[Ce(Brapi)]₂·2DMF,利用元素分析、红外光谱、紫外光谱和荧光光谱等进行了表征,并用X-射线单晶衍射测定了其晶体结构,结果表明,配合物晶体属单斜晶系,P2₁/n空间群,a=1.166 7(3) nm,b=1.348 29(3) nm,c=2.086 9(5) nm,β=96.314°,Z=2,V=3.263 0(14) nm³,D_c=1.849 Mg·m^-3,R₁=0.035 9,wR₂=0.103 6。2个配体桥联2个金属形成一种具有反演对称性的夹心式双核结构,其中每个Ce(Ⅲ)的配位环境N₄O₄都是一种四方反棱柱多面体,Ce-Ce距离为0.397 1 nm。在2～300 K范围内测定了配合物的变温磁化率,结果表明,在配合物中Ce(Ⅲ)离子间存在反铁磁性相互作用。荧光光谱分析表明,配合物的荧光属于L*-L跃迁的发光类型。     

3，5-二硝基苯甲酸镉配合物的合成、晶体结构、热稳定性和荧光性质

以3,5-二硝基苯甲酸,咪唑为配体,合成了新化合物[Cd(H₂O)₂(DNBA)(Im)₂](DNBA)·H₂O,(DNBA=3,5-二硝基苯甲酸阴离子)。该配合物属正交晶系,空间群为Ccc2,晶胞参数：a=1.324 99(4) nm,b=1.516 01(5) nm,c=2.789 22(8) nm;V=5.602 7(3) nm³,D_c=1.719 g·cm^-3,Z=8,μ=0.866 mm^-1,F(000)=2 912,最终偏离因子R₁=0.058 3,wR₂=0.146 4。该配合物中包含两个单核镉(Ⅱ)配合物,且配合物中还包含未配位的3,5-二硝基苯甲酸,金属中心均是六配位变形八面体结构。并测定和研究了标题化合物的热重和荧光性能。     

二维层状结构十钒酸盐[K(H2O)2Ni(H2O)6]2[V10O28]的合成及性质(英)

A novel heteropoly compound, containing two kinds of coordinated cations, [K(H₂O)₂Ni(H₂O)₆]₂[V₁₀O₂₈], has been synthesized through routine process and characterized by elemental analyses, IR, ⁵¹V NMR and single crystal X-ray diffraction. It crystallizes in the triclinic system, space group P1 with a=0.87382(17) nm, b=1.075 4(2) nm, c=1.111 1(2) nm, α=65.10(3)°, β=75.01(3)°, γ=70.63(3)°, V=0.884 8(3) nm³ and Z=1. The X-ray analysis reveals that the two kinds of coordinated cations are linked by three shared coordinated water molecules, and K⁺ cations coordinate with ten oxygen atoms: five of which come from V₁₀O₂₈^6- anion, the other five from water molecules. The title compound exhibits extended 2D array building up of V₁₀O₂₈^6- groups connected by ten-coordinated K⁺ cations. The hexahydrated nickel cations Ni(H₂O)₆²⁺ lie in neat apposition to three adjacent V₁₀O₂₈^6- clusters. CSD: 413271.     

两个基于2-氨基-5-巯基-1,3,4-噻二唑乙酸的稀土配合物的合成、晶体结构和性质研究

用2-氨基-5-巯基-1,3,4-噻二唑乙酸(Hatma)为配体合成出2种新型同构的稀土配合物[Ln(atma)₃(H₂O)₂]_n(Ln=La(1),Nd(2))。配体和2个配合物的结构均由X-射线单晶衍射法确定,同时对配合物进行了IR,TGA及元素分析。单晶结构表明,配体属单斜晶系,C2/c空间群,晶胞参数为a=2.1419(9)nm,b=0.40076(17)nm,c=1.7500(8)nm,V=1.4950(11)nm³,Z=4;配合物1和2的晶体都属于三斜晶系,空间群为P1,配合物1的晶胞参数为a=0.8820(3)nm,b=1.2306(4)nm,c=1.2586(4)nm,V=1.2913(7)nm³,Z=2;配合物2的晶胞参数为a=0.8834(4)nm,b=1.2283(5)nm,c=1.2510(5)nm,V=1.2821(9)nm³,Z=2。2个配合物均形成一维链状空间结构,通过丰富的氢键连接形成三维超分子结构。抗菌试验表明,配合物比配体表现出更好的生物活性。初步的植物生长实验表明,配合物对油菜和小麦的生长具有一定的促进作用。     

2-(4-甲基苯甲酰基)苯甲酸构筑的锰(Ⅱ)配合物的晶体结构、电化学、荧光及磁性研究

以2-(4-甲基苯甲酰基)苯甲酸(HL)为配体合成了一个新的锰((Ⅱ)配合物Mn(L)₂(2,2'-bipy)₂。该配合物晶体属单斜晶系,空间群P2₁/c,晶胞参数：a=1.7198(2)nm,b=1.03980(14)nm,c=2.3463(3)nm,β=95.732(3)°,V=4.1748(9)nm₃,D_c=1.346g·cm^-3,Z=4,μ(MoKα)=0.373mm^-1,F(000)=1756,最终偏离因子R₁=0.0423,wR₂=0.0949。标题配合物的中心锰(Ⅱ)离子处于变形的八面体配位环境中。测定了配合物的电化学、荧光和磁性。结果表明：在循环伏安过程中,配合物的电子转移是准可逆的,对应的电极反应是Mn(Ⅲ)/Mn(Ⅱ);配合物在536~556nm之间有一个较强的荧光发射峰;在300~2K,配合物有反铁磁性。     

三缺位杂多阴离子α-A-PW9O349-的甲基硅衍生物(TBA)3[α-A-PW9O34(CH3SiO)3(CH3Si)]的合成和晶体结构

Reaction of the trivacant heteropolyanions α-A-PW₉O₃₄^9- with CH₃SiCl₃ leads to the formation of the organosilyl derivative (TBA)₃[α-A-PW₉O₃₄(CH₃SiO)₃(CH₃Si)]. The crystal X-ray diffraction analysis shows that the crystal belongs to orthorhombic with space group Pca2₁, M=3177.09 and the unit cell parameters: a=25.761(5)?,b=14.519(3)?,c=24.396(5)?.V=9124(3)?³,Z=4,D_c=2.225g·cm^-3,μ(MoKα)=11.438mm^-1,F(000)=5464,R=0.0561,R_w=0.0866. The anion consists of one α-A-PW₉O₃₄^9- anion linked by three CH₃SiO⁺ groups, which attached to the fourth CH₃Si through three Si-O-Si bridges.     

共轭二茂铁席夫碱配合物的制备和电化学性质研究

合成了2个共轭二茂铁席夫碱配合物，用元素分析、红外光谱、紫外光谱、核磁共振等对它们进行了表征及电化学性质 研究，并用X射线衍射测定了它们的晶体结构。配合物1存在反演中心，其晶体属单斜晶系，P2₁/c空间群。晶体学数据为：a=1.148 5(2) nm，b=0.857 75(17) nm，c=1.194 4(2) nm，β=99.980(5)°,V=1.158 8(4) nm³,Z=2，μ=1.499 mm^-1,D_c=1.562 g·cm^-3，R₁=0.068 9，wR₂=0.128 0。     

Ni(Ⅱ)，Cu(Ⅱ)-邻菲咯啉-对甲苯磺酰牛磺酸配合物的合成、表征及其晶体结构

由过渡金属、邻菲咯啉与对甲苯磺酰牛磺酸反应，得到两种新型配合物[Ni(phen)₃]·2TsTausH·H₂O (1)与[Cu(phen)₂·Cl]·TsTausH·H₂O (2)(phen：邻菲咯啉；TsTausH: 对甲苯磺酰牛磺酸)，进行了元素分析、红外光谱、X射线衍射等表征。X射线衍射结果表明，配合物1属单斜晶系，空间群为Cc，晶胞参数为：a=2.917 6(4) nm，b=1.041 48(15) nm，c=2.128 7(3) nm，β=126.162(3)°，V=5.222 1(13) nm³，Z=4，D_c=1.486 g·cm^-3，μ=0.602 mm^-1，F(000)=2 440；配合物2也属单斜晶系，空间群为P2₁/c，晶胞参数为：a=1.113 70(16) nm，b=2.472 6(4) nm，c=1.185 87(18) nm，β=93.355(3)°，V=3.260 0(8) nm³，Z=4，D_c=1.540 g·cm^-3，μ=0.934 mm^-1，F(000)=1 556。同时讨论了体系中不同配位原子配位能力的差异及比较两种新型配合物的异同。     

环己基甲酸镧配合物的合成与晶体结构的研究

本文合成了环己基甲酸镧配合物La(C₆H₁₁COO)₃·(C₆H₁₁COOH)·1.5H₂O，晶体属三斜晶系，P1空间群，晶胞参数：a=15.331(4)?,b=15.555(4)?, c=16.833(5)?;α=105.48(2)°, β=96.48(2)°, γ=110.21(2)°, V=3536.9(14)?³; Z=4, D_c=1.269 g/cm³。经全矩阵最小二乘法修正，最终偏差因子R为0.0627。晶体中镧原子之间分别由两个和三个羧基桥连，形成链状聚合分子，镧原子的配位数为10，配合物为变形的双帽四方反棱柱构型。     

Luminescent core–shell Fe3O4@Gd2O3:Er3+, Li+ composite particles with enhanced optical properties

Bifunctional magneto-optical nanocomposites with Fe₃O₄ nanoparticles as a core and erbium and lithium codoped gadolinium (Gd₂O₃:Er³⁺, Li⁺) as the shell were synthesized successfully using a simple urea homogeneous precipitation method. The fabricated Fe₃O₄@Gd₂O₃:Er³⁺, Li⁺ particles were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy and quantum design vibrating sample magnetometry. The upconversion emission intensity was enhanced significantly comparing to that without Li⁺ ions. These bifunctional composites are expected to be potentially applied for drug delivery, cell separation and bioimaging.     

尖晶石型LiMn2O4晶体结构及锂离子筛H+/Li+交换性质研究

采用密度泛函理论平面波超软赝势和广义梯度近似法对尖晶石型LiMn2O4及其锂离子筛HMn2O4的晶体结构和性质进行了从头计算。PW91泛函最为有效,Li+被H+取代后HMn2O4晶胞收缩,点阵常数从LiMn2O4的0.823 nm减小至0.799 nm,其XRD峰也相应向高角度方向明显位移。经同种格点原子的XRD分析表明,Mn、O两元素对XRD方式和强度起着决定作用。其中Li呈+1价完全离子化,可被H+彻底交换,H与周围O在等电子密度图中呈现电子云相互连接,只带有0.42个正电荷。价轨道分态密度表明,Mn-O之间强的共价键合主要归因于Mn-d和O-p在费米能级下-7.3~-1.6 eV间的轨道重叠,形成了有利于H+/Li+交换的骨架空穴隧道。阵点和空穴多面体的体积遵守如下顺序:V8a>V48f>V8b、V16c>V16d、V16c>V48f。Li+最易迁移至邻近的16c位置,碱金属离子的交换受到离子半径和作用能大小的限制。     

Structural and Electrochemical Study of Vanadium‐Doped TiO2 Ramsdellite with Superior Lithium Storage Properties for Lithium‐Ion Batteries

Titanium‐oxide‐based materials are considered attractive and safe alternatives to carbonaceous anodes in Li‐ion batteries. In particular, the ramsdellite form TiO₂(R) is known for its superior lithium‐storage ability as the bulk material when compared with other titanates. In this work, we prepared V‐doped lithium titanate ramsdellites with the formula Li_0.5Ti_1?xV_xO₂ (0≤x≤0.5) by a conventional solid‐state reaction. The lithium‐free Ti_1?xV_xO₂ compounds, in which the ramsdellite framework remains virtually unaltered, are easily obtained by a simple aqueous oxidation/ion‐extraction process. Neutron powder diffraction is used to locate the Li channel site in Li_0.5Ti_1?xV_xO₂ compounds and to follow the lithium extraction by difference‐Fourier maps. Previously delithiated Ti_1?xV_xO₂ ramsdellites are able to insert up to 0.8 Li⁺ per transition‐metal atom. The initial gravimetric capacities of 270 mAh g^?1 with good cycle stability under constant current discharge conditions are among the highest reported for bulk TiO₂‐related intercalation compounds for the threshold of one e^? per formula unit.     

Reduction Processes in the Course of Mechanochemical Synthesis of Li1+xV3O8

Mechanical activation (MA) of the LiOH+V₂O₅ and Li₂CO₃+V₂O₅ mixtures followed by brief heating at 673 K was used to prepare dispersed Li_1+xV₃O₈. It was shown that structural transformations during MA are accompanied by reduction processes. EPR spectra of Li_1+xV₃O₈ are attributed to vanadyl VO²⁺ ions with weak exchange interaction. The interaction of localized electrons (V⁴⁺ ions) with electron gas (delocalized electrons), which is exhibited through the dependence of EPR line width of vanadium ions versus measurement temperature (C–S–C relaxation), is revealed. It is shown that C–S–C relaxation is different for intermediate and final products. The properties of mechanochemically prepared Li_1+xV₃O₈ are compared with those of HT-Li_1+xV₃O₈, obtained by conventional solid state reaction. Mechanochemically prepared Li_1+xV₃O₈ is characterized by a similar amount of vanadium ions, producing electron gas, but a higher specific surface area.     

Lithium insertion compounds of LiFe5O8, Li2FeMn3O8, and Li2ZnMn3O8

Lithium insertion reactions of the lithium spinels Fe[Li_0.5Fe_1.5]O₄, Li_0.5Zn_0.5[Li_0.5Mn_1.5]O₄ and Li [Fe_0.5Mn_1.5]O₄ by n-butyl lithium or electrochemically yield Li_2.5Fe_2.5O₄, Li₂Zn_0.5Mn_1.5O₄, and Li₂ Fe_0.5Mn_1.5O₄, respectively. It is shown that the [B₂]O₄ framework of the A[B₂]O₄ spinel structure remains intact upon lithium insertion, and provides a three-dimensional interstitial pathway for Li⁺ ion diffusion. Lithium insertion is completely reversible in the normal lithium spinel LiFe_0.5Mn_1.5O₄; delithiation of Li_2.5Fe_2.5O₄ results in Li_1.5Fe_2.5O₄ and none of the inserted lithium may be removed from the mixed lithium spinel Li₂Zn_0.5Mn_1.5O₄. Physicochemical properties including electrical resistivity, magnetic susceptibility, and Mössbauer spectra of the hosts and their lithiated analogs are discussed.     

Unusual valences and fast electron exchange in MoFe2O4

The distribution of d electrons over the cations in MoFe₂O₄, which is represented by the formal valence assignment, is shown to be complicated by the equilibrium reactionsFe²⁺_B+Fe³⁺_A+Mo³⁺Fe³⁺_B+Fe²⁺_A+Mo⁴⁺We have used thermal treatment to confirm that the Mo are primarily on octahedral sites; Fe_A[Mo_BFe_B]O₄. K-shell absorption and Mössbauer data at T = 423 K > T_c demonstrate that the iron has an average valence near 2.5+ with fast electron transfer (τ_h < 10⁻⁸ sec) on both octahedral and tetrahedral sites. Paramagnetic susceptibility data give a Curie constant C_M = 7.95 ± 0.2 emu/mole and a Weiss constant θ_p = −445 K; magnetometer measurements confirm a compensation point near 160 K. Transport data give a surprisingly high electronic conductivity, but also give an activated mobility similar to that found in AlFe₂O₄ and CrFe₂O₄ where mixed Fe^3+/2+ valences on both A and B sites have been demonstrated. However, a positive Seebeck coefficient and a preexponential factor one order of magnitude higher in MoFe₂O₄ point to involvement of a fraction of the Mo atoms in electronic transport, which would be consistent with the observation of a τ_h < 10⁻⁸ sec on the A sites of a spinel. An energy diagram consistent with these data and other information about the relative redox potentials of these ions in oxides are proposed for this system.     

Lithium vanadate Li3+xV6O13 at low temperature

The structure of Li_3+xV₆O₁₃ [x = 0.24 (3)] at 95 K has been solved and refined using single‐crystal X‐ray diffraction. The refined lithium content corresponds to two fully occupied Li sites and one partially occupied Li site. A doubling of the c axis is observed upon cooling from room temperature, and this change is associated with shifts of the V atoms. The resulting space group is C2/c. The Li disorder present in the Li₃V₆O₁₃ phase at room temperature is also observed in the low‐temperature phase reported here.     

Reversibility of the lithium—vanadium bronze structure when cycled

Positive electrodes of secondary lithium batteries, based on Li^{1 + x}V₃O₈ obtained by the alcoxytechnology, are studied. As lithium intercalates, the initial crystalline bronze turns amorphous, remaining single-phase. An increase in the lithiation degreex leads to an almost linear decrease in parametera and increase in parametersb andc of the bronze crystal lattice; the changes are quite reversible when cycling. A noticeable degradation of electric characteristics of electrodes is unrelated to irreversible structural changes and may be explained by the formation of passive films on the bronze surface.     

Salt catalyzed heterogeneous dilute acid hydrolysis of the difficultly accessible portion of cellulose: Effect of nature of metal co-ion

The effect of nature of metal co-ion on the rate of hydrolysis, V_c, of the difficulty accessible portion of cellulose was investigated for Li⁺, Na⁺, K⁺, and Ca²⁺. For the univalent ions V_c decreases exponentially with an increase in ionic radius for a given concentration of co-ion. For Ca²⁺, V_c is lower than would be predicted on the basis of ionic radius. This is attributed to the increased charge and/or increased degree of hydration. For the univalent ions the data presented suggest V_c increases sharply with concentration up to 0.25M, while for Ca²⁺, V_c increases more gradually up to 2.25M, before V_c begins to drop.     

Mössbauer study of the FeV2O4---Fe3O4 system

Mössbauer spectra of the Fe_1+xV_2−xO₄ spinel solid solutions are taken to investigate the cation distribution. Room temperature spectra can be interpreted by assuming that the cation distribution is represented approximately as Fe²⁺[Fe³⁺_xV³⁺_2−x]O₄ for 0 x 0.35 and Fe³⁺[Fe²⁺Fe³⁺_x−1V³⁺_2−x]O₄ for 1 x 2 and the ionic valence arrangement changes from the 2-3-3 type (Fe²⁺[Fe³⁺_xV³⁺_2−x]O₄) to the 3-2-3 one (Fe³⁺[Fe²⁺V³⁺]O₄) in the range 0.35 x 1. Fe₂VO₄ is found to be 3-2-3 spinel, Fe³⁺[Fe²⁺V³⁺]O₄. Its paramagnetic spectrum at 473°K is, however, composed of a broad single line with isomer shift value of 0.61 mm/sec relative to stainless steel, in which the line splitting due to the ferric and ferrous ions is rendered indistinguishable.