Structure characterization and physical properties of a complex with supramolecular architectures Co-2(2,6-DPC2Co(H2O)5 center dot 2H(2)O (DPC=2,6-pyridinedicarboxylate)

Reaction of 2,6-pyridinedicarboxylic with CoCl2 . 6H(2)O in aqueous solution give rise to a three-dimensional Complex CO2(2,6-DPC)(2)Co(H2O)(5).2H(2)O (DPC = 2,6-pyridinedicarboxylate) 1. It has been characterized by elemental analyses, infrared spectra (IR) spectrum, thermogravimetric (TG) analysis, EPR spectrum, and single crystal X-ray diffraction. The complex crystallizes in the P2(1)/c space group with a = 8.3906(3) Angstrom, b = 27.4005(8) Angstrom, c = 9.6192(4) A, alpha = 90.00degrees, beta = 98.327(2)degrees, gamma = 90.00degrees, V = 2188.20(14) Angstrom(3), Z = 4. There are two types of cobalt environments: Co(1) is coordinated by four oxygen atoms from four carboxyl groups and two nitrogen 2 atoms which are all from pdc(2). Co(2) is coordinated by six oxygen atoms, five from coordinated water molecules and one from a carboxyl of pdc(2) - of which the other oxygen atom is linked to the Co(1). The extensive intermolecular hydrogen bonds are formed in the crystal by means of the five coordinated water molecules.

Self-immobilized titanium and zirconium catalysts with phenoxy-imine ligands for ethylene polymerization. X-ray crystal structure of bis(N-(3-tert-butylsalicylidene)-4 '-allyloxyanilinato) zirconium(IV) dichloride

Four self-immobilized FI catalysts with allyl substituted phenoxy-imine ligands [{4-(CH2=CHCH2O)C6H5N=CH-C6H3(3-tert-C4H9)O}(2) MCl2] (1: M = Ti: 2: M = Zr), [{3-(CH2=CHCH2O)C6H5N=CH-C6H3(3-tert-C4H9)O}(2)MCl2] (3: M = Zr), [{4-(CH2=CHCH2-2,6-(iso-C3H7)(2))C6H5N=CH-C6H3(3,5-(NO2)(2))O}(2)MCl2] (4: M = Zr) have been synthesized and characterized. The molecular structure of 2 has been determined by X-ray crystallographic analysis. The results of ethylene polymerization showed that the self-immobilized titanium (IV) and zirconium (IV) catalysts 1-3 kept high activity for ethylene polymerization and 4 showed no activity. SEM showed the immobilization effect could greatly improve the morphology of polymer particles to afford micron-granula polyolefin as supported catalysts.

The structure and electrochemical characteristics of La0.67Mg0.33 (Ni0.8Co0.1Mn0.1)(x) (x=2.5-5.0) multiphase alloys for nickel-metal hydride batteries

This paper presents results concerning structure and electrochemical characteristics of the La0.67Mg0.33 (Ni0.8Co0.1Mn0.1) (x) (x=2.5-5.0) alloy. It can be found from the result of the Rietveld analyses that the structures of the alloys change obviously with increasing x from 2.5 to 5.0. The main phase of the alloys with x=2.5-3.5 is LaMg2Ni9 phase with a PuNi3-type rhombohedral structure, but the main phase of the alloys with x=4.0-5.0 is LaNi(5)phase with a CaCu5-type hexagonal structure. Furthermore, the phase ratio, lattice parameter and cell volume of the LaMg2Ni9 phase and the LaNi5 phase change with increasing x. The electrochemical studies show that the maximum discharge capacity increases from 214.7 mAh/g (x=2.5) to 391.1 mAh/g (x=3.5) and then decreases to 238.5 mAh/g (x=5.0). As the discharge current density is 1,200 mA/g, the high rate dischargeability (HRD) increases from 51.1% (x=2.5) to 83.7% (x=3.5) and then decreases to 71.6% (x=5.0). Moreover, the exchange current density (I-0) of the alloy electrodes first increases and then decrease with increasing x from 2.5 to 5.0, which is consistent with the variation of the HRD. The cell volume reduces with increasing x in the alloys, which is detrimental to hydrogen diffusion and accordingly decreases the low-temperature dischargeability of the alloy electrodes.

Syntheses and properties of novel polyimides derived from 2-(4-aminophenyl)-5-aminopyrimidine

2-(4-Aminophenyl)-5-aminopyrimidine (4) is synthesized via a condensation reaction of vinamidium salts and amidine chloride salts, followed by hydrazine palladium catalyzed reduction. A series of novel homo- and copolyimides containing pyrimidine unit are prepared from the diamine and 1,4-phenylenediamine (PDA) with pyromellitic dianhydride (PMDA) or 3,3',4,4'-biphenyl tertracarboxylic dianhydride (BPDA) via a conventional two-step thermal imidization method. The poly(amic acid) precursors had inherent viscosities of 0.97-4.38 dL/g (c = 0.5 g/dL, in DMAc, 30 degrees C) and all of them could be cast and thermally converted into flexible and tough polyimide films. All of the polyimides showed excellent thermal stability and mechanical properties. The glass transition temperatures of the resulting polyimides are in the range of 307-434 degrees C and the 10% weight loss temperature is in the range of 556-609 degrees C under air. The polyimide films possess strength at break in the range of 185-271 MPa, elongations at break in the range of 6.8-51%, and tensile modulus in the range of 3.5-6.46 GPa. The polymer films are insoluble in common organic solvents, exhibiting high chemical resistance.

BaLiF_3∶Ce~(3+)纳米粒子的制备及其光谱特性

BaLiF3属立方钙钛矿型复合氟化物,作为高效闪烁晶体可用于热中子检测[1].由于其能带隙宽,易于实现各种不同价态稀土离子掺杂,可以获得许多可调谐性质,因此它也是比较理想的光学功能材料的基质[2].Ce3+激活的BaLiF3晶体作为紫外发射的短波固体激光材料和光放大材料的研究多有报道[3~5].Ce3+的发射特性强烈依赖于基质晶体结构[6,7].氟化物基质中氧杂质的含量是影响光谱性质的重要因素[8].为了寻找氧含量低、发射波长更短、可调谐范围更宽的激光材料,本工作制备了BaLiF3∶Ce3+纳米晶,获得了一些新的有意义的实验结果.如果将其引入合适的聚合物基体制备出纳米复合体系,有可能为新一代杂化激光材料提供更理想的光学活性组分[9].1实验部分1.1仪器用日本R igaκu D/maxⅡB型X射线衍射仪(XRD)测量样品的晶体结构,辐射源CuKα1(λ=0·154 1 nm);用日本H itachi S-570环境扫描电子显微镜(ESEM)观察样品的形貌和粒径大小;用日立F-4500荧光光谱仪测试样品的激发和发射光谱;用英国VG公司ESCALAB MKⅡX射线电子能谱仪(XPS)检测样品的含氧量.1.2实验过...

BaLiF_3∶Eu,Gd中Gd~(3+)→Eu~(2+)的能量传递

研究了 Ba Li F3中 Gd3+和 Eu2 +的光谱性质及 Gd3+对 Eu2 +的能量传递过程 ,讨论了传递机理 .Gd3+的含量 (物质的量分数 )为 0 .3 %时 ,传递效率最高 ,传递几率 PSA=1 .3 5× 1 0 5s- 1 .当 Gd3+的含量高于 0 .3 %时 ,由于 Gd3+ 和 Eu2 + 竞争吸收 Gd3+ 占优势 ,增加 Gd3+ 含量 ,竞争吸收比相应增加 ,Eu2 + 自身吸收光子数目减少 ,发射强度降低

Eu~(2+),Dy~(3+)共掺杂硼铝锶长余辉玻璃陶瓷

首次介绍了一种新型长余辉材料 :Eu2 + ,Dy3 + 共掺杂硼铝锶长余辉玻璃陶瓷 ,该玻璃陶瓷用紫外灯、日光、荧光灯均可激发 ,发射黄绿色余辉 ,余辉的发射峰位于 5 16nm ,来自于Eu2 + 的 5d→ 8S7/ 2 跃迁。用12 0 0 0lx的荧光灯激发样品 2 0分钟 ,停止激发后 10秒时 ,该玻璃陶瓷的余辉亮度为 3 5 3cd/m2 ,色坐标为 :x =0 2 84 2 ,y =0 5 772 ;停止激发后 5小时 5 5分钟 ,该玻璃陶瓷的余辉亮度为 0 0 1cd/m2 ;停止激发 30小时后 ,余辉在黑暗中仍肉眼可见。文中对该玻璃陶瓷的相关性质进行了表征 ,并提出了可能的长余辉机理

A chromic molybdenum phosphate with a tunnel structure: hydrothermal synthesis and structure of (NH3CH2CH2NH3)(2) center dot (NH3CH2CH2NH2)(3)center dot[NaCr2Mo12O30(PO4)(HPO4)(4)(H2PO4)(3)]center dot 6H(2)O

A chromic molybdenum phosphate, (NH3CH2CH2NH3)(2).(NH3CH2CH2NH2)(3).[NaCr2Mo12O30(PO4)(HPO4)(3)]. 6H(2)O, involving molybdenum present in V oxidation, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction and IR spectrum. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a = 12.067(2), b = 14.677(3), c = 21.290(2) Angstrom, alpha = 80.940(10)degrees, beta = 82.960(10)degrees, gamma = 76.61(2)degrees. The structure of the title compound may be considered to be two [Mo6O15(HPO4)(H2PO4)(3)](5-) units bonded to a chromic atom, although several P-O groups are not protonated on account of coordination with a Na+ cation. The one-dimensional tunnels were formed in the solid of the title compound. (C) 2000 Elsevier Science B.V. All rights reserved.

A nickel molybdenum phosphate with tunnel: Hydrothermal synthesis and structure of (NH3CH2CH2NH3)(4)center dot(NH3CH2CH2NH2)center dot Na center dot[Ni2Mo12O30(PO4)(HPO4)(4)(H2PO4)(3)]center dot 6H(2)O

A nickel molybdenum phosphate, (NH3CH2CH2NH3)(4).(NH3CH2CH2NH2). Na .[Ni2Mo12O30(PO4)(HPO4)(4)(H2PO4)(3)]. 6H(2)O, invoicing molybdenum present in V oxidation, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a = 12,011(2), b = 14,612(3), c = 21.252(4) Angstrom, alpha = 80.54(2)degrees, beta = 83.10(2)degrees, gamma = 76.29(2)degrees, V = 3561.4(12) Angstrom(3), Z = 2, lambda(MoK alpha) = 0.71073 Angstrom (R(F) = 0.0529 for 9880 reflections), Data mere collected on a Siemens P4 diffractometer at 20 degrees C in the range of 1.75 degrees < theta < 23.02 degrees using the omega-scan technique. The structure was solved by direct methods using the program SHELXTL-93 and refined with the method of fun-matrix least-squares on F-2. The structure of the title compound may be considered to be two [Mo6O15(HPO4)(H2PO4)(3)](5-) units bonded together with a nickel atom, although several P-O groups are not protonated on account of coordination with a Na+ cation, The one-dimensional tunnels were formed in the solid of the title compound. A probe reaction of the oxidation of acetaldehyde with H2O2 using the title compound as catalyst was carried out in a liquid- solid system, showing that the title compound had high catalytic activity in the reaction, (C) 1999 Academic Press.

La~(3+)和Gd~(3+)对鼠肝癌H-35细胞Ca~(2+)内流的影响

通过测定 4 5Ca2 +摄取初速度的变化研究了La3+和Gd3+对鼠肝癌H 3 5细胞Ca2 +内流的影响 .发现低浓度La3+和Gd3+能增加肝癌H 3 5细胞Ca2 +内流初速度达 6～ 10倍 .Ca2 +内流的初速度随Ca2 +浓度变化的动力学研究表明 ,肝癌H 3 5细胞中存在 2类Ca2 +亲和部位的通道 ,即高亲和位和低亲和位Ca2 +内流通道 ,而La3+和Gd3+刺激的肝癌H 3 5细胞则只有 1类Ca2 +亲和位通道 ,La3+和Gd3+增加高亲和位Ca2 +结合通道的Km和Vmax,而对于低亲和位的Ca2 +结合通道Ca2 +内流的作用是竞争性的.

Structure/permeability and permselectivity relationship of polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride .2.

Gas permeability coefficients of a series of aromatic polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) with various aromatic diamines, to H-2, O-2 and N-2 have been measured under 7 atm and at the temperature range 30-100 degrees C. A significant change in the permeability and permselectivity resulting from the systematic variation in chemical structure of the polyetherimides was found. Among the polyetherimides, that were prepared from phenylenediamine and methyl substituted phenylenediamines, the increase of permeability is accompanied by a decrease of permselectivity. The polyetherimides that were prepared from 3,5-diaminobenzoic esters have lower permselectivity than the others. However, the polyetherimide from 3,5-diaminobenzoic acid possesses much higher permselectivity than the others due to cross-linking. Copyright (C) 1996 Elsevier Science Ltd

钴与5－Cl－PADAB反应机理及其应用的研究

对钴与４－［（５－氯－２－吡啶）偶氮］－１，３－二氨基苯（５－Ｃｌ－ＰＡＤＡＢ）形成络合物的吸收光谱进行探讨，结果表明：试剂及络合物在不同酸度条件下形成不同型体。在酸性条件下，络合物为大阳离子，钴离子以三价形式存在，钻与试剂的络合比为１：２。在强酸性介质中，将此络合物用于光度测定钻，方法选择性及稳定性好，且灵敏度极高。对水、粮食、土壤、茶叶及维生素Ｂ＿（１２）中微量钻进行直接测定，获得满意结果。

α-羰基烯酮式环二硫代缩醛化学(V)——β,β-1,3-亚丙二硫基-α,β-不饱和芳酮类化合物的合成

β,β-二烷硫基-α,β-不饱和酮类化合物作为一类具多反应中心的活泼中间体在有机合成中的应用,近20年来已引人注目并进行了深入广泛的研究~[1,2].以往的研究大多是针对β,β-二甲硫基-α,β-不饱和酮类化合物1进行的,而对结构相近的β,β-1,3-亚丙二硫基-α,β-不饱和酮类化合物2的研究较少.对于1类的合成,所用碱的选择至关重要~[1].实验证明叔丁醇钠和叔丁醇钾~[3～5]在1类的合成中效果较好.前文~[6]曾以六甲基二硅氨基锂(LHMDS)为碱高

铕和铽与3,4-呋喃二甲酸双核配合物的合成、表征及其晶体结构

本文首次合成了铕(Ⅲ)和铽(Ⅲ)与3,4-呋喃二甲酸配合物,研究了它们的IR、DTA、TG、DTG和荧光光谱等性质,并完成了单晶的晶体分析。结果表明,配合物为〔Ln·HL_2(H_2O)_2〕_2·2H_2O(Ln=Eu(Ⅲ),Tb(Ⅲ);H_2L=3,4-呋喃二甲酸),属单斜晶系,P2/c空间群,Z=2,晶胞参数对铕和铽配合物分别为α=10.842(1),10.801(4);b=8.725(2),8.664(2);c=16.366(4),16.308(6)A;β=93.50(1),93.67(3)°;V=1545.3(5),1523.0(8)A~3。

Development of the East Asian summer monsoon: Evidence from the sediment record in the South China Sea since 8.5 Ma

128 samples from Ocean Drilling Program (ODP) Site 1143 in the southern South China Sea were analyzed for grain size, clay minerals, biogenic opal content and quartz in order to reconstruct changes in East Asian monsoon climate since 8.5 Ma. An abrupt change of terrigenous mass accumulation rate (MAR), clay mineral assemblage, median grain size and biogenic opal MAR about 5.2 Ma suggests that between 8.5-5.2 Ma the source of terrigenous sediment was mainly in the region of surface uplift and basaltic volcanism in southern Vietnam. A simple model of East Asian summer monsoon evolution was based on the clay/feldspar ratio, kaolinite/chlorite ratio and biogenic opal MAR. The summer monsoon has two periods of maximum strength at 8.5-7.6 Ma and 7.1-6.2 Ma. Subsequently, there was a relatively stable period at 6.2-3.5 Ma, continued intensification about 3.5-2.5 Ma, and gradually weakening after 2.5 Ma. Since I Ma the monsoon has intensified, with remarkable high-frequency and amplitude variability. Simultaneous increase in sedimentation rates at ODP Sites 1143, 1146 and 1148, as well as in MAR of terrigenous materials, quartz, feldspar and clay minerals at ODP Site 1143 at 3.5-2.5 Ma, may be the erosional response to both global climatic deterioration and the strengthening of the East Asian summer monsoon after about 3-4 Ma. (c) 2006 Elsevier B.V. All rights reserved.