261 resultados para Aisberg-2-2004-1


Relevância:

100.00% 100.00%

Publicador:

Resumo:

A novel 3D supramolecular assembly constructed from decavanadate and caffeine building blocks, (NH4)(2)(C8H10N4O2)(4)[H4V10O28].2H(2)O (1), has been synthesized in aqueous solution and characterized by elemental analysis, IR, H-1 NMR, V-51 NMR, TG-DTA, and single crystal X-Ray diffraction. The compound 1 crystallizes in monoclinic system, space group P2(1)/n, a = 15.801(1) Angstrom, b = 12.914(1) Angstrom, c = 15.913(2) Angstrom, beta = 113.55degrees, V = 2976.4 (5) Angstrom(3), Z = 2, R = 0.0498 with 6818 reflections. Water molecules, ammonium ions, and caffeine act as "cement" linking the polyanions into 1D chain along the c-axis by hydrogen bonding. In compound 1, extensive hydrogen-bond contacts and strong pi-pi interactions lead to an ordered 3D supramolecular framework. TG-DTA curves indicate that the weight loss of the complex can be divided into three stages.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Reactions of freshly prepared M(OH)(2-2x)(CO3)(x) (.) yH(2)O (M = Mn, Zn) and 4,4'-bipyridine (bpy) with succinic acid (H2L) or famaric acid (H2L') in CH3OH-H2O afforded [Mn(H2O)(4)(bpy)]L (.) 4H(2)O, 1, [Mn(H2O)(4)(bpy)]L' (.) 4H(2)O, 2 and [Zn(H2O)(4)(bpy)]L (.) 4H(2)O, 3. The three coordination polymers are isostructural and consist of (1)(infinity)[M(H2O)(4)(bpy)(2/2)](2+) cationic chains, crystal H2O molecules and dicarboxylate anions (succinate or fumarate anions). Within the chains, the metal atoms are each octahedrally coordinated by four aqua oxygen atoms and two pyridyl nitrogen atoms from two 4,4'-bipyridine ligands. The crystal H2O molecules are hydrogen bonded to dicarboxylate anions to form ribbon-like anionic chains. The cationic and anionic chains are interconnected via hyqrogen bonds to generate a 3D network. Crystal data: 1 triclinic, P (1) over bar, a = 7.235(1), b = 7.749(2), c = 10.020(2) Angstrom, alpha = 79.95(3), beta = 88.79(3), gamma = 71.39(3)degrees, V = 523.9(2) Angstrom(3) and D-cal = 1.494 g cm(-3) for Z = 1; 2 triclinic, P (1) over bar, a = 7.127(1), b = 7.800(2), c = 9.945(2) Angstrom, alpha = 80.26(3), beta = 87.86(3), gamma = 72.69(3)degrees, V = 520.2(2) Angstrom(3) and D-cal = 1.498 g cm(-3) for Z = 1; 3 triclinic, P (1) over bar, a = 7.189(1), b = 7.764(2), c = 9.843(2) Angstrom, alpha = 79.16(3), beta = 87.80(3), gamma = 71.29(3)degrees, V = 510.9(2) Angstrom(3) and D-cal = 1.559 g cm(-3) for Z = 1.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Electroluminescence (EL) devices with Eu(HTH)(3)phen [HTH: 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione, phen: I 10-phenanthroline] as an emissive centre were fabricated using vacuum evaporation. In addition to the Eu3+ 5D0 --> F-7(J) (J = 0-4) lines that were visible in the photoluminescence signal, the device also showed strong emission from the D-5(1) --> F-7(J) (J = 0-4) transitions. The enhanced emission from the D-5(1) F-7(J) (J = 0-4) transitions was attributed to the increased excitation intensity in the EL device. The luminescence lifetimes of the 5 D, and 5 Do levels were measured to be 0.6 mus and 866 mus, respectively.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

研究了 1 苯基 3 甲基 4 苯甲酰基 -吡唑酮 5 (HPMBP)和中性有机磷 (膦 )类萃取剂Cyanex 4 71X(TIBPS ,B)在硝酸介质中对稀土元素La 的萃取 ,用斜率法和恒摩尔法探讨了萃取机理 ,确定了萃合物的组成为La(NO3 ) 2 ·PMBP·B ,计算了萃取平衡常数。比较了HPMBP与Cyanex 4 71X、Cyanex 92 1、Cyanex 92 3、Cyanex 92 5、DEH/EHP、P35 0及TBP的单独及混合体系萃取La 的性能 ,结果表明 :所有混合体系对La 均有协同效应 ,其中HPMBP与Cyanex 92 3、Cyanex 92 1、Cyanex 92 5的混合体系是萃取La 的有效体系。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A series of ansa-metallocene complexes with an allyl substituted silane bridge [(CH =CHCH2)CH3Si(C5H4)(2)]TiCl2 (1), [(CH2=CHCH2)CH3Si(C9H6)(2)]MCl2 [M = Ti (2), Zr (3), Hf (4)] and [(CH2=CHCH2)CH3Si(C13H8)(2)]ZrCl2 (6) have been synthesized and characterized. The molecular structure of 6 has been determined by X-ray crystallographic analysis. Complexes 1-4, 6 bearing allyl groups have been investigated as self-immobilized catalysts for ethylene polymerization in the presence of MMAO. The results showed that the self-immobilized catalysts 1-4, 6 kept high ethylene polymerization activities of ca. 10(6) g PE mol(-1) M h(-1) and high molecular weight (M-w approximate to 10(5)) of polyethylene.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

纳米材料特有的尺寸效应、量子效应和表面效应使其具有许多异于常规材料的性质 ,在催化、生物传感器、微电子器件和磁性材料等诸多领域都有广泛的应用前景 [1] .已有专家预言 ,与纳米材料相关的技术将在新世纪经济发展中起主导作用 ,对其研究是目前科学研究中的热点 .金纳米颗粒是目前研究得最多的金属纳米材料体系 .传统的金纳米颗粒的制备方法以溶胶 -凝胶法为主 [2~ 4 ] ,所制备的金纳米颗粒的粒径较大 (一般大于 1 0 nm) ,粒径分布不均匀 ,易于团聚 ,因而限制了其应用 .为了解决上述问题 ,Brust等 [5]将硫醇化合物在金属表面的自组装技术 [6 ]与纳米技术结合起来 ,制得了表面组装有硫醇配体稳定剂的金纳米颗粒 .采用这种方法制备的纳米颗粒的粒径小 ,且尺寸可控 (小于 5 nm) ,分布均匀 .由于表面组装的硫醇配体降低了其表面势 ,解决了纳米材料易于团聚的问题 [7] .喹啉及其衍生物是一类重要的电化学活性物质 ,同时也是一类重要的药品原料 ,在抗疟疾方面具有极为重要的应用 [8] .本文采用文献 [5 ]报道的方法 ,制备了 2 -巯基喹啉包裹的金纳米颗粒 ,并采用透射电子显微镜、紫外 -...

Relevância:

100.00% 100.00%

Publicador:

Resumo:

聚对苯二甲酸 1 ,3-丙二醇酯 ( PTT)是典型的半结晶聚合物 ,从熔体结晶形成球晶 ,在某一结晶温度范围内 ,在球晶中可观察到环带结构[1~ 4 ] .一般认为 ,环带球晶的形成归因于片晶沿球晶径向的周期性扭曲[1,2 ] .本文研究了 PTT溶液浇铸薄膜在溶剂挥发过程中等温结晶的形态结构 .1 实验部分   PTT样品为美国壳牌化学公司产品 ,熔点为 2 2 8℃ .将 PTT粒料于 1 1 0℃溶解在苯酚和1 ,1 ,2 ,2 -四氯乙烷 (质量比为 60∶ 40 )的混合溶剂中 ,配成质量分数为 0 .2 %~ 2 %的溶液 ,滴少许溶液在加热的云母片上 ,在预先设定的结晶温度 ( 90~ 2 0 0℃ )下等温结晶 ,然后将 PTT薄膜快速冷却至室温 .用 Leica DMLP偏光显微镜 ( PL M)和 SPA- HV30 0原子力显微镜 ( AFM)进行形态表征 .2 结果与讨论  图 1为 PTT溶液浇铸薄膜在不同温度下等温结晶后的 PLM图 ,可以清楚地看到 Maltese十字消光现象 .PTT溶液浇铸薄膜在 90~ 1 30℃的结晶温度范围内 ,形成环带球晶 ;当结晶温度为 1 40℃...

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the title compound, [Zn(C8H4O4)(C17H10N4O)](n), the Zn-II atom is five-coordinated by two N atoms from the phenanthro-line-derived ligand and three O atoms from one bidentate and one monodentate benzene-1,2-dicarboxylate (1,2-BDC) dianions in a distorted trigonal-bipyramidal geometry. The Zn-II atoms are bridged by the 1,2-BDC ligands to form a single-chain structure. Neighboring chains interact through pi-pi interactions, leading to a two-dimensional network.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

研究了芳烃油和环烷烃油对充油铁系1,2-聚丁二烯橡胶性能的影响。结果表明,基础胶充油后门尼粘度值下降,可塑性增加,混炼行为变佳;填充芳烃油比填充环烷烃油的橡胶在拉伸强度、撕裂强度、伸长率和生胶门尼值等方面均有所提高;充油后虽然硫化胶硬度降低,但是生热和耐磨性能提高。填充芳烃油可适当提高硫化胶的抗湿滑性,但滚动阻力也升高。环烷烃油可降低硫化胶的滚动阻力。充油可适当改善胶料的抗老化性能。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

间同立构1,2-聚丁二烯自1955年问世以来 ,引起人们的广泛关注 ,但绝大多数研究工作集中在聚合物的合成方面[1~3] ,对其形态结构方面的研究却很少报道[4] ,原因是该聚合物分子侧链含有大量双链 ,在较高温度下 (>150℃ )很容易产生热交联 ,这给结构研究造成了很大困难 .间同立构1,2-聚丁二烯的性能取决于间规度 ,低间规度聚合物呈现弹性体特征 ,而高间规度聚合物则是一种半结晶性塑料 ,其结晶为平面锯齿链正交堆砌 ,Pacm空间群[4] .本文采用一种新的催化体系 ,使合成的1,2-聚丁二烯间规度可以调控.同时首次报道了结晶性间规1,2-聚丁二烯稀溶液浇铸薄膜形成具有单晶取向的板条状片层结构,并应用电子显微学和电子衍射技术确定其晶体结构.1.实验部分1.1样品及试剂 乙酰基丙酮铁 [(Fe(acac) 3)纯度为 99.9% ],使用时配成0.2mol/ L的甲苯溶液 ;三异丁基铝 [Al(i-Bu) 3]由 Aldrich公司提供 ;氢化亚磷酸二乙酯 (DEP)及丁二烯由锦州化学公司提供 ;丁二烯通过蒸馏进行纯化 ;己烷使用前在 Na/ K合金...

Relevância:

100.00% 100.00%

Publicador:

Resumo:

近十几年来,结晶性间同立构1,2-聚丁二烯引起人们的广泛关注,但绝大多数研究工作集中在聚合物的制备、物理性质和应用方面[1~3],对于其结晶行为和晶体结构则未见报道 .原因是间同立构1,2-聚丁二烯分子侧链含有大量的双键,在较高温度下很容易交联 ,特别是高间规度的聚合物 ,由于其熔融温度高 (>200℃ )则更易产生交联,这给结晶行为和结构研究带来很大困难.结晶性间同立构1,2-聚丁二烯的晶体结构为平面锯齿链正交堆砌,Pacm空间群[4].我们曾报道了结晶性间同立构1,2-聚丁二烯的合成和溶液浇铸膜的板条状结构[5],本文采用薄膜熔体结晶的方法第一次成功地获得了间同立构1,2-聚丁二烯的单晶,并通过电子显微学和电子衍射技术确定了其晶体结构.1 实验部分1.1间同立构1,2-聚丁二烯的制备采用乙酰基丙酮铁 [Fe(acac) ]3、三异丁基铝 [Al(i-Bu)3]和氢化亚磷酸二乙酯 (DEP)的新催化体系制备间同立构1,2-聚丁二烯,具体合成路线参见文献 [5].本文所选用聚合物的1,2单元含量为 89.3 % ,间规度为 ...

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Two novel organic-inorganic hybrid compounds, (H(2)enMe)(4)(H3O)[Ni(enMe)(2)].[Na3Mo12O52P8(OH)(10)].5H(2)O (1) and (H(2)enMe)(4)(H3O)[Cu(enMe)(2)].[Na3Mo12O52P8(OH)(10)].5H(2)O (2) (enMe = 1,2-diaminopropane), have been hydrothermally synthesized and characterized by elemental analyses, IR, EPR, XPS, UV-Vis spectra and TG analyses. Single crystal X-ray diffraction shows that 1 and 2 are isostructural compounds. Both the compounds exhibit an unusual two-dimensional (2-D) window-like network consisting of one-dimensional (1-D) chains of sodium molybdenum phosphate anions connected by transition metal coordination complexes cations. Compound 1 and 2 represent the first 2-D molybdenum phosphate skeleton pillared by transition metal complex fragments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Two novel compounds, [Co(4,4'-bipy)(H2O)(4)](4-abS)(2).H2O (1) and [Mn(4,4'-bipy)(H2O)(4)](4-abs)(2).2H(2)O (2) (4,4'-bipy = 4,4'-bipyridine; 4-abs = 4-aminobenzenesulfonate), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses, UV-vis and IR spectra, and TG analysis. X-ray structural analysis revealed that 1 and 2 both possess unusual hydrogen-bonded three-dimensional (3-D) networks encapsulating one-dimensional (1-D) covalently bonded infinite [M(4,4'-bipy)(H2O)(4)](2+) (M = Co, Mn) chains. The 4-abs anions in 1 form 1-D zigzag chains through hydrogen bonds. These chains are further extended through crystallization water molecules into 3-D hydrogen-bonded networks with 1-D channels, in which the [Co(4,4'-bipy)(H2O)(4)](2+) linear covalently bonded chains are located. Crystal data for 1: C22H30CoN4O11S2, monoclinic P2(1), a = 11.380(2) Angstrom, b = 8.0274(16) Angstrom, c = 15.670(3) Angstrom, alpha = gamma = 90degrees, beta = 92.82(3)degrees, Z = 2. Compound 2 contains interesting two-dimensional (2-D) honeycomb-like networks formed by 4-abs anions and lattice water molecules via hydrogen bonding, which are extended through other crystallization water molecules into three dimensions with 1-D hexagonal channels. The [Mn(4,4'-bipy)(H2O)(4)](2+) linear covalent chains exist in these channels. Crystal data for 2: C22H32WN4O12S2, monoclinic P2(1)/c, a = 15.0833(14) Angstrom, b = 8.2887(4) Angstrom, c = 23.2228(15) Angstrom, alpha = gamma = 90degrees, beta = 95.186(3)degrees, Z = 4.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this paper, a novel monoaza-B15C5 derivative, N-(2-tosylamino)-isopentyl-monoaza-15-crown-5 (L), is used as an ionophore to facilitate alkali metal cations transfer across a water/1,2-dichloroethane (W/DCE) interface. Well-defined voltammetric behaviors are observed at the polarized W/DCE interfaces supported at micro- and nano-pipets except Cs+. The diffusion coefficient of this ionophore in the DCE phase is calculated to be equal to (3.3+/-0.2) x 10(-6) cm(2) s(-1). The experimental results indicate that a 1:1 (metal: ionophore) complex is formed at the interface with a TIC/TID mechanism. The selectivity of this ionophore towards alkali ions follows the sequence Na+ > Li+ > K+ > Rb+ > Cs+. The logarithm of the association constants (log beta(1)(0)) of the LiL+, NaL+, KL+ and RbL+ complexes in the DCE phase are calculated to be 10.6, 11.6, 9.0 and 7.1, respectively. The kinetic parameters are determined by steady-state voltammograms using nanopipets. The standard rate constants (k(0)) for Li+, Na+, K+ and Rb+ transfers facilitated by L are 0.54+/-0.05, 0.63+/-0.09, 0.51+/-0.04 and 0.46+/-0.06 cm s(-1), respectively. The pH values of aqueous solution have little effect on the electrochemical behaviors of these facilitated processes. The results predicate that this new type of ionophore might be useful to fabricate electrochemical sensor of sodium ion.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Three prototypes of dinuclear complexes were obtained from the reactions of dilithium 1,2-dicarbacloso-dodecaborane-1,2-dichalcogenolates, (B10H10)C-2-(ELi)(2) (E = S, Se), with CpFe(CO)(2)Cl (1), CpRu(PPh3)(2)Cl (2), or [Cp*RuCl2](2) (3), respectively, and their structures have been determined by X-ray crystallography.