213 resultados para 2,4,6,8-tetraoxaadamantanes


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The crystal structure of the title compound, C14H17ClN2OS2, is stabilized by intermolecular N-(HS)-S-... hydrogen bonds and pi-pi stacking interactions.

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由 5-(2-乙酰基-1-甲硫基-3-羰基-亚丁基)-丙二酸亚异丙酯 (1)与邻苯二胺及乙酸镍()经一步反应合成了3{1-[2-( -3-羟基-1-甲基-2-亚丁烯氨基)-苯亚氨基 ]-乙基} 4-甲硫基-2,4-戊二烯-2-醇(3)的不对称四齿 Schiff碱镍()配合物(2),X射线衍射结果表明,配合物 2属单斜晶系,P21/C空间群.a=1.1476(2)nm,b=1.1782(2)nm,c=1.4810(3)nm;β=111.73(2)°,V=1.8602(7)nm3,Z=4,Rf=0.0535.电化学(循环伏安)测定结果表明,该配合物在测定条件下(阳极峰电位为1.1)发生了不可逆的氧化-还原反应.

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A novel compound [Cu(en)(2)](4)[(SiMo8V4O40)-O-v(V-IV O)(2)] [MoO4](2) . 5H(2)O has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Black crystals crystallize in the tetragonal. system, space group 14/m, a = b = 14.019(2) Angstrom, c = 20.341(4) Angstrom, V = 3997.9(11) Angstrom(3), Z = 2, lambda(MoKalpha) = 0.71073 Angstrom (R(F) = 0.0443 for 1819 reflections). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range of 1.76 < theta < 24.98degrees using the omega-scan technique. The structure was solved by the direct method and refined by the full-matrix least squares on F-2 method using the SHELXL-97 software. X-ray crystallographic study showed that the title compound contained a bicapped alpha-Keggin fragment [SiMo8 (V4O40)-O-v((VO)-O-IV)(2)](4-) polyoxoanion.

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近 1 0年来 ,基质辅助激光解吸质谱 (MALDI- MS)作为一种新兴的“软电离”质谱技术 [1,2 ] ,已很快地应用于生物大分子特别是蛋白质研究领域 [3 ] .MALDI- MS可在 1 0 - 12 mol甚至 1 0 - 15mol的水平上 ,准确地测定分子量高达几万到几十万的生物大分子 ;还可通过改变基质、溶液条件和样品的制备方法等实现大分子蛋白质非共价复合物的质谱检测 [4 ] .MALDI- MS能够得到如此广泛的应用 ,在很大程度上要归功于基质的辅助效应 .基质的作用主要可以概括如下 [5~ 7] :(1 )削弱样品分子间的相互作用 ;(2 )与样品分子结合并使之快速结晶 ;(3 )帮助样品分子从激光脉冲中吸收能量 ,使其产生瞬间相变 ,当能量达到本体解吸临界值时便可得到离子信号 .Garozzo等 [8]曾报道了以羟基苯乙酮为基质可提高测量多种谷蛋白粘胶质分子量的灵敏度 .其中以 2 ,4,6 -三羟基苯乙酮 (2 ,4,6 - THAP)与 TFA混合作基质和 2 ,6 -二羟基苯乙酮 (2 ,6 - DHAP)与 H2 O,ACN混合作基质灵敏度最高 .表明这类基质在通过气相离子 ...

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The title two-dimensional coordination polymer was synthesised and characterised by X-ray diffraction analysis.

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利用核磁共振氢谱和碳谱研究了电化学探针六氟磷酸二(2,2'-联吡啶)(2,2'-联吡啶-4,4’-二羧酸)合钌(Ⅱ)的立体结构,并通过二维~1H~1同核相关及~1H-~(13)C异核相关技术对其氢谱和碳谱进行了归属.

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用~1H NMR和~(13)C NMR谱研究了新型电化学发光探针六氟磷酸二(4,4’-二甲基-2,2’-联吡啶)·(4,4’-二羧酸-2,2’-联吡啶)合钌(Ⅱ)的立体结构,通过~1H~(-1)H COSY、~(13)C~(-1)H HETCOR谱对其氢谱和碳谱中的各谱峰进行了归属,并给出了氢谱和碳谱峰的化学位移值.

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中空纤维膜萃取技术是将液液萃取过程与膜过程相结合的新型分离技术.二(2,4,4-三甲基戊基)膦酸(HBTMPP,HL)萃取稀土及其它高价金属离子时所需水相酸度低,反萃容易,加之空间位阻等因素,很可能成为优于2-乙基己基膦酸单2-乙基己基酯(HEH/EHP)…

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Molecule dynamics simulation was used on HPT(2,3,6,7,10,11-hexa-n-pentyloxytriphenylene), which is a discotic Liquid crystal. From analyzing the energy and displacement varying with the temperature, the phase transition temperature of PM6MPP can be predicted. The deviations of T-g, T-m and T-i due to the MD time scale are small enough that it should be possibly used to predict the material properties especially when more powerful computers are available.

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Experimental electron diffraction patterns and high resolution images were used to determine the space group and unit cell dimensions of 2,3,6,7,10,11-hexakispentyloxytriphenylene. Subsequently the molecular conformation was calculated by energy minimized package in Cerius2. Using this method, we got the HPT crystal structure: space group: P6/mmm; lattice type: hexogonal; the lattice parameters are a = b = 20.3 angstrom, c = 3.52 angstrom, = = 90 degrees, = 120 degrees. The core of HPT is not perpendicular to the column. The angle between a axis and HPT core plane is 9 degrees which cannot be seen in b-c projection. The simulated ED patterns and HREM images are good agreement with the experimental ED patterns and HREM images.

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A new series of mixed conducting oxides, Sr10-n/2BinFe20Om (n = 4, 6, 8, 10), were synthesized by a solid state reaction method, and they have high oxygen permeability. The oxygen permeation rate at 1150 K is 0.41 ml(STD)/ cm(2).min for n = 6 and 0.90 ml(STD)/cm(2).min for n = 10, which is two times higher than that for Sr1-xBixFeO3 (x = 0.5). For the Sr1-xBixFeO3 (x = 0.1, 0.3, 0.5) series, the oxygen flux increases with increasing Bi content. (C) 1998 Elsevier Science Ltd.

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利用TG,DTA,XRD和XPS方法研究了La0.2Ca0.8MnO3催化剂的结构和形成机理.样品用La,Ca,Mn混合硝酸盐制备.随着焙烧温度的升高发生了一系列的固相反应,发现氨氧化催化剂催化活性与生成的CaMnO3含量成正比.在900℃制备的含有CaMnO3,La0.575Ca0.425MNO3,Mn2O3和La2O3的混合物是氨氧化最佳催化剂,活性相是CaMnO3,并具有大量的氧空穴.

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用新型恒界面池法首次研究了二(2,4,4-三甲基戊基)膦酸在盐酸介质中萃取Er(Ⅲ)的动力学,测定了流体线性流速、有机相浓度、水相浓度和酸度、温度及界面面积等因素对萃取速率的影响,提出其速率方程,求出萃取反应的活化能,并对萃取反应机理进行了探讨.

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本文研究了外水相pH值、流动载体浓度、表面活性剂浓度、内相解析酸浓度、水乳比、油内比等因素对二(2,4,4-三甲基戊基)单硫代膦酸(Cyanex302)-上胺205-正庚烷乳状液 膜迁移Sc(Ⅲ)的影响。在一定条件下,Sc(Ⅲ)可以快速而完全地迁移,有可能实现Sc(Ⅲ)与Fe(Ⅲ)、Lu(Ⅲ)的分离。