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991.
Khafizova L. O. Ibragimov A. G. Yalalova D. F. Borisova A. L. Khalilov L. M. Dzhemilev U. M. 《Russian Chemical Bulletin》2003,52(9):2012-2016
A method for the synthesis of secondary and tertiary alcohols was developed. The method is based on cycloalumination of olefins with trialkylalanes in the presence of Zr-containing catalysts followed by the CuCl-catalyzed in situ reaction of the corresponding aluminacyclopentanes with aldehydes or ketones. 相似文献
992.
Synthesis and Crystal Structure Determination of Lead(II) Oxide Halide Alcoholates with Different Connectivity of Pb4O4 Heterocubane‐like Subunits The reaction of red lead(II) oxide (Litharge) and lead(II) halide (Cl? and Br?) with diethylene glycole at a temperature of 180 °C leads to the isotypic compounds [Pb6(C4H8O3)O2Cl6] (1) and [Pb6(C4H8O3)O2Br6] (2) . In a similar synthesis with PbI2 as educt at temperature of 160 °C the two modifications β‐[Pb6(C4H8O3)O2I6] (3) and α‐[Pb6(C4H8O3)O2I6] (4) were found, whereas at a reaction temperature of 180 °C [Pb9(C2H4O2)(C4H8O3)O3I8] (5) was surprisingly obtained as product. The X‐ray diffraction data show that at a temperature of 180 °C a splitting of the ether took place. The cited compounds show cubane like subunits built by lead and oxygen atoms. These fragments are connected by alkoholate molecules. In 5 additionally an I6 octahedra centered by lead is observed. 相似文献
993.
[H+]在0.01~0.70mol?L-1范围内,离子强度为1.00mol?L-1,[Fe(III)]>>[配体]、[H+]>>[配体]的条件下,研究了Fe(III)与2,3-二羟基苯磺酸钠(Tiron)的配位反应.发现当[H+]≤3.00×10-2mol?L-1时,[Fe(III)]2对反应速率有明显的贡献.求得了相关反应的动力学参数,从而揭示了FeOH2+和FeOH24+与Tiron配位的解离反应途径及FeOH32+的缔合反应机制,并提出了该配位反应的可能机理. 相似文献
994.
995.
In the present paper, we describe a microfluidics-based sensing system for nonelectroactive anions under negative separation electric field by mounting a single carbon fiber disk working electrode (WE) in the end part of a poly(dimethylsiloxane) microchannel. In contrast to work in a positive separation electric field described in our previous paper (Anal. Chem. 2004, 76, 6902-6907), here the electrochemical reduction reaction at the WE is not coupled with the separation high-voltage (HV) system, whereas the electrochemical oxidation reaction at the WE is coupled with the separation HV system. The electroactive indicator is the carbon fiber WE itself but not dissolved oxygen. This provides a convenient and sensitive means for the determination of nonelectroactive anions by amperometry. The influences of separation voltage, detection potential, and the distance between the WE and the separation channel outlet on the response of the detector have been investigated. The present detection mode is successfully used to electrochemically detect F-, Cl-, SO4(2-), CH3COO-, H2PO4-. Based on the preliminary results, a detection limit of 2 microM and a dynamic range up to three orders of magnitude for Cl- could be achieved. 相似文献
996.
合成了9种具L-氨基酸衍生物结构的介晶化合物(I-Ⅲ,Ⅳab,Ⅴa,b,Ⅵa,b)、4种氨基酸衍生物(A1-4)和6种介晶化合物(M1-6).新化合物(Ⅰ-Ⅲ,Ⅳa,b,Ⅴa,b,Ⅵa,b,A4,M3-6)的化学结构通过IR、1HNMR和元素分析证实;并用偏光显微观察和DSC分析研究了其相变行为,结果表明有8种化合物(M3-6,Ⅵa,b,Ⅴb,Ⅵb)呈现液晶相变。测定了它们的比旋光度。通过X射线衍射研究了化合物Ⅵh120~130℃和Ⅵb170~180℃的近晶结构,Ⅵb显,Ⅵb呈。测定了化合物Ⅳb的电滞回线,证明其具铁电性。 相似文献
997.
Mian Chang Jiayou Yu Shaojun Wang Liping Yang Yi Yang Shihao Cai Shouheng Shi Yan Wang P. W. Zhu 《中国科学B辑(英文版)》1997,40(5):529-534
A synthetical equation is proposed to characterize the essential features of the inverse “S” type curve on the basis of summing-up
simulation approach of “S” type curve. The two physical variables in the model obtained are discussed and the detailed method
used to determine the parameters is given. The model is then presented to describe the crystallization of poly(caryleher ether
ketone) (PEEK) and thermal decomposition of poly(amide-imide) (PAI) respectively. It is found that some thermal characteristic
parameters can be well estimated from the model simu-lated in computer. 相似文献
998.
Da Xu Zhong Lan Gao Na Li Ke An Li Key Laboratory of Bioorganic Chemistry Molecular Engineering of Ministry of Education College of Chemistry Molecular Engineering Peking University Beijing China 《中国化学快报》2007,18(5):561-564
Ru(bpy)_(3~(2 )) electrochemiluminescence (ECL) was applied to determination of rutin. ECL intensity of Ru(bpy)_(3~(2 ))could be enhanced in the presence of rutin in basic solution on platinum electrode. At pH 9.9, light emission intensity was found to be linear with rutin in the range of 1-50 mmol/L. 相似文献
999.
A highly sensitive and selective liquid chromatography-mass spectrometry (LC-MS) method has been developed for the determination of epirubicin in serum and cell specimens using daunorubicin as an internal standard. Using atmospheric pressure chemical ionisation (APCI), the epirubicin metabolites were readily distinguishable by their fragmentation pattern in the mass spectrometer. Selected reaction monitoring (SRM) mode was employed for quantitation of epirubicin and the metabolites. Following extraction, chromatography was performed on a C18 column with a mobile phase consisting of water-acetonitrile-formic acid, pH 3.2, with a flow rate of 200 μl/min. The limit of detection (LOD) and the limit of quantitation (LOQ) of this method in serum were determined to be 1.0 and 2.5 ng/ml, respectively. Linearity of the method was verified over the concentration range of 2.5-2000 ng/ml, with a high correlation coefficient (R2 ≥ 0.998). For the extraction procedure, an aliquot of 500 μl serum, spiked with internal standard, was extracted using a chloroform-2-isopropanol (2:1, v/v) mixture. The method has been applied to the analysis of epirubicin in cancer cell samples and the identification of known and unknown metabolites in clinical trial patient serum samples. 相似文献
1000.