锇(Ⅳ)-高碘酸钾-偶氮氯膦-pC催化分光光度法测定痕量锇的研究

在1．0mol／L硫酸介质中，微量锇(IV)的存在对KIO4氧化偶氮氯膦-pC的褪色反应有明显的催化作用，据此建立微量锇的催化光度分析法、方法的检出限为0．0002μg／mL，锇(IV)的含量在0．0006—0．003μg/mL之间有良好的线性关系，反应在水相中进行，应用于贵金属精矿中锇的测定，结果满意．     

A Facile Synthesis of Indolizines by 1，3－Dipolar Cycloaddition of Pyridinium and Related Heteroaromatic Ylides with Alkenes in the Presence of TPCD，Py_4Co（HCrO_4）_2

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四甲基锡在MCM-41分子筛表面的接枝反应及产物性能

研究了真空条件下SnMe4在MCM-41分子筛表面的接枝反应，并用元素分析、ICP、GC-MS、XRD、FTIR、DRS、13C及119Sn MAS NMR、XPS、BET、TPD、TPR等方法对产物的组成、结构和性质进行了表征.结果表明, 两者可以定量地进行化学反应，将确定数目的甲基锡基团接枝在分子筛表面, 形成SnMe3/MCM-41物种；接枝反应发生在分子筛表面上, 不破坏MCM-41分子筛骨架结构；改性分子筛的BET比表面积有所降低，孔体积变小, 表面性质发生变化.四甲基锡在MCM-41上接枝反应的温度为343 K,比它与HY沸石的反应温度(193 K)高得多，并且产物SnMe3/MCM-41的热稳定性也高于SnMe3/HY.     

聚偶氮酯的合成及用于乳液聚合

<正> 偶氮二异丁腈(AIBN)与二元醇反应得到聚偶氮酯(polyazoester),进而可按自由基反应引发单体聚合制备嵌段共聚物,近年来国外已有研究,其所用单体多为1,6-己二醇等低分子二元醇。本实验选用AIBN和PEG 400,用Pinner合成法经改进后制得了聚偶氮酯,分析了该产物的结构和热分解动力学,并使之部分分解引发丙烯酰胺得到了兼具表面活性和引发活性的预聚物。结果表明,这种预聚物用于醋酸乙烯聚合、苯乙烯和     

甲醇在欠电位沉积Ru修饰Pt电极上的催化氧化

采用欠电位沉积(upd)方法在Pt 表面沉积亚单层的Ru制备出upd-Ru/Pt 电极. 通过欠电位沉积前后电极在0.5 mol·L-1 H2SO4溶液中循环伏安图-152 - 128 mV(vs Ag/AgCl)电位范围内对氢区的数值积分确定Pt表面Ru 的覆盖度. 用电化学方法测试了甲醇在upd-Ru/Pt电极上的催化氧化, 并讨论分析了欠电位沉积电位和Ru的表面覆盖度对甲醇氧化的影响. 结果表明, Ru能够欠电位沉积到Pt表面. Pt表面欠电位沉积少量的Ru 即能大大促进甲醇的氧化.只要控制upd-Ru的沉积量, upd-Ru原子就能大大促进甲醇氧化而与沉积电位无关. Ru原子对甲醇氧化的促进作用与Ru和Pt是否形成合金无关, 而取决于Ru 在Pt表面的百分含量.     

Macro-, Micro-, Nano- and Crystal Structures of a Homodinuclear Complex [NH3（ CH2）3NH3]2{Na2[（C6H4O2）2]（C6H4O2H）2}

A homodinuclear complex （NH3CH2CH2CH2NH3）2 {Na2[（C6H4O2）2] （C6H4O2H）2} （1） has been synthesized by a solution-based self-assembly route. It crystallized in monoclinic system with space group P21/c. Every sodium ion coordinates in a tetragonal prism fashion with two O atoms of a terminal chelating catecholate ligand and three O atoms from two bridging catecholate ligands. Two neighboring NaO5 tetragonal prisms are edge-shared and centrosymmetric with regard to the inversion center to form a binuclear cluster {Na2[（C6H4O2）2]（C6H4OOH）2}^4- anion. The complex anions were aligned parallelly by n-n interaction and linked with the protonated 1,3-propylenediamine through hydrogen bonds which were assembled into a multi-lamellar structure with channels. The crystal exhibits rectangular geometry with an interior triangle hollow structure under optical microscopy. And the scanning electron microscopy （SEM） indicates that the wall of the tubes shows multi-lamella morphologies. Further, the transmission electron microscopy （TEM） reveals that the crystal is composed of multi-lamellar nano-tubes with diameters less than 100 nm. The molecular structure of the complex was compared with that of its isomer complex 2.     

不同光滑度立方体氧化铁对液晶电光性能的改善

向列相液晶被广泛应用于液晶显示中,但是由于杂质的存在,会导致液晶的驱动电压变大,增加能耗。 为了降低阈值电压和饱和电压,通常向液晶中添加纳米颗粒来提高电光性能。 本文利用水热法制备了表面粗糙和光滑的两种立方体Fe₂O₃纳米颗粒,其形貌均匀,尺寸约550 nm。 将二者分别掺杂到向列相液晶E7中,结果表明,粗糙立方体Fe₂O₃/E7复合体系具有比光滑立方体Fe₂O₃/E7复合体系和向列相液晶E7更优的电光性能,且在掺杂质量分数为0.4%时,其电光性能达到最优,阈值电压和饱和电压分别降低9.9%和11.6%,对比度增大80%,响应时间降低至6.0 ms。 这归因于粗糙立方体Fe₂O₃具有足够的表面积和表面所带电荷更多,所以会更易吸附体系中的杂质离子和减弱杂质离子的屏蔽作用,从而提高了电光性能。     

1，4二环己基取代六元瓜环与Na(Ⅰ)自组装实体的合成与晶体结构

A novel complex of a new 1,4-dicyclohexyl cucurbituril(DCYQ[6]) with sodium(Ⅰ) ion was synthesized, and the crystal structure was determined by X-ray diffraction technique. In this self-assembled entity both the cavity interaction of DCYQ[6] included a nitrate anion and the portal interaction of the dipole carbonyls of DCYQ[6] with sodium cations lead to form self assembled molecular capsules. The crystal structure of the entity shows a packing of the self assembled molecular capsules connected by hydrogen bonds of water molecules. CCDC: 271400.     

亮菌甲素的荧光光度法测定

对亮菌甲素的荧光特性进行了研究 ,发现该物质在四硼酸钠缓冲溶液 (pH 8.8± 0 .0 2 )介质中有很强的荧光性质 ,其激发波长为 2 81nm ,发射波长为 4 62nm ,亮菌甲素浓度在 0 .1～ 4 .5 μg·ml- 1范围内与荧光强度呈线性关系 (F =79.4C +3.4 6,r =0 .9994 )。用荧光法测定片剂中亮菌甲素的含量 ,方法简单、快捷、灵敏度高。     

Studies on Molecular Recongnition of (a)-Cyclodextrin with Diphenyl compounds

The cyclodextrins(CDs) are a class of cyclic oligosaccharides made up of six(a), seven(a)or more [a-(1,4)-linked] D-glucopyranose units, and shaped like truncated cones with primary and secondary hydroxyl groups crowning the narrower rim and wider rim respectively. As they have a hydrophobic cavity of appropriate dimension, they can bind with various guest moleculars, such as hydrocarbon, cyclohexane, aromatic compounds, to form inclusion complexes. The cyclodextins inclusion complexation has been considered an ideal model mimicking the enzyme-substrate interaction and a lot of effect has been devoted to it. In this paper, we report our investigation on the inclusion complexation behavior of a-cyclodextrin(a-CD) with diphenyl compounds in order to further explore the molecular recongnition mechanism of 2:1 inclusion complexation of a-CD with aromatic compounds.Figure 1: Possible structures of the inclusion compounds.The inclusion complexation behavior of a-CD with sym-diphenyl-urea, sym-diphenyl-thiourea and diphenyl kotone as respective guest moleclars was studied by ultraviolet spectrometric titrations.The absorption spectral changes observed for the compounds in the absence and presence of a-CD are used to draw the corresponding Benesi-Hildebrand plots and caculate the complex stability constant value (Ks) for the inclusion compounds.The 2:1 inclusion complexations show higher binding constants by cooperative binding of one guest molecular in the closely two hydrophobic cyclodextrin cavites as compared with 1:1 inclusion complexations.The highest value observed for sym-diphenyl-urea could be due to the formation of a hydrogen bond between the carbonyl group and the hydrogen in the hydroxyl group of CD and this is not possible with sym-tiphenyl-thiourea. The lowest value observed for diphenyl kotone indicate the hydrophobic interaction is one of the binding force of cyclodextrin inclusion complex.