^31P NMR Studies on the Ligand Dissociation of Trinuclear Molybde-num Cluster Compounds

A series of carboxylate-substituted trinudear molybdenum dus-ter compounds formulated as Mo3S4(DTP)3(RCO2)(L), where RffiH, CH3, C2H5, CH2Cl, CCl3, R^1C6H4(R^1 is the group on the benzene ring of aromatic carboxylate ), L=pyridine,CH3CN, DMF, have been synthesized by the ligand substitu-tion reaction. The dissociation of the loosely-coordinated ligand L from the cluster core was studied by ^31p NMR. The dissocia-tion process of L is related to the solvent, temperature, and acidity of carboxylate groups, so as to affect the solution struc-ture and reactive properties of the duster. The long-distance in-teraction between ligands RCO2 and L is transported by Mo3S4 core.     

溶胶凝胶法制备取向性氧化铝超滤陶瓷膜

用金属醇盐的溶胶-凝胶法在多孔α-Al_2O_3衬底上制备了孔径均一的γ-Al_2O_3超滤膜.经X射线衍射仪、扫描与透射电子显微镜以及静态氮吸附等手段对膜的结构、形貌与孔径大小分布等进行了表征.实验发现顶层膜取向生长,膜厚受浸取时间、溶胶浓度、粘度和实验温度等因素影响.典型条件下可在20mm×20mm衬底上制备孔径均一、大小为3.8～4.8nm和厚度2μm左右的无裂纹、无孔洞等表面缺陷的多孔γ-Al_2O_3陶瓷膜.     

三正丁基膦参与的二苯联硒与吖啶及环氧化合物的开环反应

Aziridines and epoxides were reacted with diphenyl diselenide in the presence of a stoichiometric amount of （n-Bu）3P, respectively, giving β-amino- or β-hydroxy selenides in moderate to excellent yields under mild conditions. In the reactions the （n-Bu）3P might act as a reductant though it was a nucleophilic catalyst in other similar ring-opening reactions.     

1-乙基-4-氧-7-甲基-1,8-萘啶-3-羧酸的合成

乙基氧甲基萘啶羧酸;缩合反应;成环反应;乙基化反应;水解反应;光谱特征     

在线富集-HPLC法测定水溶液中多环芳烃

本文采用在线富集-HPLC 法测定水溶液中多环芳烃。先使样品中的组分浓缩在一支短的富集柱上,然后切换阀门,将富集物洗脱到 RPHPLC 的体系中进行分离,并用紫外和荧光检定器对冼脱物进行检测。为了提高检测灵敏度和选择性,实验中采用了荧光波长程序技术。考察了富集的最佳条件,并比较了在线法与离线法的测定结果。     

氟化钾催化取代酚与硅氢化合物的反应

本文研究了氟化物存在下, 硅氢化合物与酚类反应的规律性。选择了在KF存在下, 以DMF为溶剂, 含有不同邻, 间, 对位取代酚作为反应底物与多种含氢硅烷进行了一系列反应, 在反应活性上获得了具有一定规律性的结果, 同时得到了21个末见报道的新芳氢基有机硅化合物, 所得化合物均经元素分析, IR和1H NMR测定, 确定了结构。     

基团转移聚合合成PMMA—PEA—PAN嵌段共聚物的研究

丙烯酸系橡胶的综合性能仅次于氟橡胶,成本较低,若制成可重复加工的热塑性弹性体则更有价值。前人曾用阴离子聚合法进行过合成试验,均因副反应太多等原因而未能获得满意的结果。基团转移聚合(GTP)是八十年代建立的合成高分子新方法,在室温下进行“活性聚合”是其重要特征。本文利用GTP方法、单官能团引发剂,仅通过适当控制加料次序和时机就合成了软段居中的三元共聚物,为合成全丙烯酸系热塑弹性体奠定了基础。     

2-(1-苄基-3-甲基-2-吲哚亚甲基)-3-亚异丙基丁二酸酐的合成及其光致变色性能研究

在氢化钠和甲苯存在下, 1-苄基-3-甲基吲哚-2-甲醛与亚异丙基丁二酸二乙酯发生Stobbe缩合反应, 经过碱性水解和酸化得到二酸化合物, 接着在乙酰氯存在下脱水, 合成2-(1-苄基-3-甲基-2-吲哚亚甲基)-3-亚异丙基丁二酸酐. 研究了该俘精酸酐在不同溶剂中的光致变色性能.     

18-冠醚-6包结钾离子的毛细管电泳研究

采用毛细管区带电泳前沿分析和峰漂移分析两种方法，以咪唑—醋酸为缓冲溶液，利用间接紫外检测(A=240nm)，测定了18—冠醚—6对钾离子的包结常数；两种方法得到了比较一致的结果；进一步对这两种方法求解结合常数进行了对比和讨论，总结出各自的适用范围。     

Crystal structure of the complex of trichosanthin with NADPH at 0.172 nm resolution

The orthorhombic crystal structure of the complex of trichosanthin with nicotinamide adenine dinucleotide phosphate has been determined by molecular replacement method using one of the molecules of the monoclinic crystal structure of trichosanthin at 0.27 nm resolution as the search model. The crystallographic refinement at 0.172 nm resolution led to a final R-factor of 17.4% with root-mean-square deviations of 0.0013 nm and 3.8 from the ideal bond lengths and bond angles, respectively. The quality of the structure, the polypeptide chain fold and the comparison of it with that of the monoclinic trichosanthin structure, the location of nicotinamide adenine dinucleotide phosphate, the active site structure as well as the solvent structure are described.