高钒混合杂多酸盐的合成及结构性能的研究

本文报道了四种新型高钒混合杂多酸盐K9-nPV14-nWnO42·xH2O及K9-nPV14-nMonO42·xH2O(n=1,2)的合成, 其中K9-nPV14-nMonO42·xH2O获得了单晶。X射线粉末衍射和红外光谱分析结果表明, 四种盐具有Bicapped-Keggin结构。测定了四种盐的紫外吸收和热稳定性。用量子化学方法初步探讨了四种盐的电子结构与化学键特性, 从分子水平对其结构性能进行了讨论和解析。     

Elucidation by computer simulations of the CUS regeneration mechanism during HDS over MoS<Subscript>2</Subscript> in combination with <Superscript>35</Superscript>S experiments

The first part of this paper is a short review of the ³⁵S radioactive tracer methods developed in recent years. Then, the experimental results obtained so far on Mo/Al₂O₃ catalysts are compared with computer simulation results recently claimed in order to elucidate the coordinatively unsaturated site (CUS) creation/replenishment/ regeneration mechanism over MoS₂ crystallites. The computer simulations allowed us to pre-select thermodynamically acceptable mechanisms among a set of suggested ones. Then, by comparison of the calculated activation energies with the ³⁵S experiments results we could further validate the most probable mechanism. This mechanism involved the dissociative adsorption of an H₂ molecule on the metallic edge of a MoS₂ crystallite surface with further creation of a CUS by release of one H₂S molecule in the gas phase. Both laboratory and computer simulated experiments permitted to calculate the activation energy for the H2S liberation reaction. In both cases, this energy was about 10- 12 kcal/mol, confirming the accuracy of the proposed mechanism. Moreover, the calculated activation energy of the rate-limiting step for the creation of one CUS by the proposed mechanism was about 23 kcal/mol, which was also in good agreement with the experimental activation energy of the dibenzothiophene (DBT) hydrodesulphurisation (HDS) reaction (typically about 20- 22 kcal/mol). This correlation indicated that the DBT HDS reaction rate might be intrinsically governed by the CUS formation/replenishment process, i.e. that the vacancy formation process is a crucial parameter in the global HDS reaction mechanism. Nevertheless, in the case of the 4,6-dimethyl DBT (4,6-DMDBT) HDS reaction, the experimental activation energy is higher (approx. 30 kcal/mol), confirming that external parameters induced by the 4,6-DMDBT-specific properties themselves are likely to play an important role in the reaction process, in addition to the ones intrinsic to the catalytic phase.     

阶跃伏安法中离散数据处理方法Ⅲ.样条最小二乘法

本文对采用样条最小二乘法处理低信噪比的阶法离散数据的噪声滤除,导数卷积的应用原理作了详细讨论,从理论模拟数据和实验的测试结果表明,样条最小二乘法在处理波形复杂.含强白噪声的信号时,呈现了目前文献报道的分析信号处理方法所没有的优点,具有广阔的应用前景.     

塔板理论色谱流出曲线性质的研究

塔板理论是色谱动力学理论的重要部分。本文采用数学方法把塔板理论色谱流出曲线从离散函数形式变换为连续函数形式。在此基础上运用计算机进一步研究了塔板理论色谱流出曲线的性质。     

2D-NMR测定人参皂苷Rb~1溶液中的三维空间结构

本文用一维和二维NMR归属了人参皂苷Rb~1的质子化学位移, 测定了质子偶合常数, 并用相敏NOESY谱测定了分子中质子间的距离。以所测定的化学位移, 偶合常数和质子间距等NMR结构参数为初始数据, 用自编和改进的分子结构计算程序计算出人参皂苷Rb~1在溶液中的三维空间结构。     

邻香兰素与邻苯二胺双Schiff碱镍配合物的合成, 晶体结构和热分析

合成所得的邻香兰素(2-羟基-3-甲氧基苯甲醛)与邻苯二胺双Schiff碱Ni(II)配合物的晶体[Ni(C~8H~7O~2)2(C~6H~4N~2)].H~2O, 空间群P2~1/n, a=0.8854(2),b=1.9067(5), c=1.1807(4)nm, β=99.43(2)°; Z=4; 结构解析最后的偏正因子R=0.044, R~W=0.052。标题配合物的热分解反应动力学方程式为: dα/dt=A.e^-E/RT.(3/2).(1-α)[-ln(1-α)]^1/3; 热分解反应动力学补偿效应表达式为:lnA=0.1800E+0.0789。     

天冬氨酸热解机理的MNDO研究

本文用MNDO方法全优化计算了天冬氨酸及其热解的中间产物和产物分子的几何构型.通过对计算结果如键长,键级,双原子作用能以及总能量与键长R~C~-~C,R~C~-~N变化关系的分析,提出了天冬氨酸的热解机理,与实验结果基本相符, 但关于中间产物的热解,我们认为很可能是先失去CO~2,而不是CO     

若干含氧桥双核钼(V)原子簇化合物的研究

本文在测定了五个新颖双核钼(V)簇合物的晶体结构(QH)4[Mo2O4(NCS)6](1),H(PyH)3.[Mo2O4(C2O4)2(H2O)2]2.2H2O(2), (QH)3[Mo2O4(C4H3OCOO)(NCS)4](3),(QH)3[Mo2O4.(CH2OH)(NCS)5](4)和(PyH)4[Mo2O3(SO4)(NCS)6](5)以及文献报道该类型化合物结构数据的基础上, 综述了含氧桥双核钼(V)簇合物的结构特征, 并应用SCC-EHMO方法探讨了该类型化合物的电子结构和成簇机理, 最后用简征坐标分析法, 研究了含氧桥双核钼(V)化合物簇胳单元[Mo2O4]^2^+和[Mo2O3SO4]^2^+的振动结构及其红外谱带归属。     

环糊精及其包络物的分子力学研究

本文用分子力学方法研究了环糊精及其包络物的性质, 探讨了包络过程及其驱动力, 与电化学实验结果对比获得一致性结伦。     

μ-四丁基已酰二胺镧(Ⅲ)的双核配合物La~2μ-[Bu~2CO(CH~2)~4CONBμ~2][Bu~2NCO(CH~2)~4CONBu~2]~2(NO~3)~6的合成和结构

合成的标题配合物晶体属三斜晶系,空间`群为P1.晶胞参数:a=1.4693(2),b=1.5882(3).c=1.9916(4)nm,α=90.92(2),β=92.93(1),γ=103.73(1)°,v=4.507nm^3,D~c=1.29g.cm^-3,Z=2配合物为双核分子,一个配物分子中有三个有机配体分子,其中一噶有机配体以两个羰基分别连结两个La(Ⅲ),此外,每个La(Ⅲ) 各有一个有机配体和三个硝酸根配位,有机配体以两个羰基配位,三个硝酸根都是双齿配体.两个La(Ⅲ)的配位数都是9.