不同加成数C60精氨酸衍生物的合成及其清除活性氧自由基的性能

通过控制反应配比, 首次合成了三种具有不同加成数目的水溶性C₆₀精氨酸衍生物, C₆₀[HNC(NH)NH(CH₂)₃CH(NH₂)COOH]_nH_n (n＝2, 6, 8). 采用FT-IR, UV, RF, ¹H NMR, ¹³C NMR, LC-MS, EA, 粒径分析, 透射电镜等手段对其结构进行了表征. 同时采用化学发光法考察了三种具有不同加成数目的C₆₀精氨酸衍生物对活性氧自由基(超氧阴离子O₂^－.及羟自由基•OH)清除能力, 结果表明, C₆₀精氨酸衍生物对活性氧自由基具有优良的清除能力, 且清除能力与加成基团供电效应、空间位阻及C₆₀精氨酸衍生物在水中的聚集形态等因素密切相关.     

Studies on Thermodynamics Features of the Interaction between Imidacloprid and Bovine Serum Albumin

At different temperatures, the interactions between imidacloprid （IMI） and bovine serum albumin （BSA） were investigated with a fluorescence quenching spectrum, a synchronous fluorescence spectrum, a three-dimensional fluorescence spectrum and an ultraviolet-visible spectrum. The average values of bonding constants （KLB： 3.424 × 10^4 L,mol^-1）, thermodynamic parameters （△H： 5.188 kJ,mol^-1, △G^（○—）：-26.36 kJ,mol^-1, △S： 103.9 J,K^-1,mol^-1） and the numbers of bonding sites （n： 1.156） could be obtained through Stern-Volmer, Lineweaver-Burk and ther- modynamic equations. It was shown that the fluorescence of BSA could be quenched for its reactions with IMI to form a certain kind of new compound. The quenching belonged to a static fluorescence quenching, with a non-radiation energy transfer happening within a single molecule. The thermodynamic parameters agree with △H〉 0, △S〉0 and△G^（○-）〈0, suggesting that the binding power between IMI and BSA should be mainly a hydrophobic interaction.     

One-Pot Method for Synthesis of Calix[6]biscrowns

p-tert-Butylcalix[6]-1,4-2,5-biscrown-4 is a typical member of the family of calix[6]crowns. In the literature, the compound was synthesized from calix[6]arene by two steps and the overall yield based on calix[6]arene was 24%.Herein we wish to report a one-pot method to do this work. By this method the yield was up to 48% and the reaction time was greatly reduced.     

茉莉醛相转移催化合成法的改良

茉莉醛又称2-戊基肉桂醛,具有优雅的茉莉花香,是一种深受调香师喜爱的合成香料。目前已广泛应用于各种日用化学品中。     

Mo/MCM-22分子筛碳化钼活性中心结构及甲烷活化机理的密度泛函理论研究

 应用密度泛函理论研究了Mo/MCM-22分子筛上碳化钼活性中心的几何结构和电子结构,以及甲烷在该活性中心上的活化机理. 设计了两种结构的活性中心模型: Mo(CH2)2(模型A)和Mo(CH)CH2(模型B); 它们都嫁接在MCM-22分子筛超笼边缘的T4位的Brnsted-酸性位上,用3T簇模型代替分子筛的骨架,对所设计的模型进行了几何结构优化和电子结构分析. 结构优化结果显示, Mo与CH2端基以双键结合,键长为0.18～0.19 nm, 而Mo与CH端基以叁键结合,键长为0.17 nm. 通过自然键轨道分析,证明中心钼原子以配位键与骨架氧原子结合. 根据前线分子轨道的分析,预测了甲烷活化反应将发生在甲烷分子的HOMO和钼活性中心的LUMO之间,即 C-H 键的电子流向 Mo-C 键的π*轨道. 甲烷 C-H 键发生异裂, H+和H3C-基团分别与 Mo-C 键上的Mo和C成键. 在模型A上,甲烷活化反应的活化能为119.97 kJ/mol; 在模型B上,甲烷的H原子可以分别结合到CH2端基和CH端基上,对应的活化能分别为91.37和79.07 kJ/mol.     

Three-dimensional quantum dynamics study of vibrational predissociation of HeI_2 van der Waals molecule for low vibrational excitation using the time-dependent wave packet method

Three-dimensional quantum mechanical calculations for vibrational predissociation of HeI2(B) van der Waals molecules are presented using the time-dependent wave packet technique within the golden rule approxima tion.The total and partial decay widths,lifetimes,rates and their dependence on initial vibrational states were obtained for HeI2 at low initial vibrational excited levels.Our calculations show that the calculated tota decay widths,lifetimes and rates agree well with those extrapolated from experimental data available The predicted total decay widths as a function of initial vibrational states exhibit highly nonlinear behavior.The very short propagation time (less.than 1 ps) required in the golden rule wave packet calculation is determined by the duration time of the final state inter-action between the fragments on the vibrationally deexcited adiabatic potential surface.The final state interaction between the fragments is shown to play an important role in determining the final rotational distri     

聚甲基丙烯酸甲酯辐射裂解和消旋的空间立构效应

本文研究了三种不同空间立构聚甲基丙烯酸甲酯的辐射效应,提出裂解过程是一种裂解与重合的动态平衡过程。分子量降低和消旋作用对温度的依赖性,是由于分子运动和笼罩效应以及重合的空间位阻效应所致。辐照温度愈高,裂解产额愈大。相同条件下辐照,全同立构比无规立构试样的裂解产额更大。 全同立构聚甲基丙烯酸甲酯辐照后,不仅分子链断裂,而且空间立构也发生很大变化。随着辐照剂量的增加,全同立构含量逐渐减少,而无规立构含量和间同立构含量却逐渐增加。     

细胞色素C在离子液体修饰电极上的电化学行为

分别合成了疏水和亲水性咪唑类离子液体,并制备了相应的两种离子液体修饰的玻碳电极。循环伏安法测量结果显示,细胞色素C在离子液体修饰的玻碳电极上的电子传递过程为一扩散控制的准可逆反应,表明咪唑类离子液体也可用作细胞色素C电子传递的有效促进剂。电化学交流阻抗谱的测量结果得到了与循环伏安相同的结论。     

强流射频四极加速器输入耦合环的物理设计研究

 详细讨论了强流射频四极加速器高频输入耦合环的一些基本问题，完成了高频输入耦合环的初步物理设计. 利用二维程序Superfish 的一些结果，确定了耦合环的大小，计算了耦合环的功耗，并对构成耦合环导线的粗细进行了估算。该耦合环的物理设计可作为耦合环试验的基础，同时，也可作为三维程序HFSS 模拟计算的起点。     

Trivariate Polynomial Natural Spline for 3D Scattered Data Hermit Interpolation

Consider a kind of Hermit interpolation for scattered data of 3D by trivariate polynomial natural spline,such that the objective energy functional (with natural boundary conditions) is minimal.By the s...