The syntheses,crystal structure and magnetic behavior of μ-imidazolato-dicopper(II) complexes with the dinucleating hexaazamacrocycles

The synthesis, crystal structure and magnetic properties of the imidazolate-bridged dinuclear copper(II) complex [LCu2(Im)](ClO4)3(H2O) ·1/2(MeCN), (ImH=imidazole, L=bis-p-xylylBISDIEN) have been studied. Single crystal X-ray diffraction determination reveals the distorted square planar geometries of the imidazolate bridged dicopper(II) center are incorporated within the dinucleating macrocycle. The Cu—Cu separation in the complex is 6.005Å. Magnetic measurements reveal an antiferromagnetic exchange interaction with a coupling constant of J=–26.52cm–1. The enzymatic activity of the title complex is 5.9 percent of that of the protein.     

Initial value problems for nonlinear impulsive integro-differential equations in Banach space

In this paper, by using the cone theory and the monotone iterative technique, we investigate the existence of maximal and minimal solutions of the initial value problem for second order impulsive differential equations which nonlinearly involve the derivative x^′ in Banach space and give an example to illustrate our results.     

NMR double resonance study of azide binding to cytochrome c

Equilibrium constants for the binding of azide to ferri-cytochrome c at temperature rangeof 305—325 K were determined at pH=7 by using ~1H double resonance method.Thermodynamicvalues(⊿H~o=-34.5 kJ/mol,⊿S~o=-100 J/mol)were obtained from van't Hoff's relation andwere compared with those for azide binding to other ferric hemeproteins.The reason of loweraffinity of cytochrome c for azide was discussed.     

细胞色素C在4,5-二氮芴-9-酮修饰玻碳电极上的直接电化学研究

采用循环伏安法探讨了细胞色素C(Cyt C)在4, 5-二氮芴-9-酮(dafo)修饰玻碳电极表面的电化学行为.结果表明,Cyt C在dafo修饰电极上呈现一对峰形较好且准可逆的氧化还原峰,其式电位(E0′)为13 mV,峰电流与扫描速度呈线性关系,该电极过程是表面控制过程,电化学反应效率常数(ks)为0.89/s.固定在dafo上的Cyt C能促进H2O2的催化还原,响应快速而灵敏(<10 s),峰电流与H2O2浓度在5.0×10-6～3.0×10-4 mol/L范围内呈线性关系;检出限2.5×10-6 mol/L;米氏常数为1.07 mmol/L,显示出较好的亲和力.     

Molecular structure and 1H, 13C NMR assignments of 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene

The molecule 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb) crystallizes as a monohydrate in the monoclinic space group C2/c with a = 20.888(4), b = 13.220(2), c = 14.385(2) Å, = 90.36(1)°. Two of three imidazole groups are on one side of the central benzene ring, and the other one is on the opposite side. The crystal packing of titmb is stabilized by O-H--N hydrogen bonding between the water molecule and nitrogen atoms of the imidazole group. The complete ¹H and ¹³C NMR assignments for titmb were carried out by 2D NMR spectral measurements.     

RbBr/CsBr-CH3OH/C2H5OH-H2O三元体系的溶解度

采用自制的相平衡研究装置,测定了RbBr-CH_3OH/C_2H_5OH-H_2O和CsBr-CH_3OH/C_2H_5OH-H_2O四个三元体系在25、35、45℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据.实验结果表明,在所有的体系中,随着甲醇或乙醇质量分数的增加,RbBr和CsBr在水中的溶解度逐渐降低;并且折光率也逐渐减小.用经验关联方程对溶解度进行了拟合,同时给出了CH_3OH和C_2H_5OH分别对RbBr和CsBr的盐析率曲线.     

Design and synthesis of 3'-(prop-2-yn-1-yloxy)-biphenyl substituted cyclic acylguanidine compounds as BACE1 inhibitors

Based on the lead compounds 1 and 2, a series of novel BACE1 inhibitors were designed and synthesized, among which compound 9h exhibited a 60 fold improvement in potency over the lead compound 1. This represents a good lead for the discovery of more promising BACE1 inhibitors for the potential treatment of AD. The result also showed that the prop-2-yn-1-yloxy is a suitable fragment for modification of cyclic acylguanidine BACE1 inhibitors.     

温差数据采集系统的研制及其在反应组分燃烧热测量方法测定水杨酸乙酰化反应焓实验中的应用*

为了满足化学实验教学内容拓展和化学实验技术发展的要求,研制开发了Pt1000温度传感器信号输入温差数据采集系统。介绍了该数据采集系统的硬件架构和上位机软件的主要功能,并以“反应组分燃烧热测量方法测定水杨酸乙酰化反应焓”实验为例,阐述了数据采集系统的应用在拓展实验教学内容、优化实验数据处理方法、提高实验效率和实验结果可靠性等方面的作用。     

湍流空气射流引射特性的模拟研究

本文采用数值模拟方法,研究了湍流空气射流对环境空气的引射特性,包括等温射流和非等温射流情形.结果表明,由于射流不停地引射环境空气,射流"势核"区下游的温度与轴向速度迅速降低;射流引射量的模拟结果与文献中报道的、采用多孔壁技术进行实验所建立的关联式良好符合.     

动力学方程控制表面反应的模拟模型和方法

提出了动力学方程控制表面反应的模拟模型和方法.该模型从最基本的质量作用定律出发,获得表面反应的动力学方程.而表面反应通过格子模拟反应器进行.通过表面催化样板反应"CO表面催化氧化"检验了该模拟模型和方法,与实验结果吻合.该模型可在其它复杂的表面催化反应体系中推广应用.