Selective effect of guest molecule length and hydrogen bonding on the supramolecular host structure

A host supramolecular structure consisting of bis-(2,2':6',2' '-terpyridine)-4'-oxyhexadecane (BT-O-C16) is shown to respond to guest molecules in dramatic ways, as observed by using scanning tunneling microscopy (STM) on a highly oriented pyrolytic graphite surface under ambient conditions. It is observed that small linear molecules can be encapsulated within the host supramolecular lattice. The characteristics of the host structure were nearly unaffected by the encapsulated guest molecules of terphthalic acid (TPA) dimers, whereas appreciable changes in cavity dimension can be observed with azobenzene-4,4'-dicarboxylic acid. The STM study and density functional theory (DFT) analysis reveal that intermolecular hydrogen bonding interaction plays an essential role in forming the assembling structures. The difference in guest molecule length is considered the important cause for the different guest-host complexes.     

New lignans from the heartwood of Chamaecyparis obtusa var. formosana

Four new lignans, 3',4'-O,O-demethylenehinokinin (1), chamalignolide (2), 8'beta-hydroxyhinokinin (3) and 7beta,8beta-epoxyzuonin A (4), as well as (-)-hinokinin (5), and (-)-zuonin A (6), were isolated from the heartwood of Chamaecyparis obtusa var. formosana. The structures of these lignans were unambiguously determined by spectroscopic methods. And the absolute configuration of 1 was elucidated with a circular dichroism (CD) spectrum.     

两相催化体系中α，β－不饱和醛选择加氢反应研究Ⅲ．表面活性剂、溶剂对选择加氢反应的影响

研究了水溶性钌－膦配合物催化肉桂醛选择加氢反应中，相转移剂和表面活性剂对反应转化率和选择性的影响，考察了表面活性剂ＣＴＡＢ（十六烷基三甲溴化铵）浓度以及影响两相界面性质的因素—水相和有机相体积比、有机溶剂的改变等的影响．结果表明，相转移剂可以促进反应进行，其中以季铵盐相转移剂最好；表面活性剂能够显著地加快反应，其中以阳离子表面活性剂的效果最佳，且分子中含有长链烷基者（如ＣＴＡＢ）效果更好，非离子和阴离子表面活性剂的效果较差；对于ＣＴＡＢ，其浓度的增加导致反应速度的明显加快，但ＣＴＡＢ浓度达到１．６５×１０－２ｍｏｌ／Ｌ之后，反应体系乳化严重，反应完成后，两相分离变得困难．而增加水相体积和加入适当的有机溶剂，有利于转化率和选择性的提高．     

草酸在α-Fe_2O_3上吸附的磁性研究

α—Fe_2O_3是多种工业催化剂的主要成分,有反铁磁结构的特殊性.张和Matijevie的实验曾经发现,草酸在均匀α-Fe_2O_3胶体粒子上的吸附随温度的升高而增加,这可能暗示着草酸从物理吸附向化学吸附的过渡.考虑到磁学测量需要更为明显的表面效应,我们制备了较小的α-Fe_2O_3粒子,并测定其吸附草酸前后的磁化率变化。     

Oscillator Strength Calculations with the Compromised Orbitals

The oscillator strength has been calculated from a common set of compromised orbitals, instead of sets of the two separately optimized non-orthogonal orbitals for the two states involved in the transition. Inaccuracies of two types arose from the calculations were assessed by investigating simple atomic and molecular systems.     

W／O型微乳液中超氧化物阴离子的产生——微环境中SOD酶活性测定方法 …

分别在水溶液中和W／O型CTAB／正戊醇／异辛烷／水微乳液体系中研究了测定SOD酶活性的邻苯三酚法,发现在反向微乳液中,"小水池"的低介电常数和pH抑制了底物超氧化物阴离子O2-·的产生．只有提高外加缓冲液的pH或"小水池"的水化度,才能得到所需浓度的O2-·,从而初步解决了在微乳液中SOD作用底物的产生问题,为在微乳液中准确测定SOD酶活性创造了条件．     

Study on the Biomimetic Oxidation Catalyzed by the Model Compound of Cytochrome P-450(VI)——The Influence of Substituent x in T(x-p)PMn(Ⅲ)Cl on the Hydroxylation of Alkane

The influence of monosubstitution at phonyl rings in a series of T(x-P) PMn (Ⅲ)Cl (x = o , m , p-CH3, CH3O, Cl, Br, I, NO , o-NH2, p-(CH3)3C) on the biomimetic catalytic hydroxylation and chlorizaiton of cyclohexane with PhIO was studied. The yields of cyclohexanol and chlorocyclohexane increased with the electron-withdrawing ability of the substituent in this manganese complex. The fair linear correlations between the yields of cyclohexanol and para or ortho substituent constant are presented as:logYx/YH = 0.310p+0.03, logyx/YCH3 = 0.61σ0.07Es+0.05, But there are no linear correlations between the yields of chloro-cyclohexane and either para, ortho or meta substituent constants.     

Diclobutrazol的合成及其生物活性研究

Ｄｉｃｌｏｂｕｔｒａｚｏｌ的合成及其生物活性研究张洪奎，廖联安，陈明德，叶向阳，郭奇珍（厦门大学化学系厦门３６１００５）关键词：Ｄｉｃｌｏｂｕｔｒａｚｏｌ，相转移催化，合成，生物活性Ｄｉｃｌｏｂｕｔｒａｚｏｌ（１）俗名粉锈清，是一种广谱内吸性杀菌剂，...     

微量稀土对超导稳定化基体铜材的性能和组织的影响

研究了微量稀土元素对铜的机械性能、导电性和组织的影响，在铜中加入微量钇、钕、镝、铒和富铈混合稀土后，使铜的抗拉强度有所提高，并保持良好的塑性和导电性。     

Determining PPARγ-ligand binding affinity using fluorescent assay with cis-parinaric acid as a probe

Upon the study of small-molecules binding to proteins, the traditional methods for calculating dissociation constants (Kd and Ki) have shortcomings in dealing with the single binding site models. In this paper, two equations have been derived to solve this problem. These two equations are independent of the total concentration or initial degree of saturation of receptor and the activity of the competitive molecule. Through nonlinear fitting against these two equations, Kd value of a probe can be obtained by binding assay, and Ki value of a ligand can be obtained by competitive assay. Moreover, only the total concentrations of receptor([R]t), ligand([L]t) and probe([P]t) are required for the data fitting. In this work, Ki values of some typical ligands of PPARγ were successfully determined by use of our equations, among which the Ki value of PPARγ-LY171883 was reported for the first time.