Imidazole Coordinated Sandwich-type Antimony Polyoxotungstates Na9[ {Na（H=O2}3{M（C3H4N2）}3（ Sb W9O33）2]·xH=O（M=Ni^Ⅱ, Co^Ⅱ, Zn^Ⅱ, Mn^Ⅱ）

The imidazole covalently coordinated sandwich-type heteropolymngstates Na9[ {Na（H=O2}3{M（C3H4N2）}3（ Sb W9O33）2]·xH=O（M=Ni^Ⅱ, Co^Ⅱ, Zn^Ⅱ, Mn^Ⅱ） were obtained by the reaction of Na2WO4·2H2O, SbCl3·6H2O, NiCl2·6H2O [MnSO4·H2O, Co（NO3）2·6H2O, ZnSO4·7H2O] and imidazole at pH≈7.5. The structure of Na9[{Na（H2O）2}3{Ni（C3H4N2）}3（SbW9O33）2]·32H2O was determined by single crystal X-ray diffraction. Polyanion [{Na（H2O）2}3{Ni（C3H4N2）}3（SbW9O33）2}3]^9- has approximate C3v symmetry, imidazole coordinated six-nuclear duster [{Na（H2O）2}3{Ni（C3H4N2）}3]^9＋ is encapsulated between two （α-SbW9O33）^9-, the three rings of imidazole in the polyanion are perpendicular to the horizontal plane formed by six metals （Na-Ni-Na-Ni-Na-Ni） in the central belt, and x-stacking interactions exist between imidazoles of neighboring polyanions with dihedral angel of 60%. The compounds were also characterized by IR, UV-Vis spectra, TG and DSC, and the thermal decomposition mechanism of the four compounds was suggested by TG curves.     

不对称Salen-Mn(Ⅲ)配合物催化PNPP水解的动力学研究

用分光光度法研究了两种不对称Salen-Mn(Ⅲ)配合物催化α-吡啶甲酸对硝基苯酚酯(PNPP)的水解动力学.提出了相应的PNPP催化水解机理,讨论了底物浓度、体系的酸碱度、温度以及配合物结构对PNPP催化水解反应的影响.结果表明:此两种Schiff碱锰(Ⅲ)配合物在催化PNPP水解中均表现出较好的催化活性,PNPP水解速率随着底物浓度、体系pH值的增大而增大;在15～55℃温度范围内,未观察到催化剂失活现象;其中,带有苯并氮杂-15-冠-5侧基的不对称Salen-Mn(Ⅲ)配合物比带有吗啉基的另一配合物拥有更高的催化活性,这可能主要由这两种模拟水解酶之间较大的疏水微环境差异所引起.     

A Method for Clustering and Screening of Long-dimensional Chemical Data Based on Fingerprints and Similarity Measurements

A method for the treatment of long-dimensional chemical data arrays is presented in this work with the aim of maximising classification models. The method is based on the construction of fingerprints and the subsequent generation of a similarity matrix. The similarity calculation has been modified through a scaling process to take into account different significance shown by the variables. The method was applied to spectral measurements of wines and several aspects were studied, namely: threshold considered in the construction of fingerprints and patterns, weighting factor used for scaling, normalisation method, etc. The application of both Principal Components Analysis and Soft-Independent Modelling of Class Analogies to the similarity matrices gave better classifications of the information than those obtained using original data.     

HPLC determination of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in alcoholic beverages

A method for the determination of 2-furaldehyde (F) and 5-hydroxymethyl-2-furaldehyde (HMF) in alcoholic beverages by high performance liquid chromatography (HPLC) is described. A C-18 column and an acetonitrile-water mobile phase with isocratic elution were used. UV detection at 280 nm was carried out. The method was validated according to the EURACHEM guidelines. The procedure offers a high specificity and detection limits of the order of 0.005 μg mL^− 1. Recoveries of 94-103% were obtained from spiked samples at different levels with both analytes. Intermediate precision calculated for a period of 2 months was + 0.8% for HMF and + 0.4% for F. The method was applied to the analysis of alcoholic beverages like bourbon, rum, brandy, liquors and aperitif wines.     

全反式维甲酸合钇(Ⅲ)配合物对DNA的切割和键合作用(英)

以紫外光谱、荧光光谱、粘度法和凝胶电泳方法研究了全反式维甲酸合钇(Ⅲ)配合物与DNA的作用。结果表明，该配合物能在生理条件下比配体和金属离子更有效地切割质粒DNA，体系离子强度和pH值的变化对配合物的切割活性有较大影响，自由基捕捉剂的加入不影响配合物的切割活性。该配合物对DNA的切割可能通过水解机理进行。该配合物可使DNA的粘度增加，使EB-DNA体系的荧光强度和DNA溶液的紫外吸收强度降低。据此推断，该配合物主要以嵌入方式与DNA作用。     

Unusual volumetric and hydration behavior of the catanionic system sodium undecenoate: sodecyltrimethylammonium bromide

Following the studies on the effect of double bonds in the surfactant hydrophobic tail on the formation of mixed surfactant aggregates, we studied the viscosity and density of the system Sodium 10-undecenoate (SUD)–decyltrimethylammonium bromide (DTAB)–water. We found that the partial molar volume (pmv) and intrinsic viscosity of both, micellised and unmicellised mixtures, are non-ideal, dependent on the mixture composition and related to structural changes in micelles. These phenomena are caused by the presence of the double bond at the distal extreme of the SUD molecule, which has some affinity with water by formation of hydrogen bonds. In particular, as far as we know, this is the first report on non-ideal behavior of the pmv in mixed micelles.     

Indene and pseudoazulene discotic liquid crystals: a synthetic and structural study

Several new liquid-crystalline indene and pseudoazulene systems are reported. These molecules give rise to either columnar hexagonal mesophases and/or columnar plastic phases. The unique nature of these compounds stems from their non-classical discotic structure. Although the molecules have rigid aromatic cores, they lack terminal tails and instead the polarizable atoms (S, halogens) or polar groups (CN, CO) act as unusual soft parts. On the basis of many structurally related materials, we conclude that for this type of compound molecular stacking in the solid state is a prerequisite for the appearance of a columnar mesophase, although other intermolecular interactions within the layers are also important in establishing liquid-crystalline order. The behavior reported for these mesomorphic molecules opens up new possibilities in the search for related molecular interactions that might be useful for the construction of supramolecular architectures with particular properties.     

A High Sensitivity Detection Method of Singlet Oxygen and Superoxide Anion

This paper, for the first time, reports a method that can be used as a highly sensitive probe for singlet oxygen (^1O2) and superoxide anion (O2^-) in vitro or in vivo. FCLA(3,7-dihydro-6-{4-[2-(N‘-(5-fluoresceinyl)thioureido)ethoxy]phenyl}-2-methylimidazo{1,2-a}pyrazin-3-one sodium salt), a chemiluminescence (CL) analysis reagent, has been reported to sensitively react with ^1O2 and O2^- to emit photons with a spectral peak of 525nm. In this work,when human serum albumin (HSA) was added into FCLA solution to enhance the CL intensity,approximately 20 times, compared to that without HSA. The enhanced CL had the same 525 nm spectral peak, identical to that without HSA. By gradually reducing the molecular oxygen content in the solution, we find that the auto-oxidation of oxygen molecules dissolved in the solution plays an important role in the CL process. Based on these experimental evidences, we propose a novel and highly sensitive detection method of ^1O2 and O2^- which may have a great potential in chemical and medical applications.     

Spontaneous Polymerization of An Amino Acid Based Amphiphile at Air/water Interface Investigated by ESI-MS and Transmission IR Spectrometry

Self-assemblies of amphiphilic molecules are proposed to play a ubiquitous role at the early stages of evolution in the formation of primitive biopolymers. [1] As regard to the significance of N-phosphoryl amino acids as a model for the co-evolution of protein and nucleic acids at the prebiotic stage, [2] amphiphilic N-phosphoryl amino acids with two hydrophobic tails were synthesized. [3]     

含两种不同介晶基团的半刚性共聚酯液晶态的结构研究

用Ｘ－光衍射，偏光显微镜及ＤＳＣ对含两种不同长度介晶基团４，４’－联苯二酚（Ⅰ）和对苯二甲酸二（对羟苯基）酯（Ⅱ）的系列共聚酯的液晶态进行了表征，据其液晶态中两种介晶单元的堆砌方式提出了可能的模型，这种模型很好地解释了液晶态的Ｘ－光衍射分布．