Large-scale synthesis of tube-like ZnS and cable-like ZnS-ZnO arrays: Preparation through the sulfuration conversion from ZnO arrays via a simple chemical solution route

Arrayed structures are desirable for many applications, but the fabrication of many material arrays remains a significant challenge. As a prominent II-VI semiconductor, large-scale arrayed ZnS structure has not been easily fabricated. Here, we introduce a simple structure conversion route for the synthesis of novel arrayed structures, and large-scale tube-like ZnS structure arrays and cable-like ZnS-ZnO composite arrays were successfully prepared through sulfuration conversion from arrayed rod-like ZnO structure based on a hydrothermal method at low temperature. XRD, EDS, SEM, TEM and PL are used to confirm the formation of the novel arrayed structure and trace the conversion process. The results show that the conversion ratio can be conveniently tailored by the reaction time, and the PL properties of the obtained materials can be adjusted through the conversion ratio. Especially, the cable-like structure holds the PL properties of both ZnO and ZnS structures. This simple solution method can be further extended to the preparation of other semiconductor sulfide and selenide, and can amplify the application field of large-scale arrays of semiconductors.     

四面体型过渡金属配合物的构型与CD的关系

旋光性四面体型过渡金属配合物的圆二色光谱(CD)在d-d跃迁区的特征谱线反映了该类配合物的构型特征。从极化度的多级圆球不对称性模型出发,可将这类配合物的构型与CD在d-d跃迁区的特征谱线之间建立起直接的联系。     

由水杨醇衍生的二苯并冠醚的合成和构型

将水杨醇在ＤＭＦ中与ＮａＨ和二甘醇或三某醇二对甲苯磺酸酯反，合成了２个新的二苯并冠醚（１和２），其结构由元素分析和波谱分析所表征，１ 射线衍射分析确定为反位构型，提出了合成反应的机理。     

Self-assembly of flexible supramolecular metallacyclic ensembles: structures and adsorption properties of their nanoporous crystalline frameworks

The syntheses, structures, and N2 adsorption properties of six new supramolecular metallacycles are reported. Flexible ditopic linkers, 1-4, with systematically varied lengths and conformational degrees of freedom were synthesized utilizing ester linkages. They were used in combination with (dppp)M(OTf)2, where M = Pt(II) and Pd(II), and cis-(Me3P)2Pt(OTf)2 to form flexible supramolecular metallacycles 5-10 in 88-98% isolated yields. Their structures were characterized via multinuclear NMR and X-ray crystallography. The metallacycles stack to form porous structures in the crystalline state. The pore dimensions depend on both the phosphorus ligands attached to the metals and the flexible linkers. Adsorption studies on the porous materials show that 5a, 6, 8, and 9 held 11.7, 16.5, 5.7, and 6.8 cm3/g STP of N2 at 77 K, respectively. A guest-exchange study with nitromethane and toluene reveals that the nanopore in 5 is flexible, a property which was transferred from the linker to the supramolecular structure in the solid state.     

Monitoring of the conversion from triptolide to tripchlorolide in Triptergium wilfordii by micellar electrokinetic caillary chromatography

A novel concocting method to convert Triptolide (T) into Tripchlorolide (T(4)) in the traditional Chinese herb Tripterygium wilfordii Hook F. and a micellar electrokinetic capillary chromatographic (MEKC) approach by which the conversion of Triptolide (T) and Tripchlorolide (T(4)) was identified and determined had been established. Investigations of the influence of different pH values of boric acid and borax buffer and of sodium dodecyl sulfate (SDS) and organic additive concentrations had been carried out, and the optimum separation for T and T(4) was achieved using boric acid and borax of pH 7.0 with 30 mM SDS and 20% (volume ratio) methanol as the running buffer. It was found that MEKC exhibited good accuracy, precision and repeatability and the content of T(4) was greatly increased in the herb that was treated by the new concocting method.     

Amphiphilic miktoarm star copolymers can self-assemble into micelle-like aggregates in nonselective solvents: a case study of polyoxometalate based miktoarm stars

It is well-known that amphiphilic star-shaped copolymers can self-assemble in selective solvents to form complicated micellar constructs as a synergistic result of both the topological constraints and relative volume fractions of the arms. Although the association phenomena of amphiphilic stars have been observed in nonselective solvents, both the structural detail and formation mechanism of these associates are not clear yet. Moreover, these experimental observations are controversial with respect to molecularly dispersed starlike copolymers in nonselective solvents as is popularly believed. To clarify these issues, we have synthesized a series of polyoxometalate-based polystyrene-poly(ethylene glycol)(PS-PEG) miktoarm star supramolecular copolymers(SEW-1–5) by coupling a Keggin-type polyoxometalate of K_4[α-SiW_(12)O_(40)] with 1,2,3-triazolium bridged block copolymers of-PS_n-b~+-PEG_mI~-(n=17, 26, 39, 57, 81; m=45) through ionic exchange reactions, respectively. TEM imaging,contact angle and ~1H NMR studies reveal that SEW-2–5 self-assemble in chloroform, THF, and toluene to create micellelike aggregates ranging from cylinder to sphere with a PS corona and a PEG core, while for SEW-1, reverse bilayers are captured with a PEG corona and a PS core. Among these aggregates, the Keggin clusters of [α-SiW_(12)O_(40)]~(4-) localize at the core-corona interfaces between PS and PEG. In terms of solvent quality, chloroform, THF, and toluene are only slightly poorer for PEG than that for PS with a relative order of chloroformTHFtoluene. These unexpected aggregates originate from the topological constraints of the chemically different arms of PS and PEG in the miktoarm stars, where the weak incompatibility between the PS and PEG arms is intensified appropriately. The presence of the reverse bilayered structures of SEW-1 is due to the magnified steric hindrance of the PEG45 arm with decreasing the molecular weight of the PS17 arm. However, to the best of our knowledge,these are the first examples clearly indicating that miktoarm star copolymers can self-assemble in common good solvents or slightly selective solvents to generate micellelike aggregates. This scenario is not only in sharp contrast to the intuitively considered behavior of unimolecular miktoarm stars in nonselective solvents, but also rather different from the conventional selfassembly behavior of amphiphilic star copolymers in selective solvents.     

Matrix Effects and Behaviors of Elements in Oxalic Acid Medium by Inductively Coupled Plasma Mass Spectrometry

Because of its high sensitivity, wide dynamic range and relative freedom from interferences, inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the determination of trace and ultra-trace levels of elements in various fields1. Due…     

POLYMERIZATION OF OCTAFLUOROCYCLOBUTANE IN GLOW DISCHARGE Ⅱ. ESCA AND IR CHARACTERIZATION OF POLYMER STRUCTURE*

In a capacitively coupled discharge with external electrodes, He, H_2, N_2 or Ar were used as plasmagas, polymerization of octafluorocyclobutane was carried out under different conditions by varyingdischarge power, pressure, plasma gas and plasma-gas/monomer ratio. Structure of polymerizedproducts was characterized by IR spectroscopy and ESCA measurement. It was found that therewere six elements in the products, i.e. C, F, Si, O, N and H. The probably existed groups in poly-mers wer investigated. By analyzing the resolved peaks of C_(1S) region in ESCA spectra, effect of thereaction conditions on degree of branching of the polymerized products and the relationship of thepolymer structure wth the mechanism of the competitive ablation and polymerization process werestudied. In addition, polymer deposition process occurring in glow discharge was discussed.     

沙蚕毒系化合物的结构与生物活性关系

用ＭＮＤＯ－ＰＭ３方法对沙蚕毒系化合物二氢沙蚕毒，硫氰酸酯，巴丹，杀虫单及其异构件的几何构型进行了全自由度优化，并计算了其电子结构，讨论了生物活性与几何构型和电了结构的关系。     

反相高效液相色谱法测定强化奶粉中β-胡萝卜素含量

采用碱皂化石油醚提取,Kromasil C18柱分离,以甲醇∶氯仿=75∶25等度淋洗,二极管阵列检测器检测,测定了强化奶粉中β-胡萝卜素含量.对最佳皂化用碱量、皂化时间、α、β-胡罗卜素及β-胡罗卜素异构体分离条件进行了探索.该方法回收率为91.6%~96.3%,其标准偏差、变异系数分别为1.64%及1.76%.方法简便、快速,精密度及准确度在允许范围内,适用于奶粉中β-胡罗卜素的测定.