聚合物假冠醚研究(IV) 酚醛型双氮杂假冠醚聚合物的吸附特性

研究了以双氮杂假冠醚环为主体功能基的酚醛型聚合物对金属离子的吸附性能．结果表明,聚合物对K ,Hg2 ,Na ,Cd2 ,Pb2 和Cu2 离子具有良好的吸附性能,其吸附容量分别达1．79mmol／g-r,1．38mmol／g-r,0．89mmol／g-r,0．68mmol／g-r,0．63mmol／g-r和0．57mmol／g-r,对K 和Hg2 离子具有良好的吸附选择性．通过FTIR光谱法对吸附机理作了初步探讨．     

Fluoro-tagged osmium and iridium nanoparticles in oxidation reactions

Osmium and iridium metal nanoparticles were supported on a fluorous organic-inorganic hybrid material prepared by the sol-gel process. Moreover, we also found that the thermolysis of the Ir₄(CO)₁₂ cluster in simply diphenylether also gave Ir(0) nanoparticles. All the materials were studied as catalysts in oxidation processes. Fluoro-tagged iridium nanoparticles were particularly active in aerobic oxidation processes, whereby the catalytic activity could be greatly enhanced through a simple pre-activation procedure. With this material, benzylic alcohols could be oxidized under O₂ balloon in the absence of a basic additive; the oxidative stopped selectively to the corresponding benzaldehyde. Promisingly, the same reaction conditions were used in a benzylic CH oxidation of xanthene.     

Greenish metal-lustrous organic crystals formed from 1-aryl-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrroles

On the treatment of 1-aryl-2-(2-furyl)-5-(2-thienyl)pyrroles with tetracyanoethylene, 1-aryl-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrroles were produced. These compounds formed crystals with greenish metallic luster. In their solid-state UV-vis-NIR diffuse reflection-absorption spectra, absorption band corresponding to metallic reflection spreads in the range of 550-900 nm. Furthermore, strong absorption appeared below 520-540 nm. This absorption results in the appearance of green color. Single-crystal X-ray crystallographic analysis revealed the crystal structure of 1-(4-methoxyphenyl)-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrrole (2c). The distinct features of the crystal structure are as follows: (1) the thiophene-pyrrole-furan-tricyanoethenyl π-system is approximately flat; (2) the conformational relation between the pyrrole ring and the furan ring is anti, that is, these rings are pointing in opposite directions and the dihedral angle of N-C-C-O=180°; (3) as a result, the tricyanoethenyl group is far from the 4-methoxyphenyl group; (4) the molecules of 2c are arranged in a ribbon structure; (5) the ribbons are assembled side-by-side to form a terraced layer; (6) the layers stack so that the π-orbitals of 2c become close to each other.     

垂直自支撑式金属有机框架多级结构单晶用于锂定向沉积

金属有机框架材料(MOF)是由金属离子或簇和有机配体通过配位键自组装形成的多孔晶体材料.MOF及其衍生物具有开放金属位点和极大的比表面积,广泛地应用在催化领域.然而,MOF材料由于存在暴露活性位点较少,传质受限或易发生不可控制的聚集等问题,会导致活性位点的损失,极大地限制了其在催化领域的应用.多级结构不仅提供更多的暴露...     

Thermolytic Transformation of Organometallic Polymers Containing the Cr(CO)<Subscript>5</Subscript> Precursor into Nanostructured Chromium Oxide

Thermal treatment in air of the organometallic polymer (1) results in the formation of nanometer-size metal oxide particles. Cr particles in the 35–85 nm range, mostly 54 nm, immersed in an phosphorus oxides matrix were found. ATG studies in air suggest that the formation of the nanostructures occurs in four steps, the first involving loss of the carbonyl groups of the Cr(CO)₅ fragment. The following steps involve the oxidation of the organic matter and finally the oxidation of the chromium to give the pyrolytic product. The use of these kinds of organometallic polymers as precursors for a general and potential new route to materials having metal/metal oxide nanostructures is discussed.     

Heavy metals as toxicants in big cities

Heavy Metals (HMs) can exert detrimental effects on human health and on the environment. Their ecotoxicological properties are generally well known. As regards human toxicology, new aspects should be taken into consideration—gender and age dependence. The HMs chemical risk can be estimated and in this context, city demography data help to evaluate today's ecological situation (including HMs) and to predict the dynamics of future urbanization.As regards urban atmosphere, motor vehicles (Pb) and industry (V, Ni, Cr, Cd) exert the greatest influence; water, soil, vegetation also experience menace caused by HMs. Urban environments should be protected against contamination posed by HMs: the health status of big cities is dependent on adequate and safe supply of water. Vegetation plays a helpful role in reducing HM content in the atmosphere and the soil. Awareness of the inhabitants regarding the risks posed by HMs also counts as critical factor today. Ecoeducation at the beginning of the new century can be taken into consideration.     

Optical properties of surface-patterned nanostructures

This concepts article describes our developments in nanopatterning related to photonics. We have a nanopatterning toolkit that can generate functional, nanostructured surfaces at nm-length scales and over cm²-areas in a single (or small number of) step(s). This paper will focus on three examples of surface-patterned nanostructures and their optical properties: (i) one-dimensional arrays of metallic nanoparticles; (ii) arrays of small-diameter ZnO nanowires; (iii) mesoscale structures of CdSe/ZnS nanocrystals. The potential for advances in nanopatterning to contribute to a broad range of light-based applications will be discussed.     

Multiple morphological micelles formed from the self-assembly of poly(styrene)-b-poly(4-vinylpyridine) containing cobalt dodecyl benzene sulfonate

A series of supramolecular block copolymers were prepared using poly(styrene)-b-poly(4-vinylpyridine)(PS-b-P4VP) which coordinated with cobalt dodecyl benzene sulfonate (Co(DBS)₂) in tetrahydrofuran (THF). Fourier transformation infrared spectroscopy (FTIR), UV-vis absorption spectroscopy (UV) and differential scanning calorimetry (DSC) showed that Co(DBS)₂ coordinated to the lone electron pairs of the pyridine nitrogens in the P4VP block and leaded to complexes. The supramolecular block copolymers could self-assemble into nanosized micelles with different shapes and dimensions in THF, depending on the number of Co(DBS)₂ groups per 4-vinylpyridine (repeat unit was denoted by n) and the ratio between PS block length and P4VP block length. Transmission electron microscopy (TEM) results showed that when the number of repeat units of P4VP was more than that of PS, micelles with different interesting shapes such as spheres, rods, vesicles, large compound vesicles (LCVs) and the large compound micelles (LCMs) were observed if increasing the content of the Co(DBS)₂ in PS-b-P4VP copolymer/THF solution; When the number of repeat units of P4VP was less than that of PS, the micelle morphologies changed from spheres to rods, bi-layer, and LCMs if the Co(DBS)₂ content was increased progressively.     

Interaction of CO with Cu5OZr50 metallic glass surface

The adsorption of CO has been studied on the surface of a Cu₅₀Zr₅₀ metallic glass using X-ray and ultraviolet photoelectron spectroscopic techniques. CO dissociates on both these surfaces leading to the formation of graphitic and carbidic carbon species on the surface. However a reversal in intensity of the two species is observed on the metallic glass surface compared to that on the Zr metal surface. While Zr gets oxidised due to the oxygen produced as a result of the dissociation of CO, Cu remains unoxidised. Contribution No. 501 from the Solid State and Structural Chemistry Unit.