4-(4'-Methyltetrafluorophenyl)-2,3,5,6-tetrafluorobenzyl bromide: a new electrophoric derivatizing reagent

Commercially-available 4,4'-dimethyloctafluorobiphenyl was converted in a single step to 4-(4'-methyltetrafluorophenyl)-2,3,5,6-tetrafluorobenzyl bromide (MTFP-TFBBr) for the purpose of providing a new electrophoric derivatizing reagent. When reacted with this reagent, 2-fluoro-O6-(2'-hydroxyethyl)hypoxanthine, a model analyte, gave a mixture of isomeric products (apparently substituted at N7 and N9, analogous to its known reaction with pentafluorobenzyl bromide), and 53 femtograms of the mixture was detected at S/N = 10 by gas chromatography electron capture mass spectrometry (GC-EC-MS). As intended, the volatility of the MTFB-TFBBr derivative was much less (two-fold) than that of the corresponding pentafluorobenzyl derivative. It is anticipated that MTFB-TFBBr sometimes will be useful in providing an electrophoric derivative that encounters less background noise in analysis by electrophore derivatization/GC-EC-MS.     

Synthesis of di-μ-oxo-tetra-(α-pentyloxy)tin(Ⅳ)phthalocynine

Axially substituted tin phthalocyanines, namely dichloride-tetra-(pentyloxy) tin (IV) phthalocyanine 3 and its dimmer di-cyanine 4 were synthesized. The catalytic effect of H2O-free CaCl2 in quinoline was used for condensation of dihydroxy tin phthalocyanine 3 to the cofacially array dimmer 4. Their structures were characterized by UV-vis, IR, elemental analysis, MS, as well as 1HNMR spectroscopy.     

Novel Water‐Soluble Shape‐Regulatable Luminescent Nanoparticles by Non‐Covalently Bonded Self‐Assembly

Summary: Novel non‐covalently connected water‐soluble nanoparticles that contain poly(fluorene‐co‐phenylene) with hydroxy‐capped alkoxy side chains (PF3BOH) and poly(acrylic acid) (PAA) have been obtained and characterized. With different proportions of PF3BOH and PAA, the shape and size of the nanoparticles can be regulated. The nanoparticles are quite stable in water with no precipitate being observed after weeks. Transmission electron microscopy and dynamic laser light scattering are used to confirm the morphology of the PF3BOH/PAA nanoparticles. Their optical properties have been investigated and show similar optoelectronic properties to a PF3BOH solid film although they do not undergo aggregation.

TEM images of the nanoparticles obtained upon varying the PAA/PF3BOH content.     

Investigations into the synthesis and fluorescence properties of Eu(III), Tb(III), Sm(III) and Gd(III) complexes of a novel bis-beta-diketone-type ligand

A novel bis-beta-diketon ligand, 1,1'-(2,6-bispyridyl)bis-3-phenyl-1,3-propane-dione (L), was designed and synthesized and its complexes with Eu(III), Tb(III), Sm(III) and Gd(III) ions were successfully prepared. The ligand and the corresponding metal complexes were characterized by elemental analysis, and infrared, mass and proton nuclear magnetic resonance spectroscopy. Analysis of the IR spectra suggested that each of the lanthanide metal ions coordinated to the ligand via the carbonyl oxygen atoms and the nitrogen atom of the pyridine ring. The fluorescence properties of these complexes in solid state were investigated and it was discovered that all of the lanthanide ions could be sensitized by the ligand (L) to some extent. In particular, the Tb(III) complex was an excellent green-emitter and would be a potential candidate material for applications in organic light-emitting devices (OLEDs) and medical diagnosis.     

Increasing structure dimensionality of copper(I) complexes by varying the flexible thioether ligand geometry and counteranions

This work focuses on the systematic investigation of the influences of pyrimidine-based thioether ligand geometries and counteranions on the overall molecular architectures. A N-containing heterocyclic dithioether ligand 2,6-bis(2-pyrimidinesulfanylmethyl)pyridine (L1) and three structurally related isomeric bis(2-pyrimidinesulfanylmethyl)benzene (L2-L4) ligands have been prepared. On the basis of the self-assembly of CuX (X = I, Br, Cl, SCN, or CN) and the four structurally related flexible dithioether ligands, we have synthesized and characterized 10 new metal-organic entities, Cu4(L1)2I4 1, Cu4(L1)2Br4 2, [Cu2(L2)2I2.CH3CN]n 3, [Cu(L3)I]n 4, [Cu(L3)Br]n 5, [Cu(L3)CN]n 6, [Cu(L4)CN]n 7, [Cu2(L4)I2]n 8, [Cu2(L4)(SCN)2]n 9, and [[Cu6I5(L4)3](BF4).H2O]n 10, by elemental analyses, IR spectroscopy, and X-ray crystallography. Single-crystal X-ray analyses show that the 10 Cu(I) complexes possess an increasing dimensionality from 0D (1 and 2) to 1D (3-5) to 2D (6-9) to 3D (10), which indicates that the ligand geometry takes an essential role in the framework formation of the Cu(I) complexes. The influence of counteranions and pi-pi weak interactions on the formation and dimensionality of these coordination polymers has also been explored. In addition, the photoluminescence properties of Cu(I) coordination polymers 4-10 in the solid state have been studied.     

Supramolecular assemblies with tunable morphologies from homopolymeric and small organic molecular building blocks

This work demonstrates the formation of micrometer-sized supramolecular assemblies with tunable morphologies using a homopolymer, poly(4-vinylpyridine), and a small organic acid, 5,7-dodecadiynedioic acid, as the building molecules. Three different morphologies (hollow spheres, solid spheres, and rods) were obtained, depending on the molar ratio of the building molecules. It is proposed that hydrogen bonding between P4VP and DCDA and the pi-pi stacking of the diacetylenic moieties are responsible for the formation of these assemblies. Interestingly, ordered hexagonal and lamellar mesostructures were also formed within the microstructure during the co-assembly process. As a result, UV irradiation of the supramolecular assemblies polymerized the diacetylenic moieties, resulting in cross-linked and responsive blue polydiacetylenic assemblies that can change color to red upon external stimuli (e.g., thermal stimuli). This work provides a novel concept of the synthesis of responsive supramolecular assemblies from a homopolymer and small organic molecules.     

平行平板间电流变液非零压力梯度Couette流动的稳定性分析

采用Rajagopal和Wineman所提出本构方程,对电流变液在二维平行平板间非零压力梯度Couette流动的线性稳定性问题进行研究.通过分析和数值计算发现,任何壁面运动都将使流动稳定性增强.在外加电场存在的情况下,电流变液效应也将使流动稳定性增强.     

以新型模板方法合成中孔SiO_2分子筛(英文)

以廉价、生物可降解的两性表面活性剂十四烷基甜菜碱作为模板剂,以正硅酸乙酯为硅源,在酸性条件下成功地合成了具有螺旋状孔道结构的 SiO_2中孔分子筛 .热重表征结果说明,采用溶剂萃取（乙醇的水溶液为萃取剂）的方法,近乎 100％的模板剂可以脱除回收 .     

Spontaneous coating of carbon nanotubes with an ultrathin polypyrrole layer

A novel protocol for precisely coating individual multiwall carbon nanotubes (MWCNTs) with an ultrathin layer of polypyrrole was developed. The nanocoated MWCNTs were successfully prepared by in situ chemical deposition of polypyrrole in an aqueous suspension of MWCNTs. The coating layer was very uniform and the thickness of the layer was determined by controlling the monomer concentration used, which gave nanometer precision. The products were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and conductivity and current-voltage measurements. The ultrathin polypyrrole layer could electrically insulate individual MWCNTs.