Facile synthesis of substituted dihydro-1,4-dithiins and -1,4-dithiepins from α-oxo ketene cyclic dithioacetals

A novel and facile synthesis of substituted 2,3-dihydro-1,4-dithiins and 6,7-dihydro-5H-1,4-dithiepins based on the reactions of α-bromo/hydroxy ketones with α-oxo ketene cyclic dithioacetals has been developed. A general mechanism for the reactions is proposed.     

Self-assembly between silver(I) and di- and tri-2-pyridines with flexible spacer: formation of discrete metallocycle versus coordination polymer

The self-assembly of metallosupramolecules from reactions of flexible 2-pyridyl ligands and silver salts is described. When 1,3-bis(2-pyridyl)propane (L1), tris[(2-pyridyl)methyl]methane (L2), and 1,3-bis(2-pyridyl)-2-tolylpropane (L3) are used in combination with silver ions, novel discrete metallocyclic complexes are formed in crystals. Moreover, the self-assembly of 1,3-bis(2-pyridyl)-2-phenylpropane (L4) with silver nitrate yields a coordination polymer. The examination of its solution shows that this coordination polymer is formed via the solution-based discrete metallocyclic species.     

A method to construct polyelectrolyte multilayers film containing gold nanoparticles

Gold nanoparticles in polyelectrolyte multilayers film can be easily prepared by repeating immersion of a substrate in poly(diallyl dimethylammonium) chloride (PDDA)-AuCl₄⁻ complexes solution followed by reduction Au³⁺ through heating. UV-vis spectroscopy, cyclic voltammetry (CV) and tapping-mode atomic force microscopy (AFM) are used to confirm the successful construction of the polyelectrolyte multilayers film and the formation of gold nanoparticles. The multilayers film shows electrocatalytic activity to dioxygen reduction.     

Infrared and electronic spectra of copper (II) complex of maleonitriledithiolate and 4,4'-dimethyl-2, 2'-bipyridine and their theoretical studies

The molecular structure and binding, as well as infrared and electronic spectroscopic properties for the title complex Cu(mnt)(dmbpy)(mnt(2-)=maleonitriledithiolate, dmbpy=4,4'-dimethyl-2,2'-bipyridine) were studied in this paper. With semi-empirical PM3 and non-empirical DFT (B3LYP/6-311G*) methods, the molecular geometry of the complex was optimized and corresponding vibrational spectra in the gaseous state were obtained. The calculated results derived from DFT were more reasonable than those from PM3. The point group of Cu(mnt)(dmbpy) in isolated gaseous state was C(2), in which Cu(II) adopted a distorted tetrahedral geometry and the dihedral angle between the N(2)Cu and S(2)Cu planes was about 29.814 degrees. And a complete assignment to the IR spectra of such a complicated molecule was exhibited. With ZINDO/S method an electronic spectrum was calculated. The results showed that the calculated values generally agreed with the observed ones. And a detailed explain was made on its electronic spectra.     

医用聚氯乙烯膜的等离子体表面改性

用两种不同气氛的辉光放电等离子体工艺对医用软质聚氯乙烯（ＰＶＣ）膜进行了表面改性研究。结果表明，聚合性气氛的等离子体改性效果明显优于非聚合性气氛。平整致密的聚合膜对ＰＶＣ增塑剂——邻苯二甲酸二辛酯的迁移和扩散起了阻挡作用，也使膜表面亲水性和表面张力极性成份增大，液固相界面张力减小，生物相容性得以改善。     

Structure and Two-photon Excited Blue Fluorescence of an Asymmetrical Substituted Stilbene

In common fluorescence process, molecular excitation is caused by the absorption of at least a single photon with shorter wavelength. When certain laser is used as the pump source, some compounds can be excited by simultaneous absorption of at least two photons and then the emission of up-converted fluorescence may occur. This process is called two-photon excited fluorescence (TPEF)1,2. Because of several advantages of TPEF, including intrinsic high three-dimensional resolution and the p…     

Preparation and Characterization of Nanoscopic Organic Semiconductor of Oxovanadium Phthalocyanine

Nanoscopic particles of oxovanadium phthalocyanine (VOPc, phase-II) with different particle sizes are prepared by aggregation of VOPc molecules in the presence of surfactants for the first time. A size effect in the region of nanoscale was observed in the UV-visible spectra. The photoconductivity of the nanoscopic VOPc is much higher than that of bulk VOPc. Copyright 1999 Academic Press.     

提高大分子Fullerene含量的有效方法

通过用掺有异相物质的石墨电极进行电弧反应，所得的混合物中大分子Ｆｕｌｌｅｒｅｎｅ的含量在１０％以上，为进一步分离，提纯以及深入研究大分子Ｆｕｌｌｅｒｅｎｅ打下了基础。研究发现，阳极材料中完整石墨结构的存在是生成Ｆｕｌｌｅｒｅｎｅ的必要条件，异相物质的存在为Ｆｕｌｌｅｒｅｎｅ的生长提供了热的载体，从而使产物中大分子Ｆｕｌｌｅｒｅｎｅ的含量增加。     

Synthesis of Calix[4]arene Derivatives with NLO Properties

The new chromophore compounds with NLO properties were prepared by Knoevenagel condensation from forrnyl or diformyl calix[4/arene and isophorone derivatives in the presence of piperidine and acetic acid, respectively. In these chromophore calix[4]arenes, the ring locked trienes were employed as the conjugation bridge and electron acceptor in D-π-A units. The NMR spectra demonstrated that they existed in a cone conformation and consequently non-conjugated D-π-A units could be oriented at nearly the same direction.     

A New Plate for Planar Electrochromatography

JPC – Journal of Planar Chromatography – Modern TLC - A new bonded RP-18 sintered silica gel plate for use in reversed-phase planar electrochromatography has been prepared in our...