Core/shell particles containing 3-(methacryloxypropyl)-trimethoxysilane in the shell: synthesis, characterization, and application

In comparison to the corresponding single-component counterparts, core/shell particles are widely used due to their better physical and chemical properties. The surface properties of core/shell particles evidently play an important role in the process of application. It is easy to deduce that surface properties mostly depend on the properties of the component in the shell. Therefore, desirable materials of shell are very significant for the study of composite materials, especially in core/shell field. It is well known that polysiloxane has excellent properties, such as the water repellency, high flexibility, low surface energy, and biocompatibility. Its application, however, is limited due to poor cohesiveness and poor film-forming properties. Recently, much endeavor has been made to overcome such flaws. It is found that polyacrylate is commonly considered for its good cohesiveness and excellent film-forming property. The combination of polysiloxane and polyacrylate has been shown to be important in the composite material field, especially as core/shell particles. Unfortunately, their hydrophobicity is considerably different and thus, the core/shell particles consisting of polyacrylate (PA)/polysiloxane (PSi) are hard to prepare by general seeded emulsion polymerization, and are also scarcely available in the literature. In this study, the new core/shell PA/PSi particles with poly(butyl methacrylate) (PA) as the core and poly(3-(methacryloxypropyl)-trimethoxysilane) (PSi) as the shell were prepared by dispersion polymerization under the kinetically controlled conditions. The characterization of the particles by TEM, DSC, particle size analyzer as well as static contact angle confirmed the formation of core/shell structure. The application of core/shell (PA/PSi) particles also has been considered and discussed here.TEM micrographs of core/shell (PA/PSi) particles.     

TONO萃取金(Ⅳ)及其机理的研究

本文研究在盐酸介质中以三辛胺氮氧化物(分子式为(C_8H)O,简称TOO),萃取金(Ⅲ)的行为及其机理。用等温曲线、斜率、Job法、紫外光谱、摩尔电导、红外和核磁共振等方法确定了萃合物的组成,表明系由两个TOO分子和H~+发生氢键作用,并与AuCl形成离子缔合物,其组成可表述为[TON0…H~+…0NOT]AuCl_4-。     

Expected and unexpected results from combined beta-hairpin design elements

A model beta-hairpin dodecapeptide [EFGWVpGKWTIK] was designed by including a favorable D-ProGly Type II' beta-turn sequence and a Trp-zip interaction, while also incorporating a beta-strand unfavorable glycine residue in the N-terminal strand. This peptide is highly folded and monomeric in aqueous solution as determined by combined analysis with circular dichroism and 1H NMR spectroscopy. A peptide representing the folded conformation of the model beta-hairpin [cyclic(EFGWVpGKWTIKpG)] and a linear peptide representing the unfolded conformation [EFGWVPGKWTIK] yield unexpected relative deviations between the CD and 1H NMR spectroscopic results that are attributed to variations in the packing interactions of the aromatic side chains. Mutational analysis of the model beta-hairpin indicates that the Trp-zip interaction favors folding and stability relative to an alternate hydrophobic cluster between Trp and Tyr residues [EFGYVpGKWTIK]. The significance of select diagonal interactions in the model beta-hairpin was tested by rearranging the cross-strand hydrophobic interactions to provide a folded peptide [EWFGIpGKTYWK] displaying evidence of an unusual backbone conformation at the hydrophobic cluster. This unusual conformation does not appear to be a result of the glycine residue in the beta-strand, as replacement with a serine results in a peptide [EWFSIpGKTYWK] with a similar and seemingly characteristic CD spectrum. However, an alternate arrangement of hydrophobic residues with a Trp-zip interaction in a similar position to the parent beta-hairpin [EGFWVpGKWITK] results in a folded beta-hairpin conformation. The differences between side chain packing of these peptides precludes meaningful thermodynamic analysis and illustrates the caution necessary when interpreting beta-hairpin folding thermodynamics that are driven, at least in part, by aromatic cross strand interactions.     

Rh/Al2O3上CO和NO的吸附性能及相互作用

利用ＴＰ－ＩＲ动态方法研究了ＣＯ和ＮＯ在Ｒｈ／Ａｌ２Ｏ３上吸附性能和相互作用的动态行为，结果表明，Ｒｈ／Ａｌ２Ｏ３的孪生中心对ＣＯ的吸附强于对ＮＯ的吸会，线式和桥式中心则对ＮＯ的吸附强于对ＣＯ的吸附，ＣＯ和ＮＯ共吸附－ＴＰ（ＣＯ和ＮＯ中）－ＩＲ动态过程结果揭示出２２２４ｃｍ＾－１谱带的出现和强度的增加与孪生ＣＯ谱带以及吸附的ＮＯ谱带的强度减弱同时发生，表明是由吸附的ＮＯ和孪生ＣＯ形成Ｒｈ－ＮＣＯ。     

Preparation and structural characterization of a hexanuclear molybdenum (II) cluster containing carboxylate ligands (Bu4N)2[Mo6(μ3-Cl)8(O2CMe)6]

The hexamolybdenum cluster complex [Mo₆(₃-Cl)₈(O₂CMe)₆]^2–, 1 was isolated as the Bu₄N⁺ salt in 71% yield from the reaction of (Bu₄N)₂[Mo₆(₃-Cl)₈Cl₆] with AgO₂CMe in CH₂Cl₂ solvent. The compound was characterized by single crystal X-ray diffraction analysis. The cluster contains an octahedral arrangement of six molybdenum atoms with eight chloride ligands bridging the eight trianglar faces and six carboxylate ligands terminally coordinated through one oxygen atom to each of the six molybdenum atoms. Crystal data: space group =P2₁/n,a=10.713(3)Å,b=14.43(1)Å,c=21.919(4)Å, =94.37(2)°,Z=2, 1965 reflections,R=0.036.     

Conversion of phenyl-substituted cyclopentadienes to pyrylium cations

Phenyl-substituted cyclopentadienes are proved to form phenylated pyrylium cations in the presence of silver(I) perchlorate by insertion of an oxygen atom into the cyclopentadiene-ring. Three phenylated pyrylium compounds, [(Ph(5)C(5)O(+))(ClO(4)(-))](2)(CH(2)Cl(2)) (1), Ag(ClO(4))(H(2)O)(Ph(4)HC(5)O(+)) (ClO(4)(-)) (2), and (Ph(3)H(2)C(5)O(+))(ClO(4)(-)) (3) have been synthesized and characterized. A possible reaction pathway and formation mechanism of the pyrylium cation are proposed and discussed.     

Ni^2—交换蒙脱石中的镍物种及焙烧温度影响研究

对一组自制Ｎｉ＾２＋交换蒙脱石样品中镍物种的存在在形及焙烧温度影响进行了ＴＰＲ和ＸＲＤ考察结果表明，样品中镍负载量等于或小于Ｎｉ＾２＋的交换量时，镍主要以难还原听可交换性阳离子Ｎｉ（ＯＨ）＾ｑ＋ｘ和易还原的自由态镍Ｎｉ（ＯＨ）２或ＮｉＯ两种形式存在。     

Mixed Cationic‐nonionic Surfactants and pH Adjustment Route to Synthesize High‐quality MCM‐48

Using the mixture of cetyltrimethylammonium bromide (CTAB) and p‐Octyl polyethylene glycol phenyl ether (OP‐10) as templates, siliceous MCM‐48 materials can be synthesized with low molar ratio of CTAB to silica (0.139:1) and low concentration of mixed surfactants (ca.5%) and within a wide range of OP‐10/CTAB ratio (0.08?0.25). The materials were characterized by X‐ray powder diffraction, N₂ adsorption/desorption isotherm, TEM, TG‐DSC and ²⁹Si MAS NMR. Measurements indicated that the use of mixed surfactants allowed better condensation and higher ordering of the cubic mesostructure; at the same time, some properties of these materials were sensitive to the OP‐10/CTAB ratio. It was also found that the reduced pH of the gel which had been crystallized for a certain time gave a highly reproducible synthesis with a high silica yield (about 95%). Furthermore, the reaction mechanism of the synthesis is discussed in detail.     

聚合硫酸铁絮凝剂碱度的测定

聚合硫酸铁(PFS)是一种新型高效无机高分子絮凝剂,近年来在生产、生活用水和废水处理上得到日益广泛的应用。PFS的主要成分为碱式硫酸铁的聚合物,化学式可表示为[Fe_2(OH)_n(SO_4)_(3-n/2)]m,其中,n<2,m>10.分子式中的羟基为分子聚合提供氢键,并使PFS具有宽广的pH应用范围。因此,碱度是聚合硫酸铁絮凝剂生产和使用的一个重     

Geometries,vibrational frequencies,and electron affinities of X2Cl (X=C,Si,Ge) clusters

Ab initio quantum chemical calculations have been performed on X₂Cl^? and X₂Cl (X = C, Si, Ge) clusters. The geometrical structures, vibrational frequencies, electronic properties and dissociation energies are investigated at the Hartree–Fock (HF), Møller–Plesset second‐ and fourth‐order (MP2, MP4), CCSD(T) level with the 6‐311+G(d) basis set. The X₂Cl (X = C, Si, Ge) and X₂Cl^? (X = Si, Ge) take a bent shape obtained at the ground state, while C₂Cl^? has a linear structure. The impact on internal electron transfer between the X₂Cl and the corresponding anional clusters is studied. The three different types of electron affinities (EAs) at the CCSD(T) are reported. The most reliable adiabatic electronic affinities, obtained at the CCSD(T)/cc‐pvqz level of theory, are predicted to be 3.30, 2.62, and 1.98 eV for C₂Cl, Si₂Cl, and Ge₂Cl, respectively. The calculated EAs of C₂Cl and Ge₂Cl are in good agreement with theoretical results reported. The correlation effects and basis sets effects on the geometrical structures and dissociation energies are discussed. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007