Filled latex composites with high dielectric constant, based on dispersed ferroelectrics

The possibility of controlling the physicochemical properties of suspensions and the electrical properties of filled latex composites containing dispersed ferroelectrics was examined. The use of ferroelectrics as fillers allows preparation of polymeric composites with high dielectric constant ? and low dielectric loss, used, e.g., for the development of dielectric functional layers of electroluminescence light sources.     

EFFECT OF STRESSES ON POLYMER OXIDATION. QUANTITATIVE ASPECTS. III. KINETICS

Abstract

In the previous review cyclic molecules (model compounds) in reactions not involving ring opening and physical properties of stressed polymers were considered.     

Trends in formation of the nanocrystalline structure and cationic ordering in the Dy2O3-HfO2 (1: 1) system

Evolution of the nanocrystalline structure of the complex oxide Dy₂HfO₅ in the course of thermal annealing at temperatures to 1600°C has been studied by a combination of X-ray and synchrotron methods, including traditional and anomalous X-ray diffraction, PDF, EXAFS, and SAXS. The changes in crystallite size upon annealing of the as-synthesized amorphous precursor have been analyzed in detail. The systematic distortions of a fluorite-type perfect crystal structure (space group $Fm\bar 3m$ ) related to the nonequivalence of the local environment of the Dy and Hf cations but not resulting in formation of a pyrochlore-type cationordered structure in this system have been examined.     

Ellipsometric and IR spectroscopic study of the surface interaction of binary Al-REM alloys with water

The effect of Al-REM binary alloys’ composition on the kinetics of their surface oxidation by water is studied by means of ellipsometry and IR spectroscopy. Intermetallides with ～21 at % rare-earth metal in aluminum are oxidized in distilled water at 100°C, along with alloys of eutectic composition (Al-～2 at % REM) in solid and disperse state. It is found that the kinetic dependences of the thickness of films formed on pollycrystalline alloy samples and the IR transmission spectra of dispersed samples show that increasing the quantity of dopant REM in aluminum lowers the reactive capability of aluminum under certain conditions. It is found that the experimental ellipsometric results are described by a two-layer model consisting of a substrate, an inner oxide layer and an outer layer of hydroxide.     

Regioselective Sequential Additions of Nucleophiles and Electrophiles to Perfluoroalkylfullerenes: Which Cage C Atoms Are the Most Reactive and Why?

The sequential addition of CN^? or CH₃^? and electrophiles to three perfluoroalkylfullerenes (PFAFs), C_s‐C₇₀(CF₃)₈, C₁‐C₇₀(CF₃)₁₀, and C_s‐p‐C₆₀(CF₃)₂, was carried out to determine the most reactive individual fullerene C atoms (as opposed to the most reactive C?C bonds, which has previously been studied). Each PFAF reacted with CH₃^? or CN^? to generate metastable PFAF(CN)^? or PFAF(CH₃)₂^2? species with high regioselectivity (i.e., one or two predominant isomers). They were treated with electrophiles E⁺ to generate PFAF(CN)(E) or PFAF(CH₃)₂(E)₂ derivatives, also with high regioselectivity (E⁺=CN⁺, CH₃⁺, or H⁺). All of the predominant products, characterized by mass spectrometry and ¹⁹F NMR spectroscopy, are new compounds. Some could be purified by HPLC to give single isomers. Two of them, C₇₀(CF₃)₈(CN)₂ and C₇₀(CF₃)₁₀(CH₃)₂(CN)₂, were characterized by single‐crystal X‐ray diffraction. DFT calculations were used to propose whether a particular reaction is under kinetic or thermodynamic control.     

Rapid determination of RMSDs corresponding to macromolecular rigid body motions

Finding the root mean sum of squared deviations (RMSDs) between two coordinate vectors that correspond to the rigid body motion of a macromolecule is an important problem in structural bioinformatics, computational chemistry, and molecular modeling. Standard algorithms compute the RMSD with time proportional to the number of atoms in the molecule. Here, we present RigidRMSD, a new algorithm that determines a set of RMSDs corresponding to a set of rigid body motions of a macromolecule in constant time with respect to the number of atoms in the molecule. Our algorithm is particularly useful for rigid body modeling applications, such as rigid body docking, and also for high‐throughput analysis of rigid body modeling and simulation results. We also introduce a constant‐time rotation RMSD as a similarity measure for rigid molecules. A C++ implementation of our algorithm is available at http://nano‐d.inrialpes.fr/software/RigidRMSD . © 2014 Wiley Periodicals, Inc.     

Enumeration of non-labile oxygen atoms in dissolved organic matter by use of 16O/18O exchange and Fourier transform ion-cyclotron resonance mass spectrometry

We report a simple approach for enumeration of non-labile oxygen atoms in individual molecules of dissolved organic matter (DOM), using acid-catalyzed ¹⁶O/¹⁸O exchange and ultrahigh-resolution Fourier-transform ion-cyclotron-resonance mass spectrometry (FTICR-MS). We found that by dissolving DOM in H₂ ¹⁸O at 95 °C for 20 days it is possible to replace all oxygen atoms of DOM molecules (excluding oxygen from ether groups) with ¹⁸O. The number of exchanges in each molecule can be determined using high-resolution FTICR. Using the proposed method we identified the number of non-labile oxygen atoms in 231 molecules composing DOM. Also, using a previously developed hydrogen–deuterium (H/D)-exchange approach we identified the number of labile hydrogen atoms in 450 individual molecular formulas. In addition, we observed that several backbone hydrogen atoms can be exchanged for deuterium under acidic conditions. The method can be used for structural and chemical characterization of individual DOM molecules, comparing different DOM samples, and investigation of biological pathways of DOM in the environment.     

Synthesis of New Ursane-Type Hybrids with Morpholinomethyl-, Dialkylamino-, and Hydroxyl-Substituted Azoles

Chemistry of Natural Compounds - Ursane-type triterpenoids containing functionalized heterocyclic substituents were chemically modified. Aminomethylation of ursane hybrids with 1,3,4-oxadiazole-...     

Synthesis and study of thioglycoside conjugates of 4-chloro-1,2-dithiol-3-one as potential cancer-preventive substances in vitro and in vivo

Russian Chemical Bulletin - Nucleophilic substitution of the chlorine atom in 4,5-dichloro-1,2-dithiol-3-one using 1-thio-β-d-glucopyranose and its 2,3,4,6-tetra-O-acetyl derivative in...