Fatty Acids from a Glass Sponge <Emphasis Type="Italic">Aulosaccus</Emphasis> sp. Occurrence of New Cyclopropane-Containing and Methyl-Branched Acids

In order to identify new structures, the free fatty acids from an extract of a glass sponge Aulosaccus sp. (from the north‐west Pacific) belonging to one of the least chemically investigated classes (Hexactinellida), were fractionated by RP‐HPLC and analyzed by NMR spectroscopy and GC–MS of their pyrrolidine derivatives, methyl(ethyl) esters and their dimethyl disulfide adducts. One hundred and twenty‐three C₁₂–C₃₁ acids (including nine new compounds) were detected, one hundred and ten of these compounds have not been found previously in glass sponges. The levels of common methylene‐interrupted polyenes, monoenes of the (n–7) family and less common branched‐chain components proved to be high. New acids were shown to be 5,13‐dimethyl‐tetradec‐4‐enoic, cis‐10,11‐methylene‐heptadecanoic, 10,12‐dimethyl‐octadecanoic, cis‐12,13‐methylene‐nonadecanoic, (14E)‐13‐methyl‐eicos‐14‐enoic, 19‐methyl‐eicos‐13‐enoic, cis‐20,21‐methylene‐heptacosanoic, 27‐methyl‐octacos‐21‐enoic and (22Z)‐nonacos‐22‐enoic. Some important mass spectrometric characteristics of pyrrolidides of homologous cyclopropane fatty acids are reported and discussed.     

Exchange reactions control for selective separation of glyoxylic acid in technological mixtures of glyoxal oxidation

Separation of glyoxylic acid from unpurified multicomponent technological mixtures, resulting in the process of direct oxidation of glyoxal, and preparation of sodium glyoxylate are developed. The mixtures are treated with an optimal amount of CaCO_3, which has to be prespecified by acidic–basic titration of the technological mixtures. Both separation of glyoxylic acid and preparation of sodium glyoxylate take place owing to ionic exchange reactions: calcium glyoxylate is easily converted into glyoxylic acid by action of oxalic acid. Reaction with Na₂CO₃ leads to the formation of sodium glyoxylate.     

DNA-based materials as chemical reactors for synthesis of metal nanoparticles

In this minireview we highlight a recent progress in preparation of DNA-based matrices that can be used as reactors for templating of inorganic nanomaterials and, in particular, highlight catalytic applications of such hybrid materials. We also discuss advantages and disadvantages of DNA utilization as a material and outline prospects of DNA-based technologies in future.     

Structure and conductivity of yttria and scandia‐doped zirconia crystals grown by skull melting

In this paper a detailed study of the (ZrO₂)_1‐x(Y₂O₃)_x (x=0.025–0.15), (ZrO₂)_1‐x(Sc₂O₃)_x (x = 0.06 – 0.11) and (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y (x=0.07 – 0.11; y=0.01 – 0.04) solid solution crystals grown by skull melting technique is presented. The structure, phase composition, and ion conductivity of the obtained crystals were investigated by X‐ray diffraction, transmission electron microscopy, Raman scattering spectroscopy, and impedance spectroscopy. Maximum conductivity as (ZrO₂)_1‐x(Y₂O₃)_x and (ZrO₂)_1‐x(Sc₂O₃)_x solid solution crystals is observed for the compositions containing 10 mol% stabilizing oxide, and the conductivity of 10ScSZ is ~3 times higher than for 10YSZ. Experiments on crystal growth (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y solid solutions showed that uniform, transparent crystals 7Sc3YSZ, 7Sc4YSZ, 8Sc2YSZ, 8Sc3YSZ, 9Sc2YSZ, 9Sc3YSZ, 10Sc1YSZ, and 10Sc2YSZ are single phase crystal containing t″ phase. It is established that a necessary condition of melt growth of (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y single‐phase crystals is the total concentration of the stabilizing oxides from 10 to 12 mol%. The addition of Y₂O₃ affects the (ZrO₂)_1‐x‐y(Sc₂O₃)_x(Y₂O₃)_y solid solution conductivity different ways and depends on the Sc₂O₃ content in the starting composition. The effects of structure, phase composition, concentration, and type of stabilizing oxides on the electrical characteristics of obtained crystals are discussed.     

Kinetics of phase formation in the Ln–O–S (Ln=La,Gd, Y) systems during oxide sulfidation in ammonium thiocyanate vapor

Kinetics and mechanism of phase formation in the Ln–O–S (Ln=La, Gd, Y) systems during Ln₂O₃ sulfidation in ammonium thiocyanate vapor and the identified sequence of transformations of obtained phases in the temperature range 873‐1273 K have been studied. The kinetic dependencies for the reactions involved were fitted by the Jander equation for topochemical heterogeneous reactions with a squared correlation coefficient R²=.99. The reaction rate constants, pre‐exponential factors, and effective activation energies for the reaction formation of compounds have been calculated, and approximate times and low temperatures for the formation of particular phases have been found.     

Influence of residual solvent on physical and chemical properties of amorphous glassy polymer films

One of the most important areas of current research is the study of the influence of the prehistory of samples of amorphous glassy polymers on their physical and chemical properties. The study of structural changes by high temperature IR spectroscopy compared with of quantum chemical calculations allows for an understanding of the mechanism and nature of such processes. The changes in the structure of the polymer chain depending on the type of solvent used in the formation of the films are demonstrated using the examples of several different classes of polymers. In turn, the impact of such changes in the structure on the physical and chemical properties of the polymer films is demonstrated. © 2013 Society of Chemical Industry     

Synthesis and magnetorheological characteristics of ribbon‐like,polypyrrole‐coated carbonyl iron suspensions under oscillatory shear

One of the crucial problems of classical magnetorheological (MR) fluids is their high rate of sedimentation. This disadvantage may be substantially eliminated using core‐shell particles. The aim of this study is to prepare spherical carbonyl iron (CI) particles coated with conducing polymer polypyrrole (PPy) with ribbon‐like morphology. Scanning electron microscopy proved the formation of the ribbon‐like layer onto CI particles while Fourier transform infrared spectroscopy confirmed the chemical structure of PPy. The magnetic properties observed via vibrating sample magnetometer showed decreased magnetization saturation of core‐shell‐structured particles due to the existence of non‐magnetic surface layer. MR measurements performed under oscillatory shear flow as a function of the applied magnetic flux density, temperature, and particle concentration showed that core‐shell particle‐based MR suspension exhibits sufficient MR performance for practical applications. Moreover, the suspension stability is promoted significantly when core‐shell particles are used as a dispersed phase. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

An NMR‐MOUSE® for Analysis of Thin Objects

A special unilateral NMR sensor has been designed for investigations of thin samples with a thickness of less than 1 mm and of surface effects of polymers. For use with the bar‐magnet NMR‐MOUSE®, the so‐called “crazy coil” is introduced with a low penetration depth. It is a flat meander coil etched on a printed circuit board with wiggles in the conductors. The design of the new coil and FEM simulations of the B ₁ field are presented. Different applications are discussed by means of illustrative examples. They are the detection of surface damage in rubber samples, the swelling and drying of a latex membrane exposed to cyclohexane vapor mimicking a chemical sensor, and the drying of a thin sprayed adhesive layer.

Bar‐magnet NMR‐MOUSE® with crazy coil.     

Light-induced electron spin polarization in the ground state of water-soluble copper porphyrins

Light-induced spin-polarized transient EPR spectra are reported for several water-soluble copper porphyrins. The spectra are assigned to the doublet ground state, with emissive spin polarization resulting from photoexcitation and subsequent electronic relaxation. In contrast to other systems for which polarization of a doublet ground state has been observed, the exchange interactions in the copper porphyrins are strong and the geometry is fixed. It is proposed that intersystem crossing from the photoexcited trip-doublet to the trip-quartet state can lead to net polarization of the spin system and that this polarization is maintained during electronic decay, possibly via charge-transfer and exciplex states. The intensity of the observed spin polarization is essentially independent of the molecular orientation in the external field, but is strongly dependent on the nature of the charged peripheral groups. Possible reasons for this behavior are discussed.