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21.
Tatiyana V. Serebryanskaya Ludmila S. IvashkevichAlexander S. Lyakhov Pavel N. GaponikOleg A. Ivashkevich 《Polyhedron》2010
Complexes ML12 and ML22, with M = FeII, CoII, NiII, and 1,3-bis(2-R-tetrazol-5-yl)triazenide ligands L1 (R = Me) and L2 (R = tBu), have been synthesized by the reaction of corresponding 1,3-bis(2-R-tetrazol-5-yl)triazenes with metal(II) salts in basic media and characterized by IR, UV–Vis spectroscopy, thermal and X-ray diffraction analyses. Both 1,3-bis(2-R-tetrazol-5-yl)triazenes were found to deprotonate on coordination and act as tridentate chelating ligands forming distorted MN6 octahedra around metal(II) cations. 相似文献
22.
Carlos A. Crdoba Ludmila I. Ronco Celina E. Barrios Luis M. Gugliotta Roque J. Minari 《大分子反应工程》2019,13(2)
Miniemulsion polymerization is employed to produce high solid content (50%) acrylic/melamine latexes with varied crosslinking capability, for their potential application as waterborne crosslinkable coatings. This synthesis strategy allows the efficient incorporation of a hydrophobic crosslinker, iso‐butylated melamine (iBMF), into polymer particles, and to obtain latexes with different iBMF concentrations and acrylic polymer with varied content of hydroxylic groups (OH–). The involved crosslinking mechanisms and the physical transformations during film thermosetting of acrylic/iBMF nanocomposite are exhaustively investigated by combining thermal, spectroscopic, and thermo‐mechanical analyses. The influence of reactive groups concentration (iBMF and OH– content in the acrylic polymer) on the rate of curing, the crosslinking degree, and consequently onto the sensitive properties of cured films are discussed here. 相似文献
23.
Irina Ryzhkina Ludmila Kudryavtseva Alexander Konovalov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract The kinetics of reactions of aminoinethylated calixarenes (AMC) of different structure (substituents at nitrogen atom as well as on the “lower” rim of cavity are varied) with esters of phosphorus acids has been studied under pseudofirst order conditions in water-DMF and water-alcohol (i-PrOH) solutions by spectrophotometry. The dependences of the observed rate constants of the reactions on the concentrations of AMC reach a plateaus at the investigated values of pH 8 - 1 1. This indicates binding of the substrates by the aggregates of AMC and allows to calculate the parameters of the reactions: CCA, ka, Kb. It was shown by NMR 31P method, that AMC are the catalysts of hydrolysis of esters of phosphorus acids in water-DMF solutions. The higher reactivity of AMC as compared with the one of calix[4]resorcinolarenes and o-aminomethylphenols was found. It was revealed AMC preceeds in both media, however the reactivity of the aggregates is considerably less in the water - alcohol solutions than those in the water - DMF solutions. 相似文献
24.
25.
Alexander. V. Zuraev Yuri V. Grigoriev Ludmila S. Ivashkevich Alexander S. Lyakhov Oleg A. Ivashkevich 《无机化学与普通化学杂志》2017,643(19):1215-1219
A new catalyst for cross‐coupling synthesis of 1,4‐diphenylbutadiyne‐1,3 was prepared by thermolysis of copper(II) poly‐5‐vinyltetrazolate. It presents heterogeneous catalyst, in which copper nanoparticles are supported on polymeric matrix surface. The catalyst is recovered, recycled, and shows high catalytic activity in cross‐coupling synthesis of 1,4‐diphenylbutadiyne‐1,3. The reaction proceeds in aerobic conditions at room temperature in the presence of pyridine. 相似文献
26.
An information system Xemic applicable in analytical chemistry is described and its use in capillary electrophoresis for searching suitable separation conditions is demonstrated. This system is capable to provide suitable separation conditions even for analytes for which no electrophoretic experiments have been published so far. The system works with a database of components of anionic character the analyses of which have been performed, published in reviewed scientific journals, and included into a database created by an expert. Moreover, the system learned to search also in abstracts or complete scientific articles to find articles dealing with the determination of a substance in a given sample matrix. When no experiments have been published so far for a defined substance in a specific matrix, Xemic shows the separation conditions for determination of the substance regardless of the matrix. When no response can be found for the analyte of interest at all, the system Xemic works like an expert in the field and searches chemically similar substances and offers a series of substances the physicochemical properties of which are close to the followed analyte with respect to the behavior in the electric field, and shows working conditions for their analysis. Thus, the analyst puts only the order in the form of a given analyte in a given matrix and obtains a recommendation of a separation system that should enable to perform a successful separation. The system is not rigid and enables the operator to change the importance of individual attributes used in similarity search so as to obtain a broader or narrower group of similar components. With a certain probability the analyte of interest can be successfully analyzed under separation conditions that suited for the analysis of the most similar substances in the given matrix. 相似文献
27.
Polarization reflection holographic gratings in azobenzene-containing gelatine films 总被引:1,自引:0,他引:1
We have written polarization reflection holograms in an azobenzene-containing material. Two waves with circular polarization were used to record the gratings; the light resulting from their overlap induces chirality in the samples. The holographic reflection of the polarization gratings has the properties of Bragg reflection in cholesteric liquid crystals. 相似文献
28.
Christine?Hartwig Andres?Veske Sarka?Krejcova Georg?Rosenberger Ulrich?FinckhEmail author 《BMC neuroscience》2005,6(1):53
Background
Plexins, known to date as receptors of semaphorins, are implicated in semaphorin-mediated axon repulsion and growth cone collapse. However, subtype-specific functions of the majority of the nine members of the mammalian plexin family are largely unknown. In order to investigate functional properties of B-plexins, we analyzed the expression of human and murine plexin B3 and expressed full-length human plexins B2 (B2) and B3 (B3) in NIH-3T3 cells. 相似文献29.
Zondy JJ Vedenyapin V Yelisseyev A Lobanov S Isaenko L Petrov V 《Optics letters》2005,30(18):2460-2462
Optical parametric oscillation using the new lithium selenoindate nonlinear crystal is reported for what is to our knowledge the first time. A 17 mm long, type II phase-matched sample is pumped by a 10 ns Nd:YAG laser. The minimum pump energy threshold is 3 mJ for a signal-resonant configuration. The signal and idler waves are tunable between 1.47 and 1.57 microm, and 3.3 and 3.78 microm, with a total output energy of 170 microJ corresponding to a 2.4% energy conversion at 8 mJ pump, only limited by the AR coatings damage. With optimized crystal quality and coatings, lithium selenoindate should show superior performance as compared with AgGaS(e)2 crystals, owing to its 4x larger thermal conductivity. 相似文献
30.
Boris A. Trofimov Boris G. Sukhov Svetlana F. Malysheva Natal’ya A. Belogorlova Anatolii P. Tantsirev Lidiya N. Parshina Ludmila A. Oparina Sergey P. Tunik Nina K. Gusarova 《Tetrahedron letters》2004,45(49):9143-9145
Secondary phosphines react readily with a vinyl ether of diacetone-d-glucose under radical initiation conditions to give, in high yield, anti-Markovnikov adducts, diorganyl{2-[3-O-(1,2:5,6-di-O-isopropylidene)-d-glucofuranosyloxy]ethyl}phosphines, which oxidize almost quantitatively upon reacting with air oxygen or elemental sulfur to form the corresponding optically active phosphine oxides or sulfides. 相似文献