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Timothy R. Totsch Victoria L. Stanford Oleksander Klep Mary K. Burdette Benjamin Grant Stephen H. Foulger Gary M. Gray 《Journal of polymer science. Part A, Polymer chemistry》2020,58(13):1825-1842
Linear polyphosphonates with the generic formula –[P(Ph)(X)OR′O]n– (X = S or Se) have been synthesized by polycondensations of P(Ph)(NEt2)2 and a diol (HOR′OH = 1,4-cyclohexanedimethanol, 1,4-benzenedimethanol, tetraethylene glycol, or 1,12-dodecanediol) followed by reaction with a chalcogen. Random copolymers have been synthesized by polycondensations of P(Ph)(NEt2)2 and mixture of two of the diols in a 2:1:1 mol ratio followed by reaction with a chalcogen. Block copolymers with the generic formula –[P(Ph)(X)OR′O](x + 2) –[P(Ph)(X)OR′O](x + 3)– (X = S or Se) have been synthesized by the polycondensations of Et2N[P(Ph)(X)OR′O](x + 2)P(Ph)NEt2 oligomers with HOR′O[P(Ph)(X)OR′O](x + 3)H oligomers followed by reaction with a chalcogen. The Et2N[P(Ph)(X)OR′O](x + 2)P(Ph)NEt2 oligomers are prepared by the reaction of an excess of P(Ph)(NEt2)2 with a diol while the HOR′O[P(Ph)(X)OR′O](x + 3)H oligomers are prepared by the reaction of P(Ph)(NEt2)2 with an excess of the diol. In each case the excess, x is the same and determines the average block sizes. All of the polymers were characterized using 1H, 13C{1H}, and 31P{1H} NMR spectroscopy, TGA, DSC, and SEC. 31P{1H} NMR spectroscopy demonstrates that the random and block copolymers have the expected arrangements of monomers and, in the case of block copolymers, verifies the block sizes. All polymers are thermally stable up to ~300°C, and the arrangements of monomers in the copolymers (block vs. random) affect their degradation temperatures and Tg profiles. The polymers have weight average MWs of up to 3.8 × 104 Da. 相似文献
3.
M. A. Zaporozhets S. V. Savilov O. M. Zhigalina S. N. Sul’yanov V. V. Volkov V. I. Nikolaichik S. P. Gubin A. S. Avilov 《Crystallography Reports》2012,57(3):426-433
Methods for obtaining cadmium selenide and gold nanoparticles have been developed. The sizes of the nanoparticles are determined and the morphology, structure, and chemical composition of these nanoparticles and their ensembles are studied by a complex of structural methods: electron diffraction, X-ray diffraction, energy-dispersive X-ray analysis, high-resolution transmission electron microscopy, and small-angle X-ray scattering. Gold nanoparticles are mainly spherical and have an average size of 10 nm. They are single-phase and have an fcc crystal structure. Samples of synthesized CdSe nanoparticles contain monodisperse spherical particles 12 nm in size with a wurtzite structure. The deposition of nanoparticles on a carbon substrate is accompanied by their self-organization into a closely packed two-dimensional structure with a pronounced texture in which all nanoparticles are oriented in the [001] direction perpendicularly to the carbon substrate plane. 相似文献
4.
R. V. Rodik V. Yu. Malytskyi V. S. Starova T. V. Yegorova A. I. Kysil O. A. Zaporozhets Z. V. Voitenko V. I. Kalchenko 《Journal of inclusion phenomena and macrocyclic chemistry》2013,77(1-4):343-350
New derivatives of calix[4]arenes, containing two isoindole fragments in distal positions of the macrocycle upper rim were synthesized. According to NMR and molecular modeling data, the obtained calixarenes exist in “flattened cone” conformation with inclination angles of benzene rings to the macrocycle plane equal to 133–140° and 92–100°. Fluorometric studies showed the presence of self-aggregation of isoindolenylcalixarenes in acetone solutions starting from micromolar concentrations. 相似文献
5.
M. A. Zaporozhets D. A. Baranov N. A. Kataeva I. I. Khodos V. I. Nikolaichik A. S. Avilov S. P. Gubin 《Russian Journal of Inorganic Chemistry》2009,54(4):517-520
A simple and available method is proposed for the synthesis of cobalt-containing nanoparticles. This method comprises cobalt formate thermolysis in hydrocarbon oil without extra stabilizing ligands. The size, composition, and structure of the nanoparticles are determined by transmission electron microscopy, X-ray powder diffraction, and electron diffraction. The average particle size is 10–14 nm. The major components are cobalt oxides CoO and Co3O4. Apart from these oxides, the particles contain minor metallic cobalt. 相似文献
6.
O. A. Zaporozhets T. E. Keda L. E. Seletskaya V. V. Sukhan 《Journal of Analytical Chemistry》2000,55(7):635-640
The sorption of 1,5-diphenylcarbazone on highly dispersed silica from toluene and acetone-hexane (1:4) solutions was studied.
The nature of the bonding of the reagent with the surface of silica gel was studied by absorption spectrometry. A solid-phase
reagent is proposed for the sorption-diffuse-reflection and visual test determinations of down to 0.025 and 0.05 μg/L molybdenum(VI),
respectively. The procedures were used for the determination of molybdenum in sea salt and a medicinal preparation. 相似文献
7.
The modified sorbents with dithizone and zinc dithizonate adsorbed on the silica surface were obtained. The adsorption of heavy metal ions from aqueous solutions onto loaded silicas was studied. Color scales for Ag(I), Hg(II) and Pb(II) visual test detection were worked out. The modified silica gels were established to be applicable to semi-quantitative determination of these metal ions in buttermilk, natural, mineral and waste water. 相似文献
8.
M. G. Abramyants D. A. Lomov S. N. Lyashchuk O. O. Zaporozhets 《Russian Journal of Organic Chemistry》2018,54(4):593-600
Isonicotinic acid ethyl ester reacted with substituted phenacyl bromides to give the corresponding quaternary salts which were reduced with sodium tetrahydridoborate to ethyl 1-(2-aryl-2-hydroxyethyl)-1,2,3,6- tetrahydropyridine-4-carboxylates. The presence of an electron-donating substituent in the benzene ring of the latter is a necessary condition for their acid hydrolysis with cleavage of the C–N bond and formation of isoguvacine. Analogous derivatives with electron-withdrawing substituents are not converted to isoguvacine under similar conditions. 相似文献
9.
D. N. Zaporozhets 《Journal of Mathematical Sciences》2006,137(1):4525-4530
In this note, we find the distibution of the number of real zeros of a random polynomial. We also derive a formula for the
expected number of complex zeros lying in a given domain of the complex plane. Bibliography: 7 titles.
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Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 320, 2004, pp. 69–79. 相似文献
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