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【作者单位】
="Institute of Chemistry Far-Eastern Branch of the Russian Academy of Sciences 159prosp. 100-letiya Vladivistoka 690022 Vladivistok Russian Federation."
摘要 :
Thiocarbamoyl chitosan (TCC) was synthesized by grafting thiourea on chitosan backbone in eutectic composition of ammonium thiocyanate—thiourea. Insoluble products with the amino group functionalization degree of 0.3—1.1 can be ...
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Thiocarbamoyl chitosan (TCC) was synthesized by grafting thiourea on chitosan backbone in eutectic composition of ammonium thiocyanate—thiourea. Insoluble products with the amino group functionalization degree of 0.3—1.1 can be prepared by varying the conditions of polymer-analogous (synthesis in a gel) transformation. Structure of the synthesized chitosan derivatives was characterized by elemental analysis, diffuse reflectance infrared spectroscopy, and the solid state ~(13)C NMR. Study of sorption properties of TCC shows high sorption capacity and selectivity for the ions of gold(III), platinum(IV), and palladium(II) as evidenced by results obtained at pH 2 in the presence of 100—1000-fold excess of iron(III), copper(II), zinc(II), and nickel(II). Sorption capacity of TCC for all ions increases with the increase in the degree of substitution and changes in the series: Au~(III) > Pd~(II) > Pt~(IV).
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Essential differences in the luminescence properties of dibenzoylmethanatoboron difluoride (1) bulk and microcrystals were detected. Analysis of the spectral data showed that in every case the fluorescence spectrum of 1 consisted ...
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Essential differences in the luminescence properties of dibenzoylmethanatoboron difluoride (1) bulk and microcrystals were detected. Analysis of the spectral data showed that in every case the fluorescence spectrum of 1 consisted of three components: monomer fluorescence, excimer fluorescence, and fluorescence related with interdimer interaction. Evolution of luminescence spectra observed with decrease of the crystal size are bound with decrease of monomer fluorescence intensity and considerable growth of intensity of fluorescence related to interdimer interaction. The presence of reversible luminescence thermochromism was discovered for 1: lowering the temperature from 300 to 77 K resulted in essential hypsochromic shift of the luminescence band maximum (∼60 nm) connected with considerable decrease of the distances between the planes of the neighboring molecules (∼0.1 Å) that lead to the weakening of interdimer interaction and intensification of monomer luminescence.
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摘要 :
Fluorescence properties of dilute and concentrated solutions of dibenzoylmethanatoboron difluoride and its crystals were studied.Excimers are formed in concentrated solutions and crystals of dibenzoylmethanatoboron difluoride.The ...
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Fluorescence properties of dilute and concentrated solutions of dibenzoylmethanatoboron difluoride and its crystals were studied.Excimers are formed in concentrated solutions and crystals of dibenzoylmethanatoboron difluoride.The crystal structue of dibenzoyl-methanatoboron difluoride was determined by X-ray diffraction analysis.It was found that the molecules of dibenzoylmethanatoboron difluoride are coplanar with an interplanar distance of 3.6 A.
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摘要 :
Significant differences in the luminescence properties of dibenzoylmethanate and ditoluylmethanate of boron difluoride bulk crystals and microcrystals were detected. The size-dependent blue-to-green colour change of the luminescen...
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Significant differences in the luminescence properties of dibenzoylmethanate and ditoluylmethanate of boron difluoride bulk crystals and microcrystals were detected. The size-dependent blue-to-green colour change of the luminescence is connected with the band intensity redistribution of monomer and excimer luminescence and fluorescence due to interdimer interaction.
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摘要 :
A new polyhydroxylated steroid (20R, 24S)-5alpha-cholestance-3beta, 6beta, 15beta, 24-tetraol and a known glycoside, laeviuscoloside G, was isolated from the Far-Eastern starfish Henricia sanguinolenta, collected in the sea of Okh...
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A new polyhydroxylated steroid (20R, 24S)-5alpha-cholestance-3beta, 6beta, 15beta, 24-tetraol and a known glycoside, laeviuscoloside G, was isolated from the Far-Eastern starfish Henricia sanguinolenta, collected in the sea of Okhotsk, and characterized.
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Six polyhydroxylated steroids and their derivatives were isolated from the starfish Lysastrosoma anthosticta collected in the Posyet Bay, Sea of Japan. These include a new glycoside of the steroid polyol, lysastroside A(1), which ...
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Six polyhydroxylated steroids and their derivatives were isolated from the starfish Lysastrosoma anthosticta collected in the Posyet Bay, Sea of Japan. These include a new glycoside of the steroid polyol, lysastroside A(1), which was identified as (25S)-26-O-beta-D-xylo-pyranosyl-5alpha-cholestane-3beta,6alpha,8,15beta,16beta,26-hexaol, and the previously known pycnopodioside C monoglycoside (2), marthasterone sulfate (3), (25S)-5alpha-chloestane-3beta,6alpha-8,15beta,16beta,26-hexaol (4), (25S)-5alpha-cholestane-3beta,6alpha,7alpha-8,15alpha,16beta,26-heptaol (5), and (25S)-5alpha-cholestane-3beta,6alpha,7alpha,8,15beta,16beta-heptaol (6). The compounds were tested for the haemolytic activity and the action on the embryogenesis of the sea urchin Stronglocentrotus intermedius.
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摘要 :
3,4-Dihydro-2H-naphtho[2,3-b]pyran-5,10-diones are produced by many micro- and macroorganisms in the living nature.~1,2 Most often,they are derivatives of parent 1,4-naphthoquinone or 5-hydroxy-1,4-naphthoquinone (juglone)and more...
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3,4-Dihydro-2H-naphtho[2,3-b]pyran-5,10-diones are produced by many micro- and macroorganisms in the living nature.~1,2 Most often,they are derivatives of parent 1,4-naphthoquinone or 5-hydroxy-1,4-naphthoquinone (juglone)and more rarely,of 5,8-dihydroxy-1,4-naphthoquinone (naphthazarin).
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摘要 :
6(7)-(Di)alkyl- and 6(7)-(di)alkoxy derivatives of 2,3-dihydroxynaphthazarin were converted to 5,8-dihydroxyisoquinoline-l,3,4(2H)-trione derivatives under amination reaction conditions.
摘要 :
The structures and spectral luminescence properties of two similar in structure β-diketonatoboron difluorides were studied in comparison. One of them (1-(2,4,6-trimethyl-phenyl)butane-1,3-dionatoboron difluoride (1)) contains two...
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The structures and spectral luminescence properties of two similar in structure β-diketonatoboron difluorides were studied in comparison. One of them (1-(2,4,6-trimethyl-phenyl)butane-1,3-dionatoboron difluoride (1)) contains two methyl groups in the both ortho-positions of the phenyl ring, which excludes the formation of rotamers with the planar configuration. In the second compound, 1-phenylbutane-1,3-dionatoboron difluoride (2), the α-phenyl substituent can rotate freely. The steric factor exerts no effect on monomer fluorescence but substantially affects the ability of benzoylacetonatoboron difluorides to undergo intermolecular interactions, which leads to considerable differences in the luminescence properties of concentrated solutions and crystals of compounds 1 and 2.
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摘要 :
Size-dependent luminescence properties of boron difluoride β-diketonates were detected. Most compounds investigated are characterized by noticeable hypsochromic shifts of luminescence band maxima on going from bulk crystals to mi...
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Size-dependent luminescence properties of boron difluoride β-diketonates were detected. Most compounds investigated are characterized by noticeable hypsochromic shifts of luminescence band maxima on going from bulk crystals to microcrystals. However, a decrease in the crystal size of (dibenzoylmethanato)boron difluoride with unique supramolecular structure was accompanied by abathochromic shift of the luminescence band maximum. Size-dependent luminescence properties of complexes examined were analyzed in the framework of excitonic mechanism.
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