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排序方式: 共有207条查询结果,搜索用时 15 毫秒
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Krishna Gopal Dongol M. Cristina Melo e Silva Kouki Matsubara Taisuke Matsumoto Shuntaro Mataka Thies Thiemann 《无机化学与普通化学杂志》2003,629(6):945-947
The preparation of two η6‐estra‐1, 3, 5(10), 6‐tetraene tricarbonylchromium complexes 4 and 6 are described. In both cases only one stereoisomer can be isolated, in contrast to other estrane‐tricarbonylchromium complexes, where complexations are non‐stereoselective. X‐ray crystal structural analysis of 4 discloses that only the more sterically hindered β‐facial isomer is formed. It is assumed that the 6, 7‐olefinic moiety exerts a directive influence on the complexation. 相似文献
3.
Hideo Kondo Kouki Matsubara Hideo Nagashima 《Journal of the American Chemical Society》2002,124(4):534-535
Coordinatively unsaturated diruthenium complexes, [(eta5-C5Me5)Ru(mu2-iPrNC(Me)=NiPr)Ru(eta5-C5Me5)]+, of which crystallography revealed structures bearing a bridging amidinate ligand perpendicular to the Ru-Ru axis, were synthesized by anion exchange of [(eta5-C3Me5(Ru(mu2-iPrNC(Me)=NiPr)Ru(eta5-C5Me5)]+ Br- by weakly coordinating anions. Variable-temperature NMR showed rapid motion of the bridging amidinate ligand. The coordinatively unsaturated nature of the cationic complexes provides their high reactivity toward a series of two electron donor ligands. Oxidative addition of molecular hydrogen occurred to give [(eta5-C5Me5)Ru(mu2-iPrNC(Me)=NiPr)(mu-H)Ru(eta5-C5Me5)(H)]+, which was isolated and characterized. 相似文献
4.
Ionic liquids (ILs) are salts with an extremely low melting point. Substantial efforts have been made to address their low melting point from the enthalpic standpoint (i.e. interionic interactions). However, this question is still open. In this study, we report our findings that entropic (large fusion entropy), rather than enthalpic, contributions are primarily responsible for lowering the melting point in many cases, based on a large thermodynamic dataset. We have established a computational protocol using molecular dynamics simulations to decompose fusion entropy into kinetic (translational, rotational, and intramolecular vibrational) and structural (conformational and configurational) terms and successfully applied this approach for two representatives of ILs and NaCl. It is revealed that large structural contribution, particularly configurational entropy in the liquid state, plays a deterministic role in the large fusion entropy and consequently the low melting point of the ILs.Large structural entropy makes salts liquid at room temperature. 相似文献
5.
Kazukiyo Kobayashi Hiroshi Sumitomo Akira Kobayashi Toshihiro Akaike 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5-7):655-667
Polystyrene derivatives with lactose, glucose, maltose, maltotriose, maltopentaose, and maltoheptaose on each benzene ring were prepared by the radical polymerization of a new class of macromers synthesized by coupling the corresponding oligosaccharide lactones with p-vinylbenzylamine. These polymers consisting of amphiphilic structural units were water-soluble, and organic solutes were bound to hydrophobic microenvironments of the polymers in water. α-D-Glucopyranose-carrying polymers were recognized and precipitated by concanavalin A. Cultivation of liver cells (hepatocytes) was attempted using culture dishes whose surface was coated with lactose-, glucose-, maltose-, and maltotriose-carrying polystyrenes. It has been found that a lactose-carrying polystyrene (PVLA) is a useful surface material for hepatocyte culture. 1) Highly specific adhesion of hepatocytes was attained for PVLA-coated dishes with or without serum supplement. 2) The cell adhesion was a threshold phenomenon with respect to the PVLA concentration on the dish. 3) The cell adhesion was effectively inhibited when hepatocytes were treated with PVLA molecules in the medium prior to culture. 4) The adhesion was not inhibited by albumin, an adhesion-inhibitory protein in serum. These findings suggest that pendent galactose residues of a PLVA molecule functioned as a strong recognition determinant for hepatocytes. We assume that multi-antennary, high-density galactose residues of PVLA are attributed to the specific adhesion of hepatocytes. 相似文献
6.
Ariaki Murata Ryota Akaike Tatsuya Kawahashi Ryo Tsuchiya Hiroyuki Takemoto Toshiyuki Ohnishi Yasushi Todoroki Nobuyuki Mase Mineyuki Yokoyama Kazuteru Takagi Peter Winterhalter Naoharu Watanabe 《Tetrahedron》2014
A flower-inducing compound, LDS1, was isolated from a free-floating aquatic plant, Lemna paucicostata. The chemical structure and the absolute stereochemistry of LDS1 were determined as (9R,13R,11E,15Z)-9,13-dihydroxy-10-oxooctadeca-11,15-dienoic acid for its most abundant diastereomer. LDS1 was enzymatically produced when the plant was exposed to drought stress, and induced flowering at a concentration of 10 nM. 相似文献
7.
Hanen Khadhraoui Abdelhak Othmani Abdessalem Kouki Mouldi Zouaoui 《Electroanalysis》2021,33(1):152-159
In this work we report an easy and efficient way to fabricate nanostructured cobalt oxide (Co3O4) thin films as a non-enzymatic sensor for H2O2 detection. Co3O4 thin films were grown on ITO glass substrates via the sol-gel method and characterized with several techniques including X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and optical absorbance. The Co3O4 thin films’ performance regarding hydrogen peroxide detection was studied in a 0.1 M NaOH solution using two techniques, cyclic voltammetry (CV) and amperometry. The films exhibited a high sensitivity of 1450 μA.mM−1.cm−2, a wide linear range from 0.05 μM to 1.1 mM, and a very low detection limit of 18 nM. Likewise, the Co3O4 thin films produced showed an exceptional stability and a high selectivity. 相似文献
8.
Hiromi NAKANISHI Atsushi MORI Kouki TAKEDA Houdo TANAKA Natsuko KOBAYASHI Keitaro TANOI Takashi YAMAKAWA Satoshi MORI 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2015,91(4):160-174
Six months after the explosion of TEPCO’s Fukushima Dai-ichi nuclear power plant, radioactive
silver (110mAg), was detected in concentrations of 3754 Bq/kg in Nephila
clavata (the orb-web spider; Joro-gumo in Japanese) collected at
Nimaibashi, Iitate village in Fukushima Prefecture, whereas 110mAg in the soil was
43.1 Bq/kg. A survey of 35 faunal species in the terrestrial environment during the 3.5 years
after the accident showed that most of Anthropoda had two orders higher 110mAg in
their tissues than soils, although silver is not an essential element for their life. However,
tracing of the activity of 110mAg detected in spider Atypus karschi
collected regularly at a fixed location showed that it declined much faster than the physical
half-life. These results suggest that 110mAg was at once biologically concentrated
by faunal species, especially Arthropoda, through food chain. The factors affecting the
subsequent rapid decline of 110mAg concentration in faunal species are
discussed. 相似文献
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