排序方式: 共有29条查询结果,搜索用时 31 毫秒
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W. Strek P. J. Dereń K. Maruszewski G. Malashkevich E. G. Poddenezhny I. Melnichenko A. Boiko 《Journal of fluorescence》1999,9(4):343-345
Emission and excitation spectra of ZnS:Cu microcrystals trapped in porous silica xerogels are presented. This system is characterized by intense, long-lived green emission at room temperature. It was observed that this emission was greatly reduced after compressing the xerogel samples. 相似文献
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The aim of this paper is to study on the Genocchi polynomials of higher order on P, the algebra of polynomials in the single variable x over the field C of characteristic zero and P∗, the vector spaces of all linear functional on P. By using the action of a linear functional L on a polynomial p(x) Sheffer sequences and Appell sequences, we obtain some fundamental properties of the Genocchi polynomials. Furthermore, we give relations between, the first and second kind Stirling numbers, Euler polynomials of higher order and Genocchi polynomials of higher order. 相似文献
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Canbay Canan Aksu Aziz Baiz Sivar Özkul İskender Dere Aysegül 《Journal of Thermal Analysis and Calorimetry》2020,139(2):831-831
Journal of Thermal Analysis and Calorimetry - In the original publication of the article, the second author’s family name was incorrectly published. 相似文献
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As the enantiomers of 1-phenylethanol are valuable intermediates in several industries, the lipase catalyzed kinetic resolution of (R,S) -1-phenylethanol is a relevant research topic. In this study, the goal was to determine the optimum reaction parameters to produce enantiomerically pure 1-phenylethanol by lipase (Novozyme 435) catalyzed kinetic resolution using response surface methodology (RSM). Reactions were performed with 40–400 mM (R,S)-1-phenylethanol, 120–1200 mM vinyl acetate and 2–22 mg/mL biocatalyst concentrations (BC L ), at 20–60 °C and with a stirring rate of 50–400 rpm for 5–120 min. The samples were analyzed using high performance liquid chromatography (HPLC) with a Chiralcel OB column. Optimum reaction parameters to reach 100% enantiomeric excess for the substrate ( ee s ) were determined as follows: substrate concentration (C s ): 240 mM, BC L : 11 mg/mL, at 42 °C with a reaction time of 75 min. Model validation was performed using these conditions and ee s was calculated as 100%, which indicates the predicted model was efficient and accurate. When compared to the literature, it was observed that the reaction time decreased significantly. This is an important result considering the industrial scale perspective. 相似文献
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Rahime imek Anthony Linden Cihat afak 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):351-353
The title compound, C19H18BrNO3, has potential calcium modulatory properties. The 1,4‐dihydropyridine ring has a very shallow boat conformation and is one of the most planar examples of this moiety. The 2‐bromophenyl substituent is in the axial synperiplanar orientation. The quinoline ring has a half‐chair conformation, with the unusual arrangement of the out‐of‐plane atom being on the opposite side of the ring plane to the bromophenyl substituent. The molecules are linked into chains by intermolecular hydrogen bonds. 相似文献
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Rahime Eshaghi Malekshah Maciej Kubicki Ali Khaleghian 《Journal of Coordination Chemistry》2018,71(7):952-968
Four new mononuclear copper(II) complexes with methyl acetoacetate and benzoylacetone in the presence of 1,10-phenanthroline and 2,2′-bipyridine were synthesized and characterized by elemental analyses, FT-IR, and UV–Vis spectroscopy. The molecular structures of complexes [Cu(MAA)(bpy)(ClO4)] (1a), [Cu(bzac)(bpy)]ClO4 (2a), [Cu(MAA)(phen)(ClO4)] (1b) and [Cu(bzac)(phen)(ClO4)] (2b) were determined by single crystal X-ray diffraction technique. 1a, 1b, and 2b are five coordinate with a distorted square pyramidal geometry and the structure of 2a consists of isolated [Cu(bzac)(bpy)]+ cations and perchlorate counter anions. The electrochemical studies of copper complexes in acetonitrile solution showed that CuII/CuI reduction processes are electrochemically irreversible. Cytotoxic activity of complexes was screened, including an MTT assay against gastric cancer cell line (MKN-45). The four Cu(II) complexes exhibited lethal effects against MKN-45 cell lines and the half maximal inhibitory concentration (IC50) values obtained were much lower in comparison with 5-fluorouracil. In addition, MTT and migration studies revealed that benzoylacetone complexes are more active than complexes of methyl acetoacetate against the MKN-45 cancer cell lines. Docking simulations of Cu(II) complexes on DNA revealed that the most stable adducts with DNA bind in the minor groove. All complexes display a binding specificity to the A/T rich regions. 相似文献
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Anthony Linden Miyase G. Gündüz Rahime imek Cihat afak 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(4):o227-o230
A mixture of the RR/SS and RS/SR diastereoisomeric pairs of methyl 4‐(2,4‐dichlorophenyl)‐2,7‐dimethyl‐5‐oxo‐1,4,5,6,7,8‐hexahydroquinoline‐3‐carboxylate, C19H19Cl2NO3, forms cocrystals in which there is one unique molecule in the asymmetric unit, but the molecule displays disorder in the region of the 7‐position of the quinoline ring system as a result of the random occurrence of the diastereoisomers at the same crystallographic site. A similar arrangement exists in the monohydrate cocrystals that form from a mixture of the RR/SS and RS/SR diastereoisomeric pairs of methyl 4‐(2,4‐dichlorophenyl)‐2‐methyl‐7‐phenyl‐5‐oxo‐1,4,5,6,7,8‐hexahydroquinoline‐3‐carboxylate monohydrate, C24H21Cl2NO3·H2O. These compounds belong to a class of 1,4‐dihydropyridines whose members have calcium modulatory properties. The 1,4‐dihydropyridine rings have the usual shallow boat conformation. In each structure, the 2,4‐dichlorophenyl ring is oriented such that the 2‐chloro substituent is in a synperiplanar orientation with respect to the 1,4‐dihydropyridine ring plane. In each crystal structure, the molecules are linked into chains by N—H⋯O hydrogen‐bonding interactions. 相似文献