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排序方式: 共有4517条查询结果,搜索用时 203 毫秒
1.
XPS and resistive studies on thin films of a copper(II)‐based coordination polymer deposited on functionalized interdigital electrodes 下载免费PDF全文
Michael Günthel Jörg Hübscher Rosemarie Dittrich Edwin Weber Yvonne Joseph Florian Mertens 《Journal of Polymer Science.Polymer Physics》2015,53(5):335-344
A symmetrical 2‐thiopyrimidine based molecule with an expanded π‐electron system is synthesized and used to form a self‐assembled monolayer (SAM) on gold surfaces. Utilizing chemical vapor deposition a monolayer of (3‐mercaptopropyl)triethoxysilane is formed on silicon dioxide substrates. Both of these SAM coated substrates are characterized by X‐ray photoelectron spectroscopy and the growth of a coordination polymer built up from 5,5′‐(ethyne‐1,2‐diyl)bis(2‐hydroxyacetophenone) and copper(II) on dual SAM coated transducers is studied. After the deposition procedure on interdigital electrodes the electrical properties of the polymer are investigated performing resistive measurements. A significant change of the resistance, which depends on the surrounding atmosphere, proves the sensing behavior of the synthesized coordination polymer. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 335–344 相似文献
2.
Rational Topological Design for Fluorescence Enhancement upon Aggregation of Distyrylfuran Derivatives 下载免费PDF全文
Dr. Charlotte Mallet Dr. Chady Moussallem Alexandre Faurie Magali Allain Dr. Frédéric Gohier Prof. William G. Skene Prof. Pierre Frère 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7944-7953
A series of 2,5‐distyrylfuran derivatives bearing pentafluorophenyl‐ and cyanovinyl units have been synthesized for aggregation‐induced emission (AIE). The effect of the type and extent of the supramolecular connections on the AIE of the furan derivatives were examined and correlated with their X‐ray crystal structures. It was found that the simultaneous presence of cyano and perfluorophenyl units strongly enhances the fluorescence upon aggregation. Single‐crystal X‐ray diffraction analysis confirmed that C?H???F, F???F, C?H???nitrile, Ar???ArF (Ar=aryl, ArF=fluoroaryl), and nitrile???ArF intra‐ and intermolecular interactions drive the topology of the molecule and that solid‐state supramolecular contacts favor AIE of the furan derivatives. 相似文献
3.
Lubomír Havlk Jan Fbry Margarida Henriques Michal Duek 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(7):623-630
The title structures of KScS2 (potassium scandium sulfide), RbScS2 (rubidium scandium sulfide) and KLnS2 [Ln = Nd (potassium neodymium sufide), Sm (potassium samarium sulfide), Tb (potassium terbium sulfide), Dy (potassium dysprosium sulfide), Ho (potassium holmium sulfide), Er (potassium erbium sulfide), Tm (potassium thulium sulfide) and Yb (potassium ytterbium sulfide)] are either newly determined (KScS2, RbScS2 and KTbS2) or redetermined. All of them belong to the α‐NaFeO2 structure type in agreement with the ratio of the ionic radii r3+/r+. KScS2, the member of this structural family with the smallest trivalent cation, is an extreme representative of these structures with rare earth trivalent cations. The title structures are compared with isostructural alkali rare earth sulfides in plots showing the dependence of several relevant parameters on the trivalent cation crystal radius; the parameters thus compared are c, a and c/a, the thicknesses of the S—S layers which contain the respective constituent cations, the sulfur fractional coordinates z(S2−) and the bond‐valence sums. 相似文献
4.
Yaogang Hu Peng Teng Wenyang Gao Xiaobing Zuo Lukasz Wojtas Randy W. Larsen Shengqian Ma Jianfeng Cai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2501-2507
Foldamers offer an attractive opportunity for the design of novel molecules that mimic the structures and functions of proteins and enzymes including biocatalysis and biomolecular recognition. Herein we report a new class of nonnatural helical sulfono‐γ‐AApeptide foldamers of varying lengths. The crystal structure of the sulfono‐γ‐AApeptide monomer S6 illustrates the intrinsic folding propensity of sulfono‐γ‐AApeptides, which likely originates from the bulkiness of tertiary sulfonamide moiety. The two‐dimensional solution NMR spectroscopy data for the longest sequence S1 demonstrates a 10/16 right‐handed helical structure. Optical analysis using circular dichroism further supports well‐ defined helical conformation of sulfono‐γ‐AApeptides in solution containing as few as five building blocks. Future development of sulfono‐γ‐AApeptides may lead to new foldamers with discrete functions, enabling expanded application in chemical biology and biomedical sciences. 相似文献
5.
Emily J. Hopkins Dr. Yurii Prots Dr. Ulrich Burkhardt Dr. Yves Watier Dr. Zhiwei Hu Dr. Chang‐Yang Kuo Dr. Jen‐Che Chiang Dr. Tun‐Wen Pi Dr. Arata Tanaka Prof. Liu Hao Tjeng Dr. Martin Valldor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7938-7943
Through a solid‐state reaction, a practically phase pure powder of Ba3V2S4O3 was obtained. The crystal structure was confirmed by X‐ray single‐crystal and synchrotron X‐ray powder diffraction (P63, a=10.1620(2), c=5.93212(1) Å). X‐ray absorption spectroscopy, in conjunction with multiplet calculations, clearly describes the vanadium in charge‐disproportionated VIIIS6 and VVSO3 coordinations. The compound is shown to be a strongly correlated Mott insulator, which contradicts previous predictions. Magnetic and specific heat measurements suggest dominant antiferromagnetic spin interactions concomitant with a weak residual ferromagnetic component, and that intrinsic geometric frustration prevents long‐range order from evolving. 相似文献
6.
Natalia Novikova Mikhail Kovalchuk Nina Stepina Radmir Gaynutdinov Elena Chukhrai Eleonora Yurieva 《Journal of synchrotron radiation》2015,22(4):1001-1007
The X‐ray standing‐wave method was applied to study the elemental composition and molecular organization of ordered protein films of alkaline phosphatase exposed to different xenobiotics (drug compounds, lead). Binding of metal ions from triply distilled water to protein molecules has been experimentally observed. Definite differences in the arrangement of impurity metal ions in the films have been established. The considerable enhancement of protein–metal interactions is attributed to partial rearrangement of the protein native structure, induced by xenobiotics. 相似文献
7.
A rapid and effective preparative procedure has been evaluated for the accurate determination of low-energy (40–200 keV) gamma-emitting radionuclides (210Pb, 234Th, 226Ra, 235U) in uranium ores and uranium ore concentrates (UOCs) using high-resolution gamma ray spectrometry. The measurement of low-energy gamma photons is complicated in heterogeneous samples containing high-density mineral phases and in such situations activity concentrations will be underestimated. This is because attenuation corrections, calculated based on sample mean density, do not properly correct where dense grains are dispersed within a less dense matrix (analogous to a nugget effect). The current method overcomes these problems using a lithium tetraborate fusion that readily dissolves all components including high-density, self-attenuating minerals/compounds. This is the ideal method for dissolving complex, non-volatile components in soils, rocks, mineral concentrates, and other materials where density reduction is required. Lithium borate fusion avoids the need for theoretical efficiency corrections or measurement of matrix matched calibration standards. The resulting homogeneous quenched glass produced can be quickly dissolved in nitric acid producing low-density solutions that can be counted by gamma spectrometry. The effectiveness of the technique is demonstrated using uranium-bearing Certified Reference Materials and provides accurate activity concentration determinations compared to the underestimated activity concentrations derived from direct measurements of a bulk sample. The procedure offers an effective solution for initial nuclear forensic studies where complex refractory minerals or matrices exist. It is also significantly faster, safer and simpler than alternative approaches. 相似文献
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We obtained the azo‐imine ligand (2,2′‐[4‐(5‐methoxy salicylidene‐4‐iminophenylazo)phenylimino]diethanol) (HL) and its Cu (II) complex (CuL) from the ethanol solution. The complex Cu(L)2 was obtained as single crystals from the CH3OH solution and structurally characterized. The electronic and photoluminescence properties of the ligand and its Cu (II) complex were investigated both in DMF solution and solid state. The oxidation and reduction behaviours of the compounds were studied in the solution and found that the redox processes are irreversible. Thermal studies show that the ligand has higher thermal stability than the CuL complex. Single crystals of the complex were obtained from slow evaporation of a DMF solution of the complex. Crystals of the complex showed a diffraction pattern; however, the structure of the complex was able to be solved. 相似文献