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991.
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Suzuki coupling reaction catalyzed heterogeneously by Pd(salen)/polyoxometalate compound: another example for synergistic effect of organic/inorganic hybrid 下载免费PDF全文
Jinhui Tong Haiyan Wang Xiaodong Cai Qianping Zhang Hengchang Ma Ziqiang Lei 《应用有机金属化学》2014,28(2):95-100
A hybrid compound consisting of palladium(salen) [salen = N,N′‐bis(salicylidene)ethylenediamine] complex covalently linked to a lacunary Keggin‐type polyoxometalate, K8[SiW11O39](POM), was synthesized and characterized by FT‐IR, elemental analysis, inductively coupled plasma and diffuse reflectance UV–visible spectroscopic methods. The hybrid, [Pd(salen)–POM], was investigated in the Suzuki cross‐coupling in EtOH/H2O under mild reaction conditions. In comparison to the corresponding organic and inorganic moiety, the hybrid has shown greatly improved catalytic activity, and much higher yields toward coupling products were obtained with a low catalyst loading for various aryl halides, including unreactive and sterically hindered ones. The catalyst also exhibited prominent recyclable performance and no obvious loss of activity was observed after six consecutive runs. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
994.
Basic isoreticular metal–organic framework (IRMOF‐3) porous nanomaterial as a suitable and green catalyst for selective unsymmetrical Hantzsch coupling reaction 下载免费PDF全文
A catalytic amount of the basic metal–organic framework (IRMOF‐3) with organic substrates was found to be an efficient, selective and waste‐free green approach for the unsymmetrical Hantzsch coupling reaction. The catalyst can be isolated from the reaction mixture and reused at least four times. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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996.
《Journal of Coordination Chemistry》2012,65(5):743-794
Two new isomorphous oxovanadium composite solids, [Zn(btx)V2O6] (1) and [Cu(btx)V2O6] (2) (btx = 1,4-bis(triazol-1-ylmethyl)benzene), have been synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray diffraction. The structures of 1 and 2 are composed of {MV2O6} (M = Zn or Cu) bimetallic oxide layers, linked through {MO2N2} building blocks and btx ligands into 3-D architectures. The two compounds consist of infinite spiral chains and all helical chains are meso-helices, which lead to racemic solid-state compounds. The electrochemical properties of the two compounds have been studied. 相似文献
997.
A type of organic–inorganic hybrid material layered crystalline AlSPP (AlSPP) was prepared under simple conditions, completely different to the traditional hydrothermal methods, by the reaction of oligo‐styrenyl phosphonic acid with aluminum acetate and sodium dihydrogen phosphate. The microstructure of AlSPP was characterized by X‐ray diffraction, FT‐IR, atomic absorption spectroscopy, N2 volumetric adsorption, atomic force microscopy, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. Based on the experimental date, the ideal structure model of AlSPP is proposed, which indicated that the layered crystalline AlSPP samples are special lamellar structure with many cavums, holes, channels and ravines on the surface, the interlamellar region and interlayer surfaces of the particles. Therefore AlSPP possesses excellent properties and has potential applications for heterogeneous asymmetric catalyst supports. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
998.
A hybrid time stepping scheme combining explicit Runge–Kutta with implicit LU‐SGS for Navier–Stokes equations 下载免费PDF全文
Fengling Lu 《国际流体数值方法杂志》2016,82(4):218-227
A hybrid time stepping scheme is developed and implemented by a combination of explicit Runge–Kutta with implicit LU‐SGS scheme at the level of system matrix. In this method, the explicit scheme is applied to those grid cells of blocks that have large local time steps; meanwhile, the implicit scheme is applied to other grid cells of blocks that have smaller allowable local time steps in the same flow field. As a result, the discretized governing equations can be expressed as a compound of explicit and implicit matrix operator. The proposed method has been used to compute the steady transonic turbulent flow over the RAE 2822 airfoil. The numerical results are found to be in excellent agreement with the experimental data. In the validation case, the present scheme saved at least 50% of the memory resources compared with the fully implicit LU‐SGS. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
Cover Picture: Dipolar Rotors Orderly Aligned in Mesoporous Fluorinated Organosilica Architectures (Angew. Chem. Int. Ed. 16/2015) 下载免费PDF全文
1000.
AbstractZinc oxide nanostructures have been grown by electrochemical deposition on porous silicon–silicon substrate. The photoelectric and sensory properties of the obtained ZnO–porous silicon nanosystems were investigated in both DC and AC regimes. The obtained structures were characterized by photosensitivity in the 400–1100?nm wavelength range and by high sensitivity to moisture. Increase of relative humidity resulted in significant decrease of the electrical resistance and increase of the capacitance of the hybrid structures. To estimate the sensory properties of the ZnO–porous silicon nanostructures their adsorption sensitivity and dynamic characteristics were analyzed. Discovered features of the charge transport processes broaden the prospects of the semiconductor nanosystems application in gas sensors and photodetectors. 相似文献