共查询到20条相似文献,搜索用时 15 毫秒
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Henrik Fanø Clausen 《Journal of solid state chemistry》2005,178(11):3342-3351
Two new metal organic framework (MOF) structures have been obtained from the Zn-terephthalic acid (H2BDC)-dimethyl formamide (DMF) system and examined by single-crystal X-ray diffraction: Zn(C8H4O4)(C3H7NO), 1, monoclinic C2/m, a=11.1369(5), b=14.0217(7), , β=106.316(1)°, , , Z=4, R1=0.060, wR2=0.169, S=1.27; Zn(HCO2)3(C2H8N), 2, trigonal , a=8.1818(1), , , , Z=6, R1=0.014, wR2=0.039, S=1.11. Contrary to previously published structures in the same system, the crystals were obtained by solvothermal synthesis at 381 K. Structure 1 consists of 2-D layers stacked in an offset manner to accommodate DMF moieties coordinated to Zn2+ within voids in adjacent layers. Structure 2 consists of a 3-D network constructed from Zn2+ ions bridged by deprotonated formic acid moieties. Over time, the structure of 1 rearranges to Zn(C8H4O4)(C3H7NO)(H2O) [monoclinic P21/n, a=6.6456(2), b=15.2232(5), , β=104.110(2)°, , , Z=4, R1=0.048, wR2=0.100, S=1.07], which is identical to the known MOF-2 structure, obtained by crystallization at ambient conditions. The three structures were determined from crystals with similar crystal habits picked from a single solvothermal synthesis batch. The study demonstrates that MOF syntheses can give not only multiple crystal structures under different conditions, but also that numerous different structures, including some that are metastable, can be formed under identical conditions. 相似文献
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微型化学实验与创新教育 总被引:30,自引:1,他引:29
从思维科学的角度来看,采用微型化学实验进行化学教学,能促进学生左右脑的协调发展,是培养学生创造性思维和创新能力,实施素质教育的有效途径。 相似文献
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Iridium oxide film modified microelectrode was fabricated by anodic oxidation method onto the tip of an etched iridium wire in diluted sulfuric acid solution by cyclic voltammetry. The iridium oxide film microelectrode exhibited very promising pH sensing performance, with an ideal Nernstian in the tested pH range of 0 to 14. This method for preparing microelectrode allowed accurately control of the deposited amount and the rate of the iridium oxide film growth. The electrodes demonstrated advantages of long lifetime, good selectivity and fast response with a relative time less than 0.2 s for pH changes in a large scale. The microelectrode was not interfered by a wide variety of inorganic ions and organic compounds. Furthermore, the electrodes were successfully applied to the measurement of pH in microscale of apples. 相似文献
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Three new metal phosphites, formulated as (H3O)2·Mn2(HPO3)3 (1), Co(bpy) (H2O) (HPO3) (2), and H2tmpda·Zn3(HPO3)4 (3), have been synthesized under solvent-free conditions, where bpy = 4,4′-bipyridine, and tmpda = N,N,N′,N′-tetramethyl-1,3-propanediamine. Compound 1 has a double-layered structure with a thickness of 5.68 Å. Compound 2 has an inorganic-organic hybrid framework with cobalt phosphite layers pillared by bpy ligands. Compound 3 has a three-dimensional open-framework structure containing 8-ring channels. The temperature dependence of the magnetic susceptibility of compounds 1 and 2 were also investigated. 相似文献
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《中国化学快报》2022,33(10):4559-4562
A metal-free porphyrin covalent organic framework was employed as the heterogeneous photocatalyst for the synthesis of tetrahydroquinolines under aerobic conditions. With visible light irradiation of a catalytic amount of H2P-Bph-COF at room temperature, various substituted N,N-dimethylanilines and N-aryl maleimides were transformed to tetrahydroquinoline derivatives in moderate to good yields. This was the first example of the synthesis of tetrahydroquinolines via the photocatalytic aerobic annulation reaction employing the metal-free COF as the heterogeneous photocatalyst. 相似文献
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Several transition metal oxides,including α-Fe2O3,Fe3O4,Co3O4,NiO,CuO and ZnO,were synthesized via an easily controlled hydrothermal method at assistance of organic amine(cyclohexylamine or triethylamine).The synthesized samples were identified and characterized by X-ray diffraction(XRD),Transmission Electron Microscopy(TEM),High-resolution Electron Microscopy(HR-TEM),Field Emission Scanning Electron Microscopy(FE-SEM),N2 adsorption/desorption measurement.The resultant metal oxides displayed various morphol... 相似文献
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Guoyu Wei Yuexiang Lu Shuang Liu Hongpeng Li Xuegang Liu Gang Ye Jing Chen 《中国化学快报》2021,32(1):497-500
Metal organic frameworks(MOFs) are a kind of promising materials in many applications,while the fast and controllable synthesis of MOFs is still challenging.Here,taking HKUST-1 as illustration,a microplasma electrochemistry(MIPEC) strategy was developed to accelerate the synthesis process of MOFs with micro-plasma acting as cathode.Treating the HKUST-1 precursor solution with micro-plasma cathode could not only transfer the electrons into the solution leading to the deprotonation effect,but also generate radical species to trigger and accelerate the nucleation and growth of MOFs at the plasmaliquid interface.Thus,uniform and nanosize MOFs could be prepared within minutes.The obtained MOFs show similar excellent uranium adsorption properties compared with those obtained by other method,with a highly adsorption capability of uranium with 550 mg/g in minutes.The novel MIPEC strategy developed in this work provides an alternative for controllable synthesis of MOFs,and especially has potential application in accelerating traditional organic synthesis. 相似文献
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A Zn-containing graphite carbon (Zn-GC) with uniform Zn metal sites and hierarchical pore structure was obtained by pyrolysis of Zn-based metal organic framework (MOF). Zn-GC exhibited excellent adsorption capacity and reproducibility for formaldehyde. The adsorption capacity of Zn-GC was 736 times that of commercial activated carbon and 5.6 times that of ZSM-5 adsorbents. The characterization and experimental results showed that the surface chemical characteristics of the adsorption material play an important role in the adsorption performance. The superior performance was attributed to Zn metal sites and oxygen-containing functional groups on the MOF derivative as well as hierarchical pore structure. The material showed a great potential in the field of organic pollutant removal. 相似文献
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Youssef Atoini Pengkun Chen Dries Jonckheere Dirk De Vos 《Supramolecular chemistry》2017,29(10):758-767
AbstractWe report the preparation and characterisation of new emissive materials based on the insertion of platinum(II) and iridium(III) complexes inside the Al(OH)(bipyridine dicarboxylate) metal organic framework (MOF-253). Guest incorporation is performed by coordination of a metal complex precursor, and provides increased robustness to the system compared to guest inclusion by its physical diffusion. Powder X-ray diffraction analysis highlights the high degree of crystallinity of the materials, with a complete change in the lattice parameters upon metal complex insertion. The photophysical properties of the resulting materials were thoroughly investigated. This synthetic approach is particularly attractive since, as we show, it is possible to tune the emission maxima of our materials over the entire visible range. 相似文献
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Wolfgang HörnerHelmut Bertagnolli 《Journal of organometallic chemistry》2002,649(2):128-135
An EXAFS spectroscopical study of three metal organic systems is presented. First, a series of differently concentrated Grignard compounds in solution were measured in order to obtain the degree of association and to find an eventual concentration dependence of the structure. No significant changes in the structure could be detected in the measured concentration range. The second investigated system Mg(CHBrCH2Ph)2, dissolved in THF, belongs to the relatively new class of carbenoids. A structural model of this compound, especially of the local environment of the α-carbon atom is deduced. Thirdly, Reformatsky compounds in solution with different ester groups, solvents and concentrations were studied. It is shown that the structure of these compounds depends on the polarity of the solvents. 相似文献
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Chen Wang Cheng Chen Mingxuan Ma Zijie Feng Yingxiang Du 《Journal of separation science》2022,45(14):2708-2716
Metal organic frameworks have received great attention as the chiral stationary phase for racemic drug separation because of their fascinating structures and properties. However, the most homochiral metal organic frameworks were constructed by rare and precious chiral organic ligands. In this work, an achiral metal organic framework, together with a natural chiral selector carboxymethyl β-cyclodextrin built a synergistic separation system in the open tubular capillary electrochromatography. The novel coated columns were developed by inducing metal organic framework nanoparticles to grow on the imidazolyl functional capillary inner wall. The baseline separations of hydroxychloroquine, ofloxacin, and atenolol were achieved in the synergistic separation system. The effects of the concentration of chiral selector, pH, voltage, and the concentration of organic additives were studied. Compared with chiral selector auxiliary bare capillary, the resolutions of three drugs were remarkably improved. The relative standard deviations for the retention time of intraday (n = 6), interday (n = 6), and column-to-column were less than 2.1, 2.6, and 5.2%, respectively. These results demonstrate that affordable synergistic separation systems are prospective for racemic drug enantioseparation in capillary electrochromatography. 相似文献
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Fernandez CA Nune SK Motkuri RK Thallapally PK Wang C Liu J Exarhos GJ McGrail BP 《Langmuir : the ACS journal of surfaces and colloids》2010,26(24):18591-18594
The considerable number of important physical properties, including optical, electronic, and magnetic properties, of Prussian blue (PB) analogues have attracted fundamental and industrial interest. Nevertheless, the gas sorption properties of PB coordination compounds were only investigated very recently. In this work, we report the synthesis and gas sorption properties of PB nanocomposites with different size and shape obtained by using poly(vinylpyrrolidone) (PVP), chitosan, and dioctyl sodium sulfosuccinate (AOT) as stabilizers and structure directing agents. All three porous nanocrystals show high and selective CO(2) adsorption over CH(4) or N(2). No distinct relationship was found between the size (or shape) of the nanosorbents and their gas uptake capacities. To our knowledge, this is the first report on the use of PB nanocomposites for CO(2) capture applications. 相似文献
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Alpha-Ni(OH)(2) nanobelts, nanowires, short nanowires, and beta-Ni(OH)(2) nanoplates have been successfully prepared in high yields and purities by a convenient hydrothermal method under mild conditions from very simple systems composed only of NaOH, NiSO(4), and water. It has been found that the ratio of NaOH to NiSO(4) not only affects the morphology of the Ni(OH)(2) nanostructures, but also determines whether the product is of the alpha- or beta-crystal phase. A notable finding is that porous NiO nanobelts were produced after exposure of the Ni(OH)(2) products to an electron beam for several minutes during transmission electron microscopy (TEM) observations. Another unusual feature is that rectangular nanoplates with many gaps were obtained. Furthermore, porous NiO nanobelts, nanowires, and nanoplates could also be obtained by annealing the as-prepared Ni(OH)(2) products. A sequence of dissolution, recrystallization, and oriented attachment-assisted self-assembly of nanowires into nanobelts is proposed as a plausible mechanistic interpretation for the formation of the observed structures. The method presented here possesses several advantages, including high yields, high purities, low cost, and environmental benignity. It might feasibly be scaled-up for industrial mass production. 相似文献
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Resin plugs, a unique and conveniently handled form of resin, prepared by sintering high-density polyethylene (HDPE) with pre-functionalised resins, were derivatised and loaded with palladium(0). These ‘plugs’ were used in the preparation of a Suzuki reaction based library and the removal of allyl ester protecting groups. The ‘plugs of catalyst’ were easily separated from the reaction mixture and were re-used multiple times with minimal loss of activity. 相似文献
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E. A. Karakhanov A. L. Maksimov E. A. Runova Yu. S. Kardasheva M. V. Terenina S. V. Kardashev V. A. Skorkin L. M. Karapetyan M. Yu. Talanova 《Russian Chemical Bulletin》2008,57(4):780-792
Specific features of the behavior of the supramolecular metal complex catalysts based on calixarenes, cyclodextrins, and dendrimers
in the reactions of hydroformylation, Wacker oxidation, hydroxylation of aromatics, 2-naphthol coupling, and oxidative coupling
of styrenes and benzene were studied. The factors affecting the catalytic activity and selectivity are discussed.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 766–778, April, 2008. 相似文献