共查询到20条相似文献,搜索用时 15 毫秒
1.
Modular design method for designing and synthesizing microporous metal-organic frameworks (MOFs) with selective catalytical activity was described. MOFs with both nano-sized channels and potential catalytic activities could be obtained through self-assembly of a framework unit and a catalyst unit. By selecting hexaaquo metal complexes and the ligand BTC (BTC=1,3,5-benzenetricarboxylate) as framework-building blocks and using the metal complex [M(phen)2(H2O)2]2+ (phen=1,10-phenanthroline) as a catalyst unit, a series of supramolecular MOFs 1-7 with three-dimensional nano-sized channels, i.e. [M1(H2O)6]·[M2(phen)2(H2O)2]2·2(BTC)·xH2O (M1, M2Co(II), Ni(II), Cu(II), Zn(II), or Mn(II), phen=1,10-phenanthroline, BTC=1,3,5-benzenetricarboxylate, x=22−24), were synthesized through self-assembly, and their structures were characterized by IR, elemental analysis, and single-crystal X-ray diffraction. These supramolecular microporous MOFs showed significant size and shape selectivity in the catalyzed oxidation of phenols, which is due to catalytic reactions taking place in the channels of the framework. Design strategy, synthesis, and self-assembly mechanism for the construction of these porous MOFs were discussed. 相似文献
2.
Tuoping Hu Longjie Liu Xiaoli Lv Xiaohui Chen Haiyan He Fangna Dai Guoqing Zhang Daofeng Sun 《Polyhedron》2010
Three metal-organic frameworks with 1D zigzag chain [Zn(dte)(H2O)3]·2H2O (1), 2D double layer [Cd(dtb)(H2O)(phen)] (2), 3D network [Zn(dte)(phen)] (3) based on tetrazole-based ligands (H2dtb = 1,3-dis(2H-tetrazol-5-yl)benzene, H2dte = 1,4-ditetrazolylethylene, phen = 1,10-phenanthroline), have been synthesized and characterized. All the compounds exhibit unusual strong luminescence at room temperature in the solid state and can be potentially used as luminescent materials. 相似文献
3.
以正硅酸乙酯为硅源,正十六胺为模板剂,乙醇和水为溶剂,采用水热合成法制备了纯硅HMS介孔材料.以TiCl4为钛源,采用气相接枝技术将Ti物种引入到HMS的骨架中,制得Ti/HMS催化剂;以六甲基二硅氮烷为硅烷化试剂,采用液相接枝技术,将甲基接枝到Ti/HMS催化剂表面,以提高催化剂的疏水性.采用XRD、N2吸附、TEM、UV-Vis和FT-IR等技术表征研究了催化剂的结构、表面化学组成及疏水性;以过氧化氢异丙苯为氧化剂,分别在淤浆床及固定床反应器中,研究了Ti/HMS催化剂对丙烯的催化环氧化性能及稳定性.研究结果表明,所制备的Ti/HMS催化剂具有典型的六方介孔结构特征,且钛物种主要以四配位的活性物种形式存在于骨架中;经硅烷化试剂处理后,催化剂的疏水性得到显著提高;经硅烷化处理后的催化剂对丙烯环氧化具有优异的活性、选择性和稳定性,在2400小时的稳定性实验中,CHP的转化率维持在99.0%以上,环氧丙烷的选择性维持在97.0%以上. 相似文献
4.
Schiff碱及其配合物在治疗肿瘤、抗菌、仿生载氧等方面具有优异的性能,在催化领域中也表现出多种性质。本文合成了三种结构简单的Schiff碱配体以及它们的过渡金属配合物,并研究了其对环己烯的催化环氧化性能。配体的结构如下。 相似文献
5.
《Journal of Coordination Chemistry》2012,65(2):222-231
Two new compounds, [Cd2(bptc)(bpimb)(H2O)]?·?2H2O (1) and [Cd2(bptc)(bpib)]?·?4H2O (2) (where H4bptc?=?biphenyl-3,3′,4,4′-tetracarboxylic acid, bpimb?=?1,3-bis((2-(pyridin-2-yl)-1H-imidazol-1-yl)methyl)benzene, bpib?=?1,4-bis(2-(pyridin-2-yl)-1H-imidazol-1-yl)butane), were synthesized by reactions of the corresponding metal salts with H4bptc and N-containing auxiliary ligands and their structures have been determined by single-crystal X-ray diffraction. Compound 1 is built by Cd4-clusters which further construct a 3-D (3,8)-connected framework with tfz-d notation; 2, also built by Cd4-clusters, is a 3-D (4,8)-connected framework with (32?·?42?·?52)(34?·?48?·?512?·?64) topology. In addition, the elemental analyses, infrared spectra, fluorescence, and thermogravimetric analyses for 1 and 2 are discussed. 相似文献
6.
Summary NaCl promoted VCexCu1-xO catalysts were characterized by TPR and XPS. The catalytic activities were correlated with TPR results. XPS results implied
that NaCl probably acted as an electronic promoter. 相似文献
7.
A family of isoreticular metal-organic frameworks, based on the UiO-66 structure with NH2-, OH-, HSO3-, and NO2-substituted terephthalic acid, are synthesized and tested as catalysts in liquid-phase oxidation of propylene glycol (PG) with hydrogen peroxide and compared with the catalytic performances of unsubstituted UiO-66. The obtained materials are characterized by X-ray diffraction, FT-IR, thermogravimetric analysis (TGA), nuclear magnetic resonance spectroscopy (1H NMR), and Fourier-transform infrared spectroscopy (FT-IR) of adsorbed CO and scanning electron microscopy (SEM) methods. Hydroxyacetone (HA) is the main product over all X-UiO-66 catalysts under the reaction conditions used. The nature of substituent drastically affects the PG conversion and the oxidant utilization efficiency. The presence of electron-withdrawing groups in the organic linker leads to preferential heterotic activation of H2O2, whereas the increase of electron density around Zr active sites, promoted by electron-donating groups, enhances the unproductive homolytic oxidant decomposition. The insertion of NO2 group results in almost double increase in the HA yield (15.5 vs. 8.8%) and hydrogen peroxide utilization efficiency (98 vs. 36%) in comparison with the reaction catalyzed by H-UiO-66. The NO2-UiO-66 can be recycled without the loss of the catalytic activity and preserves its structure after the catalytic cycle. 相似文献
8.
《印度化学会志》2021,98(11):100188
Clean and potable water is a growing concern around the globe. Among the different water pollutants, heavy metal ions pose a serious health concern to all living beings. The quest for new adsorbents to remove heavy metal ions received a boost with the development in the field of metal-organic framework (MOF). The advancement in synthetic strategies and designing of MOF enabled the researchers to tune the adsorption characteristics and tailor the material specific to a heavy metal ion. Similar to MOF, graphene-based two-dimensional and three-dimensional materials are also promising due to the diverse functionalization possibilities and cost-effectiveness. There had been growing interest in applying MOF and graphene-based materials for the removal of heavy metal ions in the past decade. This review summarizes these developments in detail. 相似文献
9.
Jin Zhao 《Journal of organometallic chemistry》2006,691(10):2199-2206
Ansa-bridged η5-cyclopentadienyl carbonyl molybdenum complexes were synthesized with stereogenic centers located in the side chain. An exemplary X-ray crystal structure and the catalytic activity for asymmetric olefin epoxidation are reported. In non-chiral epoxidation the compounds show a good catalytic activity, comparable to activities observed for the related non-chiral complexes of composition CpMo(CO)3X (X = Cl, CH3). For the asymmetric epoxidation of trans-β-methylstyrene the chiral induction is up to ca. 20%. The high ring strain of the ansa-bridged system hampers, unfortunately, its stability under oxidative condition. 相似文献
10.
Guojie Jin Guanzhong Lu Yanglong Guo Yun Guo Junsong Wang Xiaohui Liu 《Reaction Kinetics and Catalysis Letters》2006,89(2):253-260
Summary The performance of the Ag-MoO3/ZrO2 catalyst for propylene epoxidation by molecular oxygen is influenced obviously by the composition of feedstock. As an additive
in feedstock, the presence of organic chloride, CO2, NOx or H2 at a suitable concentration can improve the catalytic performance of Ag-MoO3/ZrO2 catalyst for the propylene epoxidation. 相似文献
11.
A metal-organic framework,Ce-FDM-50,was constructed by employing gallic acid featuring both carboxylate and pyrogallate as the coordinating sites and Ce(Ⅲ).The co-assembly of the carboxylates and pyrogallates with two metal ions have achieved a new type of paddle wheel secondary building unit.These building units were further joined by organic struts to obtain frameworks in sql topology.This synthetic approach could be expanded to five different lanthanide metals(Nd,Eu,Gd,Tb,Yb)for the construction of a series of isoreticular MOFs based on FDM-50,and even MTV-MOFs in which mixed lanthanide metals with specific ratios were distributed.In addition,featuring the lanthanide metals as the inorganic nodes in the network,Tb-FDM-50 showed distinct luminescence properties that could be furtherly tuned for variable applications. 相似文献
12.
13.
含Ti的HMS介孔材料催化剂及其对丙烯环氧化催化性能的研究 总被引:1,自引:1,他引:0
分别用水热合成法和气相四氯化钛(TiCl4)接枝法制备了Ti-HMS和Ti/HMS催化剂.表征结果表明,经过气相TiCl4接枝后的样品依然保持HMS(Hexagonal Mesoporous Silica,缩写为HMS)介孔材料特征,钛(Ti)物种主要以四配位的活性位形式存在.经过甲基接枝处理的催化材料,增加了表面的疏水性.丙烯环氧化反应结果表明,SN-Ti/HMS具有更高的催化性能.在2 500 h的稳定试验中,过氧化氢异丙苯(CHP)转化率大于99.0%,环氧丙烷(PO)选择性大于96.0%.研究和优化了环氧化反应工艺条件.采用浓度为30%的CHP为原料,CHP重量空速为1.0 h-1,床层温度为100℃,反应压力为3.0 MPa. 相似文献
14.
Propylene dimerization by a catalytic system consisting of nickel(II)acetylacetonate, triphenylphosphite and diethylaluminium
chloride has been studied. A kinetic analysis shows a first order dependence on catalyst and a second order dependence on
propylene.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
15.
采用溶剂热法, 以2, 5-二溴对苯二甲酸(H2L)为配体, 分别与六水合硝酸钕、六水合硝酸钆反应合成了 2种镧系金属有机骨架(MOFs):{[Nd2(L)3(DMF)2(H2O)2]·2DMF}n (1)和{[Gd2(L)3(DMF)2(H2O)2]·2DMF}n (2)。通过单晶X射线衍射、粉末X射线衍射、红外光谱、元素分析、荧光光谱、热重分析等测试方法对其进行了结构表征与性质研究。结果表明, 2个配合物均是以稀土离子为金属节点, 与配体相互连接, 形成无限延伸的三维网状结构。 相似文献
16.
环氧苯乙烷具有重要的经济价值,现有的工业生产技术存在能耗高及环境污染大等诸多问题,使得环境友好的苯乙烯环氧化生产工艺的开发具有重要意义.采用一步合成法制备了系列金-硅胶纳米球催化剂,实现了纳米金的高度分散(粒径6.4 nm),对苯乙烯环氧化反应表现出较好的催化活性及产物选择性.通过X射线粉末衍射、红外光谱及X射线光电子能谱等表征技术,结合苯乙烯环氧化反应性能的考察,对金-硅胶催化剂的制备条件进行了优化. 相似文献
17.
18.
《Journal of Coordination Chemistry》2012,65(3):548-559
A new cis-dioxo molybdenum(VI) complex was obtained by reaction of 2,4-dihydroxybenzylidene(5-N,N-methylphenylamino-1,3,4-thiadiazol-2-yl)hydrazone as ligand and [MoO2(acac)2] in methanol and was characterized by elemental analyses, 1H NMR, IR, and electronic spectroscopic studies. The complex was also analyzed by single-crystal X-ray diffraction. The structure determination revealed a distorted octahedral coordination geometry around molybdenum in which the tridentate NNO donor (L2–) is bonded to [MoO2]2+ through phenolic oxygen, hydrazinic nitrogen, and thiadiazole nitrogen. The sixth coordination site is occupied by a weakly bonded methanol. The complex was tested as a catalyst for homogeneous epoxidation of olefins using tert-butyl hydrogen peroxide as an oxidant. In the homogeneous catalytic system, the reactions are efficiently carried out with high yields and selectivity. 相似文献
19.
采用溶剂热法,以2,5-二溴对苯二甲酸(H2L)为配体,分别与六水合硝酸钕、六水合硝酸钆反应合成了2种镧系金属有机骨架(MOFs):{[Nd2(L)3(DMF)2(H2O)2]·2DMF}n (1)和{[Gd2(L)3(DMF)2(H2O)2]·2DMF}n (2)。通过单晶X射线衍射、粉末X射线衍射、红外光谱、元素分析、荧光光谱、热重分析等测试方法对其进行了结构表征与性质研究。结果表明,2个配合物均是以稀土离子为金属节点,与配体相互连接,形成无限延伸的三维网状结构。 相似文献
20.
V. N. Leonov A. A. Belyi G. A. Stozhkova M. B. Érman B. N. Bobylev M. E. Vol'pin 《Russian Chemical Bulletin》1988,37(9):1765-1768
Conclusions Modification with silanols results in an increase in the catalytic activity and selectivity of molybdenum complexes in the reaction of epoxidation of propene by cumene hydroperoxide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1976–1978, September, 1988. 相似文献