首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 279 毫秒
1.
Herein we report the synthesis and structures of two new small‐pore aluminophosphate molecular sieves PST‐13 and PST‐14 with mutually connected 8‐ring channels. The structure of PST‐13, synthesized using diethylamine as an organic structure‐directing agent, contains penta‐coordinated framework Al atoms bridged by hydroxy groups and thus edge‐sharing 3‐ and 5‐rings. Upon calcination, PST‐13 undergoes a transformation to PST‐14 with loss of bridging hydroxy groups and occluded organic species. The structures of both materials consist “nonjointly” of pairs of previously undiscovered 1,5‐ and 1,6‐open double 4‐rings (d4rs) which are mirror images of each other. We also present a series of novel chemically feasible hypothetical structures built from 1‐open d4r (sti) or 1,3‐open d4r (nsc) units, as well as from these two enantiomeric structural building units.  相似文献   

2.
A novel structural coding approach combining structure solution, prediction, and the targeted synthesis of new zeolites with expanding complexity and embedded isoreticular structures was recently proposed. Using this approach, the structures of two new zeolites in the RHO family, PST‐20 and PST‐25, were predicted and synthesized. Herein, by extending this approach, the next two higher generation members of this family, PST‐26 and PST‐28, have been predicted and synthesized. These two zeolites have much larger unit cell volumes (422 655 Å3 and 614 912 Å3, respectively) than those of the lower generations. Their crystallization was confirmed by a combination of both powder X‐ray and electron diffraction techniques. Aluminate and water concentrations in the synthetic mixture were found to be the two most critical factors influencing the structural expansion of embedded isoreticular zeolites under the synthetic conditions studied herein.  相似文献   

3.
Shao L  Li Y  Yu J  Xu R 《Inorganic chemistry》2012,51(1):225-229
Two divalent-metal-containing aluminophosphates, (C(5)H(14)N(2))[Co(2)Al(4)P(6)O(24)] and (C(5)H(14)N(2))[Zn(2)Al(4)P(6)O(24)] (denoted as MAPO-CJ62; M = Co, Zn), have been hydrothermally synthesized by using N-methylpiperazine as the structure directing agent. Their structures are determined by single crystal X-ray diffraction and further characterized by powder X-ray diffraction, inductively coupled plasma, and thermogravimetric and diffuse reflectance spectroscopy analyses. Both of these two compounds exhibit a new zeolite framework topology. This new zeolite framework contains 1-dimensional 8-ring channels running along the [010] direction. All the metal and P atoms are tetrahedrally coordinated and alternately connected to each other through bridging O atoms. Inductively coupled plasma analysis shows that the molar ratio of M:Al in MAPO-CJ62 is 1:2. The M(2+) ions in MAPO-CJ62 selectively occupy two of the three possible crystallographically distinct positions. A pure aluminophosphate analogue of MAPO-CJ62 without M(2+)-incorporation, denoted as AlPO-CJ62, has not been obtained in our experiment so far. The necessity of introducing M(2+) ions and their ordered distribution in MAPO-CJ62 has been elucidated by analyzing the distortions of Al-centered tetrahedra in the hypothetical framework of AlPO-CJ62.  相似文献   

4.
Herein we report the synthesis, structure solution, and catalytic properties of PST‐24, a novel channel‐based medium‐pore zeolite. This zeolite was synthesized via the excess fluoride approach. Electron diffraction shows that its structure is built by composite cas‐zigzag (cas‐zz) building chains, which are connected by double 5‐ring (d5r) columns. While the cas‐zz building chains are ordered in the PST‐24 framework, the d5r columns adopt one of two possible arrangements; the two adjacent d5r columns are either at the same height or at different heights, denoted arrangements S and D, which can be regarded as open and closed valves that connect the channels, respectively. A framework with arrangement D only has a 2D 10‐ring channel system, whereas that with arrangement S only contains 3D channels. In actual PST‐24 crystals, the open and closed valves are almost randomly dispersed to yield a zeolite framework where the channel dimensionality varies locally from 2D to 3D.  相似文献   

5.
以外消旋的2-甲基-1,5-戊二胺(MPMD)为结构导向剂,在水热条件下合成出新磷酸铝化合物[Al4P5O19(OH)][C6H18N2](AlPO-MPMD)和新磷酸镓化合物[Ga8P8O32F5.5][C6H18N2]2[H30+]1.5(GaPO-MPMD).采用单晶x射线衍射结构分析、粉末x射线衍射分析(XRD)、热重-差热分析(TGA-DTA.A)、固体核磁共振(MAs NMR)、旋光分析(Optical rotation)以及振动圆二色光谱分析(Vibrational circular dichroism,VCD)等技术对产物进行了表征.对产物的VCD实验光谱和理论模拟光谱对比分析及旋光分析表明,在水热合成过程中,具有S构象的手性结构导向剂分子比具有R构象的手性结构导向剂分子更多地进入无机化合物骨架中,显示了手性对映体分子在该水热条件下的原位手性拆分.  相似文献   

6.
Given their great potential as new industrial catalysts and adsorbents, the search for new zeolite structures is of major importance in nanoporous materials chemistry. However, although innumerable theoretical frameworks have been proposed, none of them have been synthesized by a priori design yet. We generated a library of diazolium‐based cations inspired from the organic structure‐directing agents (OSDAs) recently reported to give two structurally related zeolites (PST‐21 and PST‐22) under highly concentrated, excess‐fluoride conditions and compared the stabilization energies of each OSDA cation in ten pre‐established hypothetical structures. A combination of the ability of the OSDA selected in this way with the excess‐fluoride approach has allowed us to crystallize PST‐30, the targeted aluminosilicate zeolite structure. We anticipate that our approach, which aims to rationally couple computational predictions of OSDAs with an experimental setup, will advance further development in the synthesis of zeolites with desired properties.  相似文献   

7.
以1,2-丙二胺(1,2-DAP)为结构导向剂,在180℃加热摩尔组成为n(Al_2O_3)∶n(P_2O_5)∶n(1,2-DAP)∶n(H_2O)=1∶6∶5.5∶139的初始混合物,合成了具有AlPO-CJ31骨架结构的新型三维开放骨架磷酸铝化合物(1);加热摩尔组成为n(Al_2O_3)∶n(P_2O_5)∶n(1,2-DAP)∶n(H_2O)=1∶6∶7.5∶139的初始混合物,合成了二维层状磷酸铝化合物APDAP_(12)-150.利用X射线粉末衍射分析(XRD)、元素分析、热重/差热分析等表征手段确认了化合物1的分子式为[Al_4P_5O_(20)·H_3O·H_2O]·[H_3NCH_2CHNH_3CH_3],质子化的水分子与双质子化的1,2-丙二胺共同起到了导向化合物1的作用.调变初始混合物中1,2-丙二胺的比例可显著影响其模板效应.1,2-丙二胺比例较低[n(1,2-DAP)=5.5]时,产物为三维开放骨架化合物,而当其比例较高[n(1,2-DAP)=7.5]时,产物为二维层状化合物.  相似文献   

8.
以外消旋的2-甲基-1,5-戊二胺(MPMD)为结构导向剂,在水热条件下合成出新磷酸铝化合物[Al4P5O19(OH)][C6H18N2](AlPO-MPMD)和新磷酸镓化合物[Ga8P8O32F5.5][C6H18N2]2[H30+]1.5(GaPO-MPMD).采用单晶x射线衍射结构分析、粉末x射线衍射分析(XRD...  相似文献   

9.
A scheme to obtain approximate analytical functions for the atomic distributed multipole moments of the crystallographically different atoms within aluminosilicate and aluminophosphate sieves is discussed. Respective atomic multipole moments are derived within the CRYSTAL95 ab initio periodic Hartree–Fock code with different basis sets, from minimal STO‐3G to 6‐21G*. In order to illustrate the possible applications, distributed analyses are carried out for various structural models from all‐siliceous zeolites and aluminophosphates with ratio Al/P=1 to hydrogen forms of aluminosilicates. Simple approximate forms based on charge and geometry coordinates are proposed for the high‐order moments of each atom, which are further required for the calculation of the electrostatic field within the structures. The possibility to use this analytical approach to evaluate the electrostatic field within embedded cluster models is also shortly discussed. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 70–85, 2001  相似文献   

10.
Water adsorption in the microporous aluminophosphate AlPO4-18 is studied by a combination of solid-state NMR, X-ray diffraction, and density functional theory calculations. The change of the framework structure upon hydration is moderate, and NMR gives local information on the environment of Al and P atoms. The structural distribution of water molecules in the channels has been explored by a combination of first-principle molecular dynamics simulations and of static geometry optimizations. Two starting points have been considered for the calculations. If the structure of the dehydrated aluminophosphate is used, the simulation result is not satisfactory with an incomplete hydration and no agreement with NMR results. Starting from a partial refinement of the aluminophosphate framework for the hydrated system, a structure with six tetrahedral and six octahedral Al atoms in the unit cell is obtained, involving twelve water molecules coordinated to Al atoms and twelve others in the channels, and in good agreement with experimental data.  相似文献   

11.
Shi L  Li J  Yu J  Li Y  Ding H  Xu R 《Inorganic chemistry》2004,43(8):2703-2707
A new manganese(II)-substituted aluminophosphate, [C(6)N(2)H(14)]0.5.[MnAl(3)(PO(4))(4)(H(2)O)(2)], denoted as MnAPO-14, has been synthesized hydrothermally in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as the structure-directing agent. Its structure is determined by single-crystal X-ray diffraction analysis and further characterized by X-ray powder diffraction, ICP, and TG analyses. The structure of MnAPO-14 is built up by MnO(4)(H(2)O)(2) octahedra, AlO(4) tetrahedra, and PO(4) tetrahedra via Al-O-P and Mn-O-P linkages. Its framework is analogous to that of aluminophosphate zeotype AFN in which 25% of the aluminum sites are replaced by Mn(II) atoms. The diprotonated DABCO cations reside in the eight-membered ring channels. Computational simulations indicate that the substitution site of Mn to Al is determined by the host-guest interaction. Crystal data: [C(6)N(2)H(14)]0.5.[MnAl(3)(PO(4))(4)(H(2)O)(2)], triclinic P1 (No. 2), a = 9.5121(4) A, b = 9.8819(3) A, c = 12.1172(4) A, alpha = 70.533(2) degrees, beta = 73.473(2) degrees, gamma = 82.328(2) degrees, Z = 2, R(1) = 0.0586 (I > 2 sigma(I)), and wR(2) = 0.1877 (all data).  相似文献   

12.
Amorphous aluminophosphate (AlP) and metal‐aluminophosphates (MAlPs, where M=2.5 mol%Cu, Zn, Cr, Fe, Ce, or Zr) were prepared by coprecipitation method. Their surface properties and catalytic activity for the synthesis of jasminaldehyde through the aldol condensation of n‐heptanal and benzaldehyde were investigated. The nitrogen adsorption‐desorption isotherms showed that the microporosity exhibited by the aluminophosphate was changed to a mesoporous and macroporous structure which depended on the metal incorporated, with a concomitant change in the surface area. Temperature‐programmed desorption of NH3 and CO2 revealed that the materials possessed both acidic and basic sites. The acidic strength of the material was either increased or decreased depending on the nature of the metal. The basicity was increased compared to AlP. All the materials were X‐ray amorphous and powder X‐ray diffraction studies indicated the absence of metal oxide phases. The Fourier transform infrared analysis confirmed the presence of phosphate groups and also the absence of any M‐O moieties in the materials. The selected organic reaction occurred only in the presence of the AlP and MAlPs. The selectivity for the jasminaldehyde product was up to 75%with a yield of 65%. The best conversion of n‐heptanal with a high selectivity to jasminaldehyde was obtained with FeAlP as the catalyst, and this material was characterized to have less weak acid sites and more basic sites.  相似文献   

13.
The charge density mismatch concept was applied to the synthesis of high‐charge‐density silicoaluminophosphate SAPO‐69 (OFF) and SAPO‐79 (ERI) and zincoaluminophosphate PST‐16 (CGS), PST‐17 (BPH), PST‐19 (SBS), and ZnAPO‐88 (MER) molecular sieves. Combined alkali‐organoammonium structure direction in these systems is thus enabled. Structure direction is treated from the perspective of stabilizing an ionic framework, the relationships between reaction charge density (OH?/H3PO4), alkali and organoammonium content, and ionicity of tetrahedral framework atoms in successful structure direction are presented.  相似文献   

14.
The crystal structure of a new form of dehydrated manganese(II) acetate, poly[[hexa‐μ3‐acetato‐trimanganese(II)] acetonitrile solvate], {[Mn3(CH3COO)6]·CH3CN}n, (I), reveals a three‐dimensional polymeric structure based on an {Mn3} trimer. The {Mn3} asymmetric unit contains three crystallographically independent Mn positions, comprising a seven‐coordinate center sharing a mirror plane with a six‐coordinate center, and another six‐coordinate atom located on an inversion center. Two of the four crystallographically independent acetate (OAc) ligands, as well as the acetonitrile solvent molecule, are also located on the mirror plane. The Mn atoms are connected by a mixture of Mn—O—Mn and Mn—OCO—Mn bridging modes, giving rise to face‐ and corner‐sharing interactions between manganese polyhedra within the trimers, and edge‐ and corner‐sharing connections between the trimers. The network contains substantial pores which are tightly filled by crystallographically located acetonitrile molecules. This structure represents the first porous structurally characterized phase of anhydrous manganese(II) acetate and as such it is compared with the closely related densely packed anhydrous manganese(II) acetate phase, solvent‐free β‐Mn(OAc)2.  相似文献   

15.
The reaction of lead(II) nitrate with 4,4′‐bipyridine (4,4′‐bpy) and 4,4′‐dimethyl‐2,2′‐bipyridine (4,4′‐dm‐2,2′‐bpy) or 5,5′‐dimethyl‐2,2′‐bipyridine (5,5′‐dm‐2,2′‐bpy) resulted in the fomation of single crystals of [Pb2(4,4′‐bpy)(5,5′‐dm‐2,2′‐bpy)2(NO3)4] ( 1 ) and [Pb3(4,4′‐bpy)2(4,4′‐dm‐2,2′‐bpy)2(NO3)6] ( 2 ). The new compounds have been characterized by single‐crystal X‐ray diffraction structure analysis as well as through elemental analysis, IR, 1H‐NMR and 13C‐NMR spectroscopy and their stability has been studied by thermal analysis. In the crystal structure of ( 1 ) formula‐like dimers are further connected to a 2‐D network through the auxiliary nitrate ligands. The crystal structure of ( 2 ) exhibits two crystallographically independent PbII central atoms (in a ratio of 1:2). With the aid of the 4,4′‐bpy and the nitrate ions, a 3‐D polymeric structure is achieved.  相似文献   

16.
采用蒸气相合成法以吡啶作为蒸气源, 在吡啶气氛下磷酸铝固态凝胶被转化为一种三维骨架结构的磷酸铝微孔化合物, 用X射线单晶衍射法测定了其晶体结构, [Al3P3O12F][C5H5NH]•0.2H2O微孔化合物属三斜晶系, 空间群P-1(2), 晶胞参数a=9.127(2) Å, b=9.185(3) Å, c=9.346(2) Å, α=85.563(14)°, β=77.346(6)°, γ=89.628(17)°, V=762.2(4) Å3, Z=2, Dc=2.074 Mg/m3, Mr=468.09, F(000)=474, μ=0.64 mm-1. 其和以前报道的磷酸铝分子筛UT-6具有相同的骨架结构, 起始凝胶组分中的氟离子参与了骨架生成(Al—F—Al), 骨架中有三种相互独立的8元环孔道互相交叉最终形成类似于AlPO4-CHA型沸石的笼型结构. XRD, TG-DTA研究结果表明, 合成的样品具有较高的热稳定性, 400 ℃煅烧后, 其骨架结构保持不变.  相似文献   

17.
The title compound, potassium pentanickel hexaborophosphate tridecahydroxide, was synthesized under hydrothermal conditions from the NiCl2–K3PO4–B2O3–K2CO3–H2O system. The crystal structure was determined using single‐crystal X‐ray diffraction at 100 K. The KNi5[P6B6O23(OH)13] phase is cubic. For the three crystallographically distinct Ni centers, two occupy sites with 3 symmetry, while the third Ni and the K atom are located on sites. The structure is built from alternating borate and phosphate tetrahedra forming 12‐membered puckered rings with K+ ions at the centers. These rings are arranged as in cubic dense sphere packing. A novel feature of the new crystal structure is the presence of linear trimers of face‐sharing [NiO6] octahedra occupying the octahedral interstices of this sphere packing, and of single [NiO6] octahedra in the tetrahedral interstices. All oxygen corners of the Ni octahedra are linked to phosphate or borate tetrahedra of the 12‐membered rings to form a mixed anionic framework.  相似文献   

18.
The 1D chain red luminescent europium coordination polymer: {[Eu2L6(DMF)(H2O)] · 2DMF · H2O}n ( I ) (L = 4‐chloro‐cinnamic acid anion, C9H6ClO2, DMF = N, N‐dimethylformamide) was synthesized by the reaction of Eu(OH)3 and 4‐chloro‐cinnamic acid ligand. The structure of the coordination polymer was determined by single‐crystal X‐ray diffraction analysis. It reveals that there exists two crystallographically nonequivalent europium atoms in each unit of this coordination polymer and Eu3+ ions are connected by two alternating bridging modes to form an endless polymer structure. The luminescent properties and energy transfer process in the complex are investigated at room temperature.  相似文献   

19.
The title compound (named Mu-4) is a new layered aluminophosphate with a unusual A1/P ratio for this kind of materials. Mu-4 was obtained from a quasi non-aqueous mixture involving mainly diethylformamide (DEF) as solvent, in addition to limited amounts of water. DEF is decomposed during the synthesis and the resulting protonated diethylamine is occluded in the as-synthesized material. The crystal structure was determined by single crystal X-ray diffraction. The symmetry is triclinic, a=8.632(4) Å, b=9.267(7) Å, c= 17.461(10) Å, α=86.66(5)°, β=82.20(4)° and γ=89.28(5)°, space group P-1. The structure consists of anionic double sheets essentially built from double 4-ring (D4R) units. The inorganic layers are in strong interaction with water and the protonated amine which is located in the interlayer spacing. Another type of diethylamine protrudes into the 8-membered rings (8-MR) present in the layers. The characterization of this new aluminophosphate by 13C, 27Al and 31P solid state NMR spectroscopy is also reported.  相似文献   

20.
Aminobenzoic acid derivatives are widely used in the preparation of new coordination polymers since they contain O‐atom donors, as well as N‐atom donors, and have a rich variety of coordination modes which can lead to polymers with intriguing structures and interesting properties. Two new coordination polymers incorporating 1‐aminobenzene‐3,4,5‐tricarboxylic acid (H3abtc), namely, poly[(μ3‐1‐amino‐5‐carboxybenzene‐3,4‐dicarboxylato)diaquacadmium(II)], [Cd(C9H5NO6)(H2O)2]n, (I), and poly[[bis(μ5‐1‐aminobenzene‐3,4,5‐tricarboxylato)triaquatrizinc(II)] dihydrate], {[Zn3(C9H4NO6)2(H2O)3]·2H2O}n, (II), have been prepared and structurally characterized by single‐crystal X‐ray diffraction. In polymer (I), each tridentate 1‐amino‐5‐carboxybenzene‐3,4‐dicarboxylate (Habtc2?) ligand coordinates to three CdII ions to form a two‐dimensional network structure, in which all of the CdII ions and Habtc2? ligands are equivalent, respectively. Polymer (II) also exhibits a two‐dimensional network structure, in which three crystallographically independent ZnII ions are bridged by two crystallographically independent pentadentate 1‐aminobenzene‐3,4,5‐tricarboxylate (abtc3?) ligands. This indicates that changing the metal ion can influence the coordination mode of the H3abtc‐derived ligand and further influence the detailed architecture of the polymer. Moreover, the IR spectra, thermogravimetric analyses and fluorescence properties were investigated.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号