有机胺修饰稀土金属有机骨架：用于Knoevenagel缩合反应的三种固体碱催化剂

稀土金属有机骨架(Ln-MOFs)是利用有机配体和稀土离子之间配位自组装形成的具有超分子多孔网络结构的类沸石材料,其优点是稳定性好,一般不溶于常规的有机和无机溶剂,并且孔径、孔形及孔表面性质可通过其构建分子的选择或修饰进行灵活设计和制备.稀土离子性能独特,有机配体种类繁多,将稀土离子与有机配体可控组装可获得许多结构多样、性能优异的Ln-MOFs材料.这些功能材料已在气体吸附与分离、发光器件、化学传感以及磁性材料等多方面显示出潜在应用价值.特别是Ln-MOFs材料作为非均相催化剂具有热稳定性高、比表面积大以及稀土离子配位环境多样等优点,近年来受到国内外研究者关注和重视.后合成修饰法(PSM)是利用MOFs骨架中不饱和配位的金属离子或潜在的有机反应基团,通过配位键或共价键方式引入有机或无机分子,制备具有新功能的骨架材料.本文采用PSM策略,将三种不同的有机二胺后合成修饰到具有配位不饱和位点的稀土金属有机骨架[Er(btc)]的孔道中,得到三种固体碱催化剂：Er(btc)(ED)0.75(H2O)0.25(2), Er(btc)(PP)0.55(H2O)0.45(3)和Er(btc)(DABCO)0.15(H2O)0.85(4).其中, btc为1,3,5-均苯三甲酸, ED为乙二胺, PP为哌嗪, DABCO位为三乙烯二胺.单晶结构分析表明,在[Er(btc)(H2O)]·DMF0.7(1)中,铒离子与六个btc配体的六个羧酸氧原子和一个水分子配位,形成变形的五角双锥几何构型.每个btc配体连接六个铒离子构成具有一维开放孔道(0.7 nm′0.7 nm)的三维立体结构.重要的是,孔道中的配位水分子和游离DMF分子可通过真空加热除去而不影响其骨架结构(热稳定性达500 oC),这将有利于对其进行后合成修饰.热重分析(TGA)表明,催化剂2在25–300 oC失去孔道中配位的乙二胺和水分子;催化剂3在250 oC之前失去孔道中的哌嗪和水分子;催化剂4则在100 oC之前失去孔道中配位的三乙烯二胺和水分子.粉末X射线衍射(PXRD)结果显示,后合成修饰过程并没有改变催化剂骨架的稳定性,其稳定性在空气中超过30 d.氮气吸附实验表明, Ln-MOF 1的比表面积和孔体积分别为2000 m2/g和0.75 cm3/g,平均孔尺寸为0.65 nm,与晶体结构分析结果基本一致.相比之下,后合成修饰的催化剂2的比表面积明显降低,为650 m2/g,而催化剂3和4由于后修饰较大体积的二胺分子(哌嗪和三乙烯二胺),表现出可忽略的氮气吸附能力.上述结果表明,催化剂2具有较高的有机胺负载量、较高的热稳定性和多孔性.采用苯甲醛和丙二腈的Knoevenagel缩合反应研究了三种固体碱的非均相催化能力.结果表明,在相同反应条件下,催化剂2具有很好的首次催化能力(99%),优于催化剂3(93%)和4(63%).并且,催化剂2循环使用三次后,催化能力几乎没有改变,而催化剂3和4的催化能力则逐渐降低,催化剂4在第三次使用时已无催化能力.滤出实验显示,催化剂2在反应过程中无活性物种离去进入液相体系中,即无乙二胺分子从催化剂骨架孔道中离去,证明其为非均相催化本质.而催化剂3和4则在反应过程中有二胺分子离去,进入反应液相中,从而导致其循环使用催化能力降低.催化剂2的底物择形催化反应结果显示,先是丙二腈分子进入催化剂孔道中,形成碳负离子,然后亲核进攻醛分子生成产物.因此,体积较大的腈衍生物因不能进入孔道而不能发生反应,而体积较大的醛分子则不受影响,能顺利地发生反应.     

New 3-d chiral framework of indium with 1,3,5-benzenetricarboxylate

A new complex, [In(2)(mu-OH)(2)(btc)(2)](n)().2nHpy (1) (btc = 1,3,5-benzenetricarboxylate; py = pyridine), is hydrothermally synthesized from the reaction of InCl(3), H(3)btc, and pyridine. Complex 1 crystallizes in the monoclinic P2(1) space group [a = 7.3181(12) A, b = 17.0195(23) A, c = 10.5789(17) A, beta = 102.651(6) degrees , and Z = 2]. Indium(III) centers in 1 are bridged by btc ligands in various coordination modes to form the nonclose rings which are further interlinked along crystallographic a-axis and (011) plane to result in a nonpenetrated 3-D anionic framework growing as homochiral tunnels. Compound 1 is fully characterized by fluorescence spectroscopy, second harmonic generation measurement, infrared, and thermogravimetric analysis.     

联苯四甲酸及联吡啶构筑的一维链状银(Ⅰ)配合物的合成及晶体结构

采用水热法合成了一个新颖的配合物{[Ag(4,4′-bpy)][Ag2(H3btc)(H2btc)(4,4′-bpy)2].3H2O}n(1)(H4btc=联苯-2,2′,4,4′-四甲酸;4,4′-bpy=4,4′-联吡啶),并对其进行了元素分析、红外光谱和X射线单晶衍射测定。配合物1属于三斜晶系,空间群为P1,a=1.122 51(6)nm,b=1.554 01(8)nm,c=1.774 59(9)nm,β=91.641 0(10)°,V=2.830 8(3)nm3,Z=2,Dc=1.764 g.cm-3,μ=1.113 mm-1,F(000)=1 508,R1=0.045 0,wR2=0.086 2(I>2σ(I))。在1中,一维线性[Ag(4,4′-bpy)]+阳离子链包含在一维{[Ag2(H3btc)(H2btc)(4,4′-bpy)2]-阴离子双链与游离水分子通过分子间氢键组装成的三维超分子结构中。研究了配合物的热稳定性和电化学性质。     

Synthesis,crystal structure,thermal stability,and luminescent properties of lithium trimesate coordination polymer

Russian Chemical Bulletin - A metal-organic coordination polymer of the formula [Li3(btc)(H2O)] (1a) (H3btc is the trimesic acid, C6H3(COOH)3) was obtained upon heating a mixture of LiBH4 and H3btc...     

Morphology design of porous coordination polymer crystals by coordination modulation

The design of crystal morphology, or exposed crystal facets, has enabled the development (e.g., catalytic activities, material attributes, and oriented film formation) of porous coordination polymers (PCPs) without changing material compositions. However, because crystal growth mechanisms are not fully understood, control of crystal morphology still remains challenging. Herein, we report the morphology design of [Cu(3)(btc)(2)](n) (btc = benzene-1,3,5-tricarboxylate) by the coordination modulation method (modulator = n-dodecanoic acid or lauric acid). A morphological transition (octahedron-cuboctahedron-cube) in the [Cu(3)(btc)(2)](n) crystal was observed with an increase in concentration of the modulator. By suitably defining a coarse-grained standard unit of [Cu(3)(btc)(2)](n) as its cuboctahedron main pore and determining its attachment energy on crystal surfaces, Monte Carlo coarse-grain modeling revealed the population and orientation of carboxylates and elucidated an important role of the modulator in determining the <100>- and <111>-growth throughout the crystal growth process. This comprehension, in fact, successfully led to designed crystal morphologies with oriented growth on bare substrates. Because selective crystal orientations on the bare substrates were governed by crystal morphology, this contribution also casts a new light on the unexplored issue of the significance of morphology design of PCPs.     

One-step solid-state thermolysis of a metal-organic framework: a simple and facile route to large-scale of multiwalled carbon nanotubes

We report a simple and facile solid-state approach to large-scale synthesis of multiwalled carbon nanotubes (MCNTs), for the first time, by one-step direct thermolysis of a metal-organic framework [Ni(3)(btc)(2).12H(2)O] (btc = benzene-1,3,5-tricarboxylato) in a one-end closed conventional horizontal tube furnace under relatively low temperature without using any additional carrier gas or catalyst.     

三维稀土配位聚合物[Ce2(H2btc)(btc)(H2O)2]n的水热合成与晶体结构

含有稀土元素的无机一有机配位聚合物因在光、电、磁及催化等方面具有潜在的应用价值而引起人们的关注．芳香多羧基有机配体在合成配位聚合物和多维超分子研究领域中扮演着重要角色．1，2，4，5-均苯四甲酸(H4btc)由于具有独特的配位能力(btc^4-最多可作为八齿配体)和空间特性，     

Reconciling the discrepancies between crystallographic porosity and guest access as exemplified by Zn-HKUST-1

There are several compounds for which there exists a disconnect between porosity as predicted by crystallography and porosity measured by gas sorption analysis. In this paper, the Zn-based analogue of Cu(3)(btc)(2) (HKUST-1), Zn(3)(btc)(2) (Zn-HKUST-1; btc = 1,3,5-benzenetricarboxylate) is investigated. Conventional analysis of Zn-HKUST-1 by powder X-ray diffraction and gas sorption indicates retention of crystalline structure but negligible nitrogen uptake at 77 K. By using positron annihilation lifetime spectroscopy, a densified surface layer preventing the entry of even small molecular species into the crystal framework is revealed. The material is shown to have inherent surface instability after solvent removal, rendering it impermeable to molecular guests irrespective of handling and processing methods. This previously unobserved surface instability may provide insight into the failure of other microporous coordination polymers to exhibit significant porosity despite crystal structures indicative of regular, interconnected, microporous networks.     

Syntheses, structures and properties of two unusual silver-organic coordination networks: 1D→1D tubular intertwinement and existence of an infinite winding water chain

Two unusual metal-organic frameworks {[Ag(2)(Hbtc)(bpy)(2)]·(H(2)O)(2)}(n) (1), {[Ag(3)(btc)(bpy)(3)(H(2)O)]·(H(2)O)(7)}(n) (2) (H(3)btc = 1,2,3-benzenetricarboxylic acid, bpy = 4,4'-bipyridine) have been synthesized and characterized by single crystal X-ray diffraction. Complex 1 features an infinite 1D→1D tubular intertwinement network, while complex 2 exhibits a double ladder structure which contains rare winding water chains. Both infinite 1D→1D tubular chains in complex 1 and double ladder in 2 are mutually interconnected by hydrogen bonding and π···π stacking interactions into three-dimensional (3D) supramolecular networks. In addition, thermogravimetric analysis, powder X-ray diffraction (XRD), and photoluminescent behavior of the complexes have also been investigated.     

Effect of Metal Ions on the Structures of Coordination Polymers Based on Biphenyl‐2,2′,4,4′‐Tetracarboxylate

Two new coordination polymers, {[Cd₂(btc)(2,2′‐bpy)₂] · H₂O}_n ( 1 ) and [Zn₂(btc)(2,2′‐bpy)(H₂O)]_n ( 2 ) (H₄btc = biphenyl‐2,2′,4,4′‐tetracarboxylic acid, 2,2′‐bpy = 2,2′‐bipyridine), were synthesized hydrothermally under similar conditions and characterized by elemental analysis, IR spectra, TGA, and single‐crystal X‐ray diffraction analysis. In complexes 1 and 2 , the (btc)^4– ligand acts as connectors to link metal ions to give a 2D bilayer network of 1 and a 3D metal‐organic framework of 2 , respectively. The differences in the structures are induced by diverging coordination modes of the (btc)^4– ligand, which can be attributed to the difference metal ions in sizes. The results indicate that metal ions have significant effects on the formation and structures of the final complexes. Additionally, the fluorescent properties of the two complexes were also studied in the solid state at room temperature.     

A self-catenated network containing unprecedented 0D + 2D → 2D polycatenation array

Herein, we report a new acylamide ligand and its application in the construction of a metal-organic framework. The resultant acylamide metal-organic framework, namely [Zn(2)(L)(OH)(btc)](n) (1, L = N(1),N(4)-bis(pyridin-3-ylmethyl) naphthalene-1,4-dicarboxamide, H(3)btc = benzene-1,3,5-tricarboxylic acid), was obtained by hydrothermal synthesis. The outstanding structural feature of it is the 0D + 2D → 2D polycatenation array containing a self-catenated feature which has never previously been observed. To the best of our knowledge, the coexistence of self-catenation and polycatenation phenomena is highly exceptional.     

Stepwise deposition of metal organic frameworks on flexible synthetic polymer surfaces

Thin films of [Cu(3)(btc)(2)](n) (btc = 1,3,5-benzenetricarboxylate) metal organic framework were deposited in a stepwise manner on surfaces of flexible organic polymers. The thickness of films can be precisely controlled. The deposition of the first cycles was monitored by UV-vis spectroscopy. The porosity was proven by the adsorption of pyrazine, which was monitored by FT-IR and thermogravimetric analysis. The deposition of MOF thin films on flexible polymer surfaces might be a new path for the fabrication of functional materials for different applications, such as protection layers for working clothes and gas separation materials in the textile industry.     

Hydrothermal Syntheses and Crystal Structures of Two Layered Nickel(II) Coordination Polymers Based on 1,2,3‐Benzenetricarboxylic Acid

The hydrothermal reactions of Ni(II), 1,2,3‐benzenetricarboxylic acid (1,2,3‐H₃btc) and 4,4′‐bipyridine (4,4′‐bpy)/1,2‐bis(4‐pyridyl)ethane (bpa) yield two layered nickel(II) coordination polymers, [Ni₂(1,2,3‐btc)(OAc)‐(4,4′‐bpy)₂(H₂O)]·2H₂O ( 1 ) and [Ni(ip)(bpa)] ( 2 ) (ip=isophthalate), respectively. Both complexes are 2‐D coordination network based on 1‐D Ni‐carboxylate chains. The 1,2,3‐btc ligand adopts 3‐bridging mode in complex 1 , but transformed to isophthalate (ip) ligand through decarboxylation in 2 . The formation of the two complexes indicates that hydrothermal conditions andin‐situ ligand reaction have significant effect on constructing coordination polymers.     

Step-by-step seeding procedure for preparing HKUST-1 membrane on porous α-alumina support

Metal-organic framework (MOF) membranes have attracted considerable attention because of their striking advantages in small-molecule separation. The preparation of an integrated MOF membrane is still a major challenge. Depositing a uniform seed layer on a support for secondary growth is a main route to obtaining an integrated MOF membrane. A novel seeding method to prepare HKUST-1 (known as Cu(3)(btc)(2)) membranes on porous α-alumina supports is reported. The in situ production of the seed layer was realized in step-by-step fashion via the coordination of H(3)btc and Cu(2+) on an α-alumina support. The formation process of the seed layer was observed by ultraviolet-visible absorption spectroscopy and atomic force microscopy. An integrated HKUST-1 membrane could be synthesized by the secondary hydrothermal growth on the seeded support. The gas permeation performance of the membrane was evaluated.     

2D coordination polymers of macrocyclic oxamide with polycarboxylates: syntheses, crystal structures and magnetic properties

Five new 2D coordination polymers, [Co(nip)(CuL)(H(2)O)]·CH(3)OH (1), [Mn(ip)(NiL)]·0.63H(2)O (2), [Cu(ip)(CuL)] (3), [Mn(6)(CuL)(6)(btc)(4)(H(2)O)(4)]·7H(2)O (4), and [Cu(CuL)(Hbtc)(H(2)O)] (5)(ML, H(2)L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-diene; H(2)nip = 5-nitroisophthalic acid; H(2)ip = m-isophthalic acid; H(3)btc = 1,3,5-benzenetricarboxylic acid) have been synthesized by a solvothermal method and characterized by single-crystal X-ray diffraction. Complexes 1-5 exhibit different 2D layered structures formed by Co(2)Cu(2) (1), Mn(2)Ni(2) (2), Cu(4) (3), Mn(3)Ni(3) (4), Cu(4) (5) units, respectively, via the oxamide and diverse carboxylic acid bridges. Compounds 1, 2, 3 and 5 are uninodal 4-connected (4, 4)-grids topology, while complex 4 possesses a 2D network with (3, 4)-connected (4(2).8)(4)(4(3).6(2).8)(3) topology. The results of magnetic determination show pronounced antiferromagnetic interactions in 1-4.     

Syntheses,Crystal Structures and DNA-Binding Properties of Zn(Ⅱ)and Mn(Ⅱ)Complexes Based on Imidazole Derivatives and Carboxylic Acid

Complexes[Zn(pbm)(5-hip)3](1),[Zn(pbm)(5-nip)3](2),[Mn(pbm)(H3btc)2(H2O)](3)and[Mn(pbm)(5-nip)3](4),where H2HIPA=5-hydroxyisophthalic acid,H2nip=5-nitroisophtha...     

Facile synthesis of metal-organic framework films via in situ seeding of nanoparticles

A facile in situ nanoparticle seeding method is reported to prepare MIL-101(Cr) films on alumina supports. The in situ seeding of MIL-101(Cr) nanoparticles was promoted by use of dimethylacetamide (DMA). The generality of this approach is further demonstrated for Cu(3)(btc)(2) films by using a (poly)acrylate promoter.     

Crystallographic report: A three‐dimensional coordination polymer: poly‐[µ7‐1,2,4,5‐benzenetetracarboxylato‐bis(N,N‐dimethylformamide)dizinc(II)]

The structure of the title compound, [Zn₂(btc)(DMF)₂]_n (btc = 1,2,4,5‐benzenetetracarboxylate, DMF = N,N‐dimethylformamide), shows that the octahedrally and tetrahedrally coordinated zinc atoms (present in the ratio 1:1) are linked by btc ligands to form a three‐dimensional network comprising cross‐linked channels occupied by coordinated DMF molecules. Copyright © 2004 John Wiley & Sons, Ltd.     

Structural Modulation of Two Luminescent Bismuth-organic Frameworks by the Mixed-ligand Synthetic Strategy

Hydrothermal reactions of Bi_2O_3 with pyridine-2,6-dicarboxylic acid(2,6-H_2pdc) and trimesic acid(H3btc)/pyromellitic acid(H4pyr) lead to two bismuth-organic frameworks, namely, [Bi(2,6-pdc)(H_2btc)(H_2O)2]n(1) and [Bi_2(2,6-pdc)2(H2pyr)(H_2O)_2]n(2). Compound 1 crystallizes in the space group P2_1/c. The dimeric {Bi_2} units are linked by 2,6-pdc2-ligands to form 1D chains; Compound 2 exhibits a 2D layered structure with 44 network topology by using dimeric {Bi_2} as secondary building units(SBUs). The chains and layers in 1 and 2 are further arranged into 3D supramolecular structures via hydrogen bonding interactions. The compounds emit blue luminescence. Furthermore, the PXRD, TGA, UV-visible and IR spectra were also studied. Compounds 1, 2 represent good examples of using mixed-ligand approach to construct diversity of luminescent bismuth-organic frameworks.     

Copper(II) coordination polymers constructed from aromatic polycarboxylate and flexible triazole ligands with different spacer lengths: syntheses,structures, and properties

{[Cu₂(btm)₂(Hbtc)(H₂btc)₂(H₂O)]·9.5H₂O}_n (1), [Cu(bte)(H₂btc)₂]_n (2) {[Cu(btp)(H₂btc)₂]·0.25H₂O}_n (3) (btm?=?bis(1,2,4-triazol-1-yl)methane, bte?=?bis(1,2,4-triazol-1-yl)ethane, btp?=?bis(1,2,4-triazol-1-yl)propane, H₃btc?=?benzene-1, 3, 5-tricarboxylic acid) have been synthesized and structurally characterized. 1 features a 1-D double chain, which is interconnected by classical hydrogen-bonding (O–H?O) and π–π interactions to lead to a 3-D supramolecular architecture. 2 and 3 are both 1-D single chains, which are interconnected by π–π interactions to 2-D layer architectures. Elemental analysis, XRD, IR, TG and EPR spectra have been carried out and discussed.