Selective gas sorption within a dynamic metal-organic framework

A microporous metal-organic framework 1 Co(NDC)(4,4'-Bipy)(0.5).G(x) (NDC = 2,6-naphthalenedicarboxylate; 4,4'-Bipy = 4,4'-bipyridine; G = guest molecules) was synthesized and structurally characterized of a doubly interpenetrated primitive cubic net. To make use of the framework flexibility, 1 was activated at temperatures of 150 and 200 degrees C to form 1a and 1b, respectively, exhibiting highly selective sorption behaviors of hydrogen over nitrogen-gas molecules.     

Selective guest sorption in an interdigitated porous framework with hydrophobic pore surfaces

An interdigitated porous coordination polymer with hydrophobic pore surface shows size and affinity dependent selective gas sorption properties accompanying the reversible structure transformation.     

Understanding hydrogen sorption in a polar metal-organic framework with constricted channels

A high fidelity molecular model is developed for a metal-organic framework (MOF) with narrow (approximately 7.3 A?) nearly square channels. MOF potential models, both with and neglecting explicit polarization, are constructed. Atomic partial point charges for simulation are derived from both fragment-based and fully periodic electronic structure calculations. The molecular models are designed to accurately predict and retrodict material gas sorption properties while assessing the role of induction for molecular packing in highly restricted spaces. Thus, the MOF is assayed via grand canonical Monte Carlo (GCMC) for its potential in hydrogen storage. The confining channels are found to typically accommodate between two to three hydrogen molecules in close proximity to the MOF framework at or near saturation pressures. Further, the net attractive potential energy interactions are dominated by van der Waals interactions in the highly polar MOF - induction changes the structure of the sorbed hydrogen but not the MOF storage capacity. Thus, narrow channels, while providing reasonably promising isosteric heat values, are not the best choice of topology for gas sorption applications from both a molecular and gravimetric perspective.     

A triply interpenetrated microporous metal-organic framework for selective sorption of gas molecules

A microporous metal-organic framework Zn(ADC)(4,4'-Bpe)(0.5).xG [1; ADC = 4,4'-azobenzenedicarboxylate, 4,4'-Bpe = trans-bis(4-pyridyl)ethylene, G = guest molecules] with a triply interpenetrative primitive cubic net was synthesized and characterized. With pores of about 3.4 x 3.4 A, the activated 1a exhibits highly selective sorption behavior toward H(2)/N(2), H(2)/CO, and CO(2)/CH(4).     

Synthesis of MIL-102, a chromium carboxylate metal-organic framework, with gas sorption analysis

A new three-dimensional chromium(III) naphthalene tetracarboxylate, CrIII3O(H2O)2F{C10H4(CO2)4}1.5.6H2O (MIL-102), has been synthesized under hydrothermal conditions from an aqueous mixture of Cr(NO3)3.9H2O, naphthalene-1,4,5,8-tetracarboxylic acid, and HF. Its structure, solved ab initio from X-ray powder diffraction data, is built up from the connection of trimers of trivalent chromium octahedra and tetracarboxylate moieties. This creates a three-dimensional structure with an array of small one-dimensional channels filled with free water molecules, which interact through hydrogen bonds with terminal water molecules and oxygen atoms from the carboxylates. Thermogravimetric analysis and X-ray thermodiffractometry indicate that MIL-102 is stable up to approximately 300 degrees C and shows zeolitic behavior. Due to topological frustration effects, MIL-102 remains paramagnetic down to 5 K. Finally, MIL-102 exhibits a hydrogen storage capacity of approximately 1.0 wt % at 77 K when loaded at 3.5 MPa (35 bar). The hydrogen uptake is discussed in relation with the structural characteristics and the molecular simulation results. The adsorption behavior of MIL-102 at 304 K resembles that of small-pore zeolites, such as silicalite. Indeed, the isotherms of CO2, CH4, and N2 show a maximum uptake at 0.5 MPa, with no further significant adsorption up to 3 MPa. Crystal data for MIL-102: hexagonal space group P(-)6 (No. 169), a = 12.632(1) A, c = 9.622(1) A.     

Rational assembly of a 3D metal-organic framework for gas adsorption with predesigned cubic building blocks and 1D open channels

A novel 3D metal-organic framework with predesigned cubic building blocks and 1D open channels exhibiting significant N2 adsorption has been synthesized and characterized by single crystal X-ray diffraction analysis.     

Pore partition effect on gas sorption properties of an anionic metal-organic framework with exposed Cu2+ coordination sites

Presented here is an anionic nanoporous framework material with mobile guest cations which can perform ion exchanges with different tetraalkylammonium cations, and the resulting tunable pore structures exhibit interesting pore partition effects on gas storage and separation.     

Rationally designed micropores within a metal-organic framework for selective sorption of gas molecules

A microporous metal-organic framework, MOF, Cu(FMA)(4,4'-Bpe)0.5 (3a, FMA = fumarate; 4,4'-Bpe = 4,4'-Bpe = trans-bis(4-pyridyl)ethylene) was rationally designed from a primitive cubic net whose pores are tuned by double framework interpenetration. With pore cavities of about 3.6 A, which are interconnected by pore windows of 2.0 x 3.2 A, 3a shows highly selective sorption behaviors of gas molecules.     

金属有机框架化合物为前驱体制备MgO微粒

在溶剂热条件下,以氯化镁与3-(吡啶-3-甲氧基)邻苯二甲酸为原料,成功合成了一个镁和甲酸根构筑的三维金属有机框架化合物,X射线单晶衍射确定了其晶体结构.通过对所合成的配合物高温煅烧,得到了氧化镁微粒,应用红外光谱、粉末衍射和扫描电子显微镜等对其结构和形貌进行了表征,结果表明,合成的氧化镁纯度高,晶型完整,颗粒分布较为均匀,粒径约为50μm.     

Microporous 3-D chiral metal-organic framework with a quartzlike topology based on an achiral building unit

A zinc coordination polymer, Zn(IN)₂ · 2H₂O (1) (HIN = isonicotinic acid), has been synthesized and characterized by IR, elemental analysis, thermogravimetric analysis, and single crystal X-ray diffraction. This compound crystallizes in the chiral space group P6₂ with a = 15.512(3), b = 15.512(3), c = 6.262(2) Å, V = 1304.9(5) ų, and Z = 3. The O and N atoms of the IN ligand are coordinated to a Zn^II ion, locking the asymmetry of the IN ligand and transferring this asymmetry throughout the crystal structure to “direct” the formation of a chiral network. The structure of 1 is characteristic of a 3-D quartz-like framework, which contains hetero-chiral helical channels (pseudo-trigonal and hexagon channels) alternately along the c-axis. Compound 1 exhibits high stability and intense fluorescent emission at room temperature.     

A three-dimensional microporous metal-organic framework with large hydrogen sorption hysteresis

A three-dimensional microporous metal-organic framework [Cd(2)(Tzc)(2)](n), which is dehydrated from [Cd(2)(Tzc)(2)(H(2)O)(2)](n), exhibits selective gas adsorption and large hydrogen sorption hysteresis.     

Microporous sensor: gas sorption, guest exchange and guest-dependant luminescence of metal-organic framework

Zn(II)-containing metal-organic framework (MOF) [Zn(4)(dmf)(ur)(2)(ndc)(4)] (ndc(2-) = 2,6-naphtalenedicarboxylate, ur = urotropin, dmf = N,N'-dimethylformamide) was synthesized and characterized by X-ray crystallography and gas sorption analysis. Host MOF retains its crystallinity after guest removal and exchange. Single-crystal to single-crystal formation of different host-guest systems with benzene and ferrocene was investigated. Interesting guest-depended luminescence properties of the porous host framework were observed.     

A fluorescent 3-D metal-organic framework with unusual tetranuclear zinc secondary building units

A 3-D metal-organic framework (MOF) {Zn₄(μ₃-OH)₂(bdc)₃(pad)₂}·2H₂O (1, H₂bdc = 1,4-benzenedicarboxylic acid, pad = 1,10-phenanthroline-5,6-dione) with unusual Zn₄(μ₃-OH)₂(COO)₆(N₂)₂ secondary building units (SBUs) has been hydrothermally synthesized and characterized by single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, elemental analysis, and infrared spectroscopy. The tetranuclear Zn₄ SBU was formed through two dinuclear Zn₂ clusters by sharing two μ₃-OH bridges. Considering this Zn₄ SBU as a six-connected node, the overall framework of 1 has a pcu topology. This tetranuclear Zn₄ SBU can be used as a node in construction of MOFs.     

A lanthanide-based metal-organic framework with a dynamic porous property

Hydrothermal reaction of La(NO(3))(3), NaHCO(3) and H(3)L (H(3)L = pyrazole-3,5-dicarboxylic acid) gives a 3D metal-organic framework with a dynamic porous property.     

Enantioselective sorption of alcohols in a homochiral metal-organic framework

Single-crystal X-ray diffraction study reveals the host-guest interactions between a homochiral metal-organic framework and two enantiomers of a chiral alcohol providing the key driving force for the enantioselective sorption of alcohols in the framework.     

An unprecedented twofold interpenetrating (3,4)-connected 3-D metal-organic framework

An unprecedented twofold interpenetrating (3,4)-connected topology of the Cu(3)L(4)-type metal-organic framework was prepared using N,N',N'-tris(4-pyridinyl)-1,3,5-benzenetricarboxamide (L) as a trigonal three-connection node and the copper(ii) ion as a square planar four-connection node, where the framework contains remarkably large 1-D solvent channels.     

Microporous manganese formate: a simple metal-organic porous material with high framework stability and highly selective gas sorption properties

Novel microporous metal-organic framework material composed of Mn(II) and formate ions displays permanent porosity, high thermal stability, and size-selective gas sorption behavior. The framework is stable enough to maintain single crystallinity after the complete guest removal at 150 degrees C under a reduced pressure. Most importantly, it selectively adsorbs H2 and CO2 but not N2 and other gases with larger kinetic diameters, which appears to be due to the small aperture of the channels. Despite a moderate H2 storage capacity, which is however still higher than that of any zeolite, its H2 surface coverage is one of the highest among the known microporous materials. Thus this new zeolite-like material made of a simple organic building block may find useful applications in gas separation and sensor.     

Construction of biomimetic proton transport channels in metal-organic framework

Construction of proton transport channels in metal-organic frameworks(MOFs) with simple synthesis processes, high proton conductivities and good performance stabilities has been of great interest for proton exchange membrane fuel cell(PEMFC). Herein, we mimic the proton transport behavior of amino acid residues in bacteriorhodopsin, select UiO-66-COOH as the host, glycine and aspartic acid as the functional guest molecules, and then functionalize the MOF framework with amino acids to obtain biom...     

A new luminescent 3-D metal-organic framework of diamond-like network possessing 8-fold interpenetration

A new 3-D coordination polymer [Zn(L)₂] (1) (HL?=?4-(pyridin-4-ylmethoxy)benzolic acid) was synthesized under hydrothermal conditions with Zn(OAc)₂?·?2H₂O and HL and characterized by single crystal X-ray diffraction (XRD). Compound 1 displays a 3-D 8-fold interpenetrating structure with diamondoid framework containing large adamantanoid cages. Meanwhile, it exhibits intense fluorescence at 402?nm in the solid state. In addition, powder XRD and thermogravimetric (TG) analysis for 1 are also reported.