Selective CO2 adsorption by a triazacyclononane-bridged microporous metal-organic framework

Metal-organic frameworks constructed by self-assembly of metal ions and organic linkers have recently been of great interest in the preparation of porous hybrid materials with a wide variety of functions. Despite much research in this area and the large choice of building blocks used to fine-tune pore size and structure, it remains a challenge to synthesise frameworks composed of polyamines to tailor the porosity and adsorption properties for CO(2). Herein, we describe a rigid and microporous three-dimensional metal-organic framework with the formula [Zn(2)(L)(H(2)O)]Cl (L=1,4,7-tris(4-carboxybenzyl)-1,4,7-triazacyclononane) synthesised in a one-pot solvothermal reaction between zinc ions and a flexible cyclic polyaminocarboxylate. We have demonstrated, for the first time, that a porous rigid framework can be obtained by starting from a flexible amine building block. Sorption measurements revealed that the material exhibited a high surface area (135 m(2) g(-1)) and was the best compromise between capacity and selectivity for CO(2) over CO, CH(4), N(2) and O(2); as such it is a promising new selective adsorbent for CO(2) capture.     

一个微孔钴基金属有机骨架的合成及其选择性气体吸附

利用硝酸钴与配体5,5''-di (1H-1,2,4-triazol-1-yl)-(1,1''-biphenyl)-2,2''-dicarboxylic acid (H₂DTBDA)进行溶剂热反应,制备了一个结构新颖的金属有机骨架{[Co (DTBDA)]₂·DMF·MeOH}_n (FJI-H37)。FJI-H37不仅具有适合气体分子吸附的0.69 nm的微孔,还具有良好的热稳定性及有机溶剂容忍性。气体吸附测试表明FJI-H37不仅能从C₂H₂/CO₂(体积比50∶50)混合气中选择性吸附C₂H₂,还可以从CO₂/N₂(体积比15∶85)和CO₂/CH₄(体积比50∶50)混合气中选择性捕获CO₂;固定床突破实验进一步证实了其高效的气体分离能力。     

一个微孔钴基金属有机骨架的合成及其选择性气体吸附

利用硝酸钴与配体5,5''-di(1H-1,2,4-triazol-1-yl)-(1,1''-biphenyl)-2,2''-dicarboxylic acid (H₂DTBDA)进行溶剂热反应,制备了一个结构新颖的金属有机骨架{[Co(DTBDA)]₂·DMF·MeOH}_n (FJI-H37)。FJI-H37不仅具有适合气体分子吸附的0.69 nm的微孔,还具有良好的热稳定性及有机溶剂容忍性。气体吸附测试表明FJI-H37不仅能从C₂H₂/CO₂(体积比50:50)混合气中选择性吸附C₂H₂,还可以从CO₂/N₂(体积比15:85)和CO₂/CH₄(体积比50:50)混合气中选择性捕获CO₂;固定床突破实验进一步证实了其高效的气体分离能力。     

一个微孔钴基金属有机骨架的合成及其选择性气体吸附

利用硝酸钴与配体5,5''-di (1H-1,2,4-triazol-1-yl)-(1,1''-biphenyl)-2,2''-dicarboxylic acid (H₂DTBDA)进行溶剂热反应,制备了一个结构新颖的金属有机骨架{[Co (DTBDA)]₂·DMF·MeOH}_n (FJI-H37)。FJI-H37不仅具有适合气体分子吸附的0.69 nm的微孔,还具有良好的热稳定性及有机溶剂容忍性。气体吸附测试表明FJI-H37不仅能从C₂H₂/CO₂(体积比50∶50)混合气中选择性吸附C₂H₂,还可以从CO₂/N₂(体积比15∶85)和CO₂/CH₄(体积比50∶50)混合气中选择性捕获CO₂;固定床突破实验进一步证实了其高效的气体分离能力。     

A microporous metal-organic framework for highly selective separation of acetylene, ethylene, and ethane from methane at room temperature

A novel three‐dimensional microporous metal–organic framework Zn₄L(DMA)₄ ( UTSA‐33 , H₈L=1,2,4,5‐tetra(5‐isophthalic acid)benzene, DMA=N,N′‐dimethylacetamide) with small pores of about 4.8 to 6.5 Å was synthesized and structurally characterized as a non‐interpenetrated (4,8)‐connected network with the flu topology (Schläfli symbol: (4¹²6¹²8⁴)(4⁶)₂). The activated UTSA‐33 a exhibits highly selective separation of acetylene, ethylene, and ethane from methane with the adsorption selectivities of 12 to 20 at 296 K, which has been established exclusively by the sorption isotherms and simulated breakthrough experiments, thus methane can be readily separated from their binary and even ternary mixtures at room temperature.     

A new approach to construct a doubly interpenetrated microporous metal-organic framework of primitive cubic net for highly selective sorption of small hydrocarbon molecules

A new approach has been realized to construct a three‐dimensional doubly interpenetrated cubic metal–organic framework Zn₂(PBA)₂(BDC) ? (DMF)₃(H₂O)₄ ( UTSA‐36 , HPBA=4‐(4‐pyridyl) benzoic acid, H₂BDC=1,4‐benzenedicarboxylic acid) through the self‐assembly of the pyridylcarboxylate linker 4‐(4‐pyridyl) benzoate and bicarboxylate linker 1,4‐benzenedicarxylate with paddle‐wheel [Zn₂(COO)₄]. The activated UTSA‐36 a exhibits highly selective gas sorption of C₂H₆, C₂H₄ and C₂H₂ over CH₄ with the Henry law’s selectivities of 11 to 25 in the temperature range of 273 to 296 K attributed to the unique 3D intersected pore structure of about 3.1 to 4.8 Å within the framework, indicating that UTSA‐36 a is a potentially very useful and promising microporous material for such industrially important separation of C₂ hydrocarbons over methane.     

Photoluminescent microporous lanthanide silicate AV-21 frameworks

The hydrothermal synthesis and structural characterization of the lanthanide silicate system [Na(6)Ln(2)Si(12)O(30).x H(2)O] (Ln=La(3+), Sm(3+), Eu(3+), Gd(3+), and Tb(3+)), named AV-21, has been reported. Structural elucidation of the Sm(3+) analogue (isomorphous with the Eu(3+), Gd(3+), and Tb(3+) frameworks) using single-crystal synchrotron X-ray diffraction and solid-state NMR spectroscopy reveal disorder in the Si(1) second coordination sphere. La-AV-21 presents a distinct framework. These materials combine microporosity and interesting photoluminescence features with structural flexibility that allows the introduction of a second or third type of lanthanide center. Room-temperature lifetime decay dynamics have been used to estimate the Ln(3+)-Ln(3+) distances and the maximum distance over which energy transfer is active. Though the majority of Ln(3+) centers occupy regular framework positions, the Ln(2) defect centers are disordered over the Na(1) sites in the pores and greatly influence the energy-transfer process, providing a unique opportunity for studying the relationship between structural disorder and photoluminescence properties in framework solids.     

High gas sorption and metal-ion exchange of microporous metal-organic frameworks with incorporated imide groups

Metal-organic frameworks (MOFs), {[Cu(2)(bdcppi)(dmf)(2)]·10DMF·2H(2)O}(n) (SNU-50) and {[Zn(2)(bdcppi)(dmf)(3)]·6DMF·4H(2)O}(n) (SNU-51), have been prepared by the solvothermal reactions of N,N'-bis(3,5-dicarboxyphenyl)pyromellitic diimide (H(4)BDCPPI) with Cu(NO(3))(2) and Zn(NO(3))(2), respectively. Framework SNU-50 has an NbO-type net structure, whereas SNU-51 has a PtS-type net structure. Desolvated solid [Cu(2)(bdcppi)](n) (SNU-50'), which was prepared by guest exchange of SNU-50 with acetone followed by evacuation at 170 °C, adsorbs high amounts of N(2), H(2), O(2), CO(2), and CH(4) gases due to the presence of a vacant coordination site at every metal ion, and to the presence of imide groups in the ligand. The Langmuir surface area is 2450 m(2) g(-1). It adsorbs H(2) gas up to 2.10 wt% at 1 atm and 77 K, with zero coverage isosteric heat of 7.1 kJ mol(-1), up to a total of 7.85 wt% at 77 K and 60 bar. Its CO(2) and CH(4) adsorption capacities at 298 K are 77 wt% at 55 bar and 17 wt% at 60 bar, respectively. Of particular note is the O(2) adsorption capacity of SNU-50' (118 wt% at 77 K and 0.2 atm), which is the highest reported so far for any MOF. By metal-ion exchange of SNU-51 with Cu(II), {[Cu(2)(bdcppi)(dmf)(3)]·7DMF·5H(2)O}(n) (SNU-51-Cu(DMF)) with a PtS-type net was prepared, which could not be synthesized by a direct solvothermal reaction.     

新型三维微孔砷酸铟InAsO4(H2O)2的合成及结构

首次以有机胺为结构导向剂,在水热条件下合成了微孔砷酸铟材料InAsO4-1,并对其进行了结构及性质表征。X射线单晶结构解析表明InAsO4-1分子式为InAsO4(H2O)2。晶体学数据为：Pbca,a=0.9090(4)nm,b=1.0344(4)nm,c=1.0468(4)nm,α=β=Υ=90°,V=0.9843(7)nm^3,Z=8,R=0.0480,Rw=0.1045。InAsO4-1具有三维结构,其a,b方向分别有4元环及6元环的一维孔道,结构中还含有一8^16^44^2笼,热重分析显示其结构水较稳定。     

Hydrogen storage in microporous metal-organic frameworks with exposed metal sites

Owing to their high uptake capacity at low temperature and excellent reversibility kinetics, metal-organic frameworks have attracted considerable attention as potential solid-state hydrogen storage materials. In the last few years, researchers have also identified several strategies for increasing the affinity of these materials towards hydrogen, among which the binding of H(2) to unsaturated metal centers is one of the most promising. Herein, we review the synthetic approaches employed thus far for producing frameworks with exposed metal sites, and summarize the hydrogen uptake capacities and binding energies in these materials. In addition, results from experiments that were used to probe independently the metal-hydrogen interaction in selected materials will be discussed.