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Sample records for alkali metal-organic solvent

  1. Alkali-metal azides interacting with metal-organic frameworks.

    PubMed

    Armata, Nerina; Cortese, Remedios; Duca, Dario; Triolo, Roberto

    2013-01-14

    Interactions between alkali-metal azides and metal-organic framework (MOF) derivatives, namely, the first and third members of the isoreticular MOF (IRMOF) family, IRMOF-1 and IRMOF-3, are studied within the density functional theory (DFT) paradigm. The investigations take into account different models of the selected IRMOFs. The mutual influence between the alkali-metal azides and the π rings or Zn centers of the involved MOF derivatives are studied by considering the interactions both of the alkali-metal cations with model aromatic centers and of the alkali-metal azides with distinct sites of differently sized models of IRMOF-1 and IRMOF-3. Several exchange and correlation functionals are employed to calculate the corresponding interaction energies. Remarkably, it is found that, with increasing alkali-metal atom size, the latter decrease for cations interacting with the π-ring systems and increase for the azides interacting with the MOF fragments. The opposite behavior is explained by stabilization effects on the azide moieties and determined by the Zn atoms, which constitute the inorganic vertices of the IRMOF species. Larger cations can, in fact, coordinate more efficiently to both the aromatic center and the azide anion, and thus stabilizing bridging arrangements of the azide between one alkali-metal and two Zn atoms in an η(2) coordination mode are more favored. PMID:23161861

  2. Elucidation of transport mechanism and enhanced alkali ion transference numbers in mixed alkali metal-organic ionic molten salts.

    PubMed

    Chen, Fangfang; Forsyth, Maria

    2016-07-28

    Mixed salts of Ionic Liquids (ILs) and alkali metal salts, developed as electrolytes for lithium and sodium batteries, have shown a remarkable ability to facilitate high rate capability for lithium and sodium electrochemical cycling. It has been suggested that this may be due to a high alkali metal ion transference number at concentrations approaching 50 mol% Li(+) or Na(+), relative to lower concentrations. Computational investigations for two IL systems illustrate the formation of extended alkali-anion aggregates as the alkali metal ion concentration increases. This tends to favor the diffusion of alkali metal ions compared with other ionic species in electrolyte solutions; behavior that has recently been reported for Li(+) in a phosphonium ionic liquid, thus an increasing alkali transference number. The mechanism of alkali metal ion diffusion via this extended coordination environment present at high concentrations is explained and compared to the dynamics at lower concentrations. Heterogeneous alkali metal ion dynamics are also evident and, somewhat counter-intuitively, it appears that the faster ions are those that are generally found clustered with the anions. Furthermore these fast alkali metal ions appear to correlate with fastest ionic liquid solvent ions. PMID:27375042

  3. Highly mesoporous metal-organic framework assembled in a switchable solvent

    NASA Astrophysics Data System (ADS)

    Peng, Li; Zhang, Jianling; Xue, Zhimin; Han, Buxing; Sang, Xinxin; Liu, Chengcheng; Yang, Guanying

    2014-07-01

    The mesoporous metal-organic frameworks are a family of materials that have pore sizes ranging from 2 to 50 nm, which have shown promising applications in catalysis, adsorption, chemical sensing and so on. The preparation of mesoporous metal-organic frameworks usually needs the supramolecular or cooperative template strategy. Here we report the template-free assembly of mesoporous metal-organic frameworks by using CO2-expanded liquids as switchable solvents. The mesocellular metal-organic frameworks with large mesopores (13-23 nm) are formed, and their porosity properties can be easily adjusted by controlling CO2 pressure. Moreover, the use of CO2 can accelerate the reaction for metal-organic framework formation from metal salt and organic linker due to the viscosity-lowering effect of CO2, and the product can be recovered through CO2 extraction. The as-synthesized mesocellular metal-organic frameworks are highly active in catalysing the aerobic oxidation of benzylic alcohols under mild temperature at atmospheric pressure.

  4. A Solvent-Free Hot-Pressing Method for Preparing Metal-Organic-Framework Coatings.

    PubMed

    Chen, Yifa; Li, Siqing; Pei, Xiaokun; Zhou, Junwen; Feng, Xiao; Zhang, Shenghan; Cheng, Yuanyuan; Li, Haiwei; Han, Ruodan; Wang, Bo

    2016-03-01

    Metal-organic frameworks (MOFs), with their well-defined pores and rich structural diversity and functionality, have drawn a great deal of attention from across the scientific community. However, industrial applications are hampered by their intrinsic fragility and poor processability. Stable and resilient MOF devices with tunable flexibility are highly desirable. Herein, we present a solvent- and binder-free approach for producing stable MOF coatings by a unique hot-pressing (HoP) method, in which temperature and pressure are applied simultaneously to facilitate the rapid growth of MOF nanocrystals onto desired substrates. This strategy was proven to be applicable to carboxylate-based, imidazolate-based, and mixed-metal MOFs. We further successfully obtained superhydrophobic and "Janus" MOF films through layer-by-layer pressing. This HoP method can be scaled up in the form of roll-to-roll production and may push MOFs into unexplored industrial applications. PMID:26847472

  5. Thermodynamics of solvent interaction with the metal-organic framework MOF-5.

    PubMed

    Akimbekov, Zamirbek; Wu, Di; Brozek, Carl K; Dincă, Mircea; Navrotsky, Alexandra

    2016-01-14

    The inclusion of solvent in metal-organic framework (MOF) materials is a highly specific form of guest-host interaction. In this work, the energetics of solvent MOF-5 interactions has been investigated by solution calorimetry in 5 M sodium hydroxide (NaOH) at room temperature. Solution calorimetric measurement of enthalpy of formation (ΔH(f)) of Zn4O(C8H4O4)3·C3H7NO (MOF-5·DMF) and Zn4O(C8H4O4)3·0.60C5H11NO (MOF-5·0.60DEF) from the dense components zinc oxide (ZnO), 1,4-benzenedicarboxylic acid (H2BDC), N,N-dimethylformamide (DMF) and N,N-diethylformamide (DEF) gives values of 16.69 ± 1.21 and 45.90 ± 1.46 kJ (mol Zn4O)(-1), respectively. The enthalpies of interaction (ΔH(int)) for DMF and DEF with MOF-5 are -82.78 ± 4.84 kJ (mol DMF)(-1) and -89.28 ± 3.05 kJ (mol DEF)(-1), respectively. These exothermic interaction energies suggest that, at low guest loading, Lewis base solvents interact more strongly with electron accepting Zn4O clusters in the MOF than at high solvent loading. These data provide a quantitative thermodynamic basis to investigate transmetallation and solvent assisted linker exchange (SALE) methods and to synthesize new MOFs. PMID:26658672

  6. Reversible and selective solvent adsorption in layered metal-organic frameworks by coordination control.

    PubMed

    Yin, Xinbo; Chen, Haohong; Song, Yuna; Wang, Yang; Li, Qiaowei; Zhang, Lijuan

    2014-01-01

    With various functionalities in the framework and high thermal stability, metal-organic frameworks (MOFs) have been extensively studied for the applications in adsorption and separation. In last decade, synthesizing new MOFs with desired structures and improved chemical stability to meet these applications has drawn great attention. In this report, by using an organic ligand with azolate moiety, benzo-bis(imidazole) (H2BBI), we synthesized two new 2D layered MOF structures with distinct topologies. Framework 1 {[Zn2Cl2(BBI)(MSM)2]n, MSM=methylsulfonylmethane}, constructed from tetrahedral Zn(II) and BBI, maintains its structure in organic solvents, such as methanol and benzene, and even in water. Meanwhile, framework 2 {[Cd2Cl2(BBI)(DMSO)2]n, DMSO=dimethyl sulfoxide} differs from framework 1, and is assembled from trigonal bipyramidal Cd(II) and square planar BBI. By removing the DMSO molecules coordinated to Cd(II) (25 weight% of the structure), 2 could transform to 3 {[Cd2Cl2(BBI)]n}, which was further characterized by high-resolution powder X-ray diffraction. The solvent-free 3 retains the original connectivity within each layer, and is capable of reversible and selective adsorption of DMSO molecules. The bistable four- and five-coordinated geometry exchange of Cd(II) is the origin of this adsorption with improved selectivity and capacity. PMID:24183447

  7. Solvent-averaged potentials for alkali-, earth alkali-, and alkylammonium halide aqueous solutions

    NASA Astrophysics Data System (ADS)

    Hess, Berk; van der Vegt, Nico F. A.

    2007-12-01

    We derive effective, solvent-free ion-ion potentials for alkali-, earth alkali-, and alkylammonium halide aqueous solutions. The implicit solvent potentials are parametrized to reproduce experimental osmotic coefficients. The modeling approach minimizes the amount of input required from atomistic (force field) models, which usually predict large variations in the effective ion-ion potentials at short distances. For the smaller ion species, the reported potentials are composed of a Coulomb and a Weeks-Chandler-Andersen term. For larger ions, we find that an additional, attractive potential is required at the contact minimum, which is related to solvent degrees of freedom that are usually not accounted for in standard electrostatics models. The reported potentials provide a simple and accurate force field for use in molecular dynamics and Monte Carlo simulations of (poly-)electrolyte systems.

  8. High flux thin film nanocomposite membranes based on metal-organic frameworks for organic solvent nanofiltration.

    PubMed

    Sorribas, Sara; Gorgojo, Patricia; Téllez, Carlos; Coronas, Joaquín; Livingston, Andrew G

    2013-10-01

    Thin-film nanocomposite membranes containing a range of 50-150 nm metal-organic framework (MOF) nanoparticles [ZIF-8, MIL-53(Al), NH2-MIL-53(Al) and MIL-101(Cr)] in a polyamide (PA) thin film layer were synthesized via in situ interfacial polymerization on top of cross-linked polyimide porous supports. MOF nanoparticles were homogeneously dispersed in the organic phase containing trimesoyl chloride prior to the interfacial reaction, and their subsequent presence in the PA layer formed was inferred by a combination of contact angle measurements, FT-IR spectroscopy, SEM, EDX, XPS, and TEM. Membrane performance in organic solvent nanofiltration was evaluated on the basis of methanol (MeOH) and tetrahydrofuran (THF) permeances and rejection of styrene oligomers (PS). The effect of different post-treatments and MOF loadings on the membrane performance was also investigated. MeOH and THF permeance increased when MOFs were embedded into the PA layer, whereas the rejection remained higher than 90% (molecular weight cutoff of less than 232 and 295 g·mol(-1) for MeOH and THF, respectively) in all membranes. Moreover, permeance enhancement increased with increasing pore size and porosity of the MOF used as filler. The incorporation of nanosized MIL-101(Cr), with the largest pore size of 3.4 nm, led to an exceptional increase in permeance, from 1.5 to 3.9 and from 1.7 to 11.1 L·m(-2)·h(-1)·bar(-1) for MeOH/PS and THF/PS, respectively. PMID:24044635

  9. Immobilizing highly catalytically active Pt nanoparticles inside the pores of metal-organic framework: a double solvents approach.

    PubMed

    Aijaz, Arshad; Karkamkar, Abhi; Choi, Young Joon; Tsumori, Nobuko; Rönnebro, Ewa; Autrey, Tom; Shioyama, Hiroshi; Xu, Qiang

    2012-08-29

    Ultrafine Pt nanoparticles were successfully immobilized inside the pores of a metal-organic framework, MIL-101, without aggregation of Pt nanoparticles on the external surfaces of framework by using a "double solvents" method. TEM and electron tomographic measurements clearly demonstrated the uniform three-dimensional distribution of the ultrafine Pt NPs throughout the interior cavities of MIL-101. The resulting Pt@MIL-101 composites represent the first highly active MOF-immobilized metal nanocatalysts for catalytic reactions in all three phases: liquid-phase ammonia borane hydrolysis, solid-phase ammonia borane thermal dehydrogenation, and gas-phase CO oxidation. PMID:22888976

  10. Heavy metals, organic solvents, and multiple sclerosis: An exploratory look at gene-environment interactions.

    PubMed

    Napier, Melanie D; Poole, Charles; Satten, Glen A; Ashley-Koch, Allison; Marrie, Ruth Ann; Williamson, Dhelia M

    2016-01-01

    Exposure to heavy metals and organic solvents are potential etiologic factors for multiple sclerosis (MS), but their interaction with MS-associated genes is under-studied. The authors explored the relationship between environmental exposure to lead, mercury, and solvents and 58 single-nucleotide polymorphisms (SNPs) in MS-associated genes. Data from a population-based case-control study of 217 prevalent MS cases and 496 age-, race-, gender-, and geographically matched controls were used to fit conditional logistic regression models of the association between the chemical, gene, and MS, adjusting for education and ancestry. MS cases were more likely than controls to report lead (odds ratio [OR] = 2.03; 95% confidence interval [CI]: 1.07, 3.86) and mercury exposure (OR = 2.06; 95% CI: 1.08, 3.91). Findings of potential gene-environment interactions between SNPs in TNF-α, TNF-β, TCA-β, VDR, MBP, and APOE, and lead, mercury, or solvents should be considered cautiously due to limited sample size. PMID:25137520

  11. Influence of Solvent-Like Sidechains on the Adsorption of Light Hydrocarbons in Metal-Organic Frameworks.

    PubMed

    Schneemann, Andreas; Bloch, Eric D; Henke, Sebastian; Llewellyn, Philip L; Long, Jeffrey R; Fischer, Roland A

    2015-12-14

    A variety of strategies have been developed to adsorb and separate light hydrocarbons in metal-organic frameworks. Here, we present a new approach in which the pores of a framework are lined with four different C3 sidechains that feature various degrees of branching and saturation. These pendant groups, which essentially mimic a low-density solvent with restricted degrees of freedom, offer tunable control of dispersive host-guest interactions. The performance of a series of frameworks of the type Zn2 (fu-bdc)2 (dabco) (fu-bdc(2-) =functionalized 1,4-benzenedicarboxylate; dabco=1,4-diazabicyclo[2.2.2]octane), which feature a pillared layer structure, were investigated for the adsorption and separation of methane, ethane, ethylene, and acetylene. The four frameworks exhibit low methane uptake, whereas C2 hydrocarbon uptake is substantially higher as a result of the enhanced interaction of these molecules with the ligand sidechains. Most significantly, the adsorption quantities and selectivity were found to depend strongly upon the type of sidechains attached to the framework scaffold. PMID:26559500

  12. 1D to 3D and Chiral to Noncentrosymmetric Metal-Organic Complexes Controlled by the Amount of DEF Solvent: Photoluminescent and NLO Properties.

    PubMed

    Wen, Yuehong; Sheng, Tianlu; Zhuo, Chao; Zhu, Xiaoquan; Hu, Shengmin; Cao, Wenhai; Li, Haoran; Zhang, Hao; Wu, Xintao

    2016-05-01

    A mixture of 2D and 1D metal-organic complexes, [ZnL(H2O)2·G1·DEF·2H2O]n (1a: G1 = naphthalene-2,7-disulfonate; DEF = N,N-diethylformamide) and [ZnL(H2O)3·G1·DEF·2H2O]n (2), has been prepared from a hydrogenated Schiff base L and Zn(II) in a DEF-contained solvent system under mild conditions. The yields of 1a and 2 are equivalent; however, they can be tuned by varying the amount of DEF solvent. Increasing the use of DEF tends to form pure 1a, while decreasing it generates 2. Without DEF, another novel 3D four-connected CdSO4 (cds) framework [ZnL(H2O)2·G1·2H2O]n (3) composed of alternated right-handed and left-handed helical chains has been constructed. The amount of DEF solvent has a significant impact on the diverse coordination architectures of 1-3, which is rare in the preparation of metal-organic complexes. The photoluminescence of complexes 1-3 along with naphthalene-2,7-disulfonate has been investigated in the solid state. The luminescent emission of G1 was enhanced greatly after being confined into metal-organic networks. In addition, complexes 1-3 display second-harmonic generation efficiencies, which are approximately 0.58, 0.42, 0.32, and 0.52 times as much as that of potassium dihydrogen phosphate. PMID:27093469

  13. A fluorescent paramagnetic Mn metal-organic framework based on semi-rigid pyrene tetra-carboxylic acid: sensing of solvent polarity and explosive nitroaromatics.

    PubMed

    Bajpai, Alankriti; Mukhopadhyay, Arindam; Krishna, Manchugondanahalli Shivakumar; Govardhan, Savitha; Moorthy, Jarugu Narasimha

    2015-09-01

    An Mn metal-organic framework (Mn-MOF), Mn-L, based on a pyrene-tetraacid linker (H4 L), displays a respectable fluorescence quantum yield of 8.3% in spite of the presence of the paramagnetic metal ions, due presumably to fixation of the metal ions in geometries that do not allow complete energy/charge-transfer quenching. Remarkably, the porous Mn-L MOF with ∼25% solvent-accessible volume exhibits a heretofore unprecedented solvent-dependent fluorescence emission maximum, permitting its use as a probe of solvent polarity; the emission maxima in different solvents correlate excellently with Reichardt's solvent polarity parameter (E T (N)). Further, the applicability of Mn-L to the sensing of nitroaromatics via fluorescence quenching is demonstrated; the detection limit for TNT is shown to be 125 p.p.m. The results bring out the fact that MOFs based on paramagnetic metal ions can indeed find application when the quenching mechanisms are attenuated by certain geometries of the organic linkers of the MOF. PMID:26306197

  14. Formation of hollow and mesoporous structures in single-crystalline microcrystals of metal-organic frameworks via double-solvent mediated overgrowth

    NASA Astrophysics Data System (ADS)

    Chou, Lien-Yang; Hu, Pan; Zhuang, Jia; Morabito, Joseph V.; Ng, Ka Chon; Kao, Ya-Chuan; Wang, Shao-Chun; Shieh, Fa-Kuen; Kuo, Chun-Hong; Tsung, Chia-Kuang

    2015-11-01

    The creation of hierarchical porosity in metal-organic frameworks (MOFs) could benefit various applications of MOFs such as gas storage and separation. Having single-crystalline microcrystals instead of poly-crystalline composites is critical for these potential applications of MOFs with hierarchical porosity. We developed a room temperature synthetic method to generate uniform hollow and mesoporous zeolitic imidazolate framework-8 (ZIF-8) microcrystals with a single-crystalline structure via overgrowing a ZIF-8 shell in methanol solution on a ZIF-8 core with water adsorbed in the pores. The cavities formed as a result of the different solvent micro-environment. This double-solvent mediated overgrowth method could be applied to prepare other MOFs with hierarchical porosity.The creation of hierarchical porosity in metal-organic frameworks (MOFs) could benefit various applications of MOFs such as gas storage and separation. Having single-crystalline microcrystals instead of poly-crystalline composites is critical for these potential applications of MOFs with hierarchical porosity. We developed a room temperature synthetic method to generate uniform hollow and mesoporous zeolitic imidazolate framework-8 (ZIF-8) microcrystals with a single-crystalline structure via overgrowing a ZIF-8 shell in methanol solution on a ZIF-8 core with water adsorbed in the pores. The cavities formed as a result of the different solvent micro-environment. This double-solvent mediated overgrowth method could be applied to prepare other MOFs with hierarchical porosity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06532a

  15. Controlling nickel nanoparticle size in an organic/metal-organic matrix through the use of different solvents.

    PubMed

    Berlie, Adam; Terry, Ian; Szablewski, Marek

    2013-12-21

    Nickel nanoparticles have been created in an organic-based matrix by the reaction of Ni(COD)2 (COD = 1,5-bis-cyclooctadiene) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (TCNQF4). The size of the nickel nanoparticles can be controlled by the use of different solvents and inclusion of tetrahydrofuran (THF) within the reaction to stabilise the Ni(0) atoms from the Ni(COD)2. Materials are characterised with a combination of X-ray diffraction, electron microscopy and magnetometry and it is found that samples made using a halocarbon solvent resulted in clustered bulk Ni particles (size ≤ 10 nm) with anomalously high superparamagnetic blocking temperatures. Using an isocyanide solvent produces smaller (size ∼ 1 nm), well dispersed particles that show little evidence of superparamagnetic blocking in the range of temperatures investigated (>2 K). In all samples there is another component which dominates the magnetic response at low temperatures and shows an interesting temperature dependent scaling behaviour when plotted as M vs. B/T which we believe is related to the organo-metallic matrix that the particles are trapped within. We propose that the enhanced blocking temperature of particles synthesised using halocarbon solvents can be attributed to inter-particle dipolar interactions and nanoparticle-matrix exchange interactions. PMID:24135713

  16. High yield synthesis of Ni-BTC metal-organic framework with ultrasonic irradiation: Role of polar aprotic DMF solvent.

    PubMed

    Israr, Farrukh; Chun, Daye; Kim, Yeongmin; Kim, Duk Kyung

    2016-07-01

    Nickel based porous solid was synthesized with 20 kHz ultrasonic irradiation. The reaction of Ni(II) nitrate hexahydrate with 1,3,5-benzene tricarboxylic acid in N,N-Dimethylformamide (DMF) as the sole solvent under ultrasonic radiation produced porous Ni-BTC MOF. Choice of correct solvent for the ultrasonic treatment was proven important. The effect of varying ultrasonic powers (40%, 60% and 80% of 750 W) along with different temperature conditions (50 °C, 60 °C, 70 °C and 80 °C) influenced the respective yield. A very high yield of 88% Ni-BTC MOF was obtained from 80% ultrasonic power at 60 °C. BET surface areas of the MOF crystals measured by N2 gas adsorption isotherms were in the range of 960-1000 m(2)/g. PMID:26964927

  17. Dual-Emission of Lanthanide Metal-Organic Frameworks Encapsulating Carbon-Based Dots for Ratiometric Detection of Water in Organic Solvents.

    PubMed

    Dong, Yongqiang; Cai, Jianhua; Fang, Qingqing; You, Xu; Chi, Yuwu

    2016-02-01

    Nitrogen and sulfur codoped carbon-based dots (N,S-CDs) with strong blue light emission are encapsulated into red light-emitting europium metal-organic frameworks (Eu-MOFs) to form two color light-emitting nanohybrids (Eu-MOFs/N,S-CDs). In organic solvents, the encapsulated N,S-CDs are aggregated and confined in the cavities of the Eu-MOFs, exhibiting only a very weak photoluminescence (PL) signal. Therefore, the nanohybrids show red light emission of the Eu-MOFs. Contrarily, when the Eu-MOFs/N,S-CDs are dispersed in water, the encapsulated N,S-CDs are released into solution while the red light emission of the Eu-MOFs is quenched due to the effect of O-H oscillators. The nanohybrids are used as the probe for the water content in organic solvents. Take ethanol as an example; as the water content is increased from 0.2 to 30%, the nanoprobe provides distinguishable PL color change. The ratio of light intensity at 420 nm to that at 623 nm (I420/I623) increases linearly with increasing water content in the range from 0.05 to 4% with a low detection limit of 0.03%. PMID:26744080

  18. Solvent-induced secondary building unit (SBU) variations in a series of Cu(II) metal-organic frameworks derived from a bifunctional ligand.

    PubMed

    Chen, Di-Ming; Ma, Jian-Gong; Cheng, Peng

    2015-05-21

    The role of auxiliary solvents in the formation of metal-organic frameworks (MOFs) has been studied for a series of copper-based framework systems. Herein we show the formation of three different 3D ordered frameworks with the formulae {[Cu4(cpt)4Cl4]·2DMF·dioxane·3H2O}n (1), {[Cu8(cpt)4(Hcpt)2Cl7(μ3-OH)2(H2O)4]Cl3·4CH3CN}n (2), and {[Cu8(cpt)4Cl4(μ3-OH)2(μ4-O)2]Cl2·4H2O·2CH3CN·3MeOH}n (3) [Hcpt = 4-(4-carboxyphenyl)-1,2,4-triazole], respectively, from the same reaction mixture through varying auxiliary solvents of the medium. These MOFs were fully characterized by single-crystal X-ray diffraction, showing interesting secondary building unit (SBU) variations. The varied SBUs not only bring different framework architectures to these MOFs, but also affect their framework stability. Gas sorption studies of MOF 3 reveal high CO2-N2 selectivity at 298 K and 0.16 bar (a typical partial pressure of CO2 in an industrial flue gas). A high isosteric heat of adsorption (Qst) at zero loading (53 kJ mol(-1)) was also observed in MOF 3. PMID:25873315

  19. Multi-component synthesis of 2-amino-6-(alkyllthio)pyridine-3,5-dicarbonitriles using Zn(II) and Cd(II) metal-organic frameworks (MOFs) under solvent-free conditions

    PubMed Central

    Thimmaiah, Muralidhara; Li, Peng; Regati, Sridhar; Chen, Banglin; Zhao, John Cong-Gui

    2012-01-01

    Multi-component synthesis 2-amino-3,5-dicarbonitrile-6-thio-pyridines has been developed by using the reaction of aldehydes, malononitrile, and thiophenols in the presence of a Zn (II) or a Cd(II) metal-organic framework (MOF) as the heterogeneous catalyst. This protocol tolerates different functional groups on the substrates and does not require the use of any organic solvent. Moreover, the Zn(II) and Cd (II) MOF catalysts can be recovered and reused for a number of runs without loss of activity. PMID:23002309

  20. The ionothermal synthesis of metal organic frameworks, Ln(C 9O 6H 3)((CH 3NH) 2CO) 2, using deep eutectic solvents

    NASA Astrophysics Data System (ADS)

    Himeur, Farida; Stein, Irene; Wragg, David S.; Slawin, Alexandra M. Z.; Lightfoot, Philip; Morris, Russell E.

    2010-04-01

    Three new isostructural materials Ln(TMA)(DMU) 2 (Ln(C 9O 6H 3)((CH 3NH) 2CO) 2; Ln: La 1, Nd 2, Eu 3; TMA: trimesate, DMU: dimethylurea) have been synthesised ionothermally using a choline chloride/dimethylurea deep eutectic mixture as the solvent. Normally in ionothermal synthesis the urea portion of the deep eutectic solvent is unstable, breaking down to release ammonium cations that act as templates. In the case of 1- 3, however, the dimethylurea remains intact and is incorporated into the final structure.

  1. Exchange of Coordinated Solvent During Crystallization of a Metal-Organic Framework Observed by In Situ High-Energy X-ray Diffraction.

    PubMed

    Wu, Yue; Breeze, Matthew I; Clarkson, Guy J; Millange, Franck; O'Hare, Dermot; Walton, Richard I

    2016-04-11

    Using time-resolved monochromatic high energy X-ray diffraction, we present an in situ study of the solvothermal crystallisation of a new MOF [Yb2 (BDC)3 (DMF)2 ]⋅H2 O (BDC=benzene-1,4-dicarboxylate and DMF=N,N-dimethylformamide) under solvothermal conditions, from mixed water/DMF solvent. Analysis of high resolution powder patterns obtained reveals an evolution of lattice parameters and electron density during the crystallisation process and Rietveld analysis shows that this is due to a gradual topochemical replacement of coordinated solvent molecules. The water initially coordinated to Yb(3+) is replaced by DMF as the reaction progresses. PMID:26959076

  2. Solvent-mediated secondary building units (SBUs) diversification in a series of MnII-based metal-organic frameworks (MOFs)

    NASA Astrophysics Data System (ADS)

    Niu, Yan-Fei; Cui, Li-Ting; Han, Jie; Zhao, Xiao-Li

    2016-09-01

    The role of auxiliary solvents in the formation of MOFs has been investigated for a series of MnII-based framework systems. Reactions of 4,4‧,4″-nitrilotribenzoic acid (H3L) with MnII through varying auxiliary solvents of the medium resulted in the formation of diversified multinuclear MnII subunits in four new coordination polymers: [Mn3(L)(HCOO)3(DEF)3] (1), [Mn3(L)2(EtOH)2]·DMF (2), [Mn5(L)4(H2O)2]·2(H2NMe2)+·4DMF·2H2O (3), and [Mn3(L)2(py)4(H2O)]·H2O (4) (H3L=4,4‧,4‧-nitrilotribenzoic acid, DMF=dimethylformamide, DEF=N,N-diethylformamide, py=pyridine). These four compounds were fully characterized by single-crystal X-ray diffraction, showing interesting SBUs variations. For compound 1, it displays a (3,6)-connected kgd net with wheel [Mn6] cluster serving as SBU, whereas in 2, the sequence of Mn3(COO)9(EtOH)2 is repeated by inversion centers located between Mn1 and Mn3 to form an infinite Mn-carboxylate chain, which are further interlinked by L3- ligands to form a 3D architecture. In 3, the pentanuclear Mn5(CO2)12 clusters are interlinked to form a layer, which are further pillared by L3- to generate a 3D network. Compound 4 has a (3,6)-connected network in which the SBU is a linear trimeric Mn3(COO)6(py)4(H2O) cluster. In addition, the thermal stabilities, X-ray powder diffraction of all the compounds were studied, photoluminescence behaviors of compounds 1, 3 and 4 are discussed.

  3. ACE applied to the quantitative characterization of benzo-18-crown-6-ether binding with alkali metal ions in a methanol-water solvent system.

    PubMed

    Ehala, Sille; Makrlík, Emanuel; Toman, Petr; Kasicka, Václav

    2010-01-01

    ACE was applied to the quantitative evaluation of noncovalent binding interactions between benzo-18-crown-6-ether (B18C6) and several alkali metal ions, Li(+), Na(+), K(+), Rb(+) and Cs(+), in a mixed binary solvent system, methanol-water (50/50 v/v). The apparent binding (stability) constants (K(b)) of B18C6-alkali metal ion complexes in the hydro-organic medium above were determined from the dependence of the effective electrophoretic mobility of B18C6 on the concentration of alkali metal ions in the BGE using a nonlinear regression analysis. Before regression analysis, the mobilities measured by ACE at ambient temperature and variable ionic strength of the BGE were corrected by a new procedure to the reference temperature, 25 degrees C, and the constant ionic strength, 10 mM. In the 50% v/v methanol-water solvent system, like in pure methanol, B18C6 formed the strongest complex with potassium ion (log K(b)=2.89+/-0.17), the weakest complex with cesium ion (log K(b)=2.04+/-0.20), and no complexation was observed between B18C6 and the lithium ion. In the mixed methanol-water solvent system, the binding constants of the complexes above were found to be about two orders lower than in methanol and about one order higher than in water. PMID:20108263

  4. Flexible metal-organic frameworks.

    PubMed

    Schneemann, A; Bon, V; Schwedler, I; Senkovska, I; Kaskel, S; Fischer, R A

    2014-08-21

    Advances in flexible and functional metal-organic frameworks (MOFs), also called soft porous crystals, are reviewed by covering the literature of the five years period 2009-2013 with reference to the early pertinent work since the late 1990s. Flexible MOFs combine the crystalline order of the underlying coordination network with cooperative structural transformability. These materials can respond to physical and chemical stimuli of various kinds in a tunable fashion by molecular design, which does not exist for other known solid-state materials. Among the fascinating properties are so-called breathing and swelling phenomena as a function of host-guest interactions. Phase transitions are triggered by guest adsorption/desorption, photochemical, thermal, and mechanical stimuli. Other important flexible properties of MOFs, such as linker rotation and sub-net sliding, which are not necessarily accompanied by crystallographic phase transitions, are briefly mentioned as well. Emphasis is given on reviewing the recent progress in application of in situ characterization techniques and the results of theoretical approaches to characterize and understand the breathing mechanisms and phase transitions. The flexible MOF systems, which are discussed, are categorized by the type of metal-nodes involved and how their coordination chemistry with the linker molecules controls the framework dynamics. Aspects of tailoring the flexible and responsive properties by the mixed component solid-solution concept are included, and as well examples of possible applications of flexible metal-organic frameworks for separation, catalysis, sensing, and biomedicine. PMID:24875583

  5. PROCESS OF RECOVERING ALKALI METALS

    DOEpatents

    Wolkoff, J.

    1961-08-15

    A process is described of recovering alkali metal vapor by sorption on activated alumina, activated carbon, dehydrated zeolite, activated magnesia, or Fuller's earth preheated above the vaporization temperature of the alkali metal and subsequent desorption by heating the solvent under vacuum. (AEC)

  6. Preparation of alkali metal dispersions

    NASA Technical Reports Server (NTRS)

    Rembaum, A.; Landel, R. F. (Inventor)

    1968-01-01

    A method is described for producing alkali metal dispersions of high purity. The dispersions are prepared by varying the equilibrium solubility of the alkali metal in a suitable organic solvent in the presence of aromatic hydrocarbons. The equilibrium variation is produced by temperature change. The size of the particles is controlled by controlling the rate of temperature change.

  7. Amorphous metal-organic frameworks.

    PubMed

    Bennett, Thomas D; Cheetham, Anthony K

    2014-05-20

    Crystalline metal-organic frameworks (MOFs) are porous frameworks comprising an infinite array of metal nodes connected by organic linkers. The number of novel MOF structures reported per year is now in excess of 6000, despite significant increases in the complexity of both component units and molecular networks. Their regularly repeating structures give rise to chemically variable porous architectures, which have been studied extensively due to their sorption and separation potential. More recently, catalytic applications have been proposed that make use of their chemical tunability, while reports of negative linear compressibility and negative thermal expansion have further expanded interest in the field. Amorphous metal-organic frameworks (aMOFs) retain the basic building blocks and connectivity of their crystalline counterparts, though they lack any long-range periodic order. Aperiodic arrangements of atoms result in their X-ray diffraction patterns being dominated by broad "humps" caused by diffuse scattering and thus they are largely indistinguishable from one another. Amorphous MOFs offer many exciting opportunities for practical application, either as novel functional materials themselves or facilitating other processes, though the domain is largely unexplored (total aMOF reported structures amounting to under 30). Specifically, the use of crystalline MOFs to detect harmful guest species before subsequent stress-induced collapse and guest immobilization is of considerable interest, while functional luminescent and optically active glass-like materials may also be prepared in this manner. The ion transporting capacity of crystalline MOFs might be improved during partial structural collapse, while there are possibilities of preparing superstrong glasses and hybrid liquids during thermal amorphization. The tuning of release times of MOF drug delivery vehicles by partial structural collapse may be possible, and aMOFs are often more mechanically robust than

  8. Adsorption of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates

    SciTech Connect

    Ma Fengji; Liu Shuxia; Liang Dadong; Ren Guojian; Wei Feng; Chen Yaguang; Su Zhongmin

    2011-11-15

    The functionalization of porous metal-organic frameworks (Cu{sub 3}(BTC){sub 2}) was achieved by incorporating Keggin-type polyoxometalates (POMs), and further optimized via alkali metal ion-exchange. In addition to thermal gravimetric analysis, IR, single-crystal X-ray diffraction, and powder X-ray diffraction, the adsorption properties were characterized by N{sub 2} and volatile organic compounds (VOCs) adsorption measurements, including short-chain alcohols (C<4), cyclohexane, benzene, and toluene. The adsorption enthalpies estimated by the modified Clausius-Clapeyron equation provided insight into the impact of POMs and alkali metal cations on the adsorption of VOCs. The introduction of POMs not only improved the stability, but also brought the increase of adsorption capacity by strengthening the interaction with gas molecules. Furthermore, the exchanged alkali metal cations acted as active sites to interact with adsorbates and enhanced the adsorption of VOCs. - Graphical Abstract: The adsorption behavior of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates has been systematically evaluated. Highlights: > Functionalization of MOFs was achieved by incorporating Keggin-type POMs. > Introduction of POMs improved the thermal stability and adsorption capacity. > Alkali metal ion-exchange modified the inclusion state and also enhanced the adsorption. > Adsorption enthalpies were estimated to study the impact of POMs and alkali metal cations.

  9. Thermodynamics of Metal-Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Hughes, James Thomas

    Metal-Organic Frameworks (MOF) are crystalline nanoporous lattices constructed from the combination of cation and multi-dentate organic molecules. MOFs can display both chemical and thermal robustness while having large surface areas and pore volumes. In addition the modular composition of MOFs allows a degree of design and control of MOF structures. These unique physical properties have attracted wide interest and position MOFs to make meaningful contributions towards many applications, such as adsorption, catalysis, separation, and sensing. Despite the extensive investigative work over the last decade on MOF materials, the initial synthesis is still done by trial and error. Of the identified structures some MOFs are robust while others are fragile. It is unclear what role thermodynamics plays in the formation energies of MOFs and guest molecules interactions within the pores. Better understanding of thermochemical properties of MOFs is critical if MOF synthesis is to obtain true predictive design. To address these questions aqueous solution calorimetry was performed on ten different frameworks in both the as-synthesized and activated state. To understand the structural energetics of MOFs, the heat of formation from dense states (metal oxide and protonated organic linkers) to the open MOF framework was measured. Chapter 2 discusses the new aqueous calorimetry methodology developed to measure the enthalpy of solution for hybrid materials. Chapters 3, 4 and 5 detail the enthalpies of formation from their dense states of the frameworks: (MOF-5, ZIF-zni, ZIF-1, ZIF-3, ZIF-4, ZIF-7, ZIF-8, ZIF-9 and Cu-HKUST-1). These chapters also compare the MOF heat of formation energetics to those of zeolites, zeotypes and mesoporous silica materials. Finding that MOFs are metastable with respect to their dense states (metal oxide and protonated organic), following the current destabilization trend of the main group porous materials. The thermochemical effect of solvent on the MOF

  10. Magnetism in metal-organic capsules

    SciTech Connect

    Atwood, Jerry L.; Brechin, Euan K; Dalgarno, Scott J.; Inglis, Ross; Jones, Leigh F.; Mossine, Andrew; Paterson, Martin J.; Power, Nicholas P.; Teat, Simon J.

    2010-01-07

    Nickel and cobalt seamed metal-organic capsules have been isolated and studied using structural, magnetic and computational approaches. Antiferromagnetic exchange in the Ni capsule results from coordination environments enforced by the capsule framework.

  11. Gas adsorption on metal-organic frameworks

    DOEpatents

    Willis, Richard R.; Low, John J. , Faheem, Syed A.; Benin, Annabelle I.; Snurr, Randall Q.; Yazaydin, Ahmet Ozgur

    2012-07-24

    The present invention involves the use of certain metal organic frameworks that have been treated with water or another metal titrant in the storage of carbon dioxide. The capacity of these frameworks is significantly increased through this treatment.

  12. A visually detectable pH responsive zirconium metal-organic framework.

    PubMed

    Moon, Su-Young; Howarth, Ashlee J; Wang, Timothy; Vermeulen, Nicolaas A; Hupp, Joseph T; Farha, Omar K

    2016-02-16

    A halochromic Zr6-based metal-organic framework is synthesized using solvent-assisted linker incorporation (SALI) with NU-1000 as a platform and carboxylnaphthofluorescein as a pH sensitive ligand. The functionalized MOF can catalytically detoxify nerve agent simulants in addition to visually detecting the acidic byproduct produced during detoxification. PMID:26832648

  13. Liquid exfoliation of alkyl-ether functionalised layered metal-organic frameworks to nanosheets.

    PubMed

    Foster, Jonathan A; Henke, Sebastian; Schneemann, Andreas; Fischer, Roland A; Cheetham, Anthony K

    2016-08-18

    We report the synthesis of a 2D-layered metal-organic framework incorporating weakly interacting chains designed to aid exfoliation of the layers into nanosheets. Dispersion of the nanosheets exposes labile metal-sites which are shown to exchange solvent molecules allowing the nanosheets to act as sensors in suspension. PMID:27452790

  14. Selective Bifunctional Modification of a Non-catenated Metal-Organic Framework Material via 'Click' Chemistry

    SciTech Connect

    Gadzikwa, Tendai; Farha, Omar K.; Malliakas, Christos D.; Kanatzidis, Mercouri G.; Hupp, Joseph T.; Nguyen, SonBinh T.; NWU

    2009-12-01

    A noncatenated, Zn-based metal-organic framework (MOF) material bearing silyl-protected acetylenes was constructed and postsynthetically modified using 'click' chemistry. Using a solvent-based, selective deprotection strategy, two different organic azides were 'clicked' onto the MOF crystals, resulting in a porous material whose internal and external surfaces are differently functionalized.

  15. Nets, tiles, and metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    O'Keeffe, Michael

    2014-12-01

    An account is given of the basic nets that are important in the description and design of metal-organic framework (MOF) structures. These are generally of minimal transitivity, a concept which is explained. Derived nets are defined and the advantages of using derived nets to describe the topology of MOF frameworks with multiple branch points are emphasized.

  16. Computer simulation of metal-organic materials

    NASA Astrophysics Data System (ADS)

    Stern, Abraham C.

    Computer simulations of metal-organic frameworks are conducted to both investigate the mechanism of hydrogen sorption and to elucidate a detailed, molecular-level understanding of the physical interactions that can lead to successful material design strategies. To this end, important intermolecular interactions are identified and individually parameterized to yield a highly accurate representation of the potential energy landscape. Polarization, one such interaction found to play a significant role in H 2 sorption, is included explicitly for the first time in simulations of metal-organic frameworks. Permanent electrostatics are usually accounted for by means of an approximate fit to model compounds. The application of this method to simulations involving metal-organic frameworks introduces several substantial problems that are characterized in this work. To circumvent this, a method is developed and tested in which atomic point partial charges are computed more directly, fit to the fully periodic electrostatic potential. In this manner, long-range electrostatics are explicitly accounted for via Ewald summation. Grand canonical Monte Carlo simulations are conducted employing the force field parameterization developed here. Several of the major findings of this work are: Polarization is found to play a critical role in determining the overall structure of H2 sorbed in metal-organic frameworks, although not always the determining factor in uptake. The parameterization of atomic point charges by means of a fit to the periodic electrostatic potential is a robust, efficient method and consistently results in a reliable description of Coulombic interactions without introducing ambiguity associated with other procedures. After careful development of both hydrogen and framework potential energy functions, quantitatively accurate results have been obtained. Such predictive accuracy will aid greatly in the rational, iterative design cycle between experimental and theoretical

  17. Salts of alkali metal anions and process of preparing same

    DOEpatents

    Dye, James L.; Ceraso, Joseph M.; Tehan, Frederick J.; Lok, Mei Tak

    1978-01-01

    Compounds of alkali metal anion salts of alkali metal cations in bicyclic polyoxadiamines are disclosed. The salts are prepared by contacting an excess of alkali metal with an alkali metal dissolving solution consisting of a bicyclic polyoxadiamine in a suitable solvent, and recovered by precipitation. The salts have a gold-color crystalline appearance and are stable in a vacuum at -10.degree. C. and below.

  18. Minerals with metal-organic framework structures.

    PubMed

    Huskić, Igor; Pekov, Igor V; Krivovichev, Sergey V; Friščić, Tomislav

    2016-08-01

    Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals. PMID:27532051

  19. Minerals with metal-organic framework structures

    PubMed Central

    Huskić, Igor; Pekov, Igor V.; Krivovichev, Sergey V.; Friščić, Tomislav

    2016-01-01

    Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals. PMID:27532051

  20. Porosity in metal-organic framework glasses.

    PubMed

    Thornton, A W; Jelfs, K E; Konstas, K; Doherty, C M; Hill, A J; Cheetham, A K; Bennett, T D

    2016-03-01

    The porosity of a glass formed by melt-quenching a metal-organic framework, has been characterized by positron annihilation lifetime spectroscopy. The results reveal porosity intermediate between the related open and dense crystalline frameworks ZIF-4 and ZIF-zni. A structural model for the glass was constructed using an amorphous polymerization algorithm, providing additional insight into the gas-inaccessible nature of porosity and the possible applications of hybrid glasses. PMID:26800518

  1. Purification of metal-organic framework materials

    SciTech Connect

    Farha, Omar K.; Hupp, Joseph T.

    2012-12-04

    A method of purification of a solid mixture of a metal-organic framework (MOF) material and an unwanted second material by disposing the solid mixture in a liquid separation medium having a density that lies between those of the wanted MOF material and the unwanted material, whereby the solid mixture separates by density differences into a fraction of wanted MOF material and another fraction of unwanted material.

  2. Purification of metal-organic framework materials

    SciTech Connect

    Farha, Omar K.; Hupp, Joseph T.

    2015-06-30

    A method of purification of a solid mixture of a metal-organic framework (MOF) material and an unwanted second material by disposing the solid mixture in a liquid separation medium having a density that lies between those of the wanted MOF material and the unwanted material, whereby the solid mixture separates by density differences into a fraction of wanted MOF material and another fraction of unwanted material.

  3. Multiphoton harvesting metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Quah, Hong Sheng; Chen, Weiqiang; Schreyer, Martin K.; Yang, Hui; Wong, Ming Wah; Ji, Wei; Vittal, Jagadese J.

    2015-08-01

    Multiphoton upconversion is a process where two or more photons are absorbed simultaneously to excite an electron to an excited state and, subsequently, the relaxation of electron gives rise to the emission of a photon with frequency greater than those of the absorbed photons. Materials possessing such property attracted attention due to applications in biological imaging, photodynamic therapy, three-dimensional optical data storage, frequency-upconverted lasing and optical power limiting. Here we report four-photon upconversion in metal-organic frameworks containing the ligand, trans, trans-9,10-bis(4-pyridylethenyl)anthracene. The ligand has a symmetrical acceptor-π-donor-π-acceptor structure and a singlet biradical electronic ground state, which boosted its multiphoton absorption cross-sections. We demonstrate that the upconversion efficiency can be enhanced by Förster resonance energy transfer within host-guest metal-organic frameworks consisting of encapsulated high quantum yielding guest molecules. Using these strategies, metal-organic framework materials, which can exhibit frequency-upconverted photoluminescence excited by simultaneous multiphoton absorption, can be rationally designed and synthesized.

  4. Alkali Bee

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The alkali bee, Nomia melanderi, is native to deserts and semi-arid desert basins of the western United States. It is a very effective and manageable pollinator for the production of seed in alfalfa (=lucerne) and some other crops, such as onion. It is the world’s only intensively managed ground-n...

  5. Cloning and expression in E. coli of an organic solvent-tolerant and alkali-resistant glucose 1-dehydrogenase from Lysinibacillus sphaericus G10.

    PubMed

    Ding, Hai-Tao; Du, Yi-Qing; Liu, Dan-Feng; Li, Ze-Li; Chen, Xue-Jiao; Zhao, Yu-Hua

    2011-01-01

    The gene gdh encoding an organic solvent-tolerant and alkaline-resistant NAD(P)-dependent glucose 1-dehydrogenase (LsGDH) was cloned from Lysinibacillus sphaericus G10 and expressed in Escherichia coli. The recombinant LsGDH exhibited maximum activity at pH 9.5 and 50 °C. LsGDH displayed high stability at a wide pH ranging from 6.5 to 10.0 and was stable after incubation at 30 °C for 1 week in 25 mM sodium phosphate buffer (pH 6.5) in the absence or presence of NaCl. The activity of LsGDH was enhanced by Li+, Na+, K+, NH4+, Mg2+, and EDTA at pH 8.0. LsGDH exhibited high tolerance to 60% DMSO, 30% acetone, 30% methanol, 30% ethanol, 10% n-propanol, 30% isopropanol, 60% n-hexanol and 30% n-hexane. The relationship between stability and chain length of the alcohols fit a Gaussian distribution model (R2≥0.94), and demonstrated lowest enzyme stability in C4-alcohol. The results suggested that LsGDH was potentially useful for coenzyme regeneration in organic solvents or under alkaline conditions. PMID:20805024

  6. Synthesis and Characterization of Functionalized Metal-organic Frameworks

    PubMed Central

    Karagiaridi, Olga; Bury, Wojciech; Sarjeant, Amy A.; Hupp, Joseph T.; Farha, Omar K.

    2014-01-01

    Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy. PMID:25225784

  7. Gas promotes the crystallization of nano-sized metal-organic frameworks in ionic liquid.

    PubMed

    Liu, Chengcheng; Zhang, Bingxing; Zhang, Jianling; Peng, Li; Kang, Xinchen; Han, Buxing; Wu, Tianbin; Sang, Xinxin; Ma, Xue

    2015-07-21

    Herein it was found that gas can be utilized as an activator to promote metal-organic framework (MOF) crystallization in IL at room temperature. The ultra-small MOF nanoparticles were obtained, and their size and porosity properties can be easily modulated by controlling gas pressure. The as-synthesized nano-sized Cu-MOF is an excellent candidate catalyst for the solvent-free oxidation of cyclohexene with oxygen. PMID:26087458

  8. Microporous Metal Organic Materials for Hydrogen Storage

    SciTech Connect

    S. G. Sankar; Jing Li; Karl Johnson

    2008-11-30

    We have examined a number of Metal Organic Framework Materials for their potential in hydrogen storage applications. Results obtained in this study may, in general, be summarized as follows: (1) We have identified a new family of porous metal organic framework materials with the compositions M (bdc) (ted){sub 0.5}, {l_brace}M = Zn or Co, bdc = biphenyl dicarboxylate and ted = triethylene diamine{r_brace} that adsorb large quantities of hydrogen ({approx}4.6 wt%) at 77 K and a hydrogen pressure of 50 atm. The modeling performed on these materials agree reasonably well with the experimental results. (2) In some instances, such as in Y{sub 2}(sdba){sub 3}, even though the modeling predicted the possibility of hydrogen adsorption (although only small quantities, {approx}1.2 wt%, 77 K, 50 atm. hydrogen), our experiments indicate that the sample does not adsorb any hydrogen. This may be related to the fact that the pores are extremely small or may be attributed to the lack of proper activation process. (3) Some samples such as Zn (tbip) (tbip = 5-tert butyl isophthalate) exhibit hysteresis characteristics in hydrogen sorption between adsorption and desorption runs. Modeling studies on this sample show good agreement with the desorption behavior. It is necessary to conduct additional studies to fully understand this behavior. (4) Molecular simulations have demonstrated the need to enhance the solid-fluid potential of interaction in order to achieve much higher adsorption amounts at room temperature. We speculate that this may be accomplished through incorporation of light transition metals, such as titanium and scandium, into the metal organic framework materials.

  9. Biomimicry in metal-organic materials

    SciTech Connect

    Zhang, MW; Gu, ZY; Bosch, M; Perry, Z; Zhou, HC

    2015-06-15

    Nature has evolved a great number of biological molecules which serve as excellent constructional or functional units for metal-organic materials (MOMs). Even though the study of biomimetic MOMs is still at its embryonic stage, considerable progress has been made in the past few years. In this critical review, we will highlight the recent advances in the design, development and application of biomimetic MOMs, and illustrate how the incorporation of biological components into MOMs could further enrich their structural and functional diversity. More importantly, this review will provide a systematic overview of different methods for rational design of MOMs with biomimetic features. Published by Elsevier B.V.

  10. Defects and disorder in metal organic frameworks.

    PubMed

    Cheetham, Anthony K; Bennett, Thomas D; Coudert, François-Xavier; Goodwin, Andrew L

    2016-03-14

    The wide-ranging properties of metal organic frameworks (MOFs) rely in many cases on the presence of defects within their structures and the disorder that is inevitably associated with such defects. In the present work we review several aspects of defects in MOFs, ranging from simple substitutional defects at metal cation or ligand positions, to correlated defects on a larger length scale and the extreme case of disorder associated with amorphous MOFs. We consider both porous and dense MOFs, and focus particularly on the way in which defects and disorder can be used to tune physical properties such as gas adsorption, catalysis, photoluminescence, and electronic and mechanical properties. PMID:26836459

  11. Polyrotaxane metal-organic frameworks (PMOFs).

    PubMed

    Yang, Jin; Ma, Jian-Fang; Batten, Stuart R

    2012-08-18

    Polyrotaxane metal-organic frameworks (PMOFs), a relatively rare branch of entangled networks, have received significant attention due to their unusual entanglement topologies. The PMOFs we described here are still at an early stage of development. This feature article summarizes the recent developments in structural types of PMOFs from our own group and others. We make some generalizations about the various classes of PMOFs, and develop the definitions and nomenclature of these entanglements, including classification into trivial and nontrivial polyrotaxanes, and limits on what constitutes a (nontrivial) polyrotaxane. Finally, the synthetic strategies toward the design and preparation of new PMOFs are elucidated. PMID:22745934

  12. Template-Free Synthesis of Hierarchical Porous Metal-Organic Frameworks

    SciTech Connect

    Yue, Yanfeng; Qiao, Zhen-an; Fulvio, Pasquale F; Dai, Sheng; Binder, Andrew J; Tian, Chengcheng; Nelson, Kimberly M; Zhu, Xiang

    2013-01-01

    A template-free synthesis of a hierarchical microporous-mesoporous metal-organic framework (MOF) of Zn(II)-2,5-dihydroxy-1,4-benzenedicarboxylate, namely Zn-MOF-74, is reported. The surface morphology and porosity of the bimodal materials can be modified by etching the pore walls with the synthesis solvent under different reaction times and different solvents. This template-free strategy allows for the preparation of stable frameworks with mesopores exceeding 15 nm, which was previously unattained by the synthesis of MOFs by ligand exten-sion method.

  13. Metal-organic frameworks for photocatalysis.

    PubMed

    Li, Ying; Xu, Hua; Ouyang, Shuxin; Ye, Jinhua

    2016-03-01

    Photocatalysis is a promising technology to convert solar energy into chemical energy. Recently, metal-organic frameworks (MOFs) have emerged as novel photocatalysts owing to their inherent structural characteristics of a large surface area and a well-ordered porous structure. Most importantly, via modulation of the organic linker/metal clusters or incorporation with metal/complex catalysts, not only the reactant adsorption and light absorption but also the charge separation and reactant activation will be largely promoted, leading to superior photocatalytic performance. In this article, we will first introduce the photophysical/chemical properties of MOFs; then various strategies of modification of MOFs towards better photocatalytic activity will be presented; finally, we will address the challenge and further perspective in MOF-based photocatalysis. PMID:26535907

  14. Stimulus-responsive metal-organic frameworks.

    PubMed

    Nagarkar, Sanjog S; Desai, Aamod V; Ghosh, Sujit K

    2014-09-01

    Materials that can recognize the changes in their local environment and respond by altering their inherent physical and/or chemical properties are strong candidates for future "smart" technology materials. Metal-organic frameworks (MOFs) have attracted a great deal of attention in recent years owing to their designable architecture, host-guest chemistry, and softness as porous materials. Despite this fact, studies on the tuning of the properties of MOFs by external stimuli are still rare. This review highlights the recent developments in the field of stimulus-responsive MOFs or so-called smart MOFs. In particular, the various stimuli used and the utility of stimulus-responsive smart MOFs for various applications such as gas storage and separation, sensing, clean energy, catalysis, molecular motors, and biomedical applications are highlighted by using representative examples. Future directions in the developments of stimulus-responsive smart MOFs and their applications are proposed from a personal perspective. PMID:24844581

  15. Biomimetic catalysis of metal-organic frameworks.

    PubMed

    Chen, Yao; Ma, Shengqian

    2016-06-14

    Metal-organic frameworks (MOFs) have attracted great attention as a new type of prospective material with various merits and functionalities. MOFs can either act as biomimetic catalysts to mimic enzymatic activities or serve as hosts to encapsulate bio-active species for biomimetic catalysis. However, in comparison with the dramatic development of MOFs in other catalytic fields, MOF-based biomimetic catalysis is still in its infancy and is yet to be systematically and comprehensively explored. Herein, the principles and strategies for the design and synthesis of MOF-based biomimetic catalysts, especially the structural features of representative MOFs that are related to biomimetic catalysis, are summarized and reviewed. In addition, recent advances in biomimetic catalysis of MOFs and the relationships between their catalytic performances and the structural specificities are discussed in detail as well. PMID:27041152

  16. An Electrically Switchable Metal-Organic Framework

    PubMed Central

    Fernandez, Carlos A.; Martin, Paul C.; Schaef, Todd; Bowden, Mark E.; Thallapally, Praveen K.; Dang, Liem; Xu, Wu; Chen, Xilin; McGrail, B. Peter

    2014-01-01

    Crystalline metal organic framework (MOF) materials containing interconnected porosity can be chemically modified to promote stimulus-driven (light, magnetic or electric fields) structural transformations that can be used in a number of devices. Innovative research strategies are now focused on understanding the role of chemical bond manipulation to reversibly alter the free volume in such structures of critical importance for electro-catalysis, molecular electronics, energy storage technologies, sensor devices and smart membranes. In this letter, we study the mechanism for which an electrically switchable MOF composed of Cu(TCNQ) (TCNQ = 7,7,8,8-tetracyanoquinodimethane) transitions from a high-resistance state to a conducting state in a reversible fashion by an applied potential. The actual mechanism for this reversible electrical switching is still not understood even though a number of reports are available describing the application of electric-field-induced switching of Cu(TCNQ) in device fabrication. PMID:25135307

  17. An Electrically Switchable Metal-Organic Framework

    NASA Astrophysics Data System (ADS)

    Fernandez, Carlos A.; Martin, Paul C.; Schaef, Todd; Bowden, Mark E.; Thallapally, Praveen K.; Dang, Liem; Xu, Wu; Chen, Xilin; McGrail, B. Peter

    2014-08-01

    Crystalline metal organic framework (MOF) materials containing interconnected porosity can be chemically modified to promote stimulus-driven (light, magnetic or electric fields) structural transformations that can be used in a number of devices. Innovative research strategies are now focused on understanding the role of chemical bond manipulation to reversibly alter the free volume in such structures of critical importance for electro-catalysis, molecular electronics, energy storage technologies, sensor devices and smart membranes. In this letter, we study the mechanism for which an electrically switchable MOF composed of Cu(TCNQ) (TCNQ = 7,7,8,8-tetracyanoquinodimethane) transitions from a high-resistance state to a conducting state in a reversible fashion by an applied potential. The actual mechanism for this reversible electrical switching is still not understood even though a number of reports are available describing the application of electric-field-induced switching of Cu(TCNQ) in device fabrication.

  18. An Electrically Switchable Metal-Organic Framework

    SciTech Connect

    Fernandez, Carlos A.; Martin, Paul F.; Schaef, Herbert T.; Bowden, Mark E.; Thallapally, Praveen K.; Dang, Liem X.; Xu, Wu; Chen, Xilin; McGrail, B. Peter

    2014-08-19

    Crystalline metal organic framework (MOF) materials containing interconnected porosity can be chemically modified to promote stimulus-driven (light, magnetic or electric fields) structural transformations that can be used in a number of devices. Innovative research strategies are now focused on understanding the role of chemical bond manipulation to reversibly alter the free volume in such structures of critical importance for electro-catalysis, molecular electronics, energy storage technologies, sensor devices and smart membranes. In this letter, we study the mechanism for which an electrically switchable MOF composed of Cu(TCNQ) (TCNQ 5 7,7,8,8-tetracyanoquinodimethane) transitions from a high-resistance state to a conducting state in a reversible fashion by an applied potential. The actual mechanism for this reversible electrical switching is still not understood even though a number of reports are available describing the application of electric-field-induced switching of Cu(TCNQ) in device fabrication.

  19. An Electrically Switchable Metal-Organic Framework

    SciTech Connect

    Fernandez, CA; Martin, PC; Schaef, T; Bowden, ME; Thallapally, PK; Dang, L; Xu, W; Chen, XL; McGrail, BP

    2014-08-19

    Crystalline metal organic framework (MOF) materials containing interconnected porosity can be chemically modified to promote stimulus-driven (light, magnetic or electric fields) structural transformations that can be used in a number of devices. Innovative research strategies are now focused on understanding the role of chemical bond manipulation to reversibly alter the free volume in such structures of critical importance for electro-catalysis, molecular electronics, energy storage technologies, sensor devices and smart membranes. In this letter, we study the mechanism for which an electrically switchable MOF composed of Cu(TCNQ) (TCNQ = 7,7,8,8-tetracyanoquinodimethane) transitions from a high-resistance state to a conducting state in a reversible fashion by an applied potential. The actual mechanism for this reversible electrical switching is still not understood even though a number of reports are available describing the application of electric-field-induced switching of Cu(TCNQ) in device fabrication.

  20. Metal-organic framework materials with ultrahigh surface areas

    SciTech Connect

    Farha, Omar K.; Hupp, Joseph T.; Wilmer, Christopher E.; Eryazici, Ibrahim; Snurr, Randall Q.; Gomez-Gualdron, Diego A.; Borah, Bhaskarjyoti

    2015-12-22

    A metal organic framework (MOF) material including a Brunauer-Emmett-Teller (BET) surface area greater than 7,010 m.sup.2/g. Also a metal organic framework (MOF) material including hexa-carboxylated linkers including alkyne bond. Also a metal organic framework (MOF) material including three types of cuboctahedron cages fused to provide continuous channels. Also a method of making a metal organic framework (MOF) material including saponifying hexaester precursors having alkyne bonds to form a plurality of hexa-carboxylated linkers including alkyne bonds and performing a solvothermal reaction with the plurality of hexa-carboxylated linkers and one or more metal containing compounds to form the MOF material.

  1. SOLVENT EXTRACTION OF RUTHENIUM

    DOEpatents

    Hyman, H.H.; Leader, G.R.

    1959-07-14

    The separation of rathenium from aqueous solutions by solvent extraction is described. According to the invention, a nitrite selected from the group consisting of alkali nitrite and alkaline earth nitrite in an equimolecular quantity with regard to the quantity of rathenium present is added to an aqueous solution containing ruthenium tetrantrate to form a ruthenium complex. Adding an organic solvent such as ethyl ether to the resulting mixture selectively extracts the rathenium complex.

  2. The alkali metals: 200 years of surprises.

    PubMed

    Dye, James L

    2015-03-13

    Alkali metal compounds have been known since antiquity. In 1807, Sir Humphry Davy surprised everyone by electrolytically preparing (and naming) potassium and sodium metals. In 1808, he noted their interaction with ammonia, which, 100 years later, was attributed to solvated electrons. After 1960, pulse radiolysis of nearly any solvent produced solvated electrons, which became one of the most studied species in chemistry. In 1968, alkali metal solutions in amines and ethers were shown to contain alkali metal anions in addition to solvated electrons. The advent of crown ethers and cryptands as complexants for alkali cations greatly enhanced alkali metal solubilities. This permitted us to prepare a crystalline salt of Na(-) in 1974, followed by 30 other alkalides with Na(-), K(-), Rb(-) and Cs(-) anions. This firmly established the -1 oxidation state of alkali metals. The synthesis of alkalides led to the crystallization of electrides, with trapped electrons as the anions. Electrides have a variety of electronic and magnetic properties, depending on the geometries and connectivities of the trapping sites. In 2009, the final surprise was the experimental demonstration that alkali metals under high pressure lose their metallic character as the electrons are localized in voids between the alkali cations to become high-pressure electrides! PMID:25666067

  3. Application of metal-organic frameworks for purification of vegetable oils.

    PubMed

    Vlasova, E A; Yakimov, S A; Naidenko, E V; Kudrik, E V; Makarov, S V

    2016-01-01

    Reported here is the synthesis of aluminum-, zinc- and titanium-containing metal-organic frameworks based on terephthalic acid and an investigation on the possibility of using these compounds as adsorbents for the purification of unrefined vegetable oils. It is found that aluminum-, zinc- and titanium-containing metal-organic frameworks improve the physicochemical properties of unrefined vegetable oils (more pleasant taste and odor) due to the binding of free fatty acids and peroxide compounds. It is established that the synthesized materials are more effective in these respects as compared with traditional adsorbents. An adsorption mechanism of free fatty acids and peroxides is proposed. Last but not least, the used MOF can be easily recycled at least five times, via solvent washing. PMID:26212947

  4. Metal-organic frameworks for oxygen storage.

    PubMed

    DeCoste, Jared B; Weston, Mitchell H; Fuller, Patrick E; Tovar, Trenton M; Peterson, Gregory W; LeVan, M Douglas; Farha, Omar K

    2014-12-15

    We present a systematic study of metal-organic frameworks (MOFs) for the storage of oxygen. The study starts with grand canonical Monte Carlo simulations on a suite of 10,000 MOFs for the adsorption of oxygen. From these data, the MOFs were down selected to the prime candidates of HKUST-1 (Cu-BTC) and NU-125, both with coordinatively unsaturated Cu sites. Oxygen isotherms up to 30 bar were measured at multiple temperatures to determine the isosteric heat of adsorption for oxygen on each MOF by fitting to a Toth isotherm model. High pressure (up to 140 bar) oxygen isotherms were measured for HKUST-1 and NU-125 to determine the working capacity of each MOF. Compared to the zeolite NaX and Norit activated carbon, NU-125 has an increased excess capacity for oxygen of 237% and 98%, respectively. These materials could ultimately prove useful for oxygen storage in medical, military, and aerospace applications. PMID:25319881

  5. Thermodynamics of metal-organic frameworks

    SciTech Connect

    Wu, Di; Navrotsky, Alexandra

    2015-03-15

    Although there have been extensive studies over the past decade in the synthesis and application of metal-organic frameworks (MOFs), investigation of their thermodynamic stability and of the energetics of guest–host interactions has been much more limited. This review summarizes recent progress in experimental (calorimetric) determination of the thermodynamics of MOF materials. The enthalpies of MOFs relative to dense phase assemblages suggest only modest metastability, with a general increase of enthalpy with increasing molar volume, which becomes less pronounced at higher porosity. The energy landscape of nanoporous materials (inorganic and hybrid) consists of a pair of parallel patterns within a fairly narrow range of metastability of 5–30 kJ per mole of tetrahedra in zeolites and mesoporous silicas or per mole of metal in MOFs. Thus strong thermodynamic instability does not seem to limit framework formation. There are strong interactions within the chemisorption range for small molecule–MOF interactions with defined chemical binding at the metal centers or other specific locations. Coexistence of surface binding and confinement can lead to much stronger guest–host interactions. - Graphical abstract: Energy landscape of inorganic and hybrid porous materials. - Highlights: • Thermochemical data on various MOF structures were experimentally determined. • MOFs are moderately unstable relative to their dense phase assemblage. • Overall energetic landscape of porous materials was revealed. • Guest–host interactions in MOFs were evaluated directly using calorimetry. • Confinement effect and defined chemical binding lead to strong interactions.

  6. Metal-Organic Heat Carrier Nanofluids

    SciTech Connect

    McGrail, B. Peter; Thallapally, Praveen K.; Blanchard, Jeremy; Nune, Satish K.; Jenks, Jeromy WJ; Dang, Liem X.

    2013-09-01

    Nanofluids, dispersions of metal or oxide nanoparticles in a base working fluid, are being intensively studied due to improvements they offer in thermal properties of the working fluid. However, these benefits have been erratically demonstrated and proven impacts on thermal conductivity are modest and well described from long-established effective medium theory. In this paper, we describe a new class of metal-organic heat carrier (MOHC) nanofluid that offers potential for a larger performance boost in thermal vapor-liquid compression cycles. MOHCs are nanophase porous coordination solids designed to reversibly uptake the working fluid molecules in which the MOHCs are suspended. Additional heat can be extracted in a heat exchanger or solar collector from the endothermic enthalpy of desorption, which is then released as the nanofluid transits through a power generating device such as a turboexpander. Calculations for an R123 MOHC nanofluid indicated potential for up to 15% increase in power output. Capillary tube experiments show that liquid-vapor transitions occur without nanoparticle deposition on the tube walls provided entrance Reynolds number exceeds approximately 100.

  7. Metal-Organic Framework Isomers with Diamondoid Networks Constructed of a Semi-Rigid Tetrahedral Linker

    SciTech Connect

    Tian, Jian; Motkuri, Radha K.; Thallapally, Praveen K.; McGrail, B. Peter

    2010-10-19

    Solvothermal assembly of a semi-rigid tetrahedral carboxylate ligand tetrakis[4-(carboxyphenyl)oxamethyl]methane acid (H4X) with Cd(II) ion in different solvent systems yields three novel metal-organic framework isomers (1-3) based on different secondary building units (SBUs). Although all three frameworks have the same dia (diamondoid) topology, complex 1 and 3 are chiral and complex 2 is achiral. One of the networks, 3 shows cross-linked three-fold interpenetration of the single dia net and exhibits permanent porosities, as confirmed by BET and selective CO2 adsorption.

  8. Alkali metal nitrate purification

    DOEpatents

    Fiorucci, Louis C.; Morgan, Michael J.

    1986-02-04

    A process is disclosed for removing contaminants from impure alkali metal nitrates containing them. The process comprises heating the impure alkali metal nitrates in solution form or molten form at a temperature and for a time sufficient to effect precipitation of solid impurities and separating the solid impurities from the resulting purified alkali metal nitrates. The resulting purified alkali metal nitrates in solution form may be heated to evaporate water therefrom to produce purified molten alkali metal nitrates suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of purified alkali metal nitrates.

  9. NMR relaxation and exchange in metal-organic frameworks for surface area screening

    SciTech Connect

    Chen, JJ; Mason, JA; Bloch, ED; Gygi, D; Long, JR; Reimer, JA

    2015-03-15

    We describe a robust screening technique that correlates the surface area of metal organic frameworks to the proton T-2 relaxation behavior of imbibed solvent at low field (13 MHz). In frameworks with small pore sizes (<1 nm) or strong solvent-framework interactions, diffusional exchange between the pore-confined and inter-particle solvent populations remains slow compared to the T-2 of the pore-confined solvent, allowing for a direct porosity analysis of the T-2 spectrum obtained from Laplace inversions. Increases in framework pore-size (>1 nm) lead to corresponding increases in the rate of solvent exchange, as confirmed by T-2 relaxation exchange (REXSY) experiments; increases in the pore size also increases the T-2 of the pore-confined solvent. The combination of these two effects results in comparable rates of relaxation and exchange, which precludes the direct analysis of Laplace inversions. Thus, two- and three-site kinetics models were applied to extract porosity from relaxation decays, thereby improving the utility of the porosity screening tool. (C) 2014 Elsevier Inc. All rights reserved.

  10. Hydrogen Storage in Metal-Organic Frameworks

    SciTech Connect

    Omar M. Yaghi

    2012-04-26

    Conventional storage of large amounts of hydrogen in its molecular form is difficult and expensive because it requires employing either extremely high pressure gas or very low temperature liquid. Because of the importance of hydrogen as a fuel, the DOE has set system targets for hydrogen storage of gravimetric (5.5 wt%) and volumetric (40 g L-1) densities to be achieved by 2015. Given that these are system goals, a practical material will need to have higher capacity when the weight of the tank and associated cooling or regeneration system is considered. The size and weight of these components will vary substantially depending on whether the material operates by a chemisorption or physisorption mechanism. In the latter case, metal-organic frameworks (MOFs) have recently been identified as promising adsorbents for hydrogen storage, although little data is available for their sorption behavior. This grant was focused on the study of MOFs with these specific objectives. (1) To examine the effects of functionalization, catenation, and variation of the metal oxide and organic linkers on the low-pressure hydrogen adsorption properties of MOFs. (2) To develop a strategy for producing MOFs with high surface area and porosity to reduce the dead space and increase the hydrogen storage capacity per unit volume. (3) To functionalize MOFs by post synthetic functionalization with metals to improve the adsorption enthalpy of hydrogen for the room temperature hydrogen storage. This effort demonstrated the importance of open metal sites to improve the adsorption enthalpy by the systematic study, and this is also the origin of the new strategy, which termed isoreticular functionalization and metalation. However, a large pore volume is still a prerequisite feature. Based on our principle to design highly porous MOFs, guest-free MOFs with ultrahigh porosity have been experimentally synthesized. MOF-210, whose BET surface area is 6240 m2 g-1 (the highest among porous solids), takes up

  11. Synthesis and structure of new carbohydrate metal-organic frameworks and inclusion complexes

    NASA Astrophysics Data System (ADS)

    Sha, Jing-Quan; Wu, Lian-He; Li, Shu-Xian; Yang, Xiao-Ning; Zhang, Yu; Zhang, Qian-Nan; Zhu, Pei-Pei

    2015-12-01

    Two new metal-organic framework compounds based on natural β-cyclodextrin molecules (β-CD) and alkali metals (Na+/K+) were synthesized and characterized by elemental analyses, IR, XPRD and 1HNMR. Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 possess the bowl-like pore and the "8" type double channels configuration. Due to the [blow + channel] double configuration, 5-Fluorouracil (5-FU) and Quercetin inclusion complexes of compound 1 are studied, and the results show that the two kinds of drug with different structure and size can be included into the compound at the same time, which is expected to become a new type of multi-functional green crystalline solid material.

  12. Milk-alkali syndrome

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/000332.htm Milk-alkali syndrome To use the sharing features on this page, please enable JavaScript. Milk-alkali syndrome is a condition in which there ...

  13. Connecting small ligands to generate large tubular metal-organic architectures

    SciTech Connect

    Goforth, Andrea M.; Su, Cheng-Yong; Hipp, Rachael; Macquart, Rene B.; Smith, Mark D.; Loye, Hans-Conrad zur . E-mail: zurloye@mail.chem.sc.edu

    2005-08-15

    The new metal-organic framework materials, ZnF(Am{sub 2}TAZ).solvents and ZnF(TAZ).solvents (Am{sub 2}TAZ=3,5-diamino-1,2,4-triazole, TAZ=1,2,4-triazole), have been synthesized solvothermally and structurally characterized by either Rietveld refinement from powder XRD data or by single crystal X-ray diffraction. The three-dimensional structures of the compounds display open-ended, tubular channels, which are constituted of covalently bonded hexanuclear metallamacrocycles (Zn{sub 6}F{sub 6}(ligand){sub 6}). The tubular channels are subsequently covalently joined into a honeycomb-like hexagonal array to generate the three-dimensional porous framework. In the case of ZnF(Am{sub 2}TAZ).solvents, hydrophilic -NH{sub 2} groups point into the channels, effectively reducing their inner diameter relative to ZnF(TAZ).solvents. The present compounds are isostructural to one another and to the previously reported ZnF(AmTAZ).solvents (AmTAZ=3-amino-1,2,4-triazole), illustrative of the fact that the internal size and chemical properties of the framework may be altered by modification of the small, heterocyclic ligand. In addition to demonstrating the ability to modify the basic framework, ZnF(TAZ).solvents and ZnF(Am{sub 2}TAZ).solvents are two of the most thermally stable coordination frameworks known to date. - Graphical abstract: Top view of the open-ended, honeycomb tubular architecture of ZnF(Am{sub 2}TAZ)

  14. Theoretical study on the adsorption of carbon dioxide on individual and alkali-metal doped MOF-5s

    NASA Astrophysics Data System (ADS)

    Ha, Nguyen Thi Thu; Lefedova, O. V.; Ha, Nguyen Ngoc

    2016-01-01

    Density functional theory (DFT) calculations were performed to investigate the adsorption of carbon dioxide (CO2) on metal-organic framework (MOF-5) and alkali-metal (Li, K, Na) doped MOF-5s. The adsorption energy calculation showed that metal atom adsorption is exothermic in MOF-5 system. Moreover, alkali-metal doping can significantly improve the adsorption ability of carbon dioxide on MOF-5. The best influence is observed for Li-doping.

  15. Selective fluorescence sensors for detection of nitroaniline and metal Ions based on ligand-based luminescent metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Yu, Zongchao; Wang, Fengqin; Lin, Xiangyi; Wang, Chengmiao; Fu, Yiyuan; Wang, Xiaojun; Zhao, Yongnan; Li, Guodong

    2015-12-01

    Metal-organic frameworks (MOFs) are porous crystalline materials with high potential for applications in fluorescence sensors. In this work, two solvent-induced Zn(II)-based metal-organic frameworks, Zn3L3(DMF)2 (1) and Zn3L3(DMA)2(H2O)3 (2) (L=4,4‧-stilbenedicarboxylic acid), were investigated as selective sensing materials for detection of nitroaromatic compounds and metal ions. The sensing experiments show that 1 and 2 both exhibit selective fluorescence quenching toward nitroaniline with a low detection limit. In addition, 1 exhibits high selectivity for detection of Fe3+ and Al3+ by significant fluorescence quenching or enhancement effect. While for 2, it only exhibits significant fluorescence quenching effect for Fe3+. The results indicate that 1 and 2 are both promising fluorescence sensors for detecting and recognizing nitroaniline and metal ions with high sensitivity and selectivity.

  16. Towards multifunctional lanthanide-based metal-organic frameworks.

    PubMed

    Tobin, Gerard; Comby, Steve; Zhu, Nianyong; Clérac, Rodolphe; Gunnlaugsson, Thorfinnur; Schmitt, Wolfgang

    2015-09-01

    We report the synthesis, structure and physicochemical attributes of a new holmium(III)-based metal-organic framework whose 3D network structure gives rise to porosity; the reported structure-type can be varied using a range of different lanthanide ions to tune the photophysical properties and produce ligand-sensitised near-infrared (NIR) and visible light emitters. PMID:26207535

  17. Omar Yaghi on Chemistry and Metal Organic Frameworks

    SciTech Connect

    Omar Yaghi

    2012-07-23

    In this edited version of the hour long talk, Omar Yaghi, director of the Molecular Foundry, sat down in conversation with Jeff Miller, head of Public Affairs, on July 11th, 2012 to discuss his fascination with the hidden world of chemistry and his work on Metal Organic Frameworks.

  18. Omar Yaghi on Chemistry and Metal Organic Frameworks

    ScienceCinema

    Omar Yaghi

    2013-06-24

    In this edited version of the hour long talk, Omar Yaghi, director of the Molecular Foundry, sat down in conversation with Jeff Miller, head of Public Affairs, on July 11th, 2012 to discuss his fascination with the hidden world of chemistry and his work on Metal Organic Frameworks.

  19. Metal-organic frameworks: Shuttling in the solid state

    NASA Astrophysics Data System (ADS)

    Olson, Mark A.

    2015-06-01

    Incorporating mechanically interlocked molecular shuttles within a metal-organic framework that has enough free space in the crystal lattice to permit volume-conserving translational motion sets the stage for defect-free molecular-electronic device fabrication and more.

  20. Metal-Organic Coordination Number Determined Charge Transfer Magnitude

    NASA Astrophysics Data System (ADS)

    Yang, Hung-Hsiang; Chu, Yu-Hsun; Lu, Chun-I.; Yang, Tsung-Han; Yang, Kai-Jheng; Kaun, Chao-Cheng; Hoffmann, Germar; Lin, Minn-Tsong

    2014-03-01

    By the appropriate choice of head groups and molecular ligands, various metal-organic coordination geometries can be engineered. Such metal-organic structures provide different chemical environments for molecules and give us templates to study the charge redistribution within the metal-organic interface. We created various metal-organic bonding environment by growing self-assembly nanostructures of Fe-PTCDA (3,4,9,10-perylene tetracarboxylic dianhydride) chains and networks on a Au(111) surface. Bonding environment dependent frontier molecular orbital energies are acquired by low temperature scanning tunneling microscopy and scanning tunneling spectroscopy. By comparing the frontier energies with the molecular coordination environments, we conclude that the specific coordination affects the magnitude of charge transfer onto each PTCDA in the Fe-PTCDA hybridization system. H.-H. Yang, Y.-H. Chu, C.-I Lu, T.-H. Yang, K.-J. Yang, C.-C. Kaun, G. Hoffmann, and M.-T. Lin, ACS Nano 7, 2814 (2013).

  1. Metal-organic frameworks: A thin film opening

    NASA Astrophysics Data System (ADS)

    Sumby, Christopher J.

    2016-04-01

    The properties of metal-organic frameworks -- promising for a myriad of applications -- can be commonly tuned by judicious choice of the building blocks used to prepare the material. Now, simply downsizing a rigid, non-porous MOF to a thin film has been shown to endow it with dynamic, gate-opening-type guest uptake behaviour.

  2. Electrochemically addressable trisradical rotaxanes organized within a metal-organic framework.

    PubMed

    McGonigal, Paul R; Deria, Pravas; Hod, Idan; Moghadam, Peyman Z; Avestro, Alyssa-Jennifer; Horwitz, Noah E; Gibbs-Hall, Ian C; Blackburn, Anthea K; Chen, Dongyang; Botros, Youssry Y; Wasielewski, Michael R; Snurr, Randall Q; Hupp, Joseph T; Farha, Omar K; Stoddart, J Fraser

    2015-09-01

    The organization of trisradical rotaxanes within the channels of a Zr6-based metal-organic framework (NU-1000) has been achieved postsynthetically by solvent-assisted ligand incorporation. Robust Zr(IV)-carboxylate bonds are forged between the Zr clusters of NU-1000 and carboxylic acid groups of rotaxane precursors (semirotaxanes) as part of this building block replacement strategy. Ultraviolet-visible-near-infrared (UV-Vis-NIR), electron paramagnetic resonance (EPR), and 1H nuclear magnetic resonance (NMR) spectroscopies all confirm the capture of redox-active rotaxanes within the mesoscale hexagonal channels of NU-1000. Cyclic voltammetry measurements performed on electroactive thin films of the resulting material indicate that redox-active viologen subunits located on the rotaxane components can be accessed electrochemically in the solid state. In contradistinction to previous methods, this strategy for the incorporation of mechanically interlocked molecules within porous materials circumvents the need for de novo synthesis of a metal-organic framework, making it a particularly convenient approach for the design and creation of solid-state molecular switches and machines. The results presented here provide proof-of-concept for the application of postsynthetic transformations in the integration of dynamic molecular machines with robust porous frameworks. PMID:26283386

  3. A novel hybrid metal-organic framework-polymeric monolith for solid-phase microextraction.

    PubMed

    Lin, Chen-Lan; Lirio, Stephen; Chen, Ya-Ting; Lin, Chia-Her; Huang, Hsi-Ya

    2014-03-17

    This study describes the fabrication of a novel hybrid metal-organic framework- organic polymer (MOF-polymer) for use as a stationary phase in fritless solid-phase microextraction (SPME) for validating analytical methods. The MOF-polymer was prepared by using ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and an imidazolium-based ionic liquid as porogenic solvent followed by microwave-assisted polymerization with the addition of 25 % MOF. This novel hybrid MOF-polymer was used to extract penicillin (penicillin G, penicillin V, oxacillin, cloxacillin, nafcillin, dicloxacillin) under different conditions. Quantitative analysis of the extracted penicillin samples using the MOF-organic polymer for SPME was conducted by using capillary electrochromatography (CEC) coupled with UV analysis. The penicillin recovery was 63-96.2 % with high reproducibility, sensitivity, and reusability. The extraction time with the proposed fabricated SPME was only 34 min. PMID:24615770

  4. Synthetic Methodology for the Fabrication of Porous Porphyrin Materials with Metal-Organic-Polymer Aerogels.

    PubMed

    Zhao, Xin; Yuan, Lin; Zhang, Zeng-Qi; Wang, Yong-Song; Yu, Qiong; Li, Jun

    2016-06-01

    A promising fabrication strategy used for designing porous porphyrin materials and a group of rigid carboxyl porphyrins based metal-organic-polymer aerogels (MOPAs) has been proposed recently. These newly synthesized MOPAs were exemplarily characterized by FT-IR, UV-vis-DRS, EDS, PXRD, TGA, SEM, TEM, and gas sorption measurements. A gelation study has shown that solvents, molar ratio, temperature, and peripheral carboxyl number in porphyrins all affect gel generation. The MOPA series exhibit eminent thermal stability, high removal efficiency in dye adsorption, versatile morphologies, and permanent tunable porosity; also the BET surface areas fall within the range 249-779 m(2) g(-1). All of the mentioned properties are significantly superior to some other porous materials, which enable these compounds to be potential candidates for dye uptake, gas storage, and separation. PMID:27159626

  5. CFA-7: an interpenetrated metal-organic framework of the MFU-4 family.

    PubMed

    Schmieder, Phillip; Grzywa, Maciej; Denysenko, Dmytro; Hambach, Manuel; Volkmer, Dirk

    2015-08-01

    The novel interpenetrated metal-organic framework CFA-7 (Coordination Framework Augsburg University-7), [Zn5Cl4(tqpt)3], has been synthesized containing the organic linker {H2-tqpt = 6,6,14,14-tetramethyl-6,14-dihydroquinoxalino[2,3-b]phenazinebistriazole}. Reaction of H2-tqpt and anhydrous ZnCl2 in N,N-dimethylformamide (DMF) yields CFA-7 as pseudo-cubic crystals. CFA-7 serves as precursor for the synthesis of isostructural frameworks with redox-active metal centers, which is demonstrated by postsynthetic metal exchange of Zn(2+) by different M(2+) (M = Co, Ni, Cu) ions. The novel framework is robust upon solvent removal and has been structurally characterized by single-crystal X-ray diffraction, TGA and IR spectroscopy, as well as gas sorption (Ar, CO2 and H2). PMID:26103597

  6. Lithium inclusion in indium metal-organic frameworks showing increased surface area and hydrogen adsorption

    SciTech Connect

    Bosch, Mathieu; Zhang, Muwei; Feng, Dawei; Yuan, Shuai; Wang, Xuan; Chen, Ying-Pin; Zhou, Hong-Cai

    2014-12-01

    Investigation of counterion exchange in two anionic In-Metal-Organic Frameworks (In-MOFs) showed that partial replacement of disordered ammonium cations was achieved through the pre-synthetic addition of LiOH to the reaction mixture. This resulted in a surface area increase of over 1600% in (Li [In(1,3 − BDC){sub 2}]){sub n} and enhancement of the H{sub 2} uptake of approximately 275% at 80 000 Pa at 77 K. This method resulted in frameworks with permanent lithium content after repeated solvent exchange as confirmed by inductively coupled plasma mass spectrometry. Lithium counterion replacement appears to increase porosity after activation through replacement of bulkier, softer counterions and demonstrates tuning of pore size and properties in MOFs.

  7. A multifunctional metal-organic framework based tumor targeting drug delivery system for cancer therapy

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Gang; Dong, Zhi-Yue; Cheng, Hong; Wan, Shuang-Shuang; Chen, Wei-Hai; Zou, Mei-Zhen; Huo, Jia-Wei; Deng, He-Xiang; Zhang, Xian-Zheng

    2015-09-01

    Drug delivery systems (DDSs) with biocompatibility and precise drug delivery are eagerly needed to overcome the paradox in chemotherapy that high drug doses are required to compensate for the poor biodistribution of drugs with frequent dose-related side effects. In this work, we reported a metal-organic framework (MOF) based tumor targeting DDS developed by a one-pot, and organic solvent-free ``green'' post-synthetic surface modification procedure, starting from the nanoscale MOF MIL-101. Owing to the multifunctional surface coating, premature drug release from this DDS was prevented. Due to the pH responsive benzoic imine bond and the redox responsive disulfide bond at the modified surface, this DDS exhibited tumor acid environment enhanced cellular uptake and intracellular reducing environment triggered drug release. In vitro and in vivo results showed that DOX loaded into this DDS exhibited effective cancer cell inhibition with much reduced side effects.Drug delivery systems (DDSs) with biocompatibility and precise drug delivery are eagerly needed to overcome the paradox in chemotherapy that high drug doses are required to compensate for the poor biodistribution of drugs with frequent dose-related side effects. In this work, we reported a metal-organic framework (MOF) based tumor targeting DDS developed by a one-pot, and organic solvent-free ``green'' post-synthetic surface modification procedure, starting from the nanoscale MOF MIL-101. Owing to the multifunctional surface coating, premature drug release from this DDS was prevented. Due to the pH responsive benzoic imine bond and the redox responsive disulfide bond at the modified surface, this DDS exhibited tumor acid environment enhanced cellular uptake and intracellular reducing environment triggered drug release. In vitro and in vivo results showed that DOX loaded into this DDS exhibited effective cancer cell inhibition with much reduced side effects. Electronic supplementary information (ESI) available

  8. Alkylated lariat ethers as solvent extraction reagents: Surveying the extraction of alkali metals by bis-t-octylbenzo-14-crown-4-acetic acid by use of potentiometric two-phase titration

    SciTech Connect

    Sachleben, R.A.; Moyer, B.A.; Case, F.I.; Garmon, S.A.

    1993-01-01

    Two-phase potentiometric titrimetry was used to survey the extraction of alkali metal cations from aqueous chloride solution by the lipophilic, ionizable lariat ether bis-(t-octylbenzo)-14-crown-4-acetic acid (BOB14C4AA) in o-xylene. Analysis of the data indicates that ion-exchange extraction by the crown-carboxylic acid at low loading (i.e., low conversion of BOB14C4AA to its salt form) is stronger for lithium ion than for the other alkali metals. Little or no selectivity occurs at high loadings. In comparison with the long-chain carboxylic acid 2-methyl-2-heptylnonanoic acid (HMHN), BOB14C4AA extracts lithium and sodium at significantly lower pH; in the loading range of 0.1 to 0.7, the pH shift is 1.4-1.8 pH units for sodium ion and 1.7-2.3 pH units for lithium ion. The titration data are interpreted in terms of aggregated organic-phase species. In the case of lithium extraction, clear evidence was found for a species in which neutral BOB14C4AA participates in the organic-phase complexation of the metal cation.

  9. Increased Thermal Conductivity in Metal-Organic Heat Carrier Nanofluids

    NASA Astrophysics Data System (ADS)

    Nandasiri, Manjula I.; Liu, Jian; McGrail, B. Peter; Jenks, Jeromy; Schaef, Herbert T.; Shutthanandan, Vaithiyalingam; Nie, Zimin; Martin, Paul F.; Nune, Satish K.

    2016-06-01

    Metal-organic heat carriers (MOHCs) are recently developed nanofluids containing metal-organic framework (MOF) nanoparticles dispersed in various base fluids including refrigerants (R245Fa) and methanol. Here, we report the synthesis and characterization of MOHCs containing nanoMIL-101(Cr) and graphene oxide (GO) in an effort to improve the thermo-physical properties of various base fluids. MOHC/GO nanocomposites showed enhanced surface area, porosity, and nitrogen adsorption compared with the intrinsic nanoMIL-101(Cr) and the properties depended on the amount of GO added. MIL-101(Cr)/GO in methanol exhibited a significant increase in the thermal conductivity (by approximately 50%) relative to that of the intrinsic nanoMIL-101(Cr) in methanol. The thermal conductivity of the base fluid (methanol) was increased by about 20%. The increase in the thermal conductivity of nanoMIL-101(Cr) MOHCs due to GO functionalization is explained using a classical Maxwell model.

  10. Intrinsic electrical conductivity of nanostructured metal-organic polymer chains

    PubMed Central

    Hermosa, Cristina; Vicente Álvarez, Jose; Azani, Mohammad-Reza; Gómez-García, Carlos J.; Fritz, Michelle; Soler, Jose M.; Gómez-Herrero, Julio; Gómez-Navarro, Cristina; Zamora, Félix

    2013-01-01

    One-dimensional conductive polymers are attractive materials because of their potential in flexible and transparent electronics. Despite years of research, on the macro- and nano-scale, structural disorder represents the major hurdle in achieving high conductivities. Here we report measurements of highly ordered metal-organic nanoribbons, whose intrinsic (defect-free) conductivity is found to be 104 S m−1, three orders of magnitude higher than that of our macroscopic crystals. This magnitude is preserved for distances as large as 300 nm. Above this length, the presence of structural defects (~ 0.5%) gives rise to an inter-fibre-mediated charge transport similar to that of macroscopic crystals. We provide the first direct experimental evidence of the gapless electronic structure predicted for these compounds. Our results postulate metal-organic molecular wires as good metallic interconnectors in nanodevices. PMID:23591876

  11. Increased Thermal Conductivity in Metal-Organic Heat Carrier Nanofluids.

    PubMed

    Nandasiri, Manjula I; Liu, Jian; McGrail, B Peter; Jenks, Jeromy; Schaef, Herbert T; Shutthanandan, Vaithiyalingam; Nie, Zimin; Martin, Paul F; Nune, Satish K

    2016-01-01

    Metal-organic heat carriers (MOHCs) are recently developed nanofluids containing metal-organic framework (MOF) nanoparticles dispersed in various base fluids including refrigerants (R245Fa) and methanol. Here, we report the synthesis and characterization of MOHCs containing nanoMIL-101(Cr) and graphene oxide (GO) in an effort to improve the thermo-physical properties of various base fluids. MOHC/GO nanocomposites showed enhanced surface area, porosity, and nitrogen adsorption compared with the intrinsic nanoMIL-101(Cr) and the properties depended on the amount of GO added. MIL-101(Cr)/GO in methanol exhibited a significant increase in the thermal conductivity (by approximately 50%) relative to that of the intrinsic nanoMIL-101(Cr) in methanol. The thermal conductivity of the base fluid (methanol) was increased by about 20%. The increase in the thermal conductivity of nanoMIL-101(Cr) MOHCs due to GO functionalization is explained using a classical Maxwell model. PMID:27302196

  12. A metal-organic framework-derived bifunctional oxygen electrocatalyst

    NASA Astrophysics Data System (ADS)

    Xia, Bao Yu; Yan, Ya; Li, Nan; Wu, Hao Bin; Lou, Xiong Wen (David); Wang, Xin

    2016-01-01

    Oxygen electrocatalysis is of great importance for many energy storage and conversion technologies, including fuel cells, metal-air batteries and water electrolysis. Replacing noble metal-based electrocatalysts with highly efficient and inexpensive non-noble metal-based oxygen electrocatalysts is critical for the practical applications of these technologies. Here we report a general approach for the synthesis of hollow frameworks of nitrogen-doped carbon nanotubes derived from metal-organic frameworks, which exhibit higher electrocatalytic activity and stability for oxygen reduction and evolution than commercial Pt/C electrocatalysts. The remarkable electrochemical properties are mainly attributed to the synergistic effect from chemical compositions and the robust hollow structure composed of interconnected crystalline nitrogen-doped carbon nanotubes. The presented strategy for controlled design and synthesis of metal-organic framework-derived functional nanomaterials offers prospects in developing highly active electrocatalysts in electrochemical energy devices.

  13. Increased Thermal Conductivity in Metal-Organic Heat Carrier Nanofluids

    PubMed Central

    Nandasiri, Manjula I.; Liu, Jian; McGrail, B. Peter; Jenks, Jeromy; Schaef, Herbert T.; Shutthanandan, Vaithiyalingam; Nie, Zimin; Martin, Paul F.; Nune, Satish K.

    2016-01-01

    Metal-organic heat carriers (MOHCs) are recently developed nanofluids containing metal-organic framework (MOF) nanoparticles dispersed in various base fluids including refrigerants (R245Fa) and methanol. Here, we report the synthesis and characterization of MOHCs containing nanoMIL-101(Cr) and graphene oxide (GO) in an effort to improve the thermo-physical properties of various base fluids. MOHC/GO nanocomposites showed enhanced surface area, porosity, and nitrogen adsorption compared with the intrinsic nanoMIL-101(Cr) and the properties depended on the amount of GO added. MIL-101(Cr)/GO in methanol exhibited a significant increase in the thermal conductivity (by approximately 50%) relative to that of the intrinsic nanoMIL-101(Cr) in methanol. The thermal conductivity of the base fluid (methanol) was increased by about 20%. The increase in the thermal conductivity of nanoMIL-101(Cr) MOHCs due to GO functionalization is explained using a classical Maxwell model. PMID:27302196

  14. A dense metal-organic framework for enhanced magnetic refrigeration.

    PubMed

    Lorusso, Giulia; Sharples, Joseph W; Palacios, Elias; Roubeau, Olivier; Brechin, Euan K; Sessoli, Roberta; Rossin, Andrea; Tuna, Floriana; McInnes, Eric J L; Collison, David; Evangelisti, Marco

    2013-09-01

    The three-dimensional metal-organic framework Gd(HCOO)3 is characterized by a relatively compact crystal lattice of weakly interacting Gd(3+) spin centers interconnected via lightweight formate ligands, overall providing a remarkably large magnetic:non-magnetic elemental weight ratio. The resulting magnetocaloric effect per unit volume is decidedly superior in Gd(HCOO)3 than in the best known magnetic refrigerant materials for liquid-helium temperatures and low-moderate applied fields. PMID:23813875

  15. Perspective: Metal-organic frameworks—Opportunities and challenges

    NASA Astrophysics Data System (ADS)

    Rosseinsky, M. J.

    2014-12-01

    The interplay of metal-ligand coordination chemistry with the diverse organic chemistry of the molecular linkers in metal-organic frameworks offers exciting new directions not only in the important area of porous materials, but more generally as a route to control of function by the integration of organic and inorganic components. This makes the current APL Materials issue particularly timely. This Perspective summarises some important aspects of the current state of play.

  16. Polyoxometalate Cluster-Incorporated Metal-Organic Framework Hierarchical Nanotubes.

    PubMed

    Xu, Xiaobin; Chen, Shuangming; Chen, Yifeng; Sun, Hongyu; Song, Li; He, Wei; Wang, Xun

    2016-06-01

    A simple method to prepare metal-organic framework (MOF) nanotubes is developed by employing polyoxometalates (POMs) as modulators. The local structure of the MOF nanotubes is investigated combining XANES and EXAFS studies. These nanotubes show both an excellent catalytic performance in the detoxification of sulfur compounds in O2 atmosphere and a remarkable cycling stability as the anode material for lithium-ion batteries. PMID:27101564

  17. Evaluating metal-organic frameworks for natural gas storage

    SciTech Connect

    Mason, JA; Veenstra, M; Long, JR

    2014-01-01

    Metal-organic frameworks have received significant attention as a new class of adsorbents for natural gas storage; however, inconsistencies in reporting high-pressure adsorption data and a lack of comparative studies have made it challenging to evaluate both new and existing materials. Here, we briefly discuss high-pressure adsorption measurements and review efforts to develop metal-organic frameworks with high methane storage capacities. To illustrate the most important properties for evaluating adsorbents for natural gas storage and for designing a next generation of improved materials, six metal-organic frameworks and an activated carbon, with a range of surface areas, pore structures, and surface chemistries representative of the most promising adsorbents for methane storage, are evaluated in detail. High-pressure methane adsorption isotherms are used to compare gravimetric and volumetric capacities, isosteric heats of adsorption, and usable storage capacities. Additionally, the relative importance of increasing volumetric capacity, rather than gravimetric capacity, for extending the driving range of natural gas vehicles is highlighted. Other important systems-level factors, such as thermal management, mechanical properties, and the effects of impurities, are also considered, and potential materials synthesis contributions to improving performance in a complete adsorbed natural gas system are discussed.

  18. Alkali metal ionization detector

    DOEpatents

    Bauerle, James E.; Reed, William H.; Berkey, Edgar

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.

  19. High-internal-phase emulsions stabilized by metal-organic frameworks and derivation of ultralight metal-organic aerogels

    NASA Astrophysics Data System (ADS)

    Zhang, Bingxing; Zhang, Jianling; Liu, Chengcheng; Peng, Li; Sang, Xinxin; Han, Buxing; Ma, Xue; Luo, Tian; Tan, Xiuniang; Yang, Guanying

    2016-02-01

    To design high-internal-phase emulsion (HIPE) systems is of great interest from the viewpoints of both fundamental researches and practical applications. Here we demonstrate for the first time the utilization of metal-organic framework (MOF) for HIPE formation. By stirring the mixture of water, oil and MOF at room temperature, the HIPE stabilized by the assembly of MOF nanocrystals at oil-water interface could be formed. The MOF-stabilized HIPE provides a novel route to produce highly porous metal-organic aerogel (MOA) monolith. After removing the liquids from the MOF-stabilized HIPE, the ultralight MOA with density as low as 0.01 g·cm-3 was obtained. The HIPE approach for MOA formation has unique advantages and is versatile in producing different kinds of ultralight MOAs with tunable porosities and structures.

  20. High-internal-phase emulsions stabilized by metal-organic frameworks and derivation of ultralight metal-organic aerogels

    PubMed Central

    Zhang, Bingxing; Zhang, Jianling; Liu, Chengcheng; Peng, Li; Sang, Xinxin; Han, Buxing; Ma, Xue; Luo, Tian; Tan, Xiuniang; Yang, Guanying

    2016-01-01

    To design high-internal-phase emulsion (HIPE) systems is of great interest from the viewpoints of both fundamental researches and practical applications. Here we demonstrate for the first time the utilization of metal-organic framework (MOF) for HIPE formation. By stirring the mixture of water, oil and MOF at room temperature, the HIPE stabilized by the assembly of MOF nanocrystals at oil-water interface could be formed. The MOF-stabilized HIPE provides a novel route to produce highly porous metal-organic aerogel (MOA) monolith. After removing the liquids from the MOF-stabilized HIPE, the ultralight MOA with density as low as 0.01 g·cm−3 was obtained. The HIPE approach for MOA formation has unique advantages and is versatile in producing different kinds of ultralight MOAs with tunable porosities and structures. PMID:26892258

  1. High-internal-phase emulsions stabilized by metal-organic frameworks and derivation of ultralight metal-organic aerogels.

    PubMed

    Zhang, Bingxing; Zhang, Jianling; Liu, Chengcheng; Peng, Li; Sang, Xinxin; Han, Buxing; Ma, Xue; Luo, Tian; Tan, Xiuniang; Yang, Guanying

    2016-01-01

    To design high-internal-phase emulsion (HIPE) systems is of great interest from the viewpoints of both fundamental researches and practical applications. Here we demonstrate for the first time the utilization of metal-organic framework (MOF) for HIPE formation. By stirring the mixture of water, oil and MOF at room temperature, the HIPE stabilized by the assembly of MOF nanocrystals at oil-water interface could be formed. The MOF-stabilized HIPE provides a novel route to produce highly porous metal-organic aerogel (MOA) monolith. After removing the liquids from the MOF-stabilized HIPE, the ultralight MOA with density as low as 0.01 g·cm(-3) was obtained. The HIPE approach for MOA formation has unique advantages and is versatile in producing different kinds of ultralight MOAs with tunable porosities and structures. PMID:26892258

  2. Capillary electrochromatographic fast enantioseparation based on a chiral metal-organic framework.

    PubMed

    Fei, Zhi-Xin; Zhang, Mei; Xie, Sheng-Ming; Yuan, Li-Ming

    2014-12-01

    Metal-organic frameworks (MOFs) have received great attention because of their unusual properties and fascinating structures in separation sciences. However, to the best of our knowledge, there has been no attempt to utilize chiral MOFs as stationary phases in packed-CEC. Here, a chiral MOF [In3 O(obb)3 (HCO2 )(H2 O)]·solvent (4,4'-oxybisbenzoic acid) was explored as the chiral stationary phase in packed-CEC for separation of chiral compounds and isomers. The fabricated [In3 O(obb)3 (HCO2 )(H2 O)]·solvent packed capillary columns gave fast enantioseparation of (±)-hydrobenzoin, (±)-1-phenyl-1,2-ethanediol, and clenbuterol within 3 min in CEC. Besides, the baseline separations of nitrophenol isomers within 6 min were also achieved. The RSDs for the retention time of run-to-run, day-to-day, and column-to-column reproducibility were 1.51-3.63, 1.83-3.98, and 3.42-5.66%, respectively. These results demonstrate that chiral MOFs are promising for enantioseparation in CEC. PMID:25223618

  3. Isoreticular metal-organic frameworks, process for forming the same, and systematic design of pore size and functionality therein, with application for gas storage

    DOEpatents

    Yaghi, Omar M.; Eddaoudi, Mohamed; Li, Hailian; Kim, Jaheon; Rosi, Nathaniel

    2005-08-16

    An isoreticular metal-organic framework (IRMOF) and method for systematically forming the same. The method comprises the steps of dissolving at least one source of metal cations and at least one organic linking compound in a solvent to form a solution; and crystallizing the solution under predetermined conditions to form a predetermined IRMOF. At least one of functionality, dimension, pore size and free volume of the IRMOF is substantially determined by the organic linking compound.

  4. A Water-Stable Metal-Organic Framework with a Double-Helical Structure for Fluorescent Sensing.

    PubMed

    Liu, Xiao-Jing; Zhang, Ying-Hui; Chang, Ze; Li, Ai-Lin; Tian, Dan; Yao, Zhao-Quan; Jia, Yan-Yuan; Bu, Xian-He

    2016-08-01

    Water instability is a crucial limiting factor in the practical application of most fluorescent metal-organic frameworks (MOFs). Here, by introducing a fascinating double-helical structure generated through dense stacking of organic ligands, a water-stable fluorescence MOF has been synthesized, namely, [Cd2(tib)2(bda)2]·(solvent)n (1) [tib =1,3,5-tris(1-imidazolyl) benzene; H2bda = 2,2'-biphenyl dicarboxylic acid]. This helical structure helps to enhance the stability of 1 against common organic solvents and water, even acid/base aqueous solutions with a pH value ranging from 3 to 11. Furthermore, this material can be a potential fluorescent sensor for ketones. PMID:27409244

  5. Catalytic hydrothermal conversion of carboxymethyl cellulose to value-added chemicals over metal-organic framework MIL-53(Al).

    PubMed

    Zi, Guoli; Yan, Zhiying; Wang, Yangxia; Chen, Yongjuan; Guo, Yunlong; Yuan, Fagui; Gao, Wenyu; Wang, Yanmei; Wang, Jiaqiang

    2015-01-22

    Catalytic hydrolysis of biomass over solid catalysts can be one of the most efficient pathways for a future sustainable society dependent on cellulose biomass. In this work metal-organic framework MIL-53(Al) without any functionalization was directly employed as an efficient heterogeneous catalyst for the hydrolysis of carboxymethyl cellulose (CMC) to 5-hydroxymethyl-furaldehyde (5-HMF) in aqueous phase. A 5-HMF molar yield of 40.3% and total reducing sugar (TRS) molar yield of 54.2% were obtained with water as single solvent at 473 K for 4 h. The catalyst could be reused three times without losing activity to a greater extent. With the remarkable advantages such as the use of water as single solvent and MIL-53(Al) as a novel heterogeneous green catalyst, the work provides a new platform for the production of value added chemicals and liquid fuels from biomass. PMID:25439879

  6. Pillared metal organic frameworks for the luminescence sensing of small molecules and metal ions in aqueous solutions.

    PubMed

    Liu, Fu-Hong; Qin, Chao; Ding, Yan; Wu, Han; Shao, Kui-Zhan; Su, Zhong-Min

    2015-01-28

    Two novel pillared MOFs (metal organic frameworks) [Zn2(trz)2(tda)]·DMA CH3OH (1) and [Zn2(trz)2(bpdc)]·DMA (2) were obtained under solvothermal conditions. The resulting MOFs show similar structures but with different interlayer distances based on the different carboxylate ligands. 1 and 2 display a certain degree of framework stability in both acid/base solutions and water. The luminescence intensities of the activated phases 1a and 2a are sensitive to metal ions, particularly Fe(3+) and Cd(2+) ions. Furthermore, the luminescent properties of 1a and 2a well dispersed in different solvents have also been investigated systematically, which demonstrate distinct solvent-dependent luminescent spectra with emission intensities that are significantly quenched by acetone, nitrobenzene and trinitrotoluene. PMID:25470577

  7. Metal-Organic Frameworks as Platforms for Functional Materials.

    PubMed

    Cui, Yuanjing; Li, Bin; He, Huajun; Zhou, Wei; Chen, Banglin; Qian, Guodong

    2016-03-15

    Discoveries of novel functional materials have played very important roles to the development of science and technologies and thus to benefit our daily life. Among the diverse materials, metal-organic framework (MOF) materials are rapidly emerging as a unique type of porous and organic/inorganic hybrid materials which can be simply self-assembled from their corresponding inorganic metal ions/clusters with organic linkers, and can be straightforwardly characterized by various analytical methods. In terms of porosity, they are superior to other well-known porous materials such as zeolites and carbon materials; exhibiting extremely high porosity with surface area up to 7000 m(2)/g, tunable pore sizes, and metrics through the interplay of both organic and inorganic components with the pore sizes ranging from 3 to 100 Å, and lowest framework density down to 0.13 g/cm(3). Such unique features have enabled metal-organic frameworks to exhibit great potentials for a broad range of applications in gas storage, gas separations, enantioselective separations, heterogeneous catalysis, chemical sensing and drug delivery. On the other hand, metal-organic frameworks can be also considered as organic/inorganic self-assembled hybrid materials, we can take advantages of the physical and chemical properties of both organic and inorganic components to develop their functional optical, photonic, and magnetic materials. Furthermore, the pores within MOFs can also be utilized to encapsulate a large number of different species of diverse functions, so a variety of functional MOF/composite materials can be readily synthesized. In this Account, we describe our recent research progress on pore and function engineering to develop functional MOF materials. We have been able to tune and optimize pore spaces, immobilize specific functional groups, and introduce chiral pore environments to target MOF materials for methane storage, light hydrocarbon separations, enantioselective recognitions

  8. Hydrogen adsorption in an interpenetrated dynamic metal-organic framework.

    PubMed

    Chen, Banglin; Ma, Shengqian; Zapata, Fatima; Lobkovsky, Emil B; Yang, Jun

    2006-07-24

    A metal-organic framework Zn(NDC)(4,4'-Bpe)(0.5).xG [NDC = 2,6-naphthalenedicarboxylate; 4,4'-Bpe = 4,4'-trans-bis(4-pyridyl)ethylene; G = guest molecules] has been synthesized, structurally characterized, and rationalized to be a two-interpenetrated elongated primitive cubic net. Powder X-ray diffraction and adsorption studies reveal the dynamic feature of the framework, which can take up hydrogen of about 2.0 wt % at 77 K and 40 bar and 0.3 wt % at 298 K and 65 bar. PMID:16841969

  9. Selective gas sorption within a dynamic metal-organic framework.

    PubMed

    Chen, Banglin; Ma, Shengqian; Hurtado, Eric J; Lobkovsky, Emil B; Liang, Chengdu; Zhu, Haoguo; Dai, Sheng

    2007-10-15

    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. PMID:17880212

  10. Ultrafine Metal-Organic Right Square Prism Shaped Nanowires.

    PubMed

    Otake, Ken-Ichi; Otsubo, Kazuya; Sugimoto, Kunihisa; Fujiwara, Akihiko; Kitagawa, Hiroshi

    2016-05-23

    We report the structural design and control of electronic states of a new series of ultrafine metal-organic right square prism-shaped nanowires. These nanowires have a very small inner diameter of about 2.0 Å, which is larger than hydrogen and similar to xenon atomic diameters. The electronic states of nanowires can be widely controlled by substitution of structural components. Moreover, the platinum homometallic nanowire shows a 100 times higher proton conductivity than a palladium/platinum heterometallic one depending on the electronic states. PMID:27080935

  11. Metal-Organic Frameworks for Highly Selective Separations

    SciTech Connect

    Omar M. Yaghi

    2009-09-28

    This grant was focused on the study of metal-organic frameworks with these specific objectives. (1) To examine the use of MOFs with well-defined open metal sites for binding of gases and small organics. (2) To develop a strategy for producing MOFs that combine large pore size with high surface area for their use in gas adsorption and separation of polycyclic organic compounds. (3) To functionalize MOFs for the storage of inert gases such as methane. A brief outline of our progress towards these objectives is presented here as it forms part of the basis for the ideas to be developed under the present proposal.

  12. Catenation of Homochiral Metal-Organic Nanocages or Nanotubes.

    PubMed

    Wu, Xin; Xu, Zhong-Xuan; Wang, Fei; Zhang, Jian

    2016-06-01

    Catenation based on homochiral metal-organic nanocages or nanotubes is realized in this work for the first time. A flexible enantiopure ligand is employed to assemble metal ions, with the structure-directing effect of an auxiliary ligand, a triangular-prism-like nanocage, and a nanotube successfully built. Further 0D → 3D catenation is achieved by interlocking the nanocages, and 1D → 3D catenation based on nanotubes is also presented. This work reveals extraordinary catenating architectures from molecular cages and tubes. PMID:27158986

  13. The surface chemistry of metal-organic frameworks.

    PubMed

    McGuire, Christina V; Forgan, Ross S

    2015-03-28

    Metal-organic frameworks (MOFs) have received particular attention over the last 20 years as a result of their attractive properties offering potential applications in a number of areas. Typically, these characteristics are tuned by functionalisation of the bulk of the MOF material itself. This Feature Article focuses instead on modification of MOF particles at their surfaces only, which can also offer control over the bulk properties of the material. The differing surface modification techniques available to the synthetic chemist will be discussed, with a focus on the effect of surface modification of MOFs on their fundamental properties and application in adsorption, catalysis, drug delivery and other areas. PMID:25116412

  14. Apparatus enables accurate determination of alkali oxides in alkali metals

    NASA Technical Reports Server (NTRS)

    Dupraw, W. A.; Gahn, R. F.; Graab, J. W.; Maple, W. E.; Rosenblum, L.

    1966-01-01

    Evacuated apparatus determines the alkali oxide content of an alkali metal by separating the metal from the oxide by amalgamation with mercury. The apparatus prevents oxygen and moisture from inadvertently entering the system during the sampling and analytical procedure.

  15. Negative electrodes for non-aqueous secondary batteries composed on conjugated polymer and alkali metal alloying or inserting material

    SciTech Connect

    Shacklette, L.W.; Jow, T.R.; Toth, E.; Maxfield, M.

    1987-05-26

    A battery is described comprising: an anode comprising as the anode active materials one or more conjugated backbone polymers and one or more electroactive materials selected from the group consisting of metals which alloy with alkali metals and alkali metal cation inserting materials; an electrolyte comprising an organic solvent and an alkali-metal salt, and a cathode. The alkali-metal cations from the electrolyte are inserted into the anode as a metal alloy or as an inserted ion in the alkali metal cation inserting material during the charging of the battery.

  16. Alkalis and Skin.

    PubMed

    Greenwood, John E; Tan, Jin Lin; Ming, Justin Choong Tzen; Abell, Andrew D

    2016-01-01

    The aim of this editorial is to provide an overview of the chemical interactions occurring in the skin of our patients on contact with alkaline agents. Strongly basic alkali is highly aggressive and will readily hydrolyze (or cleave) key biological molecules such as lipids and proteins. This phenomenon is known as saponification in the case of lipids and liquefactive denaturation for peptides and proteins. A short section on current first-aid concepts is included. A better understanding of the basic science behind alkali burns will make us better teachers and provide an insight into the urgency needed in treating these common and dangerous chemical injuries. PMID:26182072

  17. Metal-Organic Frameworks as Sensory Materials and Imaging Agents

    PubMed Central

    Liu, Demin; Lu, Kuangda; Poon, Christopher

    2014-01-01

    Metal-organic frameworks (MOFs) are a class of hybrid materials self-assembled from organic bridging ligands and metal ion/cluster connecting points. The combination of a variety of organic linkers, metal ions/clusters, and structural motifs can lead to an infinite array of new materials with interesting properties for many applications. In this Forum article, we discuss the design and applications of MOFs in chemical sensing and biological imaging. The first half of this article focuses on the development of MOFs as chemical sensors by highlighting how unique attributes of MOFs can be utilized to enhance sensitivity and selectivity. We also discuss some of the issues that need to be addressed in order to develop practically useful MOF sensors. The second half of this article focuses on the design and applications of nanoscale metal-organic frameworks (NMOFs) as imaging contrast agents. NMOFs possess several interesting attributes, such as high cargo loading capacity, ease of post-modification, tunable size and shape, and intrinsic biodegradability, to make them excellent candidates as imaging contrast agents. We discuss the use of representative NMOFs in magnetic resonance imaging (MRI), X-ray computed tomography (CT), and optical imaging (OI). Although still in their infancy, we believe that the compositional tunability and mild synthetic conditions of NMOF imaging agents should greatly facilitate their further development for clinical translation. PMID:24251853

  18. Alkali metal ion battery with bimetallic electrode

    SciTech Connect

    Boysen, Dane A; Bradwell, David J; Jiang, Kai; Kim, Hojong; Ortiz, Luis A; Sadoway, Donald R; Tomaszowska, Alina A; Wei, Weifeng; Wang, Kangli

    2015-04-07

    Electrochemical cells having molten electrodes having an alkali metal provide receipt and delivery of power by transporting atoms of the alkali metal between electrode environments of disparate chemical potentials through an electrochemical pathway comprising a salt of the alkali metal. The chemical potential of the alkali metal is decreased when combined with one or more non-alkali metals, thus producing a voltage between an electrode comprising the molten the alkali metal and the electrode comprising the combined alkali/non-alkali metals.

  19. Methods of recovering alkali metals

    DOEpatents

    Krumhansl, James L; Rigali, Mark J

    2014-03-04

    Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

  20. Chlor-Alkali Technology.

    ERIC Educational Resources Information Center

    Venkatesh, S.; Tilak, B. V.

    1983-01-01

    Chlor-alkali technology is one of the largest electrochemical industries in the world, the main products being chlorine and caustic soda (sodium hydroxide) generated simultaneously by the electrolysis of sodium chloride. This technology is reviewed in terms of electrochemical principles and manufacturing processes involved. (Author/JN)

  1. Si doping of metal-organic chemical vapor deposition grown gallium nitride using ditertiarybutyl silane metal-organic source

    NASA Astrophysics Data System (ADS)

    Fong, W. K.; Leung, K. K.; Surya, C.

    2007-01-01

    Liquid Si ditertiarybutyl silane (DTBSi) metal-organic source was used as the Si dopant source for the growth of n-type GaN by metal-organic chemical vapor deposition (MOCVD) for the first time to replace the conventional gaseous Si sources like silane SiH 4 [K. Pakula, R. Bozek, J.M. Baranowski, J. Jasinski, Z. Liliental-Weber, J. Crystal Growth 267 (2004) 1] and disilane Si 2H 6 [L.B. Rowland, K. Doverspike, D.K. Gaskill, Appl. Phys. Lett. 66 (1995) 1495]. Electrical, structural, optical, and surface properties of the samples doped by DTBSi as well as an undoped control sample are determined by Hall, high resolution X-ray diffraction (HRXRD), photoluminescence (PL), and atomic force microscopy (AFM) measurements respectively. A constant doping efficiency for GaN is obtained with carrier concentration up to 10 18 cm -3. The typical HRXRD full-width at half-maximum values of symmetric (0 0 2) and asymmetric (1 0 2) planes are 284 and 482 arcsec, respectively. The near band edge PL intensity is found to be increased proportional to the doping concentration. Dark spot density is also determined from AFM measurement.

  2. Recent progress in the synthesis of metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Sun, Yujia; Zhou, Hong-Cai

    2015-10-01

    Metal-organic frameworks (MOFs) have attracted considerable attention for various applications due to their tunable structure, porosity and functionality. In general, MOFs have been synthesized from isolated metal ions and organic linkers under hydrothermal or solvothermal conditions via one-spot reactions. The emerging precursor approach and kinetically tuned dimensional augmentation strategy add more diversity to this field. In addition, to speed up the crystallization process and create uniform crystals with reduced size, many alternative synthesis routes have been explored. Recent advances in microwave-assisted synthesis and electrochemical synthesis are presented in this review. In recent years, post-synthetic approaches have been shown to be powerful tools to synthesize MOFs with modified functionality, which cannot be attained via de novo synthesis. In this review, some current accomplishments of post-synthetic modification (PSM) based on covalent transformations and coordinative interactions as well as post-synthetic exchange (PSE) in robust MOFs are provided.

  3. Controlled partial interpenetration in metal-organic frameworks.

    PubMed

    Ferguson, Alan; Liu, Lujia; Tapperwijn, Stefanus J; Perl, David; Coudert, François-Xavier; Van Cleuvenbergen, Stijn; Verbiest, Thierry; van der Veen, Monique A; Telfer, Shane G

    2016-03-01

    Interpenetration, the entwining of multiple lattices, is a common phenomenon in metal-organic frameworks (MOFs). Typically, in interpenetrated MOFs the sub-lattices are fully occupied. Here we report a family of MOFs in which one sub-lattice is fully occupied and the occupancy level of the other can be controlled during synthesis to produce frameworks with variable levels of partial interpenetration. We also report an 'autocatenation' process, a transformation of non-interpenetrated lattices into doubly interpenetrated frameworks via progressively higher degrees of interpenetration that involves no external reagents. Autocatenation maintains crystallinity and can be triggered either thermally or by shear forces. The ligand used to construct these MOFs is chiral, and both racemic and enantiopure partially interpenetrated frameworks can be accessed. X-ray diffraction, nonlinear optical microscopy and theoretical calculations offer insights into the structures and dynamic behaviour of these materials and the growth mechanisms of interpenetrated MOFs. PMID:26892557

  4. Magnetorheology of iron associated magnetic metal-organic framework nanoparticle

    NASA Astrophysics Data System (ADS)

    Quan, Xue Mei; Liu, Ying Dan; Choi, Hyoung Jin

    2015-05-01

    Metal-organic frameworks (MOFs) with zeolite-like structured materials have interesting characteristics because of their high surface areas and pore volumes. Among the various MOFs reported thus far, Fe-BTC was chosen as an additive to improve the dispersion stability of soft-magnetic carbonyl iron particle-based magnetorheological (MR) fluids. The morphology of the Fe-BTC additive was examined by TEM, and the behavior of the MR particles dispersed in silicone oil was examined using a rotational rheometer. With a typical magnetic property, the Fe-BTC additive added MR fluid showed similar MR behavior with that of the CI based MR fluid while its improved dispersion stability was observed.

  5. Flexible Zirconium Metal-Organic Frameworks as Bioinspired Switchable Catalysts.

    PubMed

    Yuan, Shuai; Zou, Lanfang; Li, Haixia; Chen, Ying-Pin; Qin, Junsheng; Zhang, Qiang; Lu, Weigang; Hall, Michael B; Zhou, Hong-Cai

    2016-08-26

    Flexible metal-organic frameworks (MOFs) are highly desirable in host-guest chemistry owing to their almost unlimited structural/functional diversities and stimuli-responsive pore architectures. Herein, we designed a flexible Zr-MOF system, namely PCN-700 series, for the realization of switchable catalysis in cycloaddition reactions of CO2 with epoxides. Their breathing behaviors were studied by successive single-crystal X-ray diffraction analyses. The breathing amplitudes of the PCN-700 series were modulated through pre-functionalization of organic linkers and post-synthetic linker installation. Experiments and molecular simulations confirm that the catalytic activities of the PCN-700 series can be switched on and off upon reversible structural transformation, which is reminiscent of sophisticated biological systems such as allosteric enzymes. PMID:27346468

  6. Metal-organic frameworks for lithium ion batteries and supercapacitors

    NASA Astrophysics Data System (ADS)

    Ke, Fu-Sheng; Wu, Yu-Shan; Deng, Hexiang

    2015-03-01

    Porous materials have been widely used in batteries and supercapacitors attribute to their large internal surface area (usually 100-1000 m2 g-1) and porosity that can favor the electrochemical reaction, interfacial charge transport, and provide short diffusion paths for ions. As a new type of porous crystalline materials, metal-organic frameworks (MOFs) have received huge attention in the past decade due to their unique properties, i.e. huge surface area (up to 7000 m2 g-1), high porosity, low density, controllable structure and tunable pore size. A wide range of applications including gas separation, storage, catalysis, and drug delivery benefit from the recent fast development of MOFs. However, their potential in electrochemical energy storage has not been fully revealed. Herein, the present mini review appraises recent and significant development of MOFs and MOF-derived materials for rechargeable lithium ion batteries and supercapacitors, to give a glimpse into these potential applications of MOFs.

  7. Superexchange Charge Transport in Loaded Metal Organic Frameworks.

    PubMed

    Neumann, Tobias; Liu, Jianxi; Wächter, Tobias; Friederich, Pascal; Symalla, Franz; Welle, Alexander; Mugnaini, Veronica; Meded, Velimir; Zharnikov, Michael; Wöll, Christof; Wenzel, Wolfgang

    2016-07-26

    In the past, nanoporous metal-organic frameworks (MOFs) have been mostly studied for their huge potential with regard to gas storage and separation. More recently, the discovery that the electrical conductivity of a widely studied, highly insulating MOF, HKUST-1, improves dramatically when loaded with guest molecules has triggered a huge interest in the charge carrier transport properties of MOFs. The observed high conductivity, however, is difficult to reconcile with conventional transport mechanisms: neither simple hopping nor band transport models are consistent with the available experimental data. Here, we combine theoretical results and new experimental data to demonstrate that the observed conductivity can be explained by an extended hopping transport model including virtual hops through localized MOF states or molecular superexchange. Predictions of this model agree well with precise conductivity measurements, where experimental artifacts and the influence of defects are largely avoided by using well-defined samples and the Hg-drop junction approach. PMID:27359160

  8. Transformation of metal-organic frameworks for molecular sieving membranes.

    PubMed

    Li, Wanbin; Zhang, Yufan; Zhang, Congyang; Meng, Qin; Xu, Zehai; Su, Pengcheng; Li, Qingbiao; Shen, Chong; Fan, Zheng; Qin, Lei; Zhang, Guoliang

    2016-01-01

    The development of simple, versatile strategies for the synthesis of metal-organic framework (MOF)-derived membranes are of increasing scientific interest, but challenges exist in understanding suitable fabrication mechanisms. Here we report a route for the complete transformation of a series of MOF membranes and particles, based on multivalent cation substitution. Through our approach, the effective pore size can be reduced through the immobilization of metal salt residues in the cavities, and appropriate MOF crystal facets can be exposed, to achieve competitive molecular sieving capabilities. The method can also be used more generally for the synthesis of a variety of MOF membranes and particles. Importantly, we design and synthesize promising MOF membranes candidates that are hard to achieve through conventional methods. For example, our CuBTC/MIL-100 membrane exhibits 89, 171, 241 and 336 times higher H2 permeance than that of CO2, O2, N2 and CH4, respectively. PMID:27090597

  9. Metal-Organic Frameworks as Catalysts for Oxidation Reactions.

    PubMed

    Dhakshinamoorthy, Amarajothi; Asiri, Abdullah M; Garcia, Hermenegildo

    2016-06-01

    This Concept is aimed at describing the current state of the art in metal-organic frameworks (MOFs) as heterogeneous catalysts for liquid-phase oxidations, focusing on three important substrates, namely, alkenes, alkanes and alcohols. Emphases are on the nature of active sites that have been incorporated within MOFs and on future targets to be set in this area. Thus, selective alkene epoxidation with peroxides or oxygen catalyzed by constitutional metal nodes of MOFs as active sites are still to be developed. Moreover, no noble metal-free MOF has been reported to date that can act as a general catalyst for the aerobic oxidation of primary and secondary aliphatic alcohols. In contrast, in the case of alkanes, a target should be to tune the polarity of MOF internal pores to control the outcome of the autooxidation process, resulting in the selective formation of alcohol/ketone mixtures at high conversion. PMID:27113486

  10. Metal-organic frameworks for artificial photosynthesis and photocatalysis.

    PubMed

    Zhang, Teng; Lin, Wenbin

    2014-08-21

    Solar energy is an alternative, sustainable energy source for mankind. Finding a convenient way to convert sunlight energy into chemical energy is a key step towards realizing large-scale solar energy utilization. Owing to their structural regularity and synthetic tunability, metal-organic frameworks (MOFs) provide an interesting platform to hierarchically organize light-harvesting antennae and catalytic centers to achieve solar energy conversion. Such photo-driven catalytic processes not only play a critical role in the solar to chemical energy conversion scheme, but also provide a novel methodology for the synthesis of fine chemicals. In this review, we summarize the fundamental principles of energy transfer and photocatalysis and provide an overview of the latest progress in energy transfer, light-harvesting, photocatalytic proton and CO2 reduction, and water oxidation using MOFs. The applications of MOFs in organic photocatalysis and degradation of model organic pollutants are also discussed. PMID:24769551

  11. Transformation of metal-organic frameworks for molecular sieving membranes

    PubMed Central

    Li, Wanbin; Zhang, Yufan; Zhang, Congyang; Meng, Qin; Xu, Zehai; Su, Pengcheng; Li, Qingbiao; Shen, Chong; Fan, Zheng; Qin, Lei; Zhang, Guoliang

    2016-01-01

    The development of simple, versatile strategies for the synthesis of metal-organic framework (MOF)-derived membranes are of increasing scientific interest, but challenges exist in understanding suitable fabrication mechanisms. Here we report a route for the complete transformation of a series of MOF membranes and particles, based on multivalent cation substitution. Through our approach, the effective pore size can be reduced through the immobilization of metal salt residues in the cavities, and appropriate MOF crystal facets can be exposed, to achieve competitive molecular sieving capabilities. The method can also be used more generally for the synthesis of a variety of MOF membranes and particles. Importantly, we design and synthesize promising MOF membranes candidates that are hard to achieve through conventional methods. For example, our CuBTC/MIL-100 membrane exhibits 89, 171, 241 and 336 times higher H2 permeance than that of CO2, O2, N2 and CH4, respectively. PMID:27090597

  12. Transformation of metal-organic frameworks for molecular sieving membranes

    NASA Astrophysics Data System (ADS)

    Li, Wanbin; Zhang, Yufan; Zhang, Congyang; Meng, Qin; Xu, Zehai; Su, Pengcheng; Li, Qingbiao; Shen, Chong; Fan, Zheng; Qin, Lei; Zhang, Guoliang

    2016-04-01

    The development of simple, versatile strategies for the synthesis of metal-organic framework (MOF)-derived membranes are of increasing scientific interest, but challenges exist in understanding suitable fabrication mechanisms. Here we report a route for the complete transformation of a series of MOF membranes and particles, based on multivalent cation substitution. Through our approach, the effective pore size can be reduced through the immobilization of metal salt residues in the cavities, and appropriate MOF crystal facets can be exposed, to achieve competitive molecular sieving capabilities. The method can also be used more generally for the synthesis of a variety of MOF membranes and particles. Importantly, we design and synthesize promising MOF membranes candidates that are hard to achieve through conventional methods. For example, our CuBTC/MIL-100 membrane exhibits 89, 171, 241 and 336 times higher H2 permeance than that of CO2, O2, N2 and CH4, respectively.

  13. Chemical, thermal and mechanical stabilities of metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Howarth, Ashlee J.; Liu, Yangyang; Li, Peng; Li, Zhanyong; Wang, Timothy C.; Hupp, Joseph T.; Farha, Omar K.

    2016-03-01

    The construction of thousands of well-defined, porous, metal-organic framework (MOF) structures, spanning a broad range of topologies and an even broader range of pore sizes and chemical functionalities, has fuelled the exploration of many applications. Accompanying this applied focus has been a recognition of the need to engender MOFs with mechanical, thermal and/or chemical stability. Chemical stability in acidic, basic and neutral aqueous solutions is important. Advances over recent years have made it possible to design MOFs that possess different combinations of mechanical, thermal and chemical stability. Here, we review these advances and the associated design principles and synthesis strategies. We focus on how these advances may render MOFs effective as heterogeneous catalysts, both in chemically harsh condensed phases and in thermally challenging conditions relevant to gas-phase reactions. Finally, we briefly discuss future directions of study for the production of highly stable MOFs.

  14. Controlled partial interpenetration in metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Ferguson, Alan; Liu, Lujia; Tapperwijn, Stefanus J.; Perl, David; Coudert, François-Xavier; van Cleuvenbergen, Stijn; Verbiest, Thierry; van der Veen, Monique A.; Telfer, Shane G.

    2016-03-01

    Interpenetration, the entwining of multiple lattices, is a common phenomenon in metal-organic frameworks (MOFs). Typically, in interpenetrated MOFs the sub-lattices are fully occupied. Here we report a family of MOFs in which one sub-lattice is fully occupied and the occupancy level of the other can be controlled during synthesis to produce frameworks with variable levels of partial interpenetration. We also report an ‘autocatenation’ process, a transformation of non-interpenetrated lattices into doubly interpenetrated frameworks via progressively higher degrees of interpenetration that involves no external reagents. Autocatenation maintains crystallinity and can be triggered either thermally or by shear forces. The ligand used to construct these MOFs is chiral, and both racemic and enantiopure partially interpenetrated frameworks can be accessed. X-ray diffraction, nonlinear optical microscopy and theoretical calculations offer insights into the structures and dynamic behaviour of these materials and the growth mechanisms of interpenetrated MOFs.

  15. Metal-organic frameworks with dynamic interlocked components

    NASA Astrophysics Data System (ADS)

    Vukotic, V. Nicholas; Harris, Kristopher J.; Zhu, Kelong; Schurko, Robert W.; Loeb, Stephen J.

    2012-06-01

    The dynamics of mechanically interlocked molecules such as rotaxanes and catenanes have been studied in solution as examples of rudimentary molecular switches and machines, but in this medium, the molecules are randomly dispersed and their motion incoherent. As a strategy for achieving a higher level of molecular organization, we have constructed a metal-organic framework material using a [2]rotaxane as the organic linker and binuclear Cu(II) units as the nodes. Activation of the as-synthesized material creates a void space inside the rigid framework that allows the soft macrocyclic ring of the [2]rotaxane to rotate rapidly, unimpeded by neighbouring molecular components. Variable-temperature 13C and 2H solid-state NMR experiments are used to characterize the nature and rate of the dynamic processes occurring inside this unique material. These results provide a blueprint for the future creation of solid-state molecular switches and molecular machines based on mechanically interlocked molecules.

  16. Metal-organic frameworks for Xe/Kr separation

    DOEpatents

    Ryan, Patrick J.; Farha, Omar K.; Broadbelt, Linda J.; Snurr, Randall Q.; Bae, Youn-Sang

    2013-08-27

    Metal-organic framework (MOF) materials are provided and are selectively adsorbent to xenon (Xe) over another noble gas such as krypton (Kr) and/or argon (Ar) as a result of having framework voids (pores) sized to this end. MOF materials having pores that are capable of accommodating a Xe atom but have a small enough pore size to receive no more than one Xe atom are desired to preferentially adsorb Xe over Kr in a multi-component (Xe--Kr mixture) adsorption method. The MOF material has 20% or more, preferably 40% or more, of the total pore volume in a pore size range of 0.45-0.75 nm which can selectively adsorb Xe over Kr in a multi-component Xe--Kr mixture over a pressure range of 0.01 to 1.0 MPa.

  17. Metal-organic frameworks for Xe/Kr separation

    DOEpatents

    Ryan, Patrick J.; Farha, Omar K.; Broadbelt, Linda J.; Snurr, Randall Q.; Bae, Youn-Sang

    2014-07-22

    Metal-organic framework (MOF) materials are provided and are selectively adsorbent to xenon (Xe) over another noble gas such as krypton (Kr) and/or argon (Ar) as a result of having framework voids (pores) sized to this end. MOF materials having pores that are capable of accommodating a Xe atom but have a small enough pore size to receive no more than one Xe atom are desired to preferentially adsorb Xe over Kr in a multi-component (Xe--Kr mixture) adsorption method. The MOF material has 20% or more, preferably 40% or more, of the total pore volume in a pore size range of 0.45-0.75 nm which can selectively adsorb Xe over Kr in a multi-component Xe--Kr mixture over a pressure range of 0.01 to 1.0 MPa.

  18. Coordinative alignment of molecules in chiral metal-organic frameworks.

    PubMed

    Lee, Seungkyu; Kapustin, Eugene A; Yaghi, Omar M

    2016-08-19

    A chiral metal-organic framework, MOF-520, was used to coordinatively bind and align molecules of varying size, complexity, and functionality. The reduced motional degrees of freedom obtained with this coordinative alignment method allowed the structures of molecules to be determined by single-crystal x-ray diffraction techniques. The chirality of the MOF backbone also served as a reference in the structure solution for an unambiguous assignment of the absolute configuration of bound molecules. Sixteen molecules representing four common functional groups (primary alcohol, phenol, vicinal diol, and carboxylic acid), ranging in complexity from methanol to plant hormones (gibberellins, containing eight stereocenters), were crystallized and had their precise structure determined. We distinguished single and double bonds in gibberellins, and we enantioselectively crystallized racemic jasmonic acid, whose absolute configuration had only been inferred from derivatives. PMID:27540171

  19. Metal-Organic Framework for Emulsifying Carbon Dioxide and Water.

    PubMed

    Liu, Chengcheng; Zhang, Jianling; Zheng, Lirong; Zhang, Jing; Sang, Xinxin; Kang, Xinchen; Zhang, Bingxing; Luo, Tian; Tan, Xiuniang; Han, Buxing

    2016-09-12

    Forming emulsions of carbon dioxide (CO2 ) and water can largely expand the utility of CO2 . Herein we propose for the first time the utilization of a metal-organic framework (MOF) for emulsifying CO2 and water. Owing to the hybrid composition, MOF particles can easily assemble at the CO2 /water interface to create a rigid protective barrier around the dispersed droplet. The MOF-stabilized CO2 and water emulsion has exceptional stability compared to those emulsions stabilized by surfactants or other solids. Moreover, the CO2 and water emulsion stabilized by MOF is "tunable" due to the designable features of MOFs and adjustable character of CO2 . Such a novel kind of emulsion composed of CO2 , water, and MOF provides a facile route for constructing MOF superstructures with many advantages. The macroporous networks and hollow capsules of different kinds of MOFs have been successfully derived from CO2 and water emulsions. PMID:27529754

  20. Adsorption of pyridine onto the metal organic framework MIL-101.

    PubMed

    Kim, Mi Jin; Park, Se Min; Song, Sun-Jung; Won, Jiyeon; Lee, Jin Yong; Yoon, Minyoung; Kim, Kimoon; Seo, Gon

    2011-09-15

    The adsorption of pyridine onto the metal organic framework MIL-101 was investigated by experimental and theoretical methods. The amount of pyridine adsorbed on MIL-101 was extraordinarily large at 20 °C, corresponding to about 950 mg/g of dried MIL-101 and approximately half of the voids being filled. Most of the pyridine that had filled the voids was rapidly removed by evacuation at room temperature, but some of the pyridine was so strongly adsorbed that it was retained even under evacuation at 150 °C. Although IR spectra of the adsorbed pyridine indicated the adsorption of pyridine as pyridinium ions and coordinated pyridine at low temperatures, increasing the adsorption temperature induced partial cleavage of the pyridine rings. The high stabilization energy of pyridine on the coordinative unsaturated sites (CUS) of MIL-101, obtained by theoretical calculation, -103 kJ/mol, supported the strong adsorption of pyridine on the CUS. PMID:21700293

  1. Scalability of Continuous Flow Production of Metal-Organic Frameworks.

    PubMed

    Rubio-Martinez, Marta; Hadley, Trevor D; Batten, Michael P; Constanti-Carey, Keri; Barton, Tim; Marley, Dylan; Mönch, Andreas; Lim, Kok-Seng; Hill, Matthew R

    2016-05-10

    Achieving the large-scale production of metal-organic frameworks (MOFs) is crucial for their utilization in applied settings. For many MOFs, quality suffers from large-scale, batch reaction systems. We have developed continuous processes for their production which showed promise owing to their versatility and the high quality of the products. Here, we report the successful upscaling of this concept by more than two orders of magnitude to deliver unprecedented production rates and space-time-yields (STYs) while maintaining the product quality. Encouragingly, no change in the reaction parameters, obtained at small scale, was required. The production of aluminium fumarate was achieved at an STY of 97 159 kg m(-3)  day(-1) and a rate of 5.6 kg h(-1) . PMID:27075923

  2. Nanoscale Metal-Organic Framework-Hemoglobin Conjugates.

    PubMed

    Wang, Weiqi; Wang, Lei; Huang, Yubin; Xie, Zhigang; Jing, Xiabin

    2016-03-01

    A metal-organic framework (MOF)-protein conjugate, NH2 -MIL-125(Ti)-hemoglobin [MIL-125(Ti)-Hb], was synthesized by a covalent postmodification strategy. The crystalline structure was maintained after chemical and protein modification. The content of grafted Hb was tuned by the stoichiometric ratio and reached 50 wt % if the mass ratio of MIL-125(Ti)/Hb was 1:1.25 in the feed. The oxygen-transporting capacity of grafted Hb was kept, and the P50 (the half O2 pressure saturated with O2 ) and Hill coefficients of the MIL-125(Ti)-Hb conjugate were found to be 22.9 mm Hg and 2.35, respectively, which are close to the respective values of free Hb. All the results indicate that the MIL-125(Ti)-Hb conjugate could be potentially used as an oxygen carrier. PMID:26692560

  3. Hydrothermal alkali metal recovery process

    DOEpatents

    Wolfs, Denise Y.; Clavenna, Le Roy R.; Eakman, James M.; Kalina, Theodore

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by treating them with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of an added base to establish a pH during the treatment step that is higher than would otherwise be possible without the addition of the base. During the treating process the relatively high pH facilitates the conversion of water-insoluble alkali metal compounds in the alkali metal residues into water-soluble alkali metal constituents. The resultant aqueous solution containing water-soluble alkali metal constituents is then separated from the residue solids, which consist of the treated particles and any insoluble materials formed during the treatment step, and recycled to the gasification process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. Preferably, the base that is added during the treatment step is an alkali metal hydroxide obtained by water washing the residue solids produced during the treatment step.

  4. Cooperative loading and release behavior of a metal-organic receptor.

    PubMed

    Gan, Quan; Ronson, Tanya K; Vosburg, David A; Thoburn, John D; Nitschke, Jonathan R

    2015-02-11

    In order to design artificial chemical systems that are capable of achieving complex functions, it is useful to design synthetic receptors that mimic their biological counterparts. Biological functions are underpinned by properties that include specific binding with high affinity and selectivity, cooperativity, and release triggered by external stimuli. Here we show that a metal-organic receptor constructed through subcomponent self-assembly can selectively and cooperatively load and release oxocarbon anions. The flexible coordination spheres of its cadmium(II) centers allow the receptor to dynamically adjust its structure upon exchanging four triflate or triflimide counterions for two oxocarbon anions, resulting in strong cooperativity and very tight binding, with an apparent association constant for C5O5(2-) of 5 × 10(10) M(-1). Substituting the cadmium(II) ions for copper(I) by switching solvent prompted a structural reorganization and release of the oxocarbon anions. Its cooperative behavior allows the receptor to carry a greater payload than would be possible in a noncooperative analogue. PMID:25615799

  5. A green strategy to prepare metal oxide superstructure from metal-organic frameworks.

    PubMed

    Song, Yonghai; Li, Xia; Wei, Changting; Fu, Jinying; Xu, Fugang; Tan, Hongliang; Tang, Juan; Wang, Li

    2015-01-01

    Metal or metal oxides with diverse superstructures have become one of the most promising functional materials in sensor, catalysis, energy conversion, etc. In this work, a novel metal-organic frameworks (MOFs)-directed method to prepare metal or metal oxide superstructure was proposed. In this strategy, nodes (metal ions) in MOFs as precursors to form ordered building blocks which are spatially separated by organic linkers were transformed into metal oxide micro/nanostructure by a green method. Two kinds of Cu-MOFs which could reciprocally transform by changing solvent were prepared as a model to test the method. Two kinds of novel CuO with three-dimensional (3D) urchin-like and 3D rods-like superstructures composed of nanoparticles, nanowires and nanosheets were both obtained by immersing the corresponding Cu-MOFs into a NaOH solution. Based on the as-formed CuO superstructures, a novel and sensitive nonenzymatic glucose sensor was developed. The small size, hierarchical superstructures and large surface area of the resulted CuO superstructures eventually contribute to good electrocatalytic activity of the prepared sensor towards the oxidation of glucose. The proposed method of hierarchical superstructures preparation is simple, efficient, cheap and easy to mass production, which is obviously superior to pyrolysis. It might open up a new way for hierarchical superstructures preparation. PMID:25669731

  6. Comparative study of metal-organic frameworks for carbon capture applications

    NASA Astrophysics Data System (ADS)

    Simmons, Jason; Zhou, Wei; Wu, Hui; Yildirim, Taner

    2010-03-01

    With the current prevalence of hydrocarbon-based energy sources, carbon capture and sequestration are essential technologies for minimizing the emission of carbon dioxide and the resulting increased atmospheric concentration of CO2. Current technologies based on absorption require high temperature regeneration of the solvent, ultimately leading to significantly decreased efficiency and increased cost. Development of an adsorption-based technology, based on physical adsorption in optimized porous media, would greatly reduce the regeneration costs. Here we discuss the carbon capture performance of a range of metal-organic frameworks (MOFs), including both high surface area materials as well as those with sites that have been engineered to have enhanced binding. In particular, we demonstrate that MOFs can capture significant amounts of CO2 and that the CO2 can be readily removed from the MOF using standard pressure/vacuum swing techniques, yielding cyclic capture capacities in excess of 5 mmol/g. Further, we discuss the role of pore geometry and surface chemistry in the capacity of CO2 that can be removed in order to best optimize these materials. Lastly, we will address the effect of flue gas impurities on the carbon capture performance of these MOFs.

  7. Synthesis of metal-organic framework films by pore diffusion method

    NASA Astrophysics Data System (ADS)

    Murayama, Naohiro; Nishimura, Yuki; Kajiro, Hiroshi; Kishida, Satoru; Kinoshita, Kentaro; Tottori Univ Team; Nippon Steel; Sumitomo Metal Co. Collaboration; Tottori Integrated Frontier Resaerch Center (Tifrec) Collaboration; Tottori University Electronic Display Resaerch Center (Tedrec) Collaboration

    Metal-organic frameworks (MOFs) presents high controllability in designing the nano-scale pore, and this enable molecular storages, catalysts, gas sensors, gas separation membranes, and electronic devices for next-generation. Therefore, a simple method for film synthesis of MOFs compared with conventional methods [1] is strongly required. In this paper, we provide pore diffusion method, in which a substrate containing constituent metals of MOF is inserted in solution that includes only linker molecules of MOF. As a result, 2D growth of MOF was effectively enhanced, and the formation of flat and dense MOF films was attained. The growth time, t, dependence of film thickness, d, can be expressed by the relation of d = Aln(t + 1) + B, where A and B are constants. It means that ionized coppers diffuse through the pores of MOFs and the synthesis reaction proceeds at the MOF/solvent interface. We demonstrated the fabrication of a HKUST-1/Cu-TPA hetero structure by synthesizing a Cu-TPA film continuously after the growth of a HKUST-1 film on the CuOx substrate.

  8. Chromophore-immobilized luminescent metal-organic frameworks as potential lighting phosphors and chemical sensors.

    PubMed

    Wang, Fangming; Liu, Wei; Teat, Simon J; Xu, Feng; Wang, Hao; Wang, Xinlong; An, Litao; Li, Jing

    2016-08-11

    An organic chromophore H4tcbpe-F was synthesized and immobilized into metal-organic frameworks along with two bipyridine derivatives as co-ligands to generate two strongly luminescent materials [Zn2(tcbpe-F)(4,4'-bpy)·xDMA] (1) and [Zn2(tcbpe-F)(bpee)·xDMA] (2) [4,4'-bpy = 4,4'-bipyridine, bpee = 4,4'-bipyridyl-ethylene, tcbpe-F = 4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis(3-fluoro-[1,1'-biphenyl]-4-carboxylic acid), DMA = N,N-dimethylacetamide]. Compounds 1 and 2 are isoreticular and feature a 2-fold interpenetrated three-dimensional porous structure. Both compounds give green-yellow emission under blue light excitation. Compound 1 has a high internal quantum yield of ∼51% when excited at 455 nm and shows selective luminescence signal change (e.g. emission energy and/or intensity) towards different solvents, including both aromatic and nonaromatic volatile organic species. These properties make it potentially useful as a lighting phosphor and a chemical sensor. PMID:27465685

  9. Unraveling the multi-functional behavior in a series of Metal Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Sanda, Suresh; Biswas, Soumava; Parshamoni, Srinivasulu; Konar, Sanjit

    2015-09-01

    Three new 2D/3D Metal-Organic Frameworks (MOFs), {[Zn(2,6-ndc)(aldrithiol)]·3(H2O)}n (1), {[Co(2,6-ndc)(aldrithiol)(H2O)2]·2(H2O)}n (2), {[Cd2(2,6-ndc)2(aldrithiol)2(H2O)2]·(aldrithiol)·(EtOH)·3(H2O)}n (3), (2,6-ndc = 2,6-naphthalene dicarboxylic acid; aldrithiol = 4,4'-dipyridyl disulphide) have been synthesized and structurally characterized. Compounds 1 and 2 have 2D layered architectures with similar framework topology whereas 3 is a 2-fold interwoven three dimensional framework. Sorption studies reveal that compounds 1-3 selectively adsorbs CO2 over other gases and H2O over other solvents. Proton conductivity study of compounds 1 and 2 show highest values of 6.73 x 10-7 S.cm-1, 1.96 x 10-5 S.cm-1 at 318 K and 95% RH and these values are humidity dependent. Photoluminescent properties of compounds 1 and 3 show metal perturbed (π*-π and π*-n) intra ligand charge transfer transitions. Additionally, Compound 3 also displays reversible adsorption of molecular iodine.

  10. A Green Strategy to Prepare Metal Oxide Superstructure from Metal-Organic Frameworks

    PubMed Central

    Song, Yonghai; Li, Xia; Wei, Changting; Fu, Jinying; Xu, Fugang; Tan, Hongliang; Tang, Juan; Wang, Li

    2015-01-01

    Metal or metal oxides with diverse superstructures have become one of the most promising functional materials in sensor, catalysis, energy conversion, etc. In this work, a novel metal-organic frameworks (MOFs)-directed method to prepare metal or metal oxide superstructure was proposed. In this strategy, nodes (metal ions) in MOFs as precursors to form ordered building blocks which are spatially separated by organic linkers were transformed into metal oxide micro/nanostructure by a green method. Two kinds of Cu-MOFs which could reciprocally transform by changing solvent were prepared as a model to test the method. Two kinds of novel CuO with three-dimensional (3D) urchin-like and 3D rods-like superstructures composed of nanoparticles, nanowires and nanosheets were both obtained by immersing the corresponding Cu-MOFs into a NaOH solution. Based on the as-formed CuO superstructures, a novel and sensitive nonenzymatic glucose sensor was developed. The small size, hierarchical superstructures and large surface area of the resulted CuO superstructures eventually contribute to good electrocatalytic activity of the prepared sensor towards the oxidation of glucose. The proposed method of hierarchical superstructures preparation is simple, efficient, cheap and easy to mass production, which is obviously superior to pyrolysis. It might open up a new way for hierarchical superstructures preparation. PMID:25669731

  11. Tuning the adsorption properties of isoreticular pyrazolate-based metal-organic frameworks through ligand modification.

    PubMed

    Colombo, Valentina; Montoro, Carmen; Maspero, Angelo; Palmisano, Giovanni; Masciocchi, Norberto; Galli, Simona; Barea, Elisa; Navarro, Jorge A R

    2012-08-01

    Two isoreticular series of pyrazolate-based 3D open metal-organic frameworks, MBDP_X, adopting the NiBDP and ZnBDP structure types [H(2)BDP = 1,4-bis(1H-pyrazol-4-yl)benzene], were synthesized with the new tagged organic linkers H(2)BDP_X (X = -NO(2), -NH(2), -OH). All of the MBDP_X materials have been characterized through a combination of techniques. IR spectroscopy proved the effective presence of tags, while X-ray powder diffraction (XRPD) witnessed their isoreticular nature. Simultaneous TG/DSC analyses (STA) demonstrated their remarkable thermal stability, while variable-temperature XRPD experiments highlighted their high degree of flexibility related to guest-induced fit processes of the solvent molecules included in the channels. A structural isomer of the parent NiBDP was obtained with a sulfonate tagged ligand, H(2)BDP_SO(3)H. Structure solution from powder diffraction data collected at three different temperatures (room temperature, 90, and 250 °C) allowed the determination of its structure and the comprehension of its solvent-related flexible behavior. Finally, the potential application of the tagged MOFs in selective adsorption processes for gas separation and purification purposes was investigated by conventional single component adsorption isotherms, as well as by advanced experiments of pulse gas chromatography and breakthrough curve measurements. Noteworthy, the results show that functionalization does not improve the adsorption selectivity (partition coefficients) for the resolution of gas mixtures characterized by similar high quadrupole moments (e.g., CO(2)/C(2)H(2)); however, the resolution of gas mixtures containing molecules with highly differentiated polarities (i.e., N(2)/CO(2) or CH(4)/CO(2)) is highly improved. PMID:22765315

  12. Simple model potential and model wave functions for (H-alkali)+ and (alkali-alkali)+ ions

    NASA Astrophysics Data System (ADS)

    Patil, S. H.; Tang, K. T.

    2000-07-01

    A simple model potential is proposed to describe the interaction of a valence electron with the alkali core, which incorporates the correct asymptotic behavior in terms of dipolar polarizabilities, and the short-range exchange effects in terms of a hard core adjusted to give the correct energy for the valence electron. Based on this potential, simple wave functions are developed to describe the (H-alkali)+ and (alkali-alkali)+ ions. These wave functions exhibit some important structures of the ions, and provide a universal description of the properties of all (H-alkali)+ and (alkali-alkali)+ ions, in particular, the equilibrium separations of the nuclei and the corresponding dissociation energies. They also allow us to calculate the dipolar polarizabilities of Li2+, Na2+, K2+, Rb2+, and Cs2+.

  13. Alkali-vapor lasers

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Komashko, A.; Krupke, W. F.

    2010-02-01

    We report on the results from several of our alkali laser systems. We show highly efficient performance from an alexandrite-pumped rubidium laser. Using a laser diode stack as a pump source, we demonstrate up to 145 W of average power from a CW system. We present a design for a transversely pumped demonstration system that will show all of the required laser physics for a high power system.

  14. Thin films by metal-organic precursor plasma spray

    SciTech Connect

    Schulz, Douglas L.; Sailer, Robert A.; Payne, Scott; Leach, James; Molz, Ronald J.

    2009-07-15

    While most plasma spray routes to coatings utilize solids as the precursor feedstock, metal-organic precursor plasma spray (MOPPS) is an area that the authors have investigated recently as a novel route to thin film materials. Very thin films are possible via MOPPS and the technology offers the possibility of forming graded structures by metering the liquid feed. The current work employs metal-organic compounds that are liquids at standard temperature-pressure conditions. In addition, these complexes contain chemical functionality that allows straightforward thermolytic transformation to targeted phases of interest. Toward that end, aluminum 3,5-heptanedionate (Al(hd){sub 3}), triethylsilane (HSi(C{sub 2}H{sub 5}){sub 3} or HSiEt{sub 3}), and titanium tetrakisdiethylamide (Ti(N(C{sub 2}H{sub 5}){sub 2}){sub 4} or Ti(NEt{sub 2}){sub 4}) were employed as precursors to aluminum oxide, silicon carbide, and titanium nitride, respectively. In all instances, the liquids contain metal-heteroatom bonds envisioned to provide atomic concentrations of the appropriate reagents at the film growth surface, thus promoting phase formation (e.g., Si-C bond in triethylsilane, Ti-N bond in titanium amide, etc.). Films were deposited using a Sulzer Metco TriplexPro-200 plasma spray system under various experimental conditions using design of experiment principles. Film compositions were analyzed by glazing incidence x-ray diffraction and elemental determination by x-ray spectroscopy. MOPPS films from HSiEt{sub 3} showed the formation of SiC phase but Al(hd){sub 3}-derived films were amorphous. The Ti(NEt{sub 2}){sub 4} precursor gave MOPPS films that appear to consist of nanosized splats of TiOCN with spheres of TiO{sub 2} anatase. While all films in this study suffered from poor adhesion, it is anticipated that the use of heated substrates will aid in the formation of dense, adherent films.

  15. Colloidal-sized metal-organic frameworks: synthesis and applications.

    PubMed

    Sindoro, Melinda; Yanai, Nobuhiro; Jee, Ah-Young; Granick, Steve

    2014-02-18

    Colloidal metal-organic frameworks (CMOFs), nanoporous colloidal-sized crystals that are uniform in both size and polyhedral shape, are crystals composed of metal ions and organic bridging ligands, which can be used as building blocks for self-assembly in organic and aqueous liquids. They stand in contrast to conventional metal-organic frameworks (MOFs), which scientists normally study in the form of bulk crystalline powders. However, powder MOFs generally have random crystal size and shape and therefore do not possess either a definite mutual arrangement with adjacent particles or uniformity. CMOFs do have this quality, which can be important in vital uptake and release kinetics. In this Account, we present the diverse methods of synthesis, pore chemistry control, surface modification, and assembly techniques of CMOFs. In addition, we survey recent achievements and future applications in this emerging field. There is potential for a paradigm shift, away from using just bulk crystalline powders, towards using particles whose size and shape are regulated. The concept of colloidal MOFs takes into account that nanoporous MOFs, conventionally prepared in the form of bulk crystalline powders with random crystal size, shape, and orientation, may also form colloidal-sized objects with uniform size and morphology. Furthermore, the traditional MOF functions that depend on porosity present additional control over those MOF functions that depend on pore interactions. They also can enable controlled spatial arrangements between neighboring particles. To begin, we discuss progress regarding synthesis of MOF nano- and microcrystals whose crystal size and shape are well regulated. Next, we review the methods to modify the surfaces with dye molecules and polymers. Dyes are useful when seeking to observe nonluminescent CMOFs in situ by optical microscopy, while polymers are useful to tune their interparticle interactions. Third, we discuss criteria to assess the stability of CMOFs

  16. Rotating phenyl rings as a guest-dependent switch in two-dimensional metal-organic frameworks.

    PubMed

    Murdock, Christopher R; McNutt, Nicholas W; Keffer, David J; Jenkins, David M

    2014-01-15

    A semirigid bis(1,2,4-triazole) ligand binds in a syn conformation between copper(I) chains to form a series of two-dimensional metal-organic frameworks that display a topology of fused one-dimensional metal-organic nanotubes. These anisotropic frameworks undergo two different transformations in the solid state as a function of solvation. The 2D sheet layers can expand or contract, or, more remarkably, the phenyl rings can rotate between two distinct positions. Rotation of the phenyl rings allows for the adjustment of the tube size, depending on the guest molecules present. This "gate" effect along the 1D tubes has been characterized through single-crystal X-ray diffraction. The transformations can also be followed by powder X-ray diffraction (PXRD) and solid-state (13)C cross-polarization magic-angle-spinning (CP-MAS) NMR. Whereas PXRD cannot differentiate between transformations, solid-state (13)C CP-MAS NMR can be employed to directly monitor phenyl rotation as a function of solvation, suggesting that this spectroscopic method is a powerful approach for monitoring breathing in this novel class of frameworks. Finally, simulations show that rotation of the phenyl ring from a parallel orientation to a perpendicular orientation occurs at the cost of framework-framework energy and that this energetic cost is offset by stronger framework-solvent interactions. PMID:24351165

  17. Conduction properties of metal/organic monolayer/semiconductor heterostructures

    SciTech Connect

    Li, D.; Bishop, A.; Gim, Y.; Shi, X.B.; Fitzsimmons, M.R.; Jia, Q.X.

    1998-11-01

    We have fabricated and characterized rectifying devices made of metal/organic monolayer/semiconductor heterostructures. The devices consist of an organic barrier layer sandwiched between an aluminum (Al) metal contact and a {ital p}-type Si semiconductor. The barrier materials were chosen from three types of self-assembled monolayers (SAMs) with different electronic properties: (1) wide-band gap poly(diallydimethyl ammonium) chloride (PDDA), (2) narrow-band gap PDDA/NiPc (nickel phthalocyanine tetrasulfonate), and (3) donor type PDDA/PPP (poly {ital p}-quaterphenylene-disulfonic-dicarboxylic acid). From current{endash}voltage (I{endash}V) measurements at room temperature, we have found the turn-on voltage of the devices can be tuned by varying the structure, hence electronic properties, of the organic monolayers, and that there exists a power-law dependence of {ital I} on V, I{proportional_to}V{sup {alpha}}, with the exponent {alpha}=2.2 for PDDA, 2.7 for PDDA/NiPc, and 1.44 for PDDA/PPP as the barrier layer, respectively. Our results imply that the transport properties are controlled by both the electronic properties of the SAMs and those of the metal and semiconductor, as indicated by the power-law dependence of the I{endash}V characteristics. {copyright} {ital 1998 American Institute of Physics.}

  18. Surface nano-architecture of a metal-organic framework

    NASA Astrophysics Data System (ADS)

    Makiura, Rie; Motoyama, Soichiro; Umemura, Yasushi; Yamanaka, Hiroaki; Sakata, Osami; Kitagawa, Hiroshi

    2010-07-01

    The rational assembly of ultrathin films of metal-organic frameworks (MOFs)-highly ordered microporous materials-with well-controlled growth direction and film thickness is a critical and as yet unrealized issue for enabling the use of MOFs in nanotechnological devices, such as sensors, catalysts and electrodes for fuel cells. Here we report the facile bottom-up fabrication at ambient temperature of such a perfect preferentially oriented MOF nanofilm on a solid surface (NAFS-1), consisting of metalloporphyrin building units. The construction of NAFS-1 was achieved by the unconventional integration in a modular fashion of a layer-by-layer growth technique coupled with the Langmuir-Blodgett method. NAFS-1 is endowed with highly crystalline order both in the out-of-plane and in-plane orientations to the substrate, as demonstrated by synchrotron X-ray surface crystallography. The proposed structural model incorporates metal-coordinated pyridine molecules projected from the two-dimensional sheets that allow each further layer to dock in a highly ordered interdigitated manner in the growth of NAFS-1. We expect that the versatility of the solution-based growth strategy presented here will allow the fabrication of various well-ordered MOF nanofilms, opening the way for their use in a range of important applications.

  19. CO2-Selective Nanoporous Metal-Organic Framework Microcantilevers

    PubMed Central

    Yim, Changyong; Lee, Moonchan; Yun, Minhyuk; Kim, Gook-Hee; Kim, Kyong Tae; Jeon, Sangmin

    2015-01-01

    Nanoporous anodic aluminum oxide (AAO) microcantilevers are fabricated and MIL-53 (Al) metal-organic framework (MOF) layers are directly synthesized on each cantilever surface by using the aluminum oxide as the metal ion source. Exposure of the MIL53-AAO cantilevers to various concentrations of CO2, N2, CO, and Ar induces changes in their deflections and resonance frequencies. The results of the resonance frequency measurements for the different adsorbed gas molecules are almost identical when the frequency changes are normalized by the molecular weights of the gases. In contrast, the deflection measurements show that only CO2 adsorption induces substantial bending of the MIL53-AAO cantilevers. This selective deflection of the cantilevers is attributed to the strong interactions between CO2 and the hydroxyl groups in MIL-53, which induce structural changes in the MIL-53 layers. Simultaneous measurements of the resonance frequency and the deflection are performed to show that the diffusion of CO2 into the nanoporous MIL-53 layers occurs very rapidly, whereas the binding of CO2 to hydroxyl groups occurs relatively slowly, which indicates that the adsorption of CO2 onto the MIL-53 layers and the desorption of CO2 from the MIL-53 layers are reaction limited. PMID:26035805

  20. Thermodynamics of the structural transition in metal-organic frameworks.

    PubMed

    Rodriguez, J; Beurroies, I; Coulet, M-V; Fabry, P; Devic, T; Serre, C; Denoyel, R; Llewellyn, P L

    2016-03-01

    A thermodynamic study of the structural large-pore (LP) to narrow pore (NP) transition in various Metal Organic Frameworks (MOFs) is presented. First, the pressure induced transition at a constant temperature is investigated using a Tian-Calvet microcalorimeter set-up equipped with a high pressure cell. This device permits simultaneous measurements of the mechanical work and heat associated with the LP → NP transition. It is shown that MIL-53(Al) and MIL-53(Cr) have similar thermodynamic and mechanical behaviour whilst the MIL-47(V) system is characterized by much higher transition energy and mechanical work. Second, the temperature induced transition at ambient pressure is studied by means of differential scanning calorimetry (DSC) combined with X-ray absorption spectroscopy. This set-up enables one to follow simultaneously the structural changes associated with the phase transition detected by DSC. The MIL-53(Cr)-Br functionalized MOF is chosen here as a case study where both energetics and structural changes are discussed. PMID:26574728

  1. Metal-organic framework composites: from fundamentals to applications

    NASA Astrophysics Data System (ADS)

    Li, Shaozhou; Huo, Fengwei

    2015-04-01

    Metal-organic frameworks (MOFs) are a class of crystallized porous polymeric materials consisting of metal ions or clusters linked together by organic bridging ligands. Due to their permanent porosity, rich surface chemistry and tuneable pore sizes, MOFs have emerged as one type of important porous solid and have attracted intensive interests in catalysis, gas adsorption, separation and storage over the past two decades. When compared with pure MOFs, the combination of MOFs with functional species or matrix materials not only shows enhanced properties, but also broadens the applications of MOFs in new fields, such as bio-imaging, drug delivery and electrical catalysis, owing to the interactions of the functional species/matrix with the MOF structures. Although the synthesis, chemical modification and potential applications of MOFs have been reviewed previously, there is an increasing awareness on the synthesis and applications of their composites, which have rarely been reviewed. This review aims to fill this gap and discuss the fabrication, properties, and applications of MOF composites. The remaining challenges and future opportunities in this field, in terms of processing techniques, maximizing composite properties, and prospects for applications, have also been indicated.

  2. Energy Transfer Dynamics in Metal-Organic Frameworks

    SciTech Connect

    Kent, Caleb A.; Mehl, Brian P.; Ma, Liqing; Papanikolas, John M.; Meyer, Thomas J.; Lin, Wenbin

    2010-09-22

    Isomorphous metal-organic frameworks (MOFs) based on {M[4,4'-(HO2C)2-bpy]2bpy2+ building blocks (where M = Ru or Os) were designed and synthesized to study the classic Ru to Os energy transfer process that has potential applications in light-harvesting with supramolecular assemblies. The crystalline nature of the MOFs allows precise determination of the distances between metal centers by X-ray diffraction, thereby facilitating the study of the Ru→Os energy transfer process. The mixed-metal MOFs with 0.3, 0.6, 1.4, and 2.6 mol % Os doping were also synthesized in order to study the energy transfer dynamics with a two-photon excitation at 850 nm. The Ru lifetime at 620 nm decreases from 171 ns in the pure Ru MOF to 29 ns in the sample with 2.6 mol % Os doping. In the mixed-metal samples, energy transfer was observed with an initial growth in Os emission corresponding with the rate of decay of the Ru excited state. These results demonstrate rapid, efficient energy migration and long distance transfer in isomorphous MOFs.

  3. Understanding DABCO Nanorotor Dynamics in Isostructural Metal-Organic Frameworks.

    PubMed

    Burtch, Nicholas C; Torres-Knoop, Ariana; Foo, Guo Shiou; Leisen, Johannes; Sievers, Carsten; Ensing, Bernd; Dubbeldam, David; Walton, Krista S

    2015-03-01

    Flexible framework dynamics present in the subset of metal-organic frameworks known as soft porous crystals give rise to interesting structural properties that are unique to this class of materials. In this work, we use experiments and molecular simulation to understand the highly dynamic nanorotor behavior of the 1,4-diazabicyclo[2.2.2]octane (DABCO) ligand in the pillared Zn-DMOF and Zn-DMOF-TM (TM = tetramethyl) structures. While DABCO is known to be displaced in the presence of water in the parent Zn-DMOF structure, the Zn-DMOF-TM variation is highly stable even after adsorbing significant amounts of water vapor. The dynamics of DABCO in the presence of water guest molecules is therefore also explored in the Zn-DMOF-TM structure via in situ NMR and IR experiments. This analysis shows that the rotational motion of the DABCO linkers is dependent on water content, but not a likely source of water instability because the dynamics are fast and largely unaffected by the presence of methyl functional groups. PMID:26262657

  4. Metal-organic frameworks for lithium ion batteries and supercapacitors

    SciTech Connect

    Ke, Fu-Sheng; Wu, Yu-Shan; Deng, Hexiang

    2015-03-15

    Porous materials have been widely used in batteries and supercapacitors attribute to their large internal surface area (usually 100–1000 m{sup 2} g{sup −1}) and porosity that can favor the electrochemical reaction, interfacial charge transport, and provide short diffusion paths for ions. As a new type of porous crystalline materials, metal-organic frameworks (MOFs) have received huge attention in the past decade due to their unique properties, i.e. huge surface area (up to 7000 m{sup 2} g{sup −1}), high porosity, low density, controllable structure and tunable pore size. A wide range of applications including gas separation, storage, catalysis, and drug delivery benefit from the recent fast development of MOFs. However, their potential in electrochemical energy storage has not been fully revealed. Herein, the present mini review appraises recent and significant development of MOFs and MOF-derived materials for rechargeable lithium ion batteries and supercapacitors, to give a glimpse into these potential applications of MOFs. - Graphical abstract: MOFs with large surface area and high porosity can offer more reaction sites and charge carriers diffusion path. Thus MOFs are used as cathode, anode, electrolyte, matrix and precursor materials for lithium ion battery, and also as electrode and precursor materials for supercapacitors. - Highlights: • MOFs have potential in electrochemical area due to their high porosity and diversity. • We summarized and compared works on MOFs for lithium ion battery and supercapacitor. • We pointed out critical challenges and provided possible solutions for future study.

  5. Destruction of chemical warfare agents using metal-organic frameworks.

    PubMed

    Mondloch, Joseph E; Katz, Michael J; Isley, William C; Ghosh, Pritha; Liao, Peilin; Bury, Wojciech; Wagner, George W; Hall, Morgan G; DeCoste, Jared B; Peterson, Gregory W; Snurr, Randall Q; Cramer, Christopher J; Hupp, Joseph T; Farha, Omar K

    2015-05-01

    Chemical warfare agents containing phosphonate ester bonds are among the most toxic chemicals known to mankind. Recent global military events, such as the conflict and disarmament in Syria, have brought into focus the need to find effective strategies for the rapid destruction of these banned chemicals. Solutions are needed for immediate personal protection (for example, the filtration and catalytic destruction of airborne versions of agents), bulk destruction of chemical weapon stockpiles, protection (via coating) of clothing, equipment and buildings, and containment of agent spills. Solid heterogeneous materials such as modified activated carbon or metal oxides exhibit many desirable characteristics for the destruction of chemical warfare agents. However, low sorptive capacities, low effective active site loadings, deactivation of the active site, slow degradation kinetics, and/or a lack of tailorability offer significant room for improvement in these materials. Here, we report a carefully chosen metal-organic framework (MOF) material featuring high porosity and exceptional chemical stability that is extraordinarily effective for the degradation of nerve agents and their simulants. Experimental and computational evidence points to Lewis-acidic Zr(IV) ions as the active sites and to their superb accessibility as a defining element of their efficacy. PMID:25774952

  6. Melt-Quenched Glasses of Metal-Organic Frameworks.

    PubMed

    Bennett, Thomas D; Yue, Yuanzheng; Li, Peng; Qiao, Ang; Tao, Haizheng; Greaves, Neville G; Richards, Tom; Lampronti, Giulio I; Redfern, Simon A T; Blanc, Frédéric; Farha, Omar K; Hupp, Joseph T; Cheetham, Anthony K; Keen, David A

    2016-03-16

    Crystalline solids dominate the field of metal-organic frameworks (MOFs), with access to the liquid and glass states of matter usually prohibited by relatively low temperatures of thermal decomposition. In this work, we give due consideration to framework chemistry and topology to expand the phenomenon of the melting of 3D MOFs, linking crystal chemistry to framework melting temperature and kinetic fragility of the glass-forming liquids. Here we show that melting temperatures can be lowered by altering the chemistry of the crystalline MOF state, which provides a route to facilitate the melting of other MOFs. The glasses formed upon vitrification are chemically and structurally distinct from the three other existing categories of melt-quenched glasses (inorganic nonmetallic, organic, and metallic), and retain the basic metal-ligand connectivity of crystalline MOFs, which connects their mechanical properties to their starting chemical composition. The transfer of functionality from crystal to glass points toward new routes to tunable, functional hybrid glasses. PMID:26885940

  7. Increasing the Stability of Metal-Organic Frameworks

    DOE PAGESBeta

    Bosch, Mathieu; Zhang, Muwei; Zhou, Hong-Cai

    2014-01-01

    Metal-organic frameworks (MOFs) are a new category of advanced porous materials undergoing study by many researchers for their vast variety of both novel structures and potentially useful properties arising from them. Their high porosities, tunable structures, and convenient process of introducing both customizable functional groups and unsaturated metal centers have afforded excellent gas sorption and separation ability, catalytic activity, luminescent properties, and more. However, the robustness and reactivity of a given framework are largely dependent on its metal-ligand interactions, where the metal-containing clusters are often vulnerable to ligand substitution by water or other nucleophiles, meaning that the frameworks may collapsemore » upon exposure even to moist air. Other frameworks may collapse upon thermal or vacuum treatment or simply over time. This instability limits the practical uses of many MOFs. In order to further enhance the stability of the framework, many different approaches, such as the utilization of high-valence metal ions or nitrogen-donor ligands, were recently investigated. This review details the efforts of both our research group and others to synthesize MOFs possessing drastically increased chemical and thermal stability, in addition to exemplary performance for catalysis, gas sorption, and separation.« less

  8. Deliberate design of an acentric diamondoid metal-organic network

    SciTech Connect

    Yang Caiqin; Wang Jing; Wang Wei; Zhan Wenhong

    2011-09-15

    Reaction of 2.5-dicarboxy-1-methylpyridinium (DCMP) chloride and Zn(NO{sub 3}){sub 2}.6H{sub 2}O in the presence of NaHCO{sub 3} in water gave an expected acentric diamondoid network [Zn(DCMP){sub 2}] with a three-fold interpenetration. With long Zn-Zn separations, very large cavities are formed within each diamondoid network with high propensity to interpenetration, which makes it show a promising non-linear optical property with SHG efficiency approximately 7 times higher than that of potassium dihydrogen phosphate (KDP). The design strategy of ligand through methylation of the corresponding pyrdinecarboxylic acid can be extended to other widely used carboxylic acids, more importantly, to lead to an unsymmetric bifunctional bridging ligand, which is essential for generating polar solids. - Graphical Abstract: Reaction of Zn(NO{sub 3}){sub 2}.6H{sub 2}O with a deliberately designed unsymmetrical ligand 2.5-dicarboxy-1-methylpyridinium (DCMP) chloride and in the presence of NaHCO{sub 3} gave an expected noncentric diamondoid network [Zn(DCMP){sub 2}], which has its SHG response approximately 7 times higher than that of potassium dihydrogen phosphate (KDP). Highlights: > DCMP as an unsymmetrical organic ligand to design metal organic framework. > Long Zn-Zn separations and very large cavities formed. > Diamondoid network with high propensity to interpenetration formed. > Bifunctional bridging ligand was used to generate polar solids with large SHG response.

  9. Guest-Induced Emergent Properties in Metal-Organic Frameworks.

    PubMed

    Allendorf, Mark D; Foster, Michael E; Léonard, François; Stavila, Vitalie; Feng, Patrick L; Doty, F Patrick; Leong, Kirsty; Ma, Eric Yue; Johnston, Scott R; Talin, A Alec

    2015-04-01

    Metal-organic frameworks (MOFs) are crystalline nanoporous materials comprised of organic electron donors linked to metal ions by strong coordination bonds. Applications such as gas storage and separations are currently receiving considerable attention, but if the unique properties of MOFs could be extended to electronics, magnetics, and photonics, the impact on material science would greatly increase. Recently, we obtained "emergent properties," such as electronic conductivity and energy transfer, by infiltrating MOF pores with "guest" molecules that interact with the framework electronic structure. In this Perspective, we define a path to emergent properties based on the Guest@MOF concept, using zinc-carboxylate and copper-paddlewheel MOFs for illustration. Energy transfer and light harvesting are discussed for zinc carboxylate frameworks infiltrated with triplet-scavenging organometallic compounds and thiophene- and fullerene-infiltrated MOF-177. In addition, we discuss the mechanism of charge transport in TCNQ-infiltrated HKUST-1, the first MOF with electrical conductivity approaching conducting organic polymers. These examples show that guest molecules in MOF pores should be considered not merely as impurities or analytes to be sensed but also as an important aspect of rational design. PMID:26262970

  10. Conductive metal-organic frameworks and networks: fact or fantasy?

    PubMed

    Hendon, Christopher H; Tiana, Davide; Walsh, Aron

    2012-10-14

    Electrical conduction is well understood in materials formed from inorganic or organic building blocks, but their combination to produce conductive hybrid frameworks and networks is an emerging and rapidly developing field of research. Self-assembling organic-inorganic compounds offer immense potential for functionalising material properties for a wide scope of applications including solar cells, light emitters, gas sensors and bipolar transparent conductors. The flexibility of combining two distinct material classes into a single solid-state system provides an almost infinite number of chemical and structural possibilities; however, there is currently no systematic approach established for designing new compositions and configurations with targeted electronic or optical properties. We review the current status in the field, in particular, the range of hybrid systems reported to date and the important role of materials modelling in the field. From theoretical arguments, the Mott insulator-to-metal transition should be possible in semiconducting metal-organic frameworks, but has yet to be observed. The question remains as to whether electro-active hybrid materials will evolve from chemical curiosities towards practical applications in the near term. PMID:22858739

  11. Destruction of chemical warfare agents using metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Mondloch, Joseph E.; Katz, Michael J.; Isley, William C., III; Ghosh, Pritha; Liao, Peilin; Bury, Wojciech; Wagner, George W.; Hall, Morgan G.; Decoste, Jared B.; Peterson, Gregory W.; Snurr, Randall Q.; Cramer, Christopher J.; Hupp, Joseph T.; Farha, Omar K.

    2015-05-01

    Chemical warfare agents containing phosphonate ester bonds are among the most toxic chemicals known to mankind. Recent global military events, such as the conflict and disarmament in Syria, have brought into focus the need to find effective strategies for the rapid destruction of these banned chemicals. Solutions are needed for immediate personal protection (for example, the filtration and catalytic destruction of airborne versions of agents), bulk destruction of chemical weapon stockpiles, protection (via coating) of clothing, equipment and buildings, and containment of agent spills. Solid heterogeneous materials such as modified activated carbon or metal oxides exhibit many desirable characteristics for the destruction of chemical warfare agents. However, low sorptive capacities, low effective active site loadings, deactivation of the active site, slow degradation kinetics, and/or a lack of tailorability offer significant room for improvement in these materials. Here, we report a carefully chosen metal-organic framework (MOF) material featuring high porosity and exceptional chemical stability that is extraordinarily effective for the degradation of nerve agents and their simulants. Experimental and computational evidence points to Lewis-acidic ZrIV ions as the active sites and to their superb accessibility as a defining element of their efficacy.

  12. Atomistic Simulation of Protein Encapsulation in Metal-Organic Frameworks.

    PubMed

    Zhang, Haiyang; Lv, Yongqin; Tan, Tianwei; van der Spoel, David

    2016-01-28

    Fabrication of metal-organic frameworks (MOFs) with large apertures triggers a brand-new research area for selective encapsulation of biomolecules within MOF nanopores. The underlying inclusion mechanism is yet to be clarified however. Here we report a molecular dynamics study on the mechanism of protein encapsulation in MOFs. Evaluation for the binding of amino acid side chain analogues reveals that van der Waals interaction is the main driving force for the binding and that guest size acts as a key factor predicting protein binding with MOFs. Analysis on the conformation and thermodynamic stability of the miniprotein Trp-cage encapsulated in a series of MOFs with varying pore apertures and surface chemistries indicates that protein encapsulation can be achieved via maintaining a polar/nonpolar balance in the MOF surface through tunable modification of organic linkers and Mg-O chelating moieties. Such modifications endow MOFs with a more biocompatible confinement. This work provides guidelines for selective inclusion of biomolecules within MOFs and facilitates MOF functions as a new class of host materials and molecular chaperones. PMID:26730607

  13. Governing metal-organic frameworks towards high stability.

    PubMed

    Li, Na; Xu, Jian; Feng, Rui; Hu, Tong-Liang; Bu, Xian-He

    2016-06-30

    Metal-organic frameworks (MOFs) constructed with metal ions/clusters and organic ligands have emerged as an important family of porous materials for various applications. However, the stability of this class of materials is crucial for their practical applications, which might be improved by varying their chemical composition and/or structurally tuning them. To fabricate MOFs with high stability, several strategies for enhancing the stability of MOFs have been developed, in which the strength of metal-ligand bonds is especially considered: the use of highly charged cations and higher pKa ligands, and varying the chemical functionality of linkers. On the other hand, the regulation of their structural architectures is also investigated: interpenetrated frameworks, multi-walled frameworks, and self-strengthening of the frameworks. In addition, the surface modification can also improve the stability of the materials. In this review, we introduce and summarize these strategies from the viewpoint of structural tuning and component choosing, providing useful instructions for the further design and synthesis of MOFs with high-level stability. PMID:27230794

  14. Dispersive micro-solid-phase extraction of herbicides in vegetable oil with metal-organic framework MIL-101.

    PubMed

    Li, Na; Zhang, Liyuan; Nian, Li; Cao, Bocheng; Wang, Zhibing; Lei, Lei; Yang, Xiao; Sui, Jiaqi; Zhang, Hanqi; Yu, Aimin

    2015-03-01

    Dispersive microsolid-phase extraction based on metal-organic framework has been developed and applied to the extraction of triazine and phenylurea herbicides in vegetable oils in this work. The herbicides were directly extracted with MIL-101 from diluted vegetables oils without any further cleanup. The separation and determination of herbicides were carried out on high performance liquid chromatography. The effects of experimental parameters, including volume ratio of n-hexane to oil sample, mass of MIL-101, extraction time, centrifugation time, eluting solvent, and elution time were investigated. The Student's t test was applied to evaluate the selected experimental conditions. The limits of detection for the herbicides ranged from 0.585 to 1.04 μg/L. The recoveries of the herbicides ranged from 87.3 to 107%. Our results showed that the present method is rapid, simple, and effective for extracting herbicides in vegetable oils. PMID:25665636

  15. Fabrication of Isolated Metal-Organic Polyhedra in Confined Cavities: Adsorbents/Catalysts with Unusual Dispersity and Activity.

    PubMed

    Kang, Ying-Hu; Liu, Xiao-Dan; Yan, Ni; Jiang, Yao; Liu, Xiao-Qin; Sun, Lin-Bing; Li, Jian-Rong

    2016-05-18

    Metal-organic polyhedra (MOPs) have attracted great attention due to their intriguing structure. However, the applications of MOPs are severely hindered by two shortcomings, namely low dispersity and poor stability. Here we report the introduction of four MOPs (constructed from dicopper and carboxylates) to cavity-structured mesoporous silica SBA-16 via a double-solvent strategy to overcome both shortcomings simultaneously. By judicious design, the dimension of MOPs is just between the size of cavities and entrances of SBA-16, MOP molecules are thus confined in the cavities. This leads to the formation of isolated MOPs with unusual dispersion, making the active sites highly accessible. Hence, the adsorption capacity on carbon dioxide and propene as well as catalytic performance on ring opening are much superior to bulk MOPs. More importantly, the structure and catalytic activity of MOPs in confined cavities are well preserved after exposure to humid atmosphere, whereas those of bulk MOPs are degraded seriously. PMID:27049737

  16. Redox-Active Metal-Organic Composites for Highly Selective Oxygen Separation Applications.

    PubMed

    Zhang, Wen; Banerjee, Debasis; Liu, Jian; Schaef, Herbert T; Crum, Jarrod V; Fernandez, Carlos A; Kukkadapu, Ravi K; Nie, Zimin; Nune, Satish K; Motkuri, Radha K; Chapman, Karena W; Engelhard, Mark H; Hayes, James C; Silvers, Kurt L; Krishna, Rajamani; McGrail, B Peter; Liu, Jun; Thallapally, Praveen K

    2016-05-01

    A redox-active metal-organic composite material shows improved and selective O2 adsorption over N2 with respect to individual components (MIL-101 and ferrocene). The O2 sensitivity of the composite material arises due to the formation of maghemite nanoparticles with the pore of the metal-organic framework material. PMID:26953336

  17. Selective interfacial synthesis of metal-organic frameworks on a polybenzimidazole hollow fiber membrane for gas separation

    NASA Astrophysics Data System (ADS)

    Biswal, Bishnu P.; Bhaskar, Anand; Banerjee, Rahul; Kharul, Ulhas K.

    2015-04-01

    Metal-organic frameworks (MOFs) have gained immense attention as new age materials due to their tuneable properties and diverse applicability. However, efforts on developing promising materials for membrane based gas separation, and control over the crystal growth positions on polymeric hollow fiber membranes still remain key challenges. In this investigation, a new, convenient and scalable room temperature interfacial method for growing MOFs (ZIF-8 and CuBTC) on either the outer or inner side of a polybenzimidazole based hollow fiber (PBI-BuI-HF) membrane surface has been achieved in a controlled manner. This was made possible by the appropriate selection of an immiscible solvent pair and the synthetic conditions. The growth of MOFs on the PBI-BuI-HF membrane by the interfacial method was continuous and showed an appreciable gas separation performance, conveying promise for their applicability.Metal-organic frameworks (MOFs) have gained immense attention as new age materials due to their tuneable properties and diverse applicability. However, efforts on developing promising materials for membrane based gas separation, and control over the crystal growth positions on polymeric hollow fiber membranes still remain key challenges. In this investigation, a new, convenient and scalable room temperature interfacial method for growing MOFs (ZIF-8 and CuBTC) on either the outer or inner side of a polybenzimidazole based hollow fiber (PBI-BuI-HF) membrane surface has been achieved in a controlled manner. This was made possible by the appropriate selection of an immiscible solvent pair and the synthetic conditions. The growth of MOFs on the PBI-BuI-HF membrane by the interfacial method was continuous and showed an appreciable gas separation performance, conveying promise for their applicability. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00299k

  18. Adsorption on Alkali Halides.

    NASA Astrophysics Data System (ADS)

    Urzua Duran, Gilberto Antonio

    1995-01-01

    Using a variety of interionic potentials, I have computed the configurations of adsorbed alkali halides monomers on the (001) surface of selected alkali halides crystals. In the majority of cases studied it is found that the monomer adsorbs perpendicular to the surface with the cation sitting nearly on top of the surface anion. In about ten percent of the cases though the monomer adsorbs tilted from the vertical. In these cases the ion that is closer to the surface can be the cation or the anion. The effect of polarization forces is found to be important. In order to discuss the effects of surface retaxation with adsorbates, I have evaluated the surface relaxation of the alkali halide crystals, using a shell model for the interionic forces. It is found that surface relaxation and rumpling are generally small, especially when the van der Waals forces are included. A theory of the effect of substrate vibrations on the binding of an adsorbed atom is developed. At T = 0 the binding energy is D_0-E, where D_0 is the surface well depth (classical binding energy) and E is the quantum correction. For several simple models, it is found that E is surprisingly model-independent. We compare D _0-E with the binding energies to a rigid substrate, D_0-E_{rs}, and to a vibrationally averaged substrate, D _0-E_{va}. We prove that E_{va}>=q E>=q E_ {rs} and that similar relations hold at finite temperature for the free energy of binding. In most cases E_{rs} is better than E_{va} as an approximation to E.

  19. Solvent and process for recovery of hydroxide from aqueous mixtures

    DOEpatents

    Moyer, Bruce A.; Chambliss, C. Kevin; Bonnesen, Peter V.; Keever, Tamara J.

    2001-01-01

    Hydroxide values and associated alkali metal may be recovered from alkaline aqueous solutions using classes of fluorinated alcohols in a water immiscible solvent. The alcohols are characterized by fluorine substituents which are proximal to the acidic alcohol protons and are located to adjust the acidity of the extractant and the solubility of the extractant in the solvent. A method for stripping the extractant and solvent to regenerate the extractant and purified aqueous hydroxide solution is described.

  20. Investigation of metal hydride nanoparticles templated in metal organic frameworks.

    SciTech Connect

    Jacobs, Benjamin W.; Herberg, Julie L.; Highley, Aaron M.; Grossman, Jeffrey; Wagner, Lucas; Bhakta, Raghu; Peaslee, D.; Allendorf, Mark D.; Liu, X.; Behrens, Richard, Jr.; Majzoub, Eric H.

    2010-11-01

    Hydrogen is proposed as an ideal carrier for storage, transport, and conversion of energy. However, its storage is a key problem in the development of hydrogen economy. Metal hydrides hold promise in effectively storing hydrogen. For this reason, metal hydrides have been the focus of intensive research. The chemical bonds in light metal hydrides are predominantly covalent, polar covalent or ionic. These bonds are often strong, resulting in high thermodynamic stability and low equilibrium hydrogen pressures. In addition, the directionality of the covalent/ionic bonds in these systems leads to large activation barriers for atomic motion, resulting in slow hydrogen sorption kinetics and limited reversibility. One method for enhancing reaction kinetics is to reduce the size of the metal hydrides to nano scale. This method exploits the short diffusion distances and constrained environment that exist in nanoscale hydride materials. In order to reduce the particle size of metal hydrides, mechanical ball milling is widely used. However, microscopic mechanisms responsible for the changes in kinetics resulting from ball milling are still being investigated. The objective of this work is to use metal organic frameworks (MOFs) as templates for the synthesis of nano-scale NaAlH4 particles, to measure the H2 desorption kinetics and thermodynamics, and to determine quantitative differences from corresponding bulk properties. Metal-organic frameworks (MOFs) offer an attractive alternative to traditional scaffolds because their ordered crystalline lattice provides a highly controlled and understandable environment. The present work demonstrates that MOFs are stable hosts for metal hydrides and their reactive precursors and that they can be used as templates to form metal hydride nanoclusters on the scale of their pores (1-2 nm). We find that using the MOF HKUST-1 as template, NaAlH4 nanoclusters as small as 8 formula units can be synthesized inside the pores. A detailed picture of

  1. Band gap modulation of functionalized metal-organic frameworks.

    PubMed

    Musho, Terence; Li, Jiangtan; Wu, Nianqiang

    2014-11-21

    Metal-organic frameworks (MOFs) have been envisioned as alternatives to planar metallic catalysts for solar-to-fuel conversion. This is a direct result of their porous structure and the ability to tailor their optical absorption properties. This study investigates the band gap modulation of Zr-UiO-66 MOFs from both the computational and experimental points of view for three linker designs that include benzenedicarboxylate (BDC), BDC-NO2, and BDC-NH2. Emphasis in this study was aimed at understanding the influence of the bonding between the aromatic ring and the functional group. A ground state density functional theory (DFT) calculation was carried out to investigate the projected density of states and the origins of the modulation. A time-dependent density functional theory (TDDFT) calculation of the hydrogen terminated linkers confirmed the modulation and accounted for the electron charge transfer providing comparable optical band gap predictions to experimental results. Computational results confirmed the hybridization of the carbon-nitrogen bond in conjunction with the donor state resulting from the NH2 functionalization. The NO2 functionalization resulted in an acceptor configuration with marginal modification to the valence band maximum. The largest modulation was BDC-NH2 with a band gap of 2.75 eV, followed by BDC-NO2 with a band gap of 2.93 eV and BDC with a band gap of 3.76 eV. The electron effective mass was predicted from the band structure to be 8.9 me for all MOF designs. PMID:25269595

  2. A biomimetic tongue by photoluminescent metal-organic frameworks.

    PubMed

    Lee, Tu; Lin Lee, Hung; Hsun Tsai, Meng; Cheng, Shao-Liang; Lee, Sheng-Wei; Hu, Jung-Chih; Chen, Lien-Tai

    2013-05-15

    The taste sensing capabilities of a "biomimetic tongue" based on the photoluminescence (PL) responses of metal-organic frameworks (MOFs), [In(OH)(bdc)]n (bdc=1,4-benzenedicarboxylate), [Tb(btc)]n (MOF-76, btc=benzene-1,3,5-tricarboxylate), and [Ca3(btc)2(DMF)2(H2O)2]·3H2O are proven on aqueous solutions of five basic tastants: sucrose (sweet), caffeine (bitter), citric acid (sour), sodium chloride (salty) and monosodium glutamate (umami). For [In(OH)(bdc)]n, the tastant interacts stereochemically with poly(acrylic acid) (PAA) and alters its conformations. The frequency and magnitude of chelation between COO(-) pendant groups of PAA and In(3+) nodes of [In(OH)(bdc)]n framework influence the corresponding PL reponses. For MOF-76, the tastant interacts with incorporated water in MOF-76 through hydrogen bonding. The limitation of O-H bond stretching of water results in the enhancement of the PL intensity. For [Ca3(BTC)2(DMF)2(H2O)2]·3H2O, it is added as a third MOF component to increase the precision on taste discrimination. The significance of MOF-based "biomimetic tongue" includes: (1) PAA on [In(OH)(bdc)]n mimics the taste receptor cells (TRCs) for their structural flexibility, (2) the Weber-Fechner law of human sensing that sensation is proportional to the logarithm of the stimulus intensity is observed between the PL emission response of MOF-76 and the concentration of tastant, (3) the strength of taste is quantified by the τ scale and the PL emission intensity of MOF-76, which are dependent on the logarithmic tastant concentration, (4) the tastant is identified by the shape of the 3D principal component analysis contour map (i.e., pattern recognition method), and (5) the fabrication of [In(OH)(bdc)]n/PAA film by brushing is illustrated. PMID:23277340

  3. Adsorptive desulfurization and denitrogenation using metal-organic frameworks.

    PubMed

    Ahmed, Imteaz; Jhung, Sung Hwa

    2016-01-15

    With the increasing worldwide demand for energy, utilization of fossil fuels is increasing proportionally. Additionally, new and unconventional energy sources are also being utilized at an increasing rate day-by-day. These sources, along with some industrial processes, result in the exposal of several sulfur- and nitrogen-containing compounds (SCCs and NCCs, respectively) to the environment, and the exposure is one of the greatest environmental threats in the recent years. Although, several methods were established for the removal of these pollutants during the last few decades, recent advancements in adsorptive desulfurization and denitrogenation (ADS and ADN, respectively) with metal-organic frameworks (MOFs) make this the most promising and remarkable method. Therefore, many research groups are currently involved with ADS and ADN with MOFs, and the results are improving gradually by modifying the MOF adsorbents according to several specific adsorption mechanisms. In this review, ADS and ADN studies are thoroughly discussed for both liquid-phase and gas-phase adsorption. The MOF modification procedures, which are important for improved adsorption, are also described. To improve the knowledge among the scientific community, it is very important to understand the detailed chemistry and mechanism involved in a chemical process, which also creates the possibility and pathway for further developments in research and applications. Therefore, the mechanisms related to the adsorption procedures are also discussed in detail. From this review, it can be expected that the scientific community will obtain an understanding of the current state of ADS and ADN, their importance, and some encouragement and insight to take the research knowledge base to a higher level. PMID:26368800

  4. Anisotropic thermal expansion in a metal-organic framework.

    PubMed

    Madsen, Solveig Røgild; Lock, Nina; Overgaard, Jacob; Iversen, Bo Brummerstedt

    2014-06-01

    Ionothermal reaction between Mn(II)(acetate)2·4H2O and 1,3,5-benzenetricarboxylic acid (H3BTC) in either of the two ionic liquids 1-ethyl-3-methylimidazolium bromide (EMIMBr) and 1-ethyl-3-methylimidazolium tosylate (EMIMOTs) resulted in the formation of the new metal-organic framework (MOF) EMIM[Mn(II)BTC] (BTC = 1,3,5-benzenetricarboxylate). The compound crystallizes in the orthorhombic space group Pbca with unit-cell parameters of a = 14.66658 (12), b = 12.39497 (9), c = 16.63509 (14) Å at 100 K. Multi-temperature single-crystal (15-340 K) and powder X-ray diffraction studies (100-400 K) reveal strongly anisotropic thermal expansion properties. The linear thermal expansion coefficients, αL(l), attain maximum values at 400 K along the a- and b-axis, with αL(a) = 115 × 10(-6) K(-1) and αL(b) = 75 × 10(-6) K(-1). At 400 K a negative thermal expansion coefficient of -40 × 10(-6) K(-1) is observed along the c-axis. The thermal expansion is coupled to a continuous deformation of the framework, which causes the structure to expand in two directions. Due to the rigidity of the linker, the expansion in the ab plane causes the network to contract along the c-axis. Hirshfeld surface analysis has been used to describe the interaction between the framework structure and the EMIM cation that resides within the channel. This reveals a number of rather weak interactions and one governing hydrogen-bonding interactions. PMID:24892606

  5. Hydrophobic and moisture-stable metal-organic frameworks.

    PubMed

    Fernandez, Carlos A; Nune, Satish K; Annapureddy, Harsha V; Dang, Liem X; McGrail, B Peter; Zheng, Feng; Polikarpov, Evgueni; King, David L; Freeman, Charles; Brooks, Kriston P

    2015-08-14

    Metal-organic frameworks (MOFs) have proved to be very attractive for applications including gas storage, separation, sensing and catalysis. In particular, CO(2) separation from flue gas in post-combustion processes is one of the main focuses of research among the scientific community. One of the major issues that are preventing the successful commercialization of these novel materials is their high affinity towards water that not only compromises gas sorption capacity but also the chemical stability. In this paper, we demonstrate a novel post-synthesis modification approach to modify MOFs towards increasing hydrophobic behaviour and chemical stability against moisture without compromising CO(2) sorption capacity. Our approach consists of incorporating hydrophobic moieties on the external surface of the MOFs via physical adsorption. The rationale behind this concept is to increase the surface hydrophobicity in the porous materials without the need of introducing bulky functionalities inside the pore which compromises the sorption capacity toward other gases. We herein report preliminary results on routinely studied MOF materials [MIL-101(Cr) and NiDOBDC] demonstrating that the polymer-modified MOFs retain CO(2) sorption capacity while reducing the water adsorption up to three times, with respect to the un-modified materials, via an equilibrium effect. Furthermore, the water stability of the polymer-functionalized MOFs is significantly higher than the water stability of the bare material. Molecular dynamic simulations demonstrated that this equilibrium effect implies a fundamental and permanent change in the water sorption capacity of MOFs. This approach can also be employed to render moisture stability and selectivity to MOFs that find applications in gas separations, catalysis and sensing where water plays a critical role in compromising MOF performance and recyclability. PMID:25970023

  6. Purification of alkali metal nitrates

    DOEpatents

    Fiorucci, Louis C.; Gregory, Kevin M.

    1985-05-14

    A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

  7. Solvent substitution

    SciTech Connect

    Not Available

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  8. Facile synthesis and characterization of trimesic acid-Cu based metal organic frameworks

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Sel, Kivanc; Ozturk, Omer Faruk; Demirci, Sahin; Terzi, Gozde

    2014-09-01

    Metal-organic frameworks based on trimesic acid (TMA) as organic linker and Cu (II) as metal ions from different metal salts such as CuCl2, Cu(NO3)2, CuSO4 and Cu(CH3COOH)2 were prepared in relatively environmentally friendly media e.g., at room temperature in DI water and at the boiling point of ethanol. The prepared TMA-Cu MOFs showed very interesting porosity and optical coloring based on the source of the used metal salts and preparation medium. The prepared MOFs were characterized in terms of their porosity with BET measurements and it was found that about 850 m2/g for the MOF prepared from Cu(NO3)2 salt in ethanol. The amounts of metal ions connected to TMA were determined by atomic absorption spectroscopy measurements (AAS) after dissolution of TMA-Cu MOFs by concentrated HCl treatments. From AAS measurements the mole ratio of Cu(II) to TMA was found to vary between 1.5 and 2, depending on the source of metal ions and the solvent used during preparation. The structural analysis and thermal characterization of the prepared MOFs were done by using FT-IR and TGA analysis, respectively. Additionally, TMA-Cu based MOF disks were prepared and their conductivities were determined by I-V measurements. The conductivity of TMA-Cu MOFs was calculated to be between 8.26E-08 and 5.29E-11 S/cm.

  9. Heteropolyacid-functionalized aluminum 2-aminoterephthalate metal-organic frameworks as reactive aldehyde sorbents and catalysts.

    PubMed

    Bromberg, Lev; Su, Xiao; Hatton, T Alan

    2013-06-26

    Porous materials based on aluminum(III) 2-aminoterephthalate metal organic frameworks (MOFs NH2MIL101(Al) and NH2MIL53(Al)) and their composites with phosphotungstic acid (PTA) were studied as sorbents of saturated vapors of acetaldehyde, acrolein, and butyraldehyde. MOF functionalization by PTA impregnation from aqueous/methanol solutions resulted in MOF with the original crystal topology with the presence of an ordered PTA phase in the MOF/PTA composite. The MOF/PTA composites contained 29-32 wt % PTA and were stable against loss of PTA through leaching to the aqueous/organic solvent solutions. The MOF and MOF/PTA materials exhibited equilibrium uptake of acetaldehyde from its saturated vapor phase exceeding 50 and 600 wt %, respectively, at 25 °C. The acetaldehyde vapor uptake occurs through the vapor condensation, pore-filling mechanism with simultaneous conversion of acetaldehyde to crotonaldehyde and higher-molecular-weight compounds resulting from repeated aldol condensation. The products of aldehyde condensation and polymerization were identified by MALDI-TOF and electrospray mass spectrometry. The kinetics of the MOF- and MOF/PTA-catalyzed aldol condensation of acetaldehyde were studied in water-acetonitrile mixtures. The aldol condensation kinetics in MOF suspensions were rapid and pseudo-first-order. The apparent second-order rate constants for the aldol condensation catalyzed by MOF/PTA were estimated to be 5 × 10(-4) to 1.5 × 10(-3) M(-1)s(-1), which are higher than those reported in the case of homogeneous catalysis by amino acids or sulfuric acid. MOF and MOF/PTA materials are efficient heterogeneous catalysts for the aldehyde self-condensation in aqueous-organic media. PMID:23673368

  10. Methods for associating or dissociating guest materials with a metal organic framework, systems for associating or dissociating guest materials within a series of metal organic frameworks, thermal energy transfer assemblies, and methods for transferring thermal energy

    DOEpatents

    McGrail, B. Peter; Brown, Daryl R.; Thallapally, Praveen K.

    2016-08-02

    Methods for releasing associated guest materials from a metal organic framework are provided. Methods for associating guest materials with a metal organic framework are also provided. Methods are provided for selectively associating or dissociating guest materials with a metal organic framework. Systems for associating or dissociating guest materials within a series of metal organic frameworks are provided. Thermal energy transfer assemblies are provided. Methods for transferring thermal energy are also provided.

  11. Methods for associating or dissociating guest materials with a metal organic framework, systems for associating or dissociating guest materials within a series of metal organic frameworks, thermal energy transfer assemblies, and methods for transferring thermal energy

    DOEpatents

    McGrail, B. Peter; Brown, Daryl R.; Thallapally, Praveen K.

    2014-08-05

    Methods for releasing associated guest materials from a metal organic framework are provided. Methods for associating guest materials with a metal organic framework are also provided. Methods are provided for selectively associating or dissociating guest materials with a metal organic framework. Systems for associating or dissociating guest materials within a series of metal organic frameworks are provided. Thermal energy transfer assemblies are provided. Methods for transferring thermal energy are also provided.

  12. Functionalization of cotton fiber by partial etherification and self-assembly of polyoxometalate encapsulated in Cu3(BTC)2 metal-organic framework.

    PubMed

    Lange, Laura E; Obendorf, S Kay

    2015-02-25

    A combination of a Keggin-type polyoxometalate (POM), [CuPW11O39](5-), with a Cu3(BTC)2 metal-organic framework (MOF-199/HKUST-1; where BTC is benzene-1,3,5-tricarboxylate), was successfully self-assembled on a cellulose substrate (cotton) with a room-temperature process. Cotton fibers were functionalized by partial etherification. Cu3(BTC)2 metal-organic framework and polyoxometalate encapsulated in Cu3(BTC)2 metal-organic framework were self-assembled on the carboxymethylate ion sites initiated with copper nitrate using ethanol and water as solvents. Octahedral crystals were observed on both MOF-cotton and POM-MOF-cotton; both contained copper while the POM-MOF-cotton also contained tungsten. Occupancy of POM in MOF cages was calculated to be about 13%. Moisture content remained at 3 to 4 wt % similar to that of untreated cotton. Reactivity to both hydrogen sulfide and methyl parathion was higher for POM-MOF-cotton due to the Keggin polyoxometalate and the extra-framework cations Cu(2+) ions compensating the charges of the encapsulated Keggins. The POM-MOF material was found to effectively remove 0.089 mg of methyl parathion per mg of MOF from a hexane solution while MOF-cotton removed only 0.054 mg of methyl parathion per mg of MOF. PMID:25647089

  13. Carbon Dioxide Separation with Novel Microporous Metal Organic Frameworks

    SciTech Connect

    Richard Willis; Annabelle Benin; John Low; Ganesh Venimadhavan; Syed Faheem; David Lesch; Adam Matzger; Randy Snurr

    2008-02-04

    The goal of this program was to develop a low cost novel sorbent to remove carbon dioxide from flue gas and gasification streams in electric utilities. Porous materials named metal-organic frameworks (MOFs) were found to have good capacity and selectivity for the capture of carbon dioxide. Several materials from the initial set of reference MOFs showed extremely high CO{sub 2} adsorption capacities and very desirable linear isotherm shapes. Sample preparation occurred at a high level, with a new family of materials suitable for intellectual property protection prepared and characterized. Raman spectroscopy was shown to be useful for the facile characterization of MOF materials during adsorption and especially, desorption. Further, the development of a Raman spectroscopic-based method of determining binary adsorption isotherms was initiated. It was discovered that a stronger base functionality will need to be added to MOF linkers in order to enhance CO{sub 2} selectivity over other gases via a chemisorption mechanism. A concentrated effort was expended on being able to accurately predict CO{sub 2} selectivities and on the calculation of predicted MOF surface area values from first principles. A method of modeling hydrolysis on MOF materials that correlates with experimental data was developed and refined. Complimentary experimental data were recorded via utilization of a combinatorial chemistry heat treatment unit and high-throughput X-ray diffractometer. The three main Deliverables for the project, namely (a) a MOF for pre-combustion (e.g., IGCC) CO{sub 2} capture, (b) a MOF for post-combustion (flue gas) CO{sub 2} capture, and (c) an assessment of commercial potential for a MOF in the IGCC application, were completed. The key properties for MOFs to work in this application - high CO{sub 2} capacity, good adsorption/desorption rates, high adsorption selectivity for CO{sub 2} over other gases such as methane and nitrogen, high stability to contaminants, namely

  14. Alkali metal and alkali earth metal gadolinium halide scintillators

    DOEpatents

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

    2016-08-02

    The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  15. Unraveling the multi-functional behavior in a series of Metal Organic Frameworks

    SciTech Connect

    Sanda, Suresh; Biswas, Soumava; Parshamoni, Srinivasulu; Konar, Sanjit

    2015-09-15

    Three new 2D/3D Metal-Organic Frameworks (MOFs), ([Zn(2,6-ndc)(aldrithiol)]·3(H{sub 2}O)){sub n} (1), ([Co(2,6-ndc)(aldrithiol)(H{sub 2}O){sub 2}]·2(H{sub 2}O)){sub n} (2), ([Cd{sub 2}(2,6-ndc){sub 2}(aldrithiol){sub 2}(H{sub 2}O){sub 2}]·(aldrithiol)·(EtOH)·3(H{sub 2}O)){sub n} (3), (2,6-ndc = 2,6-naphthalene dicarboxylic acid; aldrithiol = 4,4'-dipyridyl disulphide) have been synthesized and structurally characterized. Compounds 1 and 2 have 2D layered architectures with similar framework topology whereas 3 is a 2-fold interwoven three dimensional framework. Sorption studies reveal that compounds 1-3 selectively adsorbs CO{sub 2} over other gases and H{sub 2}O over other solvents. Proton conductivity study of compounds 1 and 2 show highest values of 6.73 x 10{sup -7} S.cm{sup -1}, 1.96 x 10{sup -5} S.cm{sup -1} at 318 K and 95% RH and these values are humidity dependent. Photoluminescent properties of compounds 1 and 3 show metal perturbed (π*–π and π*-n) intra ligand charge transfer transitions. Additionally, Compound 3 also displays reversible adsorption of molecular iodine. - Graphical abstarct: Three new 2D/3D interpenetrated MOFs are synthesized and their multifunctional material properties such as adsorption, proton conduction, iodine adsorption as well as luminscence have been explored. - Highlights: • We report multifunctional material properties in a series MOFs (Compounds 1-3) • All the compounds show selective adsorption of CO{sub 2} over other gases and H{sub 2}O over other solvents. • The proton conduction property studies of all the compounds reveal the humidity dependent conductivity. • Compound 2 shows reversible adsorption of molecular iodine in the framework. • Photoluminescent properties of compounds 1 and 2 show metal perturbed intra ligand charge transfer transitions.

  16. A water-free metal organic deposition method for YBa2Cu3O7-δ thin film fabrication

    NASA Astrophysics Data System (ADS)

    Huang, Rongxia; Feng, Feng; Wu, Wei; Xue, Yunran; Zhang, Yanyi; Shi, Kai; Qu, Timing; Zhao, Yongjie; Wang, Xiaohao; Zhang, Xiaowen; Han, Zhenghe

    2013-11-01

    During the fabrication of YBa2Cu3O7-δ (YBCO) thin films via the metal organic deposition (MOD) method, the water content of the precursor solution should be reduced to prevent precipitation and other detriment. In most of the reported MOD-YBCO studies, water was used as a solvent, and vacuum distillation was utilized to reduce the water content of the precursor solution. In this study, we propose a water-free MOD method using propionic anhydride and methanol as the solvents. The crystal water of raw precursor salts was removed by heating, and the water content in the final precursor solution was as low as 0.2 wt%. Using this solution with low fluorine content and the optimized maximum temperature of pyrolysis, the final YBCO thin films about 250 nm thick had the critical current density (Jc) of 3.8 MA cm-2 (77 K, self-field). The water content of the precursor solution was further reduced to less than 10-2 wt% by vacuum distillation. According to the Jc performance, thermal analysis, x-ray diffraction investigations, and morphology observations, no significant improvement was found for the final YBCO thin films fabricated by the distilled solution, indicating that vacuum distillation is not necessary in the water-free MOD method.

  17. Microporous Cd(II) metal-organic framework as fluorescent sensor for nitroaromatic explosives at the sub-ppm level

    NASA Astrophysics Data System (ADS)

    Wang, Xing-Po; Han, Lu-Lu; Wang, Zhi; Guo, Ling-Yu; Sun, Di

    2016-03-01

    A novel Cd(II) metal-organic framework (MOF) based on a rigid biphenyltetracarboxylic acid, [Cd4(bptc)2(DMA)4(H2O)2·4DMA] (1) was successfully synthesized under the solvothermal condition and characterized by single-crystal X-ray diffraction and further consolidated by elemental analyses, powder X-ray diffraction (PXRD), infrared spectra (IR) and luminescent measurements. Single crystal X-ray diffraction analysis reveals that compound 1 is 4-connected PtS (Point symbol: {42·84}) network based on [Cd2(COO)4] secondary building units (SBUs). Its inherent porous and emissive characteristics make them to be a suitable fluorescent probe to sense small solvents and nitroaromatic explosives. Compound 1 shows obviously solvent-dependent emissive behaviors, especially for acetone with very high fluorescence quenching effect. Moreover, compound 1 displays excellent sensing of nitroaromatic explosives at sub-ppm level, giving a detection limit of 0.43 ppm and 0.37 ppm for nitrobenzene (NB) and p-nitrotoluene (PNT), respectively. This shows this Cd(II) MOF can be used as fluorescence probe for the detection of nitroaromatic explosives.

  18. A luminescent microporous metal-organic framework for the recognition and sensing of anions.

    PubMed

    Chen, Banglin; Wang, Liangbo; Zapata, Fatima; Qian, Guodong; Lobkovsky, Emil B

    2008-05-28

    A luminescent microporous metal-organic framework Tb(BTC)G has been developed for the recognition and sensing of anions, exhibiting a high-sensitivity sensing function with respect to fluoride. PMID:18452294

  19. Rapidly assessing the activation conditions and porosity of metal-organic frameworks using thermogravimetric analysis

    SciTech Connect

    McDonald, TM; Bloch, ED; Long, JR

    2015-01-01

    A methodology utilizing a thermogravimetric analyzer to monitor propane uptake following incremental increases of the temperature is demonstrated as a means of rapidly identifying porous materials and determining the optimum activation conditions of metal-organic frameworks.

  20. A porous metal-organic framework with -COOH groups for highly efficient pollutant removal.

    PubMed

    Zhang, Qi; Yu, Jiancan; Cai, Jianfeng; Song, Ruijing; Cui, Yuanjing; Yang, Yu; Chen, Banglin; Qian, Guodong

    2014-11-28

    A new metal-organic framework with -COOH groups has been realized and demonstrates strong interactions with methylene blue and thus the complete removal of methylene blue from aqueous solution. PMID:25303384

  1. Metal-organic framework materials based on icosahedral boranes and carboranes

    DOEpatents

    Mirkin, Chad A.; Hupp, Joseph T.; Farha, Omar K.; Spokoyny, Alexander M.; Mulfort, Karen L.

    2010-11-02

    Disclosed herein are metal-organic frameworks of metals and boron rich ligands, such as carboranes and icosahedral boranes. Methods of synthesizing and using these materials in gas uptake are disclosed.

  2. Bioinspired Design of Ultrathin 2D Bimetallic Metal-Organic-Framework Nanosheets Used as Biomimetic Enzymes.

    PubMed

    Wang, Yixian; Zhao, Meiting; Ping, Jianfeng; Chen, Bo; Cao, Xiehong; Huang, Ying; Tan, Chaoliang; Ma, Qinglang; Wu, Shixin; Yu, Yifu; Lu, Qipeng; Chen, Junze; Zhao, Wei; Ying, Yibin; Zhang, Hua

    2016-06-01

    With the bioinspired design of organic ligands and metallic nodes, novel ultrathin 2D bimetallic metal-organic-framework nanosheets are successfully synthesized, which can serve as advanced 2D biomimetic nanomaterials to mimic heme proteins. PMID:27008574

  3. Tetratopic phenyl compounds, related metal-organic framework materials and post-assembly elaboration

    DOEpatents

    Farha, Omar K; Hupp, Joseph T

    2013-06-25

    Disclosed are tetratopic carboxylic acid phenyl for use in metal-organic framework compounds. These compounds are useful in catalysis, gas storage, sensing, biological imaging, drug delivery and gas adsorption separation.

  4. Tetratopic phenyl compounds, related metal-organic framework materials and post-assembly elaboration

    DOEpatents

    Farha, Omar K.; Hupp, Joseph T.

    2012-09-11

    Disclosed are tetratopic carboxylic acid phenyl for use in metal-organic framework compounds. These compounds are useful in catalysis, gas storage, sensing, biological imaging, drug delivery and gas adsorption separation.

  5. Metal organic frameworks for enzyme immobilization in biofuel cells

    NASA Astrophysics Data System (ADS)

    Bodell, JaDee

    Interest in biofuel cells has been rapidly expanding as an ever-growing segment of the population gains access to electronic devices. The largest areas of growth for new populations using electronic devices are often in communities without electrical infrastructure. This lack of infrastructure in remote environments is one of the key driving factors behind the development of biofuel cells. Biofuel cells employ biological catalysts such as enzymes to catalyze oxidation and reduction reactions of select fuels to generate power. There are several benefits to using enzymes to catalyze reactions as compared to traditional fuel cells which use metal catalysts. First, enzymes are able to catalyze reactions at or near room temperature, whereas traditional metal catalysts are only efficient at very high temperatures. Second, biofuel cells can operate under mild pH conditions which is important for the eventual design of safe, commercially viable devices. Also, biofuel cells allow for implantable and flexible technologies. Finally, enzymes exhibit high selectivity and can be combined to fully oxidize or reduce the fuel which can generate several electrons from a single molecule of fuel, increasing the overall device efficiency. One of the main challenges which persist in biofuel cells is the instability of enzymes over time which tend to denature after hours or days. For a viable commercial biofuel cell to be produced, the stability of enzymes must be extended to months or years. Enzymes have been shown to have improved stability after being immobilized. The focus of this research was to find a metal organic framework (MOF) structure which could successfully immobilize enzymes while still allowing for electron transport to occur between the catalytic center of the enzyme and the electrode surface within a biofuel cell for power generation. Four MOF structures were successfully synthesized and were subsequently tested to determine the MOF's ability to immobilize the following

  6. Studies of gas adsorption in flexible Metal-Organic frameworks

    NASA Astrophysics Data System (ADS)

    Sircar, Sarmishtha

    Flexible Metal-Organic frameworks that exhibit a gate-opening (GO) adsorption mechanism have potential for gas separations and gas storage. The GO phenomenon occurs when molecular gates in the structure expand/contract in response to the activation/de-activation of a system variable e.g. temperature, pressure or gas. Sharp discontinuities in the isotherm leading to S-shapes and large adsorption-desorption hysteresis are typical of this phenomenon. This study investigates the kinetics and thermodynamics of the GO behavior by combining adsorption measurements and analytical modeling of adsorption kinetics and capacity as a function of adsorbate, GO pressure, and temperature. Basic understanding of GO mechanism will help harness GO-MOF's as adsorbents for gas separations and storage. Experiments were performed on two precharacterized MOFs with verified GO behavior. These are (1) Zn2(bpdc)2(bpee), which expands from a relative amorphous to crystalline structure and (2) Cu[(dhbc) 2(4,4f-bpy)]H2O, a mutually interdigitated 2-D structure (bpdc = biphenyldicarboxylate, bpee = 1,2]bipyridylethene; DMF = N,N-dimethyl formamide, dhbc= 2,5-dihydroxybenzoic acid, bpy=bipyridine). Both sub- and super-critical adsorption data were collected using three adsorption units: a standard low-pressure volumetric adsorption unit, a commercial high-pressure gravimetric analyzer and a custom-built high-pressure differential volumetric unit. Collected laboratory data were combined with published adsorption rate and isotherm data for analysis to broaden the range of data collection. The accuracy of the high-pressure differential unit was improved by over 300-fold by changing analytical methods of processing data to establish a reliable null correction. A pronounced effect of the allowed experimental time was found at cryogenic temperatures on (1). Tightening the stability criteria used by the adsorption equipment to determine equilibration increased the experimental time from the order of

  7. Upgrading platform using alkali metals

    SciTech Connect

    Gordon, John Howard

    2014-09-09

    A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

  8. Hybrid metal organic scintillator materials system and particle detector

    DOEpatents

    Bauer, Christina A.; Allendorf, Mark D.; Doty, F. Patrick; Simmons, Blake A.

    2011-07-26

    We describe the preparation and characterization of two zinc hybrid luminescent structures based on the flexible and emissive linker molecule, trans-(4-R,4'-R') stilbene, where R and R' are mono- or poly-coordinating groups, which retain their luminescence within these solid materials. For example, reaction of trans-4,4'-stilbenedicarboxylic acid and zinc nitrate in the solvent dimethylformamide (DMF) yielded a dense 2-D network featuring zinc in both octahedral and tetrahedral coordination environments connected by trans-stilbene links. Similar reaction in diethylformamide (DEF) at higher temperatures resulted in a porous, 3-D framework structure consisting of two interpenetrating cubic lattices, each featuring basic to zinc carboxylate vertices joined by trans-stilbene, analogous to the isoreticular MOF (IRMOF) series. We demonstrate that the optical properties of both embodiments correlate directly with the local ligand environments observed in the crystal structures. We further demonstrate that these materials produce high luminescent response to proton radiation and high radiation tolerance relative to prior scintillators. These features can be used to create sophisticated scintillating detection sensors.

  9. An Efficient Visible and Near-Infrared (NIR) Emitting Sm(III) Metal-Organic Framework (Sm-MOF) Sensitized by Excited-State Intramolecular Proton Transfer (ESIPT) Ligand.

    PubMed

    Chen, Ling; Zhang, Hao; Pan, Mei; Wei, Zhang-Wen; Wang, Hai-Ping; Fan, Ya-Nan; Su, Cheng-Yong

    2016-06-21

    We report herein an unprecedented example of a luminescent Sm(III) metal-organic framework (Sm-MOF), in which both the visible and near-infrared (NIR) emissions of Sm(3+) ions are able to be sensitized by an excited-state intramolecular proton transfer (ESIPT) ligand. Due to the solvent-mediated interchange between enol and keto excited states of the ligand and subsequent energy transfer rate to Sm(3+) ions, the luminescent decay lifetime of the Sm-MOF can be tuned in different solvent-grinding systems. PMID:27140938

  10. Studies of gas adsorption in flexible Metal-Organic frameworks

    NASA Astrophysics Data System (ADS)

    Sircar, Sarmishtha

    Flexible Metal-Organic frameworks that exhibit a gate-opening (GO) adsorption mechanism have potential for gas separations and gas storage. The GO phenomenon occurs when molecular gates in the structure expand/contract in response to the activation/de-activation of a system variable e.g. temperature, pressure or gas. Sharp discontinuities in the isotherm leading to S-shapes and large adsorption-desorption hysteresis are typical of this phenomenon. This study investigates the kinetics and thermodynamics of the GO behavior by combining adsorption measurements and analytical modeling of adsorption kinetics and capacity as a function of adsorbate, GO pressure, and temperature. Basic understanding of GO mechanism will help harness GO-MOF's as adsorbents for gas separations and storage. Experiments were performed on two precharacterized MOFs with verified GO behavior. These are (1) Zn2(bpdc)2(bpee), which expands from a relative amorphous to crystalline structure and (2) Cu[(dhbc) 2(4,4f-bpy)]H2O, a mutually interdigitated 2-D structure (bpdc = biphenyldicarboxylate, bpee = 1,2]bipyridylethene; DMF = N,N-dimethyl formamide, dhbc= 2,5-dihydroxybenzoic acid, bpy=bipyridine). Both sub- and super-critical adsorption data were collected using three adsorption units: a standard low-pressure volumetric adsorption unit, a commercial high-pressure gravimetric analyzer and a custom-built high-pressure differential volumetric unit. Collected laboratory data were combined with published adsorption rate and isotherm data for analysis to broaden the range of data collection. The accuracy of the high-pressure differential unit was improved by over 300-fold by changing analytical methods of processing data to establish a reliable null correction. A pronounced effect of the allowed experimental time was found at cryogenic temperatures on (1). Tightening the stability criteria used by the adsorption equipment to determine equilibration increased the experimental time from the order of

  11. Solvent Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article describes production of butanol [acetone-butanol-ethanol, (also called AB or ABE or solvent)] by fermentation using both traditional and current technologies. AB production from agricultural commodities such as corn and molasses was an important historical fermentation. Unfortunately,...

  12. Method and composition for testing for the presence of an alkali metal

    DOEpatents

    Guon, Jerold

    1981-01-01

    A method and composition for detecting the presence of an alkali metal on the surface of a body such as a metal plate, tank, pipe or the like is provided. The method comprises contacting the surface with a thin film of a liquid composition comprising a light-colored pigment, an acid-base indicator, and a nonionic wetting agent dispersed in a liquid carrier comprising a minor amount of water and a major amount of an organic solvent selected from the group consisting of the lower aliphatic alcohols, ketones and ethers. Any alkali metal present on the surface in elemental form or as an alkali metal hydroxide or alkali metal carbonate will react with the acid-base indicator to produce a contrasting color change in the thin film, which is readily discernible by visual observation or automatic techniques.

  13. Alkali extraction and in vitro antioxidant activity of Monascus mycelium polysaccharides.

    PubMed

    Wang, Pengrong; Chen, Danfeng; Jiang, Donghua; Dong, Xiameng; Chen, Panpan; Lin, Yaoxue

    2014-07-01

    In the present work, alkali extraction technology was used to optimize the extraction of Monascus mycelium polysaccharides for the first time. The extracting parameters of alkali extracted Monascus mycelium polysaccharides were optimized by Box-Behnken design (BBD). The optimum conditions were extraction temperature 49 °C, alkali concentration 7%, solvent/material ratio 23:1 (ml/g) and extraction time 2.3 h with an enhanced yield of 10.1%, compared with the yield 4.76% of hot water extraction, indicating that alkali extraction is a more efficient way. In order to discuss the biological activity of alkali extracted polysaccharides, we compared the in vitro antioxidant activity of alkali extracted polysaccharides (AMP) with hot water extracted polysaccharides (HMP). The result showed that AMP have the similar capability of scavenging both superoxide radical and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical of HMP in vitro. Therefore, alkali extraction technology is not only a high-efficiency way to extract AMP, but also can retain the natural antioxidant activities of AMP, which can be used in pharmaceutical and food industries. PMID:24966417

  14. The effect of pressure on the post-synthetic modification of a nanoporous metal-organic framework

    NASA Astrophysics Data System (ADS)

    McKellar, Scott C.; Graham, Alexander J.; Allan, David R.; Mohideen, M. Infas H.; Morris, Russell E.; Moggach, Stephen A.

    2014-03-01

    Here we report four post-synthetic modifications, including the first ever example of a high pressure-induced post-synthetic modification, of a porous copper-based metal-organic framework. Ligand exchange with a water ligand at the axial metal site occurs with methanol, acetonitrile, methylamine and ethylamine within a single-crystal and without the need to expose a free metal site prior to modification, resulting in significant changes in the pore size, shape and functionality. Pressure experiments carried out using isopropylalcohol and acetaldehyde, however, results in no ligand exchange. By using these solvents as hydrostatic media for high-pressure single-crystal X-ray diffraction experiments, we have investigated the effect of ligand exchange on the stability and compressibility of the framework and demonstrate that post-synthetic ligand exchange is very sensitive to both the molecular size and functionality of the exchanged ligand. We also demonstrate the ability to force hydrophilic molecules into hydrophobic pores using high pressures which results in a pressure-induced chemical decomposition of the Cu-framework.Here we report four post-synthetic modifications, including the first ever example of a high pressure-induced post-synthetic modification, of a porous copper-based metal-organic framework. Ligand exchange with a water ligand at the axial metal site occurs with methanol, acetonitrile, methylamine and ethylamine within a single-crystal and without the need to expose a free metal site prior to modification, resulting in significant changes in the pore size, shape and functionality. Pressure experiments carried out using isopropylalcohol and acetaldehyde, however, results in no ligand exchange. By using these solvents as hydrostatic media for high-pressure single-crystal X-ray diffraction experiments, we have investigated the effect of ligand exchange on the stability and compressibility of the framework and demonstrate that post-synthetic ligand

  15. Synthesis and Characterization of Metal-Organic Frameworks (MOFs) That Are Difficult to Access De Novo

    NASA Astrophysics Data System (ADS)

    Karagiaridi, Olga

    Metal-organic frameworks (MOFs) are a class of intriguing hybrid materials, comprised of metal-based nodes joined by organic linkers into a crystalline, porous, three-dimensional lattice. Their signature properties (well-defined surfaces, tailorability and ultra-high porosity) render them promising candidates for many applications, including, but not limited to, gas storage, gas separation, catalysis and sensing. One of the greatest challenges associated with MOF synthesis lies in the fact that obtaining a desired MOF structure that is tailored to perform a specific application is often not trivial. Traditional synthetic pathways termed "de novo synthesis" (typically one-pot reactions between the MOF structural building blocks under solvothermal conditions) often give rise to side products that do not possess the desired structure. To circumvent this problem, we have studied in depth two powerful MOF synthetic techniques -- solvent-assisted linker exchange (SALE) and transmetalation. These are heterogeneous reactions of parent MOF crystals with concentrated solutions of organic linkers and inorganic metal salts, respectively, that lead to the replacement of the linkers or metal nodes within the parent MOFs by the desired components, while the overall framework topology is preserved. The projects described in this dissertation have aimed to apply these techniques to transform simple (unfunctionalized) and easy to synthesize representative materials from various MOF systems to structurally and functionally interesting daughter products. Examples include synthesis of MOFs that are energetically "unfavorable", extension of MOF cages by longer linker incorporation, functionalization of MOF pores and endowment of MOFs with permanent and persistent porosity. Through these projects, we have been able to formulate a set of rules that can be applied to predict the successful outcome of SALE. Since the allure of MOFs lies in their applications, expanding the range of

  16. Functional tetrametallic linker modules for coordination polymers and metal-organic frameworks.

    PubMed

    Johansson, Frank B; Bond, Andrew D; McKenzie, Christine J

    2007-03-19

    potential construction of 1-D and 2-D coordination polymers/metal-organic frameworks (MOFs) capable of reversible O2 binding. PMID:17315867

  17. Hierarchical Metal-Organic Framework Hybrids: Perturbation-Assisted Nanofusion Synthesis.

    PubMed

    Yue, Yanfeng; Fulvio, Pasquale F; Dai, Sheng

    2015-12-15

    Metal-organic frameworks (MOFs) represent a new family of microporous materials; however, microporous-mesoporous hierarchical MOF materials have been less investigated because of the lack of simple, reliable methods to introduce mesopores to the crystalline microporous particles. State-of-the-art MOF hierarchical materials have been prepared by ligand extension methods or by using a template, resulting in intrinsic mesopores of longer ligands or replicated pores from template agents, respectively. However, mesoporous MOF materials obtained through ligand extension often collapse in the absence of guest molecules, which dramatically reduces the size of the pore aperture. Although the template-directed strategy allows for the preparation of hierarchical materials with larger mesopores, the latter requires a template removal step, which may result in the collapse of the implemented mesopores. Recently, a general template-free synthesis of hierarchical microporous crystalline frameworks, such as MOFs and Prussian blue analogues (PBAs), has been reported. This new method is based on the kinetically controlled precipitation (perturbation), with simultaneous condensation and redissolution of polymorphic nanocrystallites in the mother liquor. This method further eliminates the use of extended organic ligands and the micropores do not collapse upon removal of trapped guest solvent molecules, thus yielding hierarchical MOF materials with intriguing porosity in the gram scale. The hierarchical MOF materials prepared in this way exhibited exceptional properties when tested for the adsorption of large organic dyes over their corresponding microporous frameworks, due to the enhanced pore accessibility and electrolyte diffusion within the mesopores. As for PBAs, the pore size distribution of these materials can be tailored by changing the metals substituting Fe cations in the PB lattice. For these, the textural mesopores increased from approximately 10 nm for Cu analogue (meso

  18. High H2 uptake in Li-, Na-, K-metalated covalent organic frameworks and metal organic frameworks at 298 K.

    PubMed

    Mendoza-Cortés, José L; Han, Sang Soo; Goddard, William A

    2012-02-16

    The Yaghi laboratory has developed porous covalent organic frameworks (COFs), COF102, COF103, and COF202, and metal-organic frameworks (MOFs), MOF177, MOF180, MOF200, MOF205, and MOF210, with ultrahigh porosity and outstanding H(2) storage properties at 77 K. Using grand canonical Monte Carlo (GCMC) simulations with our recently developed first principles based force field (FF) from accurate quantum mechanics (QM), we calculated the molecular hydrogen (H(2)) uptake at 298 K for these systems, including the uptake for Li-, Na-, and K-metalated systems. We report the total, delivery and excess amount in gravimetric and volumetric units for all these compounds. For the gravimetric delivery amount from 1 to 100 bar, we find that eleven of these compounds reach the 2010 DOE target of 4.5 wt % at 298 K. The best of these compounds are MOF200-Li (6.34) and MOF200-Na (5.94), both reaching the 2015 DOE target of 5.5 wt % at 298 K. Among the undoped systems, we find that MOF200 gives a delivery amount as high as 3.24 wt % while MOF210 gives 2.90 wt % both from 1 to 100 bar and 298 K. However, none of these compounds reach the volumetric 2010 DOE target of 28 g H(2)/L. The best volumetric performance is for COF102-Na (24.9), COF102-Li (23.8), COF103-Na (22.8), and COF103-Li (21.7), all using delivery g H(2)/L units for 1-100 bar. These are the highest volumetric molecular hydrogen uptakes for a porous material under these thermodynamic conditions. Thus, one can obtain outstanding H(2) uptakes with Li, Na, and K doping of simple frameworks constructed from simple, cheap organic linkers. We present suggestions for strategies for synthesis of alkali metal-doped MOFs or COFs. PMID:22188543

  19. Hydrothermal alkali metal catalyst recovery process

    DOEpatents

    Eakman, James M.; Clavenna, LeRoy R.

    1979-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles primarily in the form of water soluble alkali metal formates by treating the particles with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of added carbon monoxide. During the treating process the water insoluble alkali metal compounds comprising the insoluble alkali metal residues are converted into water soluble alkali metal formates. The resultant aqueous solution containing water soluble alkali metal formates is then separated from the treated particles and any insoluble materials formed during the treatment process, and recycled to the gasification process where the alkali metal formates serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. This process permits increased recovery of alkali metal constituents, thereby decreasing the overall cost of the gasification process by reducing the amount of makeup alkali metal compounds necessary.

  20. Selective Catalysis in Nanoparticle Metal-Organic Framework Composites

    NASA Astrophysics Data System (ADS)

    Stephenson, Casey Justin

    -8 and Au/ZIF-8 shows that the nanoparticles of Au ZIF-8 remain within experimental uncertainty and unchanged, whereas Au nanoparticles of Au/ZIF suffered from server sintering. We performed solvent assisted linker exchange, a single-crystal to single-crystal transformation, on Pt ZIF-8 to exchange the 2-methylimidazole linkers with imidazole to form Pt SALEM-2. Since Pt SALEM-2 should have larger apertures than Pt ZIF-8, we investigated Pt ZIF-8 and Pt SALEM-2 as catalysts for the hydrogenation of substrates with increasingly larger kinetic diameter: 1-octene, cis-cyclohexene, and beta-pinene. Both catalysts were active for the hydrogenation of 1-octene, while only Pt SALEM-2 was active for cis-cyclohexene hydrogenation. Neither catalyst was active for the hydrogenation of beta-pinene, indicating that the Pt nanoparticles remained well encapsulated throughout the SALE process.

  1. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance.

    PubMed

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B Peter; Motkuri, Radha Kishan

    2016-01-01

    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method. PMID:27306598

  2. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance

    NASA Astrophysics Data System (ADS)

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B. Peter; Motkuri, Radha Kishan

    2016-06-01

    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method.

  3. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance

    PubMed Central

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B. Peter; Motkuri, Radha Kishan

    2016-01-01

    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method. PMID:27306598

  4. The dynamics of some metal-organic and organic molecules in water solution studied by molecular mechanical and molecular dynamical methods

    NASA Astrophysics Data System (ADS)

    Broo, Anders

    1993-07-01

    A force field is developed to reproduce geometries and vibration spectra of rutheniumhexaamine(III) and rutheniumhexamine(II) complexes. The force constants for ruthenium were then used in molecular dynamics simulation of a Ru 2+ ion, a Ru 3+ ion and Ru(NH 3) 5-pyrazine 2+ in water solution. Simulations of pyrazine and 1,3-dimethyluracile in water solution were also performed. A comparison of different ways of how to include solvation effects in quantum chemical calculations is discussed using the results from the simulations. The MD simulations show that the solvent surrounding a small charged ion, such as a Ru 2+ ion, have a pronounced shell structure and the first layer of solvent molecules is stable during a 61 ps simulation. For a metal-organic molecule as Ru(NH 3) 5-pyrazine the solvent shows shell structure, but the water molecules are exchanged frequently. In the relatively charge-symmetric pyrazine the solvent is not polarized around the molecule. In a molecule like 1,3-dimethyluracile, which is non-symmetric in the charge distribution, the water is strongly polarized.

  5. Integration of metal-organic frameworks into an electrochemical dielectric thin film for electronic applications

    PubMed Central

    Li, Wei-Jin; Liu, Juan; Sun, Zhi-Hua; Liu, Tian-Fu; Lü, Jian; Gao, Shui-Ying; He, Chao; Cao, Rong; Luo, Jun-Hua

    2016-01-01

    The integration of porous metal-organic frameworks onto the surface of materials, for use as functional devices, is currently emerging as a promising approach for gas sensing and flexible displays. However, research focused on potential applications in electronic devices is in its infancy. Here we present a facile strategy by which interpenetrated, crystalline metal-organic framework films are deposited onto conductive metal-plate anodes via in situ temperature-controlled electrochemical assembly. The nanostructure of the surface as well as the thickness and uniformity of the film are well controlled. More importantly, the resulting films exhibit enhanced dielectric properties compared to traditional inorganic or organic gate dielectrics. This study demonstrates the successful implementation of the rational design of metal-organic framework thin films on conductive supports with high-performance dielectric properties. PMID:27282348

  6. Integration of metal-organic frameworks into an electrochemical dielectric thin film for electronic applications

    NASA Astrophysics Data System (ADS)

    Li, Wei-Jin; Liu, Juan; Sun, Zhi-Hua; Liu, Tian-Fu; Lü, Jian; Gao, Shui-Ying; He, Chao; Cao, Rong; Luo, Jun-Hua

    2016-06-01

    The integration of porous metal-organic frameworks onto the surface of materials, for use as functional devices, is currently emerging as a promising approach for gas sensing and flexible displays. However, research focused on potential applications in electronic devices is in its infancy. Here we present a facile strategy by which interpenetrated, crystalline metal-organic framework films are deposited onto conductive metal-plate anodes via in situ temperature-controlled electrochemical assembly. The nanostructure of the surface as well as the thickness and uniformity of the film are well controlled. More importantly, the resulting films exhibit enhanced dielectric properties compared to traditional inorganic or organic gate dielectrics. This study demonstrates the successful implementation of the rational design of metal-organic framework thin films on conductive supports with high-performance dielectric properties.

  7. Biomimetic mineralization of metal-organic frameworks as protective coatings for biomacromolecules

    NASA Astrophysics Data System (ADS)

    Liang, Kang; Ricco, Raffaele; Doherty, Cara M.; Styles, Mark J.; Bell, Stephen; Kirby, Nigel; Mudie, Stephen; Haylock, David; Hill, Anita J.; Doonan, Christian J.; Falcaro, Paolo

    2015-06-01

    Enhancing the robustness of functional biomacromolecules is a critical challenge in biotechnology, which if addressed would enhance their use in pharmaceuticals, chemical processing and biostorage. Here we report a novel method, inspired by natural biomineralization processes, which provides unprecedented protection of biomacromolecules by encapsulating them within a class of porous materials termed metal-organic frameworks. We show that proteins, enzymes and DNA rapidly induce the formation of protective metal-organic framework coatings under physiological conditions by concentrating the framework building blocks and facilitating crystallization around the biomacromolecules. The resulting biocomposite is stable under conditions that would normally decompose many biological macromolecules. For example, urease and horseradish peroxidase protected within a metal-organic framework shell are found to retain bioactivity after being treated at 80 °C and boiled in dimethylformamide (153 °C), respectively. This rapid, low-cost biomimetic mineralization process gives rise to new possibilities for the exploitation of biomacromolecules.

  8. A Combined Experimental and Computational Study on the Stability of Nanofluids Containing Metal Organic Frameworks.

    PubMed

    Annapureddy, Harsha V R; Nune, Satish K; Motkuri, Radha Kishan; McGrail, B Peter; Dang, Liem X

    2015-07-23

    Computational studies on nanofluids composed of metal organic frameworks were performed using molecular modeling techniques. Grand Canonical Monte Carlo simulations were used to study the adsorption behavior of 1,1,1,3,3-pentafluoropropane (R-245fa) in a MIL-101 metal organic frameworks at various temperatures. To understand the stability of the nanofluid composed of MIL-101 particles, we performed molecular dynamics simulations to compute potentials of mean force between hypothetical MIL-101 fragments terminated with two different kinds of modulators in R-245fa and water. Our computed potentials of mean force results indicate that the metal organic frameworks particles tend to disperse better in water than in R-245fa. The reasons for this difference in dispersion were analyzed and are discussed in the paper. Our results agree with experimental results indicating that the potential models employed and modeling approaches provide good descriptions of molecular interactions and the reliabilities. PMID:25569021

  9. Biomimetic mineralization of metal-organic frameworks as protective coatings for biomacromolecules

    PubMed Central

    Liang, Kang; Ricco, Raffaele; Doherty, Cara M.; Styles, Mark J.; Bell, Stephen; Kirby, Nigel; Mudie, Stephen; Haylock, David; Hill, Anita J.; Doonan, Christian J.; Falcaro, Paolo

    2015-01-01

    Enhancing the robustness of functional biomacromolecules is a critical challenge in biotechnology, which if addressed would enhance their use in pharmaceuticals, chemical processing and biostorage. Here we report a novel method, inspired by natural biomineralization processes, which provides unprecedented protection of biomacromolecules by encapsulating them within a class of porous materials termed metal-organic frameworks. We show that proteins, enzymes and DNA rapidly induce the formation of protective metal-organic framework coatings under physiological conditions by concentrating the framework building blocks and facilitating crystallization around the biomacromolecules. The resulting biocomposite is stable under conditions that would normally decompose many biological macromolecules. For example, urease and horseradish peroxidase protected within a metal-organic framework shell are found to retain bioactivity after being treated at 80 °C and boiled in dimethylformamide (153 °C), respectively. This rapid, low-cost biomimetic mineralization process gives rise to new possibilities for the exploitation of biomacromolecules. PMID:26041070

  10. Poly(isophthalic acid)(ethylene oxide) as a Macromolecular Modulator for Metal-Organic Polyhedra.

    PubMed

    Chen, Teng-Hao; Wang, Le; Trueblood, Jonathan V; Grassian, Vicki H; Cohen, Seth M

    2016-08-01

    A new strategy was developed by using a polymer ligand, poly(isophthalic acid)(ethylene oxide), to modulate the growth of metal-organic polyhedra (MOP) crystals. This macromolecular modulator can effectively control the crystal habit of several different Cu24L24 (L = isophthalic acid derivatives) MOPs. The polymer also directed the formation of MOP structures under reaction conditions that only produce metal-organic frameworks in the absence of modulator. Moreover, the polymer also enabled the deposition of MOP crystals on glass surfaces. This macromolecular modulator strategy provides an innovative approach to control the morphology and assembly of MOP particles. PMID:27400759

  11. Multirate delivery of multiple therapeutic agents from metal-organic frameworks

    SciTech Connect

    McKinlay, Alistair C.; Allan, Phoebe K.; Renouf, Catherine L.; Duncan, Morven J.; Wheatley, Paul S.; Warrender, Stewart J.; Dawson, Daniel; Ashbrook, Sharon E.; Gil, Barbara; Marszalek, Bartosz; Düren, Tina; Williams, Jennifer J.; Charrier, Cedric; Mercer, Derry K.; Teat, Simon J.; Morris, Russell E.

    2014-12-01

    The highly porous nature of metal-organic frameworks (MOFs) offers great potential for the delivery of therapeutic agents. Here, we show that highly porous metal-organic frameworks can be used to deliver multiple therapeutic agents—a biologically active gas, an antibiotic drug molecule, and an active metal ion—simultaneously but at different rates. The possibilities offered by delivery of multiple agents with different mechanisms of action and, in particular, variable timescales may allow new therapy approaches. Here, we show that the loaded MOFs are highly active against various strains of bacteria.

  12. A mixed molecular building block strategy for the design of nested polyhedron metal-organic frameworks.

    PubMed

    Tian, Dan; Chen, Qiang; Li, Yue; Zhang, Ying-Hui; Chang, Ze; Bu, Xian-He

    2014-01-13

    A mixed molecular building block (MBB) strategy for the synthesis of double-walled cage-based porous metal-organic frameworks (MOFs) is presented. By means of this method, two isostructural porous MOFs built from unprecedented double-walled metal-organic octahedron were obtained by introducing two size-matching C3 -symmetric molecular building blocks with different rigidities. With their unique framework structures, these MOFs provide, to the best of our knowledge, the first examples of double-walled octahedron-based MOFs. PMID:24282117

  13. Metal-organic frameworks as host materials of confined supercooled liquids

    NASA Astrophysics Data System (ADS)

    Fischer, J. K. H.; Sippel, P.; Denysenko, D.; Lunkenheimer, P.; Volkmer, D.; Loidl, A.

    2015-10-01

    In this work, we examine the use of metal-organic framework (MOF) systems as host materials for the investigation of glassy dynamics in confined geometry. We investigate the confinement of the molecular glass former glycerol in three MFU-type MOFs with different pore sizes (MFU stands for "Metal-Organic Framework Ulm-University") and study the dynamics of the confined liquid via dielectric spectroscopy. In accord with previous reports on confined glass formers, we find different degrees of deviations from bulk behavior depending on pore size, demonstrating that MOFs are well-suited host systems for confinement investigations.

  14. Tunable electrical conductivity in metal-organic framework thin film devices

    DOEpatents

    Talin, Albert Alec; Allendorf, Mark D.; Stavila, Vitalie; Leonard, Francois

    2016-05-24

    A composition including a porous metal organic framework (MOF) including an open metal site and a guest species capable of charge transfer that can coordinate with the open metal site, wherein the composition is electrically conductive. A method including infiltrating a porous metal organic framework (MOF) including an open metal site with a guest species that is capable of charge transfer; and coordinating the guest species to the open metal site to form a composition including an electrical conductivity greater than an electrical conductivity of the MOF.

  15. Crystal growth of sulfide materials from alkali polysulfide liquids

    NASA Technical Reports Server (NTRS)

    White, W. B.

    1979-01-01

    The fluids experiment system was designed for low temperature solution growth, nominally aqueous solution growth. The alkali polysulfides, compositions in the systems Na2S-S and K2S-S form liquids in the temperature range of 190 C to 400 C. These can be used as solvents for other important classes of materials such as transition metal and other sulfides which are not soluble in aqueous media. Among these materials are luminescent and electroluminescent crystals whose physical properties are sensitive functions of crystal perfection and which could, therefore, serve as test materials for perfection improvement under microgravity conditions.

  16. cis-to-trans isomerization of azobenzene investigated by using thin films of metal-organic frameworks.

    PubMed

    Yu, Xiaojuan; Wang, Zhengbang; Buchholz, Maria; Füllgrabe, Nena; Grosjean, Sylvain; Bebensee, Fabian; Bräse, Stefan; Wöll, Christof; Heinke, Lars

    2015-09-21

    The activation barrier for cis-to-trans isomerization is a key parameter for governing the properties of photoswitchable molecules. This quantity can be computed by using theoretical methods, but experimental determination is not straightforward. Photoswitchable molecules typically do not change their conformation in the pure crystalline state. When the molecules are in solution, the switching is affected by the viscosity and polarity of the solvent and when embedded in polymers, the conformational change is affected by the polymer matrix. Here, we describe a novel approach where the photoswitchable group is integrated in a highly crystalline, porous molecular framework. Sufficiently large pore sizes in such metal-organic frameworks, MOFs, allow unhindered switching and the strictly periodic structure of the lattice eliminates virtually all contributions from inhomogeneities. Using IR spectroscopy to probe the conformational state of azobenzene, the energy barrier separating the cis and the trans state could be determined by an Arrhenius analysis of the data accumulated in a temperature regime between 314 K and 385 K. The result, 1.09 ± 0.09 eV, is in very good agreement with the activation energy reported for the thermal cis-to-trans isomerization of free azobenzene as computed by DFT calculations. PMID:26255748

  17. A novel porous anionic metal-organic framework with pillared double-layer structure for selective adsorption of dyes

    NASA Astrophysics Data System (ADS)

    Sheng, Shu-Nan; Han, Yi; Wang, Bin; Zhao, Cui; Yang, Fan; Zhao, Min-Jian; Xie, Ya-Bo; Li, Jian-Rong

    2016-01-01

    A novel porous anionic metal-organic framework, (Me2NH2)2[Zn2L1.5bpy]·2DMF (BUT-201; H4L=4,8-disulfonaphthalene-2,6-dicarboxylic acid; bpy=4,4-bipyridine; DMF=N,N-dimethylformamide), with pillared double-layer structure has been synthesized through the reaction of a sulfonated carboxylic acid ligand and Zn(NO3)2·6H2O with 4,4-bipyridine as a co-ligand. It is found that BUT-201 can rapidly adsorb cationic dyes with a smaller size such as Methylene Blue (MB) and Acriflavine Hydrochloride (AH) by substitution of guest (CH3)2NH2+, but has no adsorption towards the cationic dyes with a lager size such as Methylene Violet (MV), the anionic dyes like C. I. Acid Yellow 1 (AY1) and neutral dyes like C. I. Solvent Yellow 7 (SY7), respectively. The results show that the adsorption behavior of BUT-201 relates not only to the charge but also to the size/shape of dyes. Furthermore, the adsorbed dyes can be gradually released in the methanol solution of LiNO3.

  18. Rationally tuned micropores within enantiopure metal-organic frameworks for highly selective separation of acetylene and ethylene

    SciTech Connect

    Xiang, Sheng-Chang; Zhang, Zhangjing; Zhao, Cong-Gui; Hong, Kunlun; Zhao, Xuebo; Ding, De-Rong; Xie, Ming-Hua; Wu, Chuan-De; Madhab, Das; Gill, Rachel; Thomas, K Mark; Chen, Banglin

    2011-01-01

    Separation of acetylene and ethylene is an important industrial process because both compounds are essential reagents for a range of chemical products and materials. Current separation approaches include the partial hydrogenation of acetylene into ethylene over a supported Pd catalyst, and the extraction of cracked olefins using an organic solvent; both routes are costly and energy consuming. Adsorption technologies may allow separation, but microporous materials exhibiting highly selective adsorption of C{sub 2}H{sub 2}/C{sub 2}H{sub 4} have not been realized to date. Here, we report the development of tunable microporous enantiopure mixed-metal-organic framework (M'MOF) materials for highly selective separation of C{sub 2}H{sub 2} and C{sub 2}H{sub 4}. The high selectivities achieved suggest the potential application of microporous M'MOFs for practical adsorption-based separation of C{sub 2}H{sub 2}/C{sub 2}H{sub 4}.

  19. Micro-solid-phase extraction of organochlorine pesticides using porous metal-organic framework MIL-101 as sorbent.

    PubMed

    Huang, Zhenzhen; Lee, Hian Kee

    2015-07-01

    In this study, a metal-organic framework material, MIL-101, used as a micro-solid-phase extraction (μ-SPE) sorbent for efficient enrichment of five organochlorine pesticides (OCPs), including α-HCH, Aldrin, α-Chlordane, Dieldrin and p,p'-DDD from water samples, followed by gas chromatography-mass spectrometry, is reported. This study demonstrated a new application of MIL-101 using μ-SPE, an advantage of the latter being its ability to process complex aqueous matrices, due to the protection of the sorbent afforded by the hollow fiber membrane bag. Key factors affecting extraction efficiency were studied, including elution solvent, extraction and desorption time. Under the optimal extraction conditions, the calibration plots were linear from 0.05 to 50 ng/mL for α-HCH and p,p'-DDD, and 0.1 to 50 ng/mL for the other three analytes. The limits of detection were between 0.0025 and 0.016 ng/mL. The relative recoveries of the OCPs spiked into real water samples (at 5 ng/mL of each analyte) ranged from 87.6 to 98.6% with relative standard deviations of <10%. PMID:25987299

  20. A Mesoporous Indium Metal-Organic Framework: Remarkable Advances in Catalytic Activity for Strecker Reaction of Ketones.

    PubMed

    Reinares-Fisac, Daniel; Aguirre-Díaz, Lina María; Iglesias, Marta; Snejko, Natalia; Gutiérrez-Puebla, Enrique; Monge, M Ángeles; Gándara, Felipe

    2016-07-27

    With the aim of developing new highly porous, heterogeneous Lewis acid catalysts for multicomponent reactions, a new mesoporous metal-organic framework, InPF-110 ([In3O(btb)2(HCOO)(L)], (H3btb = 1,3,5-tris(4-carboxyphenyl)benzene acid, L = methanol, water, or ethanol), has been prepared with indium as the metal center. It exhibits a Langmuir surface area of 1470 m(2) g(-1), and its structure consists of hexagonal pores with a 2.8 nm aperture, which allows the diffusion of multiple substrates. This material presents a large density of active metal sites resulting in outstanding catalytic activity in the formation of substituted α-aminonitriles through the one-pot Strecker reaction of ketones. In this respect, InPF-110 stands out compared to other catalysts for this reaction due to the small catalyst loadings required, and without the need for heat or solvents. Furthermore, X-ray single crystal diffraction studies clearly show the framework-substrate interaction through coordination to the accessible indium sites. PMID:27420904

  1. A water resistant solid-phase microextraction fiber with high selectivity prepared by a metal organic framework with perfluorinated pores.

    PubMed

    Niu, Jiajia; Li, Zhongyue; Yang, Huijuan; Ye, Changwen; Chen, Chen; Li, Dong; Xu, Jun; Fan, Li

    2016-04-01

    A novel solid-phase microextraction (SPME) fiber was fabricated by the construction of fluorous metal organic frameworks (FMOF) and a polyimide (PI) composite strategy. As an auxiliary material, PI was expected to help FMOF particles form well-knit film on the surface of stainless steel wire and reinforce the coating, and FMOF was expected to afford a special structure to absorb, extract and enrich. Furthermore, it was explored for the headspace SPME (HS-SPME) of six volatile aromatic compounds (VACs) from water samples followed by gas chromatographic (GC) separation with flame ionization detection. Under the optimized conditions, the fiber afforded wide linear ranges (1-1000 μgL(-1)), low detection limits (0.15-0.9 μgL(-1)) and acceptable repeatability (<4.6%) and reproducibility (<7.3%). The FMOF@PI coated fiber not only offered large enhancement factors for benzene (1227) but also exhibited high extraction selectivity for benzene to other benzene homologues, hydrocarbons and phenols; for example, the extraction ratio of benzene to toluene, n-hexane and phenol could be as high as 10.2, 64.1 and 32.3, respectively. Moreover, the FMOF@PI-coated fiber afforded good thermal, water and organic solvent stabilities, and a long lifetime (over 200 times). The developed method was successfully applied to the determination of VACs in wastewater samples. PMID:26949215

  2. A spray-drying strategy for synthesis of nanoscale metal-organic frameworks and their assembly into hollow superstructures

    NASA Astrophysics Data System (ADS)

    Carné-Sánchez, Arnau; Imaz, Inhar; Cano-Sarabia, Mary; Maspoch, Daniel

    2013-03-01

    Metal-organic frameworks (MOFs) are among the most attractive porous materials known today. Their miniaturization to the nanoscale—into nanoMOFs—is expected to serve myriad applications from drug delivery to membranes, to open up novel avenues to more traditional storage and catalysis applications, and to enable the creation of sophisticated superstructures. Here, we report the use of spray-drying as a versatile methodology to assemble nanoMOFs, yielding spherical hollow superstructures with diameters smaller than 5 µm. This strategy conceptually mimics the emulsions used by chemists to confine the synthesis of materials, but does not require secondary immiscible solvents or surfactants. We demonstrate that the resulting spherical, hollow superstructures can be processed into stable colloids, whose disassembly by sonication affords discrete, homogeneous nanoMOFs. This spray-drying strategy enables the construction of multicomponent MOF superstructures, and the encapsulation of guest species within these superstructures. We anticipate that this will provide new routes to capsules, reactors and composite materials.

  3. Glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101: a molecular simulation study

    NASA Astrophysics Data System (ADS)

    Gupta, Krishna M.; Zhang, Kang; Jiang, Jianwen

    2015-08-01

    A molecular simulation study is reported on glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101. The F atom of MIL-101 is identified to be the most favorable adsorption site. Among three MIL-101-X (X = H, NH2 or CH3), the parent MIL-101 exhibits the highest adsorption capacity and recovery efficacy. Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose. The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility. Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed. The simulation study provides useful structural and dynamic properties of glucose in MIL-101, and it suggests that MIL-101 might be a potential candidate for glucose recovery.

  4. Electrolytic method to make alkali alcoholates using ion conducting alkali electrolyte/separator

    DOEpatents

    Joshi, Ashok V.; Balagopal, Shekar; Pendelton, Justin

    2011-12-13

    Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. An alkali ion conducting solid electrolyte configured to selectively transport alkali ions is positioned between the anolyte compartment and the buffer compartment. An alkali ion permeable separator is positioned between the buffer compartment and the catholyte compartment. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

  5. The calcium-alkali syndrome.

    PubMed

    Arroyo, Mariangeli; Fenves, Andrew Z; Emmett, Michael

    2013-04-01

    The milk-alkali syndrome was a common cause of hypercalcemia, metabolic alkalosis, and renal failure in the early 20th century. It was caused by the ingestion of large quantities of milk and absorbable alkali to treat peptic ulcer disease. The syndrome virtually vanished after introduction of histamine-2 blockers and proton pump inhibitors. More recently, a similar condition called the calcium-alkali syndrome has emerged as a common cause of hypercalcemia and alkalosis. It is usually caused by the ingestion of large amounts of calcium carbonate salts to prevent or treat osteoporosis and dyspepsia. We describe a 78-year-old woman who presented with weakness, malaise, and confusion. She was found to have hypercalcemia, acute renal failure, and metabolic alkalosis. Upon further questioning, she reported use of large amounts of calcium carbonate tablets to treat recent heartburn symptoms. Calcium supplements were discontinued, and she was treated with intravenous normal saline. After 5 days, the calcium and bicarbonate levels normalized and renal function returned to baseline. In this article, we review the pathogenesis of the calcium-alkali syndrome as well as the differences between the traditional and modern syndromes. PMID:23543983

  6. Lithium-Ion-Battery Anode Materials with Improved Capacity from a Metal-Organic Framework.

    PubMed

    Lin, Xiao-Ming; Niu, Ji-Liang; Lin, Jia; Wei, Lei-Ming; Hu, Lei; Zhang, Gang; Cai, Yue-Peng

    2016-09-01

    We present a porous metal-organic framework (MOF) with remarkable thermal stability that exhibits a discharge capacity of 300 mAh g(-1) as an anode material for a lithium-ion battery. Pyrolysis of the obtained MOF gives an anode material with improved capacity (741 mAh g(-1)) and superior cyclic stability. PMID:27548622

  7. High-throughput synthesis and characterization of nanocrystalline porphyrinic zirconium metal-organic frameworks.

    PubMed

    Kelty, M L; Morris, W; Gallagher, A T; Anderson, J S; Brown, K A; Mirkin, C A; Harris, T D

    2016-06-14

    We describe and employ a high-throughput screening method to accelerate the synthesis and identification of pure-phase, nanocrystalline metal-organic frameworks (MOFs). We demonstrate the efficacy of this method through its application to a series of porphyrinic zirconium MOFs, resulting in the isolation of MOF-525, MOF-545, and PCN-223 on the nanoscale. PMID:27247981

  8. Metal-organic scintillator crystals for X-ray, gamma ray, and neutron detection

    SciTech Connect

    Boatner, Lynn A; Kolopus, James A.; Neal, John S; Ramey, Joanne Oxendine; Wisniewski, Dariusz J

    2012-01-03

    New metal-organic materials are useful as scintillators and have the chemical formula LX.sub.3(CH.sub.3OH).sub.4 where L is Y, Sc, or a lanthanide element, and X is a halogen element. An example of the scintillator materials is CeCl.sub.3(CH.sub.3OH).sub.4.

  9. A Microporous Metal-Organic Framework for Gas Chromatographic Separation of Alkanes

    SciTech Connect

    Chen, Banglin; Liang, Chengdu; Yang, Jun; Contreras, Damacio; Clancy, Yvette; Lobkovsky, Emil B.; Yaghi, Omar; Dai, Sheng

    2006-01-01

    A zinc-based metal-organic framework (MOF) can be transformed reversibly from an open (a) to a dense (b) configuration. The microporous solid is the first example of a MOF that is highly selective in the gas-chromatographic separation of alkanes.

  10. A microporous metal-organic framework with polarized trifluoromethyl groups for high methane storage.

    PubMed

    Chang, Ganggang; Li, Bin; Wang, Hailong; Bao, Zongbi; Yildirim, Taner; Yao, Zizhu; Xiang, Shengchang; Zhou, Wei; Chen, Banglin

    2015-10-11

    A novel NbO-type metal-organic framework UTSA-88a with polarized trifluoromethyl groups exhibits a notably high methane storage capacity of 248 cm(3) (STP) cm(-3) (at room temperature and 65 bar) and a working capacity of 185 cm(3) (STP) cm(-3). PMID:26300179

  11. Chiral DHIP-Based Metal-Organic Frameworks for Enantioselective Recognition and Separation.

    PubMed

    Zhang, Jie; Li, Zijian; Gong, Wei; Han, Xing; Liu, Yan; Cui, Yong

    2016-08-01

    Two chiral porous 2,3-dihydroimidazo[1,2-a]pyridine (DHIP)-based metal-organic frameworks (MOFs) are assembled from an enantiopure dipyridyl-functionalized DHIP bridging ligand. The Zn-DHIP MOF shows a good enantioseparation performance toward aromatic sulfoxides, and the heterogeneous adsorbent can be readily recovered and reused without significant degradation of the separation performance. PMID:27227785

  12. A multifunctional lanthanide metal-organic framework supported by Keggin type polyoxometalates.

    PubMed

    Zhu, Wen-Hua; Zeng, Min; Wang, Juan; Li, Chen-Yang; Tian, Li-Hong; Yin, Jia-Cheng; Liu, Yu-Kun

    2016-06-21

    A neodymium metal-organic framework with 1D nanotubular channels incorporating Keggin type [SiWWO38](3-) has been synthesized by utilizing pyridine-2,5-dicarboxylic acid as an organic ligand. It represents an unusual polyoxometalate-templated framework with the multifunctionality of magnetism, near-infrared luminescence and the selective adsorption of Rhodamine B dye molecules. PMID:27242190

  13. A NbO-type metal-organic framework exhibiting high deliverable capacity for methane storage.

    PubMed

    Song, Chengling; Ling, Yajing; Feng, Yunlong; Zhou, Wei; Yildirim, Taner; He, Yabing

    2015-05-18

    A copper-based NbO-type metal-organic framework constructed from a tetracarboxylate incorporating phenylethyne as a spacer exhibited an exceptionally high methane working capacity of 184 cm(3) (STP) cm(-3) for methane storage. The value is among the highest reported for MOF materials. PMID:25892102

  14. Aqueous phase nitric oxide detection by an amine-decorated metal-organic framework.

    PubMed

    Desai, Aamod V; Samanta, Partha; Manna, Biplab; Ghosh, Sujit K

    2015-04-11

    Selective and sensitive aqueous phase nitric oxide (NO) detection has been demonstrated by implementing an unsophisticated approach of ligand modulation in a porous, robust metal-organic framework (MOF). The detection is achieved through deamination by NO in an amine-decorated luminescent MOF. This is the first report of employing a physiologically stable, functionalized MOF as a NO sensor. PMID:25744379

  15. Capturing neon - the first experimental structure of neon trapped within a metal-organic environment.

    PubMed

    Wood, Peter A; Sarjeant, Amy A; Yakovenko, Andrey A; Ward, Suzanna C; Groom, Colin R

    2016-08-21

    Despite being the fifth most abundant element in the atmosphere, neon has never been observed in an organic or metal-organic environment. This study shows the adsorption of this highly unreactive element within such an environment and reveals the first crystallographic observation of an interaction between neon and a transition metal. PMID:27452474

  16. Adsorption of two gas molecules at a single metal site in a metal-organic framework.

    PubMed

    Runčevski, Tomče; Kapelewski, Matthew T; Torres-Gavosto, Rodolfo M; Tarver, Jacob D; Brown, Craig M; Long, Jeffrey R

    2016-07-01

    One strategy to markedly increase the gas storage capacity of metal-organic frameworks is to introduce coordinatively-unsaturated metal centers capable of binding multiple gas molecules. Herein, we provide an initial demonstration that a single metal site within a framework can support the terminal coordination of two gas molecules-specifically hydrogen, methane, or carbon dioxide. PMID:27284590

  17. Surface functionalization of metal-organic polyhedron for homogeneous cyclopropanation catalysis

    SciTech Connect

    Lu, Weigang; Yuan, Daqiang; Yakovenko, Andrey; Zhou, Hong-Cai

    2012-03-13

    A super-paddlewheel (comprised of two paddlewheels) metal-organic polyhedron (MOP) containing surface hydroxyl groups was synthesized and characterized. Condensation reactions with linear alkyl anhydrides lead to new MOPs with enhanced solubility. As a result, the surface-modified MOP 4 was demonstrated as a homogeneous Lewis-acid catalyst.

  18. A highly sensitive near-infrared luminescent metal-organic framework thermometer in the physiological range.

    PubMed

    Zhao, Dian; Zhang, Jun; Yue, Dan; Lian, Xiusheng; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2016-07-01

    A near-infrared luminescent metal-organic framework Nd0.866Yb0.134BTB was developed as a self-calibrated thermometer in the physiological range. Its features include high sensitivity and resolution, and good biocompatibility, making such a material useful for biomedical applications. PMID:27284589

  19. Synthesis of well dispersed polymer grafted metal-organic framework nanoparticles.

    PubMed

    Xie, K; Fu, Q; He, Y; Kim, J; Goh, S J; Nam, E; Qiao, G G; Webley, P A

    2015-11-01

    Novel polymer grafted metal-organic framework (MOF) nanoparticles were synthesized. The formed core/shell nanoparticles exhibit outstanding water dispersity and pH sensitivity, and show their catalytic effect for the reduction reaction of 4-nitrophenol (NP) to 4-aminophenol (AP) when loaded with Pd(0) catalyst. PMID:26355917

  20. A vanadium(IV) pyrazolate metal-organic polyhedron with permanent porosity and adsorption selectivity.

    PubMed

    Augustyniak, A W; Fandzloch, M; Domingo, M; Łakomska, I; Navarro, J A R

    2015-10-11

    A vanadium(IV) pyrazolate-based open metal-organic polyhedron of [V3(μ3-O)O(OH)2(μ4-BPD)1.5(μ-HCOO)3] (BDP = benzene-1,4-bipyrazolate) formulation gives rise to a porous crystal structure exhibiting micro and mesoporosity which is useful for selective adsorption of gases. PMID:26291304

  1. Design of hydrophilic metal organic framework water adsorbents for heat reallocation.

    PubMed

    Cadiau, Amandine; Lee, Ji Sun; Damasceno Borges, Daiane; Fabry, Paul; Devic, Thomas; Wharmby, Michael T; Martineau, Charlotte; Foucher, Damien; Taulelle, Francis; Jun, Chul-Ho; Hwang, Young Kyu; Stock, Norbert; De Lange, Martijn F; Kapteijn, Freek; Gascon, Jorge; Maurin, Guillaume; Chang, Jong-San; Serre, Christian

    2015-08-26

    A new hydrothermally stable Al polycarboxylate metal-organic framework (MOF) based on a heteroatom bio-derived aromatic spacer is designed through a template-free green synthesis process. It appears that in some test conditions this MOF outperforms the heat reallocation performances of commercial SAPO-34. PMID:26193346

  2. On the dielectric and optical properties of surface-anchored metal-organic frameworks: A study on epitaxially grown thin films

    NASA Astrophysics Data System (ADS)

    Redel, Engelbert; Wang, Zhengbang; Walheim, Stefan; Liu, Jinxuan; Gliemann, Hartmut; Wöll, Christof

    2013-08-01

    We determine the optical constants of two highly porous, crystalline metal-organic frameworks (MOFs). Since it is problematic to determine the optical constants for the standard powder modification of these porous solids, we instead use surface-anchored metal-organic frameworks (SURMOFs). These MOF thin films are grown using liquid phase epitaxy (LPE) on modified silicon substrates. The produced SURMOF thin films exhibit good optical properties; these porous coatings are smooth as well as crack-free, they do not scatter visible light, and they have a homogenous interference color over the entire sample. Therefore, spectroscopic ellipsometry (SE) can be used in a straightforward fashion to determine the corresponding SURMOF optical properties. After careful removal of the solvent molecules used in the fabrication process as well as the residual water adsorbed in the voids of this highly porous solid, we determine an optical constant of n = 1.39 at a wavelength of 750 nm for HKUST-1 (stands for Hong Kong University of Science and Technology-1; and was first discovered there) or [Cu3(BTC)2]. After exposing these SURMOF thin films to moisture/EtOH atmosphere, the refractive index (n) increases to n = 1.55-1.6. This dependence of the optical properties on water/EtOH adsorption demonstrates the potential of such SURMOF materials for optical sensing.

  3. A 3D chiral metal-organic framework based on left-handed helices containing 3-amino-1 H-1,2,4-triazole ligand

    NASA Astrophysics Data System (ADS)

    Liu, Bing; Yang, Tian-Yi; Feng, Hui-Jun; Zhang, Zong-Hui; Xu, Ling

    2015-10-01

    A chiral metal-organic framework, [Cu(atr)(OH)]·0.5H2O·0.5en (1) (Hatr=3-amino-1 H-1,2,4-triazole, en=ethylenediamine), was constructed via diffusion reaction of the achiral Hatr ligand and CuSO4 as starting materials. Compound 1 crystallizes in the chiral space group P3221 and features a porous metal-organic framework with 44.1% solvent-accessible volume fabricated by left-handed helices with a pitch height of lp=10.442 Å. Six helices gather around in a cycle forming a large honeycomb channel with a 6.58 Å inner diameter. Cu(II) center and atr‒ ligand regarded as 3-connected nodes, compound 1 can be simplified to a 3-c uninodal {4.122} (qtz-h) topological network. A gradual decreasing in the magnetic moment depending on temperature decreasing indicates an antiferromagnetic interaction in 1. The powder XRD confirms the bulk sample is a single crystal pure phase, and the thermogravimetric analysis shows the thermal stability of 1 is up to ca. 240 °C.

  4. Solvation structure and transport properties of alkali cations in dimethyl sulfoxide under exogenous static electric fields

    SciTech Connect

    Kerisit, Sebastien; Vijayakumar, M. E-mail: karl.mueller@pnnl.gov; Han, Kee Sung; Mueller, Karl T. E-mail: karl.mueller@pnnl.gov

    2015-06-14

    A combination of molecular dynamics simulations and pulsed field gradient nuclear magnetic resonance spectroscopy is used to investigate the role of exogenous electric fields on the solvation structure and dynamics of alkali ions in dimethyl sulfoxide (DMSO) and as a function of temperature. Good agreement was obtained, for select alkali ions in the absence of an electric field, between calculated and experimentally determined diffusion coefficients normalized to that of pure DMSO. Our results indicate that temperatures of up to 400 K and external electric fields of up to 1 V nm{sup −1} have minimal effects on the solvation structure of the smaller alkali cations (Li{sup +} and Na{sup +}) due to their relatively strong ion-solvent interactions, whereas the solvation structures of the larger alkali cations (K{sup +}, Rb{sup +}, and Cs{sup +}) are significantly affected. In addition, although the DMSO exchange dynamics in the first solvation shell differ markedly for the two groups, the drift velocities and mobilities are not significantly affected by the nature of the alkali ion. Overall, although exogenous electric fields induce a drift displacement, their presence does not significantly affect the random diffusive displacement of the alkali ions in DMSO. System temperature is found to have generally a stronger influence on dynamical properties, such as the DMSO exchange dynamics and the ion mobilities, than the presence of electric fields.

  5. Metal-Organic Frameworks: Bimetallic Metal-Organic Frameworks: Probing the Lewis Acid Site for CO2 Conversion (Small 17/2016).

    PubMed

    Zou, Ruyi; Li, Pei-Zhou; Zeng, Yong-Fei; Liu, Jia; Zhao, Ruo; Duan, Hui; Luo, Zhong; Wang, Jin-Gui; Zou, Ruqiang; Zhao, Yanli

    2016-05-01

    On page 2334, R. Q. Zou, Y. L. Zhao, and co-workers present a porous metal-organic framework (MOF) that serves as a platform for studying the metal exchange effect on both CO2 adsorption and catalytic fixation. The effect is demonstrated by catalytic CO2 cycloaddition with propylene oxide to produce propylene carbonate. Molecular dynamic simulations are carried out to further confirm the catalytic performance of these MOFs on chemical fixation of CO2 to carbonates. This research sheds light on how metal exchange could influence the intrinsic properties of MOFs. PMID:27124007

  6. The Construction of Metal-Organic Framework with Active Backbones by the Utilization of Reticular Chemistry

    NASA Astrophysics Data System (ADS)

    Choi, Eunwoo

    With the principles of reticular chemistry, metal-organic frameworks with ultra-high porosity, chiral-recognition unit as a chiral stationary phase, metalloporhyrins for enhanced hydrogen adsorption and an intrinsic conductivity to form porous conductors, have been prepared. This dissertation presents how the principles of reticular chemistry were utilized to achieve in the preparations of metal-organic frameworks with a large surface area and active backbones. Through the simple isoreticular (having the same framework topology) expansion from MOF-177 composed with 1,3,5-tris(4'-carboxyphenyl-)benzene (BTB3-) as the strut; MOF-200 was prepared with 4,4',4"-(benzene-1,3,5-triyl-tris(benzene-4,1-diy1))tribenzoic acid an extension from BTB3- by a phenylene unit to yield one of the most porous MOFs with a Langmuir surface area of 10,400 m2. and the lowest density of 0.22 cm3.g-1. A successful thermal polymerization reaction at 325 °C inside of the pores of highly porous MOF, MOF-177, was performed and verified the integrity of the MOF structure even after the thermal reaction. 1,4-Diphenylbutadiyne that is known to polymerize upon heating to form a conjugated backbone was impregnated via solution-diffusion into MOF-177 and then subsequently polymerized by heat to form polymer impregnated MOF-177. Characterization was carried out using powder X-ray diffraction and volumetric sorption analyzer. MOF-1020 with a linear quaterphenyl dicarboxylate-based strut was designed to contain a chiral bisbinaphthyl crown-ether moiety for alkyl ammonium resolution was precisely placed into a Zn4O(CO2)6-based cubic MOF structure. Unfortunately, the chiral resolution was not achieved due to the sensitivity and the pore environment of MOF-1020. However, an interesting phenomenon was observed, where the loss of crystallinity occurs upon solvent removal while the crystallites remain shiny and crystalline, but it readily is restored upon re-solvation of the crystallites. This rare

  7. Progress in Understanding Alkali-Alkali Spin Relaxation

    NASA Astrophysics Data System (ADS)

    Erickson, Christopher J.; Happer, William; Chann, Bien; Kadlecek, Stephen; Anderson, L. W.; Walker, Thad G.

    2000-06-01

    In extensive experiments we have shown that a spin interaction with a relatively long correlation time causes much of the spin relaxation in very dense alkali-metal vapors. The spin relaxation is affected by the pressure of the helium or nitrogen buffer gas, although there is little dependence at pressures above one atmosphere. There are substantial differences in the relaxation rates for different isotopes of the same element, for example ^87Rb and ^85Rb. We have completed extensive modeling of how singlet and triplet dimers and doublet trimers of the alkali-metal atoms could cause spin relaxation in dense alkali-metal vapors. In the case of doublet trimers or triplet dimers, we assume the main coupling to the nuclear spins is through the Fermi Contact interaction with the unpaired electrons. Spin loss to the rotation of the molecule is assumed to occur through the electronic spin-rotation and spin-axis (dipole-dipole) interactions for the triplet dimers. For the singlet dimers, we assume that the nuclear spins couple directly to the rotational angular momentum of the molecule through the electric quadrupole interaction. We account for all of the total nuclear spin states that occur for the dimers and trimers. We have also considered the possibility that the collisional breakup and formation rates of the dimers or trimers could saturate with increasing buffer gas pressure. Such saturation occurs in many other unimolecular reactions and is often ascribed to breakup through activated states.

  8. Selectively catalytic activity of metal-organic frameworks depending on the N-position within the pyridine ring of their building blocks

    NASA Astrophysics Data System (ADS)

    Xu, Haitao; Gou, Yongxia; Ye, Jing; Xu, Zhen-liang; Wang, Zixuan

    2016-05-01

    Iron metal-organic frameworks (MOFs) [Fe(L)2(SCN)2]∝ (L1: 4-bpdh=2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene for 1Fe; and L2: 3-bpdh=2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene for 2Fe) were assembled in a MeOH-H2O solvent system. 1Fe exhibits a two-dimensional extended-grid network, whereas 2Fe exhibits a stair-like double-chain; the N-position within the pyridine ring of the complexes was observed to regulate the MOF structure as layers or chains. Furthermore, selectively catalytic activity was observed for the layered MOF but not the chain-structured MOF; micro/nanoparticles of the layered MOF were therefore investigated for new potential applications of micro/nano MOFs.

  9. Tunable Electrical Conductivity and Magnetic Property of the Two Dimensional Metal Organic Framework [Cu(TPyP)Cu2(O2CCH3)4].

    PubMed

    Sengupta, Ananya; Datta, Subhadeep; Su, Chenliang; Herng, Tun Seng; Ding, Jun; Vittal, Jagadese J; Loh, Kian Ping

    2016-06-29

    The coordination chemistry between copper acetate [Cu2(OAc)4] and 5,10,15,20-tetra-4-pyridyl-21H,23H-porphine (porphyrin, H2TPyP) is found to give rise to either a 2D metal-organic framework (MOF) [Cu(TPyP)Cu2(O2CCH3)4] or a 3D MOF [Cu(TPyP)CuCl2]·2.5TCE·7H2O], depending on the choice of solvent. The 2D MOF can be made into a film, which was doped with 7,7,8,8-tetracyanoquinodimethane (TCNQ), and the electrical conductivity of the thin film was increased by 3 orders of magnitude with respect to that of the undoped Cu-MOF. The formation of a charge-transfer complex between TCNQ and the 2D Cu-MOF also imparts stronger paramagnetic properties than for the undoped MOF. PMID:27268770

  10. Structural diversity and magnetic properties of six metal-organic coordination polymers based on semi-rigid V-shape tetracarboxylic acid ligand

    NASA Astrophysics Data System (ADS)

    Yang, Shanshan; Bai, Yue-Ling; Xing, Feifei; Zhao, Yongmei; Li, Ming-Xing; Shao, Min; Zhu, Shourong

    2016-04-01

    Six Mn metal-organic frameworks have been synthesized under solvothermal conditions with V-shaped terphenyl tetracarboxylate ligands (H4ttac). Their structures were characterized by elemental analysis, infrared spectra, PXRD, thermogravimetric analysis, and single-crystal X-ray diffraction analysis. Crystal structures reveal that the coordination number of H4ttac ligand varies from 6 to 10, and each ligand links 4-8 Mn(II) ions. Coordination modes vary from η6μ4 to η10μ8. The existence of DMF solvent can increase coordination number of the ligand. The first coordination saturated phthalate is presented. The variable-temperature magnetic studies indicate that complexes exhibit dominant antiferromagnetic behaviors. Structural parameters and coordination modes were summarized. The porosity of these complexes is less than 15%, indicating that the V-shape ligand is not a good choice to construct porous coordination polymers.

  11. An anionic zeolite-like metal-organic framework (AZMOF) with a Moravia network for organic dye absorption through cation-exchange.

    PubMed

    Shen, Yu; Fan, Cong-Cong; Wei, Yu-Zhen; Du, Jie; Zhu, Hai-Bin; Zhao, Yue

    2016-07-01

    An anionic zeolite-like metal-organic framework (AZMOF) with a twisted partially augmented the net, known as the "Moravia" net, [(CH3)2NH2]6[Sr13(O)3()8(OH)2(H2O)16]·xS (, where S represents non-coordinated solvent molecules, and is the abbreviation of benzo-(1,2;3,4;5,6)-tris-(thiophene-2'-carboxylic acid)), has been solvothermally synthesized and characterized, which possesses an anionic framework and nano-sized sodalite cage. Through cation-exchange, is capable of uptaking large organic cationic dyes including Rhodamine B (RB), Basic Red 2 (BR2), Crystal Violet (CV) and Methylene Blue (MB), amongst which the adsorption capability for RB (up to 545 mg g(-1)), and BR2 (up to 675 mg g(-1)) is the highest for reported absorbants to date. PMID:27301344

  12. Influence of Guest Exchange on the Magnetization Dynamics of Dilanthanide Single-Molecule-Magnet Nodes within a Metal-Organic Framework.

    PubMed

    Zhang, Xuejing; Vieru, Veacheslav; Feng, Xiaowen; Liu, Jun-Liang; Zhang, Zhenjie; Na, Bo; Shi, Wei; Wang, Bing-Wu; Powell, Annie K; Chibotaru, Liviu F; Gao, Song; Cheng, Peng; Long, Jeffrey R

    2015-08-17

    Multitopic organic linkers can provide a means to organize metal cluster nodes in a regular three-dimensional array. Herein, we show that isonicotinic acid N-oxide (HINO) serves as the linker in the formation of a metal-organic framework featuring Dy2 single-molecule magnets as nodes. Importantly, guest solvent exchange induces a reversible single-crystal to single-crystal transformation between the phases Dy2(INO)4(NO3)2⋅2 solvent (solvent=DMF (Dy2-DMF), CH3CN (Dy2-CH3CN)), thereby switching the effective magnetic relaxation barrier (determined by ac magnetic susceptibility measurements) between a negligible value for Dy2-DMF and 76 cm(-1) for Dy2-CH3CN. Ab initio calculations indicate that this difference arises not from a significant change in the intrinsic relaxation barrier of the Dy2 nodes, but rather from a slowing of the relaxation rate of incoherent quantum tunneling of the magnetization by two orders of magnitude. PMID:26119180

  13. Metal-organic frameworks for analytical chemistry: from sample collection to chromatographic separation.

    PubMed

    Gu, Zhi-Yuan; Yang, Cheng-Xiong; Chang, Na; Yan, Xiu-Ping

    2012-05-15

    In modern analytical chemistry researchers pursue novel materials to meet analytical challenges such as improvements in sensitivity, selectivity, and detection limit. Metal-organic frameworks (MOFs) are an emerging class of microporous materials, and their unusual properties such as high surface area, good thermal stability, uniform structured nanoscale cavities, and the availability of in-pore functionality and outer-surface modification are attractive for diverse analytical applications. This Account summarizes our research on the analytical applications of MOFs ranging from sampling to chromatographic separation. MOFs have been either directly used or engineered to meet the demands of various analytical applications. Bulk MOFs with microsized crystals are convenient sorbents for direct application to in-field sampling and solid-phase extraction. Quartz tubes packed with MOF-5 have shown excellent stability, adsorption efficiency, and reproducibility for in-field sampling and trapping of atmospheric formaldehyde. The 2D copper(II) isonicotinate packed microcolumn has demonstrated large enhancement factors and good shape- and size-selectivity when applied to on-line solid-phase extraction of polycyclic aromatic hydrocarbons in water samples. We have explored the molecular sieving effect of MOFs for the efficient enrichment of peptides with simultaneous exclusion of proteins from biological fluids. These results show promise for the future of MOFs in peptidomics research. Moreover, nanosized MOFs and engineered thin films of MOFs are promising materials as novel coatings for solid-phase microextraction. We have developed an in situ hydrothermal growth approach to fabricate thin films of MOF-199 on etched stainless steel wire for solid-phase microextraction of volatile benzene homologues with large enhancement factors and wide linearity. Their high thermal stability and easy-to-engineer nanocrystals make MOFs attractive as new stationary phases to fabricate MOF

  14. Potential of metal-organic frameworks for separation of xenon and krypton.

    PubMed

    Banerjee, Debasis; Cairns, Amy J; Liu, Jian; Motkuri, Radha K; Nune, Satish K; Fernandez, Carlos A; Krishna, Rajamani; Strachan, Denis M; Thallapally, Praveen K

    2015-02-17

    dissolution in solvents and physisorption on porous materials. Physisorption-based separation and adsorption on highly functional porous materials are promising alternatives to the energy-intensive cryogenic distillation process, where the adsorbents are characterized by high surface areas and thus high removal capacities and often can be chemically fine-tuned to enhance the adsorbate-adsorbent interactions for optimum selectivity. Several traditional porous adsorbents such as zeolites and activated carbon have been tested for noble gas capture but have shown low capacity, selectivity, and lack of modularity. Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) are an emerging class of solid-state adsorbents that can be tailor-made for applications ranging from gas adsorption and separation to catalysis and sensing. Herein we give a concise summary of the background and development of Xe/Kr separation technologies with a focus on UNF reprocessing and the prospects of MOF-based adsorbents for that particular application. PMID:25479165

  15. Positron-alkali atom scattering

    NASA Technical Reports Server (NTRS)

    Mceachran, R. P.; Horbatsch, M.; Stauffer, A. D.; Ward, S. J.

    1990-01-01

    Positron-alkali atom scattering was recently investigated both theoretically and experimentally in the energy range from a few eV up to 100 eV. On the theoretical side calculations of the integrated elastic and excitation cross sections as well as total cross sections for Li, Na and K were based upon either the close-coupling method or the modified Glauber approximation. These theoretical results are in good agreement with experimental measurements of the total cross section for both Na and K. Resonance structures were also found in the L = 0, 1 and 2 partial waves for positron scattering from the alkalis. The structure of these resonances appears to be quite complex and, as expected, they occur in conjunction with the atomic excitation thresholds. Currently both theoretical and experimental work is in progress on positron-Rb scattering in the same energy range.

  16. Alkali metal/sulfur battery

    DOEpatents

    Anand, Joginder N.

    1978-01-01

    Alkali metal/sulfur batteries in which the electrolyte-separator is a relatively fragile membrane are improved by providing means for separating the molten sulfur/sulfide catholyte from contact with the membrane prior to cooling the cell to temperatures at which the catholyte will solidify. If the catholyte is permitted to solidify while in contact with the membrane, the latter may be damaged. The improvement permits such batteries to be prefilled with catholyte and shipped, at ordinary temperatures.

  17. Superconductivity in alkali metal fullerides

    NASA Astrophysics Data System (ADS)

    Murphy, D. W.; Rosseinsky, M. J.; Haddon, R. C.; Ramirez, A. P.; Hebard, A. F.; Tycko, R.; Fleming, R. M.; Dabbagh, G.

    1991-12-01

    The recent synthesis of macroscopic quantities of spherical molecular carbon compounds, commonly called fullerenes, has stimulated a wide variety of studies of the chemical and physical properties of this novel class of compounds. We discovered that the smallest of the known fullerenes, C 60, could be made conducting and superconducting by reaction with alkali metals. In this paper, an overview of the motivation for these discoveries and some recent results are presented.

  18. Alkali metal sources for OLED devices

    NASA Astrophysics Data System (ADS)

    Cattaneo, Lorena; Longoni, Giorgio; Bonucci, Antonio; Tominetti, Stefano

    2005-07-01

    In OLED organic layers electron injection is improved by using alkali metals as cathodes, to lower work function or, as dopants of organic layer at cathode interface. The creation of an alkali metal layer can be accomplished through conventional physical vapor deposition from a heated dispenser. However alkali metals are very reactive and must be handled in inert atmosphere all through the entire process. If a contamination takes place, it reduces the lithium deposition rate and also the lithium total yield in a not controlled way. An innovative alkali metal dispensing technology has been developed to overcome these problems and ensure OLED alkali metal cathode reliability. The alkali Metal dispenser, called Alkamax, will be able to release up to a few grams of alkali metals (in particular Li and Cs) throughout the adoption of a very stable form of the alkali metal. Lithium, for example, can be evaporated "on demand": the evaporation could be stopped and re-activated without losing alkali metal yield because the metal not yet consumed remains in its stable form. A full characterization of dispensing material, dispenser configuration and dispensing process has been carried out in order to optimize the evaporation and deposition dynamics of alkali metals layers. The study has been performed applying also inside developed simulations tools.

  19. Giant negative linear compression positively coupled to massive thermal expansion in a metal-organic framework.

    PubMed

    Cai, Weizhao; Katrusiak, Andrzej

    2014-01-01

    Materials with negative linear compressibility are sought for various technological applications. Such effects were reported mainly in framework materials. When heated, they typically contract in the same direction of negative linear compression. Here we show that this common inverse relationship rule does not apply to a three-dimensional metal-organic framework crystal, [Ag(ethylenediamine)]NO3. In this material, the direction of the largest intrinsic negative linear compression yet observed in metal-organic frameworks coincides with the strongest positive thermal expansion. In the perpendicular direction, the large linear negative thermal expansion and the strongest crystal compressibility are collinear. This seemingly irrational positive relationship of temperature and pressure effects is explained and the mechanism of coupling of compressibility with expansivity is presented. The positive coupling between compression and thermal expansion in this material enhances its piezo-mechanical response in adiabatic process, which may be used for designing new artificial composites and ultrasensitive measuring devices. PMID:24993679

  20. Metal-organic frameworks with wine-rack motif: What determines their flexibility and elastic properties?

    NASA Astrophysics Data System (ADS)

    Ortiz, Aurélie U.; Boutin, A.; Fuchs, Alain H.; Coudert, François-Xavier

    2013-05-01

    We present here a framework for the analysis of the full tensors of second-order elastic constants of metal-organic frameworks, which can be obtained by ab initio calculations. We describe the various mechanical properties one can derive from such tensors: directional Young's modulus, shear modulus, Poisson ratio, and linear compressibility. We then apply this methodology to four different metal-organic frameworks displaying a wine-rack structure: MIL-53(Al), MIL-47, MIL-122(In), and MIL-140A. From these results, we shed some light into the link between mechanical properties, geometric shape, and compliance of the framework of these porous solids. We conclude by proposing a simple criterion to assess the framework compliance, based on the lowest eigenvalue of its second-order elastic tensor.

  1. Computational studies of adsorption in metal organic frameworks and interaction of nanoparticles in condensed phases

    SciTech Connect

    Annapureddy, HVR; Motkuri, RK; Nguyen, PTM; Truong, TB; Thallapally, PK; McGrail, BP; Dang, LX

    2014-02-05

    In this review, we describe recent efforts to systematically study nano-structured metal organic frameworks (MOFs), also known as metal organic heat carriers, with particular emphasis on their application in heating and cooling processes. We used both molecular dynamics and grand canonical Monte Carlo simulation techniques to gain a molecular-level understanding of the adsorption mechanism of gases in these porous materials. We investigated the uptake of various gases such as refrigerants R12 and R143a. We also evaluated the effects of temperature and pressure on the uptake mechanism. Our computed results compared reasonably well with available measurements from experiments, thus validating our potential models and approaches. In addition, we investigated the structural, diffusive and adsorption properties of different hydrocarbons in Ni-2(dhtp). Finally, to elucidate the mechanism of nanoparticle dispersion in condensed phases, we studied the interactions among nanoparticles in various liquids, such as n-hexane, water and methanol.

  2. Doping of Metal-Organic Frameworks with Functional Guest Molecules and Nanoparticles

    NASA Astrophysics Data System (ADS)

    Schröder, Felicitas; Fischer, Roland A.

    Nanoparticle synthesis within metal-organic frameworks (MOFs) is performed by the adsorption of suitable precursor molecules for the metal component and subsequent decomposition to the composite materials nanoparticles@MOF. This chapter will review different approaches of loading MOFs with more complex organic molecules and metal-organic precursor molecules. The related reactions inside MOFs are discussed with a focus on stabilizing reactive intermediates in the corresponding cavities. The syntheses of metal and metal oxide nanoparticles inside MOFs are reviewed, and different synthetic routes compared. Emphasis is placed on the micro structural characterization of the materials nanoparticles@MOF with a particular focus on the location of embedded nanoparticles using TEM methods. Some first examples of applications of the doped MOFs in heterogeneous catalysis and hydrogen storage are described.

  3. Life cycle cost study for coated conductor manufacture by metal organic chemical vapor deposition

    SciTech Connect

    Chapman, J.N.

    1999-07-13

    The purpose of this report is to calculate the cost of producing high temperature superconducting wire by the Metal Organic Chemical Vapor Deposition (MOCVD) process. The technology status is reviewed from the literature and a plant conceptual design is assumed for the cost calculation. The critical issues discussed are the high cost of the metal organic precursors, the material utilization efficiency and the capability of the final product as measured by the critical current density achieved. Capital, operating and material costs are estimated and summed as the basis for calculating the cost per unit length of wire. Sensitivity analyses of key assumptions are examined to determine their effects on the final wire cost. Additionally, the cost of wire on the basis of cost per kiloampere per meter is calculated for operation at lower temperatures than the liquid nitrogen boiling temperature. It is concluded that this process should not be ruled out on the basis of high cost of precursors alone.

  4. Self-Supporting Metal-Organic Layers as Single-Site Solid Catalysts.

    PubMed

    Cao, Lingyun; Lin, Zekai; Peng, Fei; Wang, Weiwei; Huang, Ruiyun; Wang, Cheng; Yan, Jiawei; Liang, Jie; Zhang, Zhiming; Zhang, Teng; Long, Lasheng; Sun, Junliang; Lin, Wenbin

    2016-04-11

    Metal-organic layers (MOLs) represent an emerging class of tunable and functionalizable two-dimensional materials. In this work, the scalable solvothermal synthesis of self-supporting MOLs composed of [Hf6 O4 (OH)4 (HCO2 )6 ] secondary building units (SBUs) and benzene-1,3,5-tribenzoate (BTB) bridging ligands is reported. The MOL structures were directly imaged by TEM and AFM, and doped with 4'-(4-benzoate)-(2,2',2''-terpyridine)-5,5''-dicarboxylate (TPY) before being coordinated with iron centers to afford highly active and reusable single-site solid catalysts for the hydrosilylation of terminal olefins. MOL-based heterogeneous catalysts are free from the diffusional constraints placed on all known porous solid catalysts, including metal-organic frameworks. This work uncovers an entirely new strategy for designing single-site solid catalysts and opens the door to a new class of two-dimensional coordination materials with molecular functionalities. PMID:26954885

  5. Dynamics and thermal stability of surface-confined metal-organic chains

    NASA Astrophysics Data System (ADS)

    Ecija, D.; Marschall, M.; Reichert, J.; Kasperski, A.; Nieckarz, D.; Szabelski, P.; Auwärter, W.; Barth, J. V.

    2016-01-01

    Understanding the dynamics and thermal stability of metallosupramolecular chains on surfaces is of relevance for the development of molecular connectors in nanoelectronics or other fields. Here we present a combined study using temperature-controlled STM and Monte Carlo simulations to explore the behavior of metal-organic porphyrin chains on Cu(111) based on two-fold pyridyl-Cu-pyridyl coordination motifs. We monitor their behavior in the 180-360 K range, revealing three thermal regimes: i) flexibility up to 240 K, ii) diffusion of chain fragments and partial dissociation into a fluid phase for T > 240 K, and iii) full dissolution with temperatures exceeding ~ 320 K. The experimentally estimated reaction enthalpy of the metal-organic bonding is ~ 0.6 eV. Monte Carlo simulations reproduce qualitatively our STM observations and reveal the preference for linear and extended supramolecular chains with reduced substrate temperatures.

  6. Chromophore-Based Luminescent Metal-Organic Frameworks as Lighting Phosphors.

    PubMed

    Lustig, William P; Wang, Fangming; Teat, Simon J; Hu, Zhichao; Gong, Qihan; Li, Jing

    2016-08-01

    Energy-efficient solid-state-lighting (SSL) technologies are rapidly developing, but the lack of stable, high-performance rare-earth free phosphors may impede the growth of the SSL market. One possible alternative is organic phosphor materials, but these can suffer from lower quantum yields and thermal instability compared to rare-earth phosphors. However, if luminescent organic chromophores can be built into a rigid metal-organic framework, their quantum yields and thermal stability can be greatly improved. This Forum Article discusses the design of a group of such chromophore-based luminescent metal-organic frameworks with exceptionally high performance and rational control of the important parameters that influence their emission properties, including electronic structures of chromophore, coligands, metal ions, and guest molecules. PMID:27244591

  7. Metal-organic frameworks: structure, properties, methods of synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Butova, V. V.; Soldatov, M. A.; Guda, A. A.; Lomachenko, K. A.; Lamberti, C.

    2016-03-01

    This review deals with key methods of synthesis and characterization of metal-organic frameworks (MOFs). The modular structure affords a wide variety of MOFs with different active metal sites and organic linkers. These compounds represent a new stage of development of porous materials in which the pore size and the active site structure can be modified within wide limits. The set of experimental methods considered in this review is sufficient for studying the short-range and long-range order of the MOF crystal structure, determining the morphology of samples and elucidating the processes that occur at the active metal site in the course of chemical reactions. The interest in metal-organic frameworks results, first of all, from their numerous possible applications, ranging from gas separation and storage to chemical reactions within the pores. The bibliography includes 362 references.

  8. Chemical pretreatment of olive oil mill wastewater using a metal-organic framework catalyst.

    PubMed

    De Rosa, Salvatore; Giordano, Girolamo; Granato, Teresa; Katovic, Andrea; Siciliano, Alessio; Tripicchio, Francesco

    2005-10-19

    Olive oil mill wastewaters (OOMW) are not suited for direct biological treatment because of their nonbiodegradable and phytotoxic compound (such as polyphenols) content. Advanced technologies for treatment of OOMW consider mainly the use of solid catalysts in processes that can be operated at room conditions. A system based on combined actions of catalytic oxidations and microbial technologies was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process is one of the new emerging oxidation processes particularly attractive for the pretreatment of highly polluted OOMW containing polyphenols that are not suited for classical treatments. In this work, the biodegradability of OOMW was evaluated before and after treating the wastewater samples by the WHPCO process using a metal-organic framework (MOF) as a catalyst. This material, containing Cu and prepared with benzene-1,3,5-tricarboxylic acid (BTC), is a robust metal-organic polymer with a microporous structure that is reminiscent of the topology of zeolite frameworks. PMID:16218680

  9. A Nanoscale Multiresponsive Luminescent Sensor Based on a Terbium(III) Metal-Organic Framework.

    PubMed

    Dang, Song; Wang, Ting; Yi, Feiyan; Liu, Qinghui; Yang, Weiting; Sun, Zhong-Ming

    2015-08-01

    A nanoscale terbium-containing metal-organic framework (nTbL), with a layer-like structure and [H2 NMe2 ](+) cations located in the framework channels, was synthesized under hydrothermal conditions. The structure of the as-prepared sample was systematically confirmed by powder XRD and elemental analysis; the morphology was characterized by field-emission SEM and TEM. The photoluminescence studies revealed that rod-like nTbL exhibited bright-green emission, corresponding to (5)D4 →(7)FJ (J=6-3) transitions of the Tb(3+) ion under excitation. Further sensing measurements revealed that as-prepared nTbL could be utilized as a multiresponsive luminescent sensor, which showed significant and exclusive detection ability for Fe(3+) ions and phenylmethanol. These results highlight the practical applications of lanthanide-containing metal-organic frameworks as fluorescent probes. PMID:25965107

  10. Polydopamine tethered enzyme/metal-organic framework composites with high stability and reusability

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoling; Yang, Cheng; Ge, Jun; Liu, Zheng

    2015-11-01

    An enzyme/metal-organic framework (MOF) composite with both highly stable and easily reusable features was prepared via tethering enzyme/MOF nanocrystals with polydopamine (PDA). The micrometer-sized PDA tethered enzyme/MOF composite can be easily repeatedly used without obvious activity loss, promising for efficient enzymatic catalysis at low cost with long-term operational stability under harsh conditions.An enzyme/metal-organic framework (MOF) composite with both highly stable and easily reusable features was prepared via tethering enzyme/MOF nanocrystals with polydopamine (PDA). The micrometer-sized PDA tethered enzyme/MOF composite can be easily repeatedly used without obvious activity loss, promising for efficient enzymatic catalysis at low cost with long-term operational stability under harsh conditions. Electronic supplementary information (ESI) available: Synthesis of enzyme-MOF nanocrystals, SEM, TEM, CLSM characterization and measurements of enzymatic performances. See DOI: 10.1039/c5nr05190h

  11. Metal-organic extended 2D structures: Fe-PTCDA on Au(111).

    PubMed

    Alvarez, Lucía; Peláez, Samuel; Caillard, Renaud; Serena, Pedro A; Martín-Gago, José A; Méndez, Javier

    2010-07-30

    In this work we combine organic molecules of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) with iron atoms on an Au (111) substrate in ultra-high vacuum conditions at different temperatures. By means of scanning tunnelling microscopy (STM) we study the formation of stable 2D metal-organic structures. We show that at certain growth conditions (temperature, time and coverage) stable 'ladder-like' nanostructures are obtained. These are the result of connecting together two metal-organic chains through PTCDA molecules placed perpendicularly, as rungs of a ladder. These structures, stable up to 450 K, can be extended in a 2D layer covering the entire surface and presenting different rotation domains. STM images at both polarities show a contrast reversal between the two molecules at the unit cell. By means of density functional theory (DFT) calculations, we confirm the stability of these structures and that their molecular orbitals are placed separately at the different molecules. PMID:20603531

  12. Pd nanoparticles embedded into a metal-organic framework: synthesis, structural characteristics, and hydrogen sorption properties.

    PubMed

    Zlotea, Claudia; Campesi, Renato; Cuevas, Fermin; Leroy, Eric; Dibandjo, Philippe; Volkringer, Christophe; Loiseau, Thierry; Férey, Gérard; Latroche, Michel

    2010-03-10

    The metal-organic framework MIL-100(Al) has been used as a host to synthesize Pd nanoparticles (around 2.0 nm) embedded within the pores of the MIL, showing one of the highest metal contents (10 wt %) without degradation of the porous host. Textural properties of MIL-100(Al) are strongly modified by Pd insertion, leading to significant changes in gas sorption properties. The loss of excess hydrogen storage at low temperature can be correlated with the decrease of the specific surface area and pore volume after Pd impregnation. At room temperature, the hydrogen uptake in the composite MIL-100(Al)/Pd is almost twice that of the pristine material. This can be only partially accounted by Pd hydride formation, and a "spillover" mechanism is expected to take place promoting the dissociation of molecular hydrogen at the surface of the metal nanoparticles and the diffusion of monatomic hydrogen into the porosity of the host metal-organic framework. PMID:20155921

  13. Wavelength-Tunable Microlasers Based on the Encapsulation of Organic Dye in Metal-Organic Frameworks.

    PubMed

    Wei, Yanhui; Dong, Haiyun; Wei, Cong; Zhang, Wei; Yan, Yongli; Zhao, Yong Sheng

    2016-09-01

    A wavelength-tunable microlaser is realized based on the controlled intramolecular charge transfer (ICT) process in dye-encapsulated metal-organic framework (MOF) material. The confinement effect of the MOFs is beneficial for low-threshold lasing. By effectively controlling the polarity of the MOF pores, the population distribution between the locally excited and ICT states is continuously modulated, thus achieving broadband tunable MOF-based microlasers. PMID:27314453

  14. Metal-organic framework tethering PNIPAM for ON-OFF controlled release in solution.

    PubMed

    Nagata, Shunjiro; Kokado, Kenta; Sada, Kazuki

    2015-05-21

    A smart metal-organic framework (MOF) exhibiting controlled release was achieved by modification with a thermoresponsive polymer (PNIPAM) via a surface-selective post-synthetic modification technique. Simple temperature variation readily switches "open" (lower temperature) and "closed" (higher temperature) states of the polymer-modified MOF through conformational change of PNIPAM grafted onto the MOF, resulting in controlled release of the included guest molecules such as resorufin, caffeine, and procainamide. PMID:25896867

  15. Visible-light-driven photocatalytic water oxidation catalysed by iron-based metal-organic frameworks.

    PubMed

    Horiuchi, Yu; Toyao, Takashi; Miyahara, Kenta; Zakary, Lionet; Van, Dang Do; Kamata, Yusuke; Kim, Tae-Ho; Lee, Soo Wohn; Matsuoka, Masaya

    2016-04-14

    An iron-based metal-organic framework, MIL-101(Fe), promotes photocatalytic water oxidation to produce oxygen from aqueous silver nitrate solution under visible-light irradiation. The finely dispersed iron-oxo clusters embedded as nodes of the porous framework would contribute importantly to the efficient promotion of the reaction as compared to bulk hematite (α-Fe2O3). PMID:26996996

  16. Twelve-connected porous metal-organic frameworks with high H(2) adsorption.

    PubMed

    Jia, Junhua; Lin, Xiang; Wilson, Claire; Blake, Alexander J; Champness, Neil R; Hubberstey, Peter; Walker, Gavin; Cussen, Edmund J; Schröder, Martin

    2007-02-28

    The twelve-connected metal-organic frameworks {[Ni(3)(OH)(L)(3)].n(solv)}(infinity) and {[Fe(3)(O)(L)(3)].n(solv)}(infinity) [LH(2) = pyridine-3,5-bis(phenyl-4-carboxylic acid)] have been prepared and characterised: these materials can be desolvated to form porous materials that show adsorption of H(2) up to 4.15 wt% at 77 K. PMID:17308649

  17. Designing Higher Surface Area Metal-Organic Frameworks: Are Triple Bonds Better than Phenyls?

    SciTech Connect

    Farha, O. K.; Wilmer, C. E.; Eryazici, I.; Hauser, B. G.; Parilla, P. A.; Oneill, K.; Sarjeant, A. A.; Nguyen, S. T.; Snurr, R. Q.; Hupp, J. T.

    2012-06-20

    We have synthesized, characterized, and computationally validated the high Brunauer-Emmett-Teller surface area and hydrogen uptake of a new, noncatenating metal-organic framework (MOF) material, NU-111. Our results imply that replacing the phenyl spacers of organic linkers with triple-bond spacers is an effective strategy for boosting molecule-accessible gravimetric surface areas of MOFs and related high-porosity materials.

  18. Aldehyde-Tagged Zirconium Metal-Organic Frameworks: a Versatile Platform for Postsynthetic Modification.

    PubMed

    Xi, Fu-Gui; Liu, Hui; Yang, Ning-Ning; Gao, En-Qing

    2016-05-16

    Aldehyde-tagged UiO-67-type metal-organic frameworks (MOFs) have been synthesized via the direct solvothermal method or postsynthetic ligand exchange. Various functionalities have been introduced into the MOFs via postsynthetic modification (PSM) employing C-N and C-C coupling reactions of the aldehyde tag. Tandem PSM has also been demonstrated. An amino-functionalized MOF obtained by PSM is shown to be an efficient, heterogeneous, and recyclable catalyst for Knoevenagel condensation. PMID:27136395

  19. 3D metal-organic frameworks based on elongated tetracarboxylate building blocks for hydrogen storage.

    PubMed

    Ma, Liqing; Lee, Jeong Yong; Li, Jing; Lin, Wenbin

    2008-05-19

    Two 3D metal-organic frameworks (MOFs) with a new biphenol-derived tetracarboxylate linker and Cu(II) and Zn(II) metal-connecting points were synthesized and characterized by single-crystal X-ray crystallographic studies. The two isostructural MOFs exhibit distorted PtS network topology and show markedly different framework stability. The porosity and hydrogen uptake of the frameworks were determined by gas adsorption experiments. PMID:18416546

  20. Metal-Organic and Organic TADF-Materials: Status, Challenges and Characterization.

    PubMed

    Bergmann, Larissa; Zink, Daniel M; Bräse, Stefan; Baumann, Thomas; Volz, Daniel

    2016-06-01

    This section covers both metal-organic and organic materials that feature thermally activated delayed fluorescence (TADF). Such materials are especially useful for organic light-emitting diodes (OLEDs), a technology that was introduced in commercial displays only recently. We compare both material classes to show commonalities and differences, highlighting current issues and challenges. Advanced spectroscopic techniques as valuable tools to develop solutions to those issues are introduced. Finally, we provide an outlook over the field and highlight future trends. PMID:27573262

  1. GaN Stress Evolution During Metal-Organic Chemical Vapor Deposition

    SciTech Connect

    Amano, H.; Chason, E.; Figiel, J.; Floro, J.A.; Han, J.; Hearne, S.; Hunter, J.; Tsong, I.

    1998-10-14

    The evolution of stress in gallium nitride films on sapphire has been measured in real- time during metal organic chemical vapor deposition. In spite of the 161%0 compressive lattice mismatch of GaN to sapphire, we find that GaN consistently grows in tension at 1050"C. Furthermore, in-situ stress monitoring indicates that there is no measurable relaxation of the tensile growth stress during annealing or thermal cycling.

  2. Metal-organic frameworks reactivate deceased diatoms to be efficient CO(2) absorbents.

    PubMed

    Liu, Dingxin; Gu, Jiajun; Liu, Qinglei; Tan, Yongwen; Li, Zhuo; Zhang, Wang; Su, Yishi; Li, Wuxia; Cui, Ajuan; Gu, Changzhi; Zhang, Di

    2014-02-26

    Diatomite combined with certain metal-organic frameworks (MOFs) is shown to be an effective CO2 absorbent, although diatomite alone is regarded as inert with respect to CO2 absorption. This finding opens the prospect of reactivating millions of tons of diatomite for CO2 absorption. It also shows for the first time that diatom frustules can act as CO2 buffers, an important link in a successive biological CO2 concentration mechanism chain that impacts on global warming. PMID:24285587

  3. Separation of polar compounds using a flexible metal-organic framework

    SciTech Connect

    Motkuri, Radha K.; Thallapally, Praveen K.; Annapureddy, Harsha V.; Dang, Liem X.; Krishna, Rajamani; Nune, Satish K.; Fernandez, Carlos A.; Liu, Jian; McGrail, B. Peter

    2015-01-01

    A flexible metal-organic framework constructed from a flexible linker is shown to possess the capability of separating mixtures of polar compounds by exploiting the differences in the saturation capacities of the constituents. The separation possibilities with the flexible MOF include mixtures of propanol isomers, and various azeotropes. Transient breakthrough simulations show that these sorption-based separations are in favor of the component with higher saturation capacity.

  4. High index of refraction films for dielectric mirrors prepared by metal-organic chemical vapor deposition

    SciTech Connect

    Brusasco, R.M.

    1989-01-01

    A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs.

  5. Stabilization of a highly porous metal-organic framework utilizing a carborane-based linker.

    PubMed

    Clingerman, Daniel J; Morris, William; Mondloch, Joseph E; Kennedy, Robert D; Sarjeant, Amy A; Stern, Charlotte; Hupp, Joseph T; Farha, Omar K; Mirkin, Chad A

    2015-04-18

    The first tritopic carborane-based linker, H3BCA (C15B24O6H30), based on closo-1,10-C2B8H10, has been synthesized and incorporated into a metal-organic framework (MOF), NU-700 (Cu3(BCA)2). In contrast to the analogous MOF-143, NU-700 can be activated with retention of porosity, yielding a BET surface area of 1870 m(2) g(-1). PMID:25767827

  6. Removal of chlorine gas by an amine functionalized metal-organic framework via electrophilic aromatic substitution.

    PubMed

    DeCoste, Jared B; Browe, Matthew A; Wagner, George W; Rossin, Joseph A; Peterson, Gregory W

    2015-08-11

    Here we report the removal of chlorine gas from air via a reaction with an amine functionalized metal-organic framework (MOF). It is found that UiO-66-NH2 has the ability to remove 1.24 g of Cl2 per g of MOF via an electrophilic aromatic substitution reaction producing HCl, which is subsequently neutralized by the MOF. PMID:26146024

  7. A Naphthalenediimide-Based Metal-Organic Framework and Thin Film Exhibiting Photochromic and Electrochromic Properties.

    PubMed

    Xie, Yi-Xin; Zhao, Wen-Na; Li, Guo-Chang; Liu, Peng-Fei; Han, Lei

    2016-01-19

    A multifunctional metal-organic framework, NBU-3, has been explored as a 2D three-connected network based on a naphthalenediimide-based ligand. The NBU-3 crystals display photochromic properties, and NBU-3 thin films on FTO substrates exhibit electrochromic properties. NBU-3 is the first example of MOF materials containing both photochromic and electrochromic properties, which can be desirable for thin film devices. PMID:26713454

  8. High methane storage and working capacities in a NbO-type metal-organic framework.

    PubMed

    Song, Chengling; Liu, Huimin; Jiao, Jingjing; Bai, Dongjie; Zhou, Wei; Yildirim, Taner; He, Yabing

    2016-05-01

    To improve methane adsorption by pore structure optimization, we developed a new organic linker and used it to construct a NbO-type metal-organic framework ZJNU-53 that, after activation, exhibits exceptionally high methane storage and working capacities of 241 and 190 cm(3) (STP) cm(-3) at 298 K and 65 bar, respectively, if the packing loss is not considered, which are among the highest reported for MOF materials. PMID:27083013

  9. Metal-organic framework templated inorganic sorbents for rapid and efficient extraction of heavy metals.

    PubMed

    Abney, C W; Gilhula, J C; Lu, K; Lin, W

    2014-12-17

    An innovative wet-treatment with Na2 S transforms two indium metal-organic frameworks (MOFs) into a series of porous inorganic sorbents. These MOF-templated materials display remarkable affinity for heavy metals with saturation occurring in less than 1 h. The saturation capacity for Hg(II) exceeds 2 g g(-1) , more than doubling the best thiol-functionalized sorbents in the literature. PMID:25348588

  10. Metal-organic frameworks as cathode materials for Li-O2 batteries.

    PubMed

    Wu, Doufeng; Guo, Ziyang; Yin, Xinbo; Pang, Qingqing; Tu, Binbin; Zhang, Lijuan; Wang, Yong-Gang; Li, Qiaowei

    2014-05-28

    Metal-organic frameworks (MOFs) with open metal sites enrich the population of O2 in the pores significantly and assist the Li-O2 reaction when employed as a cell electrode material. A primary capacity of 9420 mA h g(-1) is achieved in a cell with Mn-MOF-74; more than four times higher than the value obtained in a cell without an MOF. PMID:24616022

  11. Ultraselective Gas Separation by Nanoporous Metal-Organic Frameworks Embedded in Gas-Barrier Nanocellulose Films.

    PubMed

    Matsumoto, Makoto; Kitaoka, Takuya

    2016-03-01

    Metal-organic frameworks (MOFs) are synthesized at carboxy groups on crystalline TEMPO-oxidized cellulose nanofibers (TOCNs). MOF-TOCN films coated on a paper filter have a hierarchical structure from the nano- to macroscale, and demonstrate a high CO2 /CH4 selectivity, over 120 for CO2 at a high gas flux, by the combination of the nanoporous MOFs and the gas-barrier TOCNs, which have strong affinity with each other. PMID:26669724

  12. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, Sheldon H. D.

    1992-01-01

    A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases.

  13. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, S.H.D.

    1992-12-22

    A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases. 6 figs.

  14. A homochiral metal-organic porous material for enantioselective separation and catalysis

    NASA Astrophysics Data System (ADS)

    Seo, Jung Soo; Whang, Dongmok; Lee, Hyoyoung; Jun, Sung Im; Oh, Jinho; Jeon, Young Jin; Kim, Kimoon

    2000-04-01

    Inorganic zeolites are used for many practical applications that exploit the microporosity intrinsic to their crystal structures. Organic analogues, which are assembled from modular organic building blocks linked through non-covalent interactions, are of interest for similar applications. These range from catalysis, separation and sensor technology to optoelectronics, with enantioselective separation and catalysis being especially important for the chemical and pharmaceutical industries. The modular construction of these analogues allows flexible and rational design, as both the architecture and chemical functionality of the micropores can, in principle, be precisely controlled. Porous organic solids with large voids and high framework stability have been produced, and investigations into the range of accessible pore functionalities have been initiated. For example, catalytically active organic zeolite analogues are known, as are chiral metal-organic open-framework materials. However, the latter are only available as racemic mixtures, or lack the degree of framework stability or void space that is required for practical applications. Here we report the synthesis of a homochiral metal-organic porous material that allows the enantioselective inclusion of metal complexes in its pores and catalyses a transesterification reaction in an enantioselective manner. Our synthesis strategy, which uses enantiopure metal-organic clusters as secondary building blocks, should be readily applicable to chemically modified cluster components and thus provide access to a wide range of porous organic materials suitable for enantioselective separation and catalysis.

  15. Computational studies of adsorption in metal organic frameworks and interaction of nanoparticles in condensed phases

    SciTech Connect

    Annapureddy, Harsha V.; Motkuri, Radha K.; Nguyen, Phuong T.; Truong, T. B.; Thallapally, Praveen K.; McGrail, B. Peter; Dang, Liem X.

    2014-01-08

    In this review, we describe recent efforts in which computer simulations were used to systematically study nano-structured metal organic frameworks, with particular emphasis on their application in heating and cooling processes. These materials also are known as metal organic heat carriers. We used both molecular dynamics and Grand Canonical Monte Carlo simulation techniques to gain a molecular-level understanding of the adsorption mechanism of gases in these porous materials. We investigated the uptake of various gases such as refrigerants R12 and R143a and also the elemental gases Xe and Rn by the metal organic framework (i.e., Ni2(dhtp)). We also evaluated the effects of temperature and pressure on the uptake mechanism. Our computed results compared reasonably well with available experimental measurements, thus validating our potential models and approaches. In addition, we also investigated the structural, diffusive, and adsorption properties of different hydrocarbons in Ni2(dhtp). To elucidate the mechanism of nanoparticle dispersion in condensed phases, we also studied the interactions among nanoparticles in various liquids, such as n-hexane, water and methanol. This work was performed at Pacific Northwest National Laboratory (PNNL) and was supported by the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Sciences, U.S. Department of Energy (DOE). PNNL is operated by Battelle for the DOE. The authors also gratefully acknowledge support received from the National Energy Technology Laboratory of DOE's Office of Fossil Energy.

  16. Gas sorption and transition-metal cation separation with a thienothiophene based zirconium metal-organic framework

    NASA Astrophysics Data System (ADS)

    SK, Mostakim; Grzywa, Maciej; Volkmer, Dirk; Biswas, Shyam

    2015-12-01

    The modulated synthesis of the thienothiophene based zirconium metal-organic framework (MOF) material having formula [Zr6O4(OH)4(DMTDC)6]·4.8DMF·10H2O (1) (H2DMTDC=3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid; DMF=N,N'-dimethylformamide) was carried out by heating a mixture of ZrCl4, H2DMTDC linker and benzoic acid (used as a modulator) with a molar ratio of 1:1:30 in DMF at 150 °C for 24 h. Systematic investigations have been performed in order to realize the effect of ZrCl4/benzoic acid molar ratio on the crystallinity of the material. The activation (i.e., the removal of the guest solvent molecules from the pores) of as-synthesized compound was achieved by stirring it with methanol and subsequently heating under vacuum. A combination of X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric (TG) and elemental analysis was used to examine the phase purity of the as-synthesized and thermally activated 1. The material displays high thermal stability up to 310 °C in an air atmosphere. As revealed from the XRD measurements, the compound retains its crystallinity when treated with water, acetic acid and 1 M HCl solutions. The N2 and CO2 sorption analyses suggest that the material possesses remarkably high microporosity (SBET=1236 m2 g-1; CO2 uptake=3.5 mmol g-1 at 1 bar and 0 °C). The compound also shows selective adsorption behavior for Cu2+ over Co2+ and Ni2+ ions.

  17. Comparative Study of MIL-96(Al) as Continuous Metal-Organic Frameworks Layer and Mixed-Matrix Membrane.

    PubMed

    Knebel, Alexander; Friebe, Sebastian; Bigall, Nadja Carola; Benzaqui, Marvin; Serre, Christian; Caro, Jürgen

    2016-03-23

    MIL-96(Al) layers were prepared as supported metal-organic frameworks membrane via reactive seeding using the α-alumina support as the Al source for the formation of the MIL-96(Al) seeds. Depending on the solvent mixture employed during seed formation, two different crystal morphologies, with different orientation of the transport-active channels, have been formed. This crystal orientation and habit is predefined by the seed crystals and is kept in the subsequent growth of the seeds to continuous layers. In the gas separation of an equimolar H2/CO2 mixture, the hydrogen permeability of the two supported MIL-96(Al) layers was found to be highly dependent on the crystal morphology and the accompanied channel orientation in the layer. In addition to the neat supported MIL-96(Al) membrane layers, mixed-matrix membranes (MMMs, 10 wt % filler loading) as a composite of MIL-96(Al) particles as filler in a continuous Matrimid polymer phase have been prepared. Five particle sizes of MIL-96(Al) between 3.2 μm and 55 nm were synthesized. In the preparation of the MIL-96(Al)/Matrimid MMM (10 wt % filler loading), the following preparation problems have been identified: The bigger micrometer-sized MIL-96(Al) crystals show a trend toward sedimentation during casting of the MMM, whereas for nanoparticles aggregation and recrystallization to micrometer-sized MIL-96(Al) crystals has been observed. Because of these preparation problems for MMM, the neat supported MIL-96(Al) layers show a relatively high H2/CO2 selectivity (≈9) and a hydrogen permeance approximately 2 magnitudes higher than that of the best MMM. PMID:26886432

  18. Selective Adsorption of n-Alkanes from n-Octane on Metal-Organic Frameworks: Length Selectivity.

    PubMed

    Bhadra, Biswa Nath; Jhung, Sung Hwa

    2016-03-16

    The liquid-phase adsorption of n-alkanes (from n-octane (C8) solvent) with different chain lengths was carried out over three metal-organic frameworks (MOFs), viz., metal-azolate framework-6 (MAF-6), copper-benzenetricarboxylate (Cu-BTC), and iron-benzenetricarboxylate (MIL-100(Fe)), and a conventional adsorbent activated carbon (AC). MAF-6 and Cu-BTC were found to have significant selectivity for the adsorption of n-dodecane (C12) and n-heptane (C7), respectively, from C8. Selectivity for C12 on MAF-6 was also observed in competitive adsorption from binary adsorbate systems. To understand the selective adsorption of C12 on MAF-6 more, the adsorption of C12 from C8 over MAF-6 was investigated in detail and compared with that over AC. The obtained selectivities over MAF-6 and Cu-BTC for C12 and C7, respectively, might be explained by the similarity between cavity size of adsorbents and molecular length of n-alkanes. In the case of AC and MIL-100(Fe), no specific adsorption selectivity was observed because the cavity sizes of the two adsorbents are larger than the size of the n-alkanes used in this study. The adsorption capacities (qt) of n-alkanes over AC and MIL-100(Fe) decreased and increased, respectively, as the polarity (or length) of the adsorbates increased, probably because of nonpolar and polar interactions between the adsorbents and n-alkanes. On the basis of the results obtained, it can be concluded that matching the cavity size (of adsorbents) with the molecular length (of n-alknaes) is more important parameter than the MOF's hydrophilicity/hydrophobicity for the selective adsorption/separation of alkanes. PMID:26905721

  19. Barcoded materials based on photoluminescent hybrid system of lanthanide ions-doped metal organic framework and silica via ion exchange.

    PubMed

    Shen, Xiang; Yan, Bing

    2016-04-15

    A multicolored photoluminescent hybrid system based on lanthanide ions-doped metal organic frameworks/silica composite host has potential in display and barcode applications. By controlling the stoichiometry of the lanthanides via cation exchange, proportional various lanthanide ions are successfully introduced into metal organic frameworks, whose emission intensity is correspondingly proportional to its amount. The resulting luminescent barcodes depend on the lanthanide ions ratios and compositions. Subsequently, the lanthanide ions located in the channels of metal organic frameworks are protected from any interaction with the environment after the modification of silica on the surface. The optical and thermal stability of the hybrid materials are improved for technological application. PMID:26852345

  20. Alkali-Metal Spin Maser.

    PubMed

    Chalupczak, W; Josephs-Franks, P

    2015-07-17

    Quantum measurement is a combination of a read-out and a perturbation of the quantum system. We explore the nonlinear spin dynamics generated by a linearly polarized probe beam in a continuous measurement of the collective spin state in a thermal alkali-metal atomic sample. We demonstrate that the probe-beam-driven perturbation leads, in the presence of indirect pumping, to complete polarization of the sample and macroscopic coherent spin oscillations. As a consequence of the former we report observation of spectral profiles free from collisional broadening. Nonlinear dynamics is studied through exploring its effect on radio frequency as well as spin noise spectra. PMID:26230788

  1. Water in Metal-Organic Frameworks: A Computational Study of Adsorption in Porous Materials in the Presence of Ambient Humidity

    NASA Astrophysics Data System (ADS)

    Ghosh, Pritha

    Metal-organic frameworks, or MOFs, are a class of porous crystalline materials renowned for their chemically tunable nature. In this work, molecular-level modeling is used to assess MOFs as potential adsorbents for a variety of applications where ambient humidity is present, such as toxic gas capture, nerve agent decomposition, and sensing via changes in proton conductivity. The concept of hydrophobicity in MOFs is explored from a number of angles. Classical simulation methods and quantum chemistry calculations are used to predict adsorption behavior and to shed light on experimentally observed phenomena. Hydrophobic MOFs are attractive candidates for selective gas capture under ambient conditions, and in this work hydrophobic MOFs are examined for two particular applications: ammonia capture and CO2 capture. In the first study, GCMC simulations are used to evaluate a set of three hydrophobic MOFs for ammonia capture at three humidity conditions: 0% relative humdity (RH), 36% RH, and 80% RH. In the second study, GCMC simulations predict the CO2 loading in a hydrophobic fluorinated MOF at 80% RH, which is the humidity of flue gas. In both of these studies, results demonstrate that hydrophobic MOFs are equally capable of capturing the target adsorbate under humid or dry conditions. In related work, water adsorption behavior is investigated for a fairly hydrophilic Zr MOF, and it is revealed that missing linker defects engender hydrophilicity in this framework. An ideal, defect-free version of this Zr MOF demonstrates hydrophobic behavior. Additionally, perfluoroalkane adsorption is predicted in a related material, a faujasite-type zeolite, and the results suggest the presence of co-adsorbed water molecules. MOFs with coordinated solvent molecules can be used as catalysts and novel chemical sensors. In this work, quantum chemistry calculations are used to study the interaction of a nerve agent simulant with a Zr MOF node. Results indicate that it is favorable for a

  2. Moisture-Stable Zn(II) Metal-Organic Framework as a Multifunctional Platform for Highly Efficient CO2 Capture and Nitro Pollutant Vapor Detection.

    PubMed

    Chen, Di-Ming; Tian, Jia-Yue; Chen, Min; Liu, Chun-Sen; Du, Miao

    2016-07-20

    A moisture-stable three-dimensional (3D) metal-organic framework (MOF), {(Me2NH2)[Zn2(bpydb)2(ATZ)](DMA)(NMF)2}n (1, where bpydb = 4,4'-(4,4'-bipyridine-2,6-diyl)dibenzoate, ATZ = deprotonated 5-aminotetrazole, DMA = N,N-dimethylacetamide, and NMF = N-methylformamide), with uncoordinated N-donor sites and charged framework skeleton was fabricated. This MOF exhibits interesting structural dynamic upon CO2 sorption at 195 K and high CO2/N2 (127) and CO2/CH4 (131) sorption selectivity at 298 K and 1 bar. Particularly, its CO2/CH4 selectivity is among the highest MOFs for selective CO2 separation. The results of Grand Canonical Monte Carlo (GCMC) simulation indicate that the polar framework contributes to the strong framework-CO2 binding at zero loading, and the tetrazole pillar contributes to the high CO2 uptake capacity at high loading. Furthermore, the solvent-responsive luminescent properties of 1 indicate that it could be utilized as a fluorescent sensor to detect trace amounts of nitrobenzene in both solvent and vapor systems. PMID:27340895

  3. Versatile Tailoring of Paddle-Wheel Zn(II) Metal-Organic Frameworks through Single-Crystal-to-Single-Crystal Transformations.

    PubMed

    Pal, Tapan K; Neogi, Subhadip; Bharadwaj, Parimal K

    2015-11-01

    A new tetracarboxylate ligand having short and long arms formed 2D layer Zn(II) coordination polymer 1 with paddle-wheel secondary building units under solvothermal conditions. The framework undergoes solvent-specific single crystal-to-single crystal (SC-SC) transmetalation to produce 1Cu . With a sterically encumbered dipyridyl linker, the same ligand forms non-interpenetrated, 3D, pillared-layer Zn(II) metal-organic framework (MOF) 2, which takes part in SC-SC linker-exchange reactions to produce three daughter frameworks. The parent MOF 2 shows preferential incorporation of the longest linker in competitive linker-exchange experiments. All the 3D MOFs undergo complete SC-SC transmetalation with Cu(II) , whereby metal exchange in different solvents and monitoring of X-ray structures revealed that bulky solvated metal ions lead to ordering of the shortest linker in the framework, which confirms that the solvated metal ions enter through the pores along the linker axis. PMID:26383591

  4. Process for the disposal of alkali metals

    DOEpatents

    Lewis, Leroy C.

    1977-01-01

    Large quantities of alkali metals may be safely reacted for ultimate disposal by contact with a hot concentrated caustic solution. The alkali metals react with water in the caustic solution in a controlled reaction while steam dilutes the hydrogen formed by the reaction to a safe level.

  5. Porous molybdenum carbide nano-octahedrons synthesized via confined carburization in metal-organic frameworks for efficient hydrogen production

    PubMed Central

    Wu, Hao Bin; Xia, Bao Yu; Yu, Le; Yu, Xin-Yao; Lou, Xiong Wen (David)

    2015-01-01

    Electrochemical water splitting has been considered as a promising approach to produce clean and sustainable hydrogen fuel. However, the lack of high-performance and low-cost electrocatalysts for hydrogen evolution reaction hinders the large-scale application. As a new class of porous materials with tunable structure and composition, metal-organic frameworks have been considered as promising candidates to synthesize various functional materials. Here we demonstrate a metal-organic frameworks-assisted strategy for synthesizing nanostructured transition metal carbides based on the confined carburization in metal-organic frameworks matrix. Starting from a compound consisting of copper-based metal-organic frameworks host and molybdenum-based polyoxometalates guest, mesoporous molybdenum carbide nano-octahedrons composed of ultrafine nanocrystallites are successfully prepared as a proof of concept, which exhibit remarkable electrocatalytic performance for hydrogen production from both acidic and basic solutions. The present study provides some guidelines for the design and synthesis of nanostructured electrocatalysts. PMID:25758159

  6. Porous molybdenum carbide nano-octahedrons synthesized via confined carburization in metal-organic frameworks for efficient hydrogen production

    NASA Astrophysics Data System (ADS)

    Wu, Hao Bin; Xia, Bao Yu; Yu, Le; Yu, Xin-Yao; Lou, Xiong Wen (David)

    2015-03-01

    Electrochemical water splitting has been considered as a promising approach to produce clean and sustainable hydrogen fuel. However, the lack of high-performance and low-cost electrocatalysts for hydrogen evolution reaction hinders the large-scale application. As a new class of porous materials with tunable structure and composition, metal-organic frameworks have been considered as promising candidates to synthesize various functional materials. Here we demonstrate a metal-organic frameworks-assisted strategy for synthesizing nanostructured transition metal carbides based on the confined carburization in metal-organic frameworks matrix. Starting from a compound consisting of copper-based metal-organic frameworks host and molybdenum-based polyoxometalates guest, mesoporous molybdenum carbide nano-octahedrons composed of ultrafine nanocrystallites are successfully prepared as a proof of concept, which exhibit remarkable electrocatalytic performance for hydrogen production from both acidic and basic solutions. The present study provides some guidelines for the design and synthesis of nanostructured electrocatalysts.

  7. Unique gas and hydrocarbon adsorption in a highly porous metal-organic framework made of extended aliphatic ligands.

    PubMed

    Li, Kunhao; Lee, Jeongyong; Olson, David H; Emge, Thomas J; Bi, Wenhua; Eibling, Matthew J; Li, Jing

    2008-12-14

    High and unique gas and hydrocarbon adsorption in a highly stable guest-free microporous metal-organic framework constructed on rigid aliphatic ligands, H(2)bodc and ted, is reported in this work. PMID:19082093

  8. The influence of the enantiomeric ratio of an organic ligand on the structure and chirality of Metal-Organic Frameworks

    PubMed Central

    Burneo, Iván; Stylianou, Kyriakos C.; Imaz, Inhar; Maspoch, Daniel

    2016-01-01

    We have prepared three distinct polyamino acid-based metal-organic frameworks (MOFs) with different chirality and porosity using the same chemistry, by simply modifying the enantiomeric ratio of the chiral organic ligand used. PMID:25253285

  9. Solvent wash solution

    DOEpatents

    Neace, J.C.

    1984-03-13

    A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  10. Solvent wash solution

    DOEpatents

    Neace, James C.

    1986-01-01

    Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  11. Method of handling radioactive alkali metal waste

    DOEpatents

    Wolson, Raymond D.; McPheeters, Charles C.

    1980-01-01

    Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

  12. Method of handling radioactive alkali metal waste

    DOEpatents

    Wolson, R.D.; McPheeters, C.C.

    Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

  13. Exact matrix treatment of an osmotic ensemble model of adsorption and pressure induced structural transitions in metal organic frameworks.

    PubMed

    Dunne, Lawrence J; Manos, George

    2016-03-14

    Here we present an exactly treated quasi-one dimensional statistical mechanical osmotic ensemble model of pressure and adsorption induced breathing structural transformations of metal-organic frameworks (MOFs). The treatment uses a transfer matrix method. The model successfully reproduces the gas and pressure induced structural changes which are observed experimentally in MOFs. The model treatment presented here is a significant step towards analytical statistical mechanical treatments of flexible metal-organic frameworks. PMID:26514851

  14. A synthetic route to ultralight hierarchically micro/mesoporous Al(III)-carboxylate metal-organic aerogels

    PubMed Central

    Li, Lei; Xiang, Shenglin; Cao, Shuqi; Zhang, Jianyong; Ouyang, Gangfeng; Chen, Liuping; Su, Cheng-Yong

    2013-01-01

    Developing a synthetic methodology for the fabrication of hierarchically porous metal-organic monoliths that feature high surface area, low density and tunable porosity is imperative for mass transfer applications, including bulky molecule capture, heterogeneous catalysis and drug delivery. Here we report a versatile and facile synthetic route towards ultralight micro/mesoporous metal-organic aerogels based on the two-step gelation of metal-organic framework nanoparticles. Heating represents a key factor in the control of gelation versus crystallization of Al(III)-multicarboxylate systems. The porosity of the resulting metal-organic aerogels can be readily tuned, leading to the formation of well-ordered intraparticle micropores and aerogel-specific interparticle mesopores, thereby integrating the merits of both crystalline metal-organic frameworks and light aerogels. The hierarchical micro/mesoporosity of the Al-metal-organic aerogels is thoroughly evaluated by N2 sorption. The good accessibility of the micro/mesopores is verified by vapour/dye uptake, and their potential for utilization as effective fibre-coating absorbents is tested in solid-phase microextraction analyses. PMID:23653186

  15. A 3D chiral metal-organic framework based on left-handed helices containing 3-amino-1 H-1,2,4-triazole ligand

    SciTech Connect

    Liu, Bing; Yang, Tian-Yi; Feng, Hui-Jun; Zhang, Zong-Hui; Xu, Ling

    2015-10-15

    A chiral metal-organic framework, [Cu(atr)(OH)]·0.5H{sub 2}O·0.5en (1) (Hatr=3-amino-1 H-1,2,4-triazole, en=ethylenediamine), was constructed via diffusion reaction of the achiral Hatr ligand and CuSO{sub 4} as starting materials. Compound 1 crystallizes in the chiral space group P3{sub 2}21 and features a porous metal-organic framework with 44.1% solvent-accessible volume fabricated by left-handed helices with a pitch height of l{sub p}=10.442 Å. Six helices gather around in a cycle forming a large honeycomb channel with a 6.58 Å inner diameter. Cu(II) center and atr{sup ‒} ligand regarded as 3-connected nodes, compound 1 can be simplified to a 3-c uninodal (4.12{sup 2}) (qtz-h) topological network. A gradual decreasing in the magnetic moment depending on temperature decreasing indicates an antiferromagnetic interaction in 1. The powder XRD confirms the bulk sample is a single crystal pure phase, and the thermogravimetric analysis shows the thermal stability of 1 is up to ca. 240 °C. - Highlights: • The present 3D chiral MOF is built from achiral Hatr ligand. • Six left-handed helices gather into a honeycomb channel in chiral sp P3{sub 2}21. • Compound 1 shows a 3-c uninodal (4.12{sup 2}) or qtz-h topological network. • Compound 1 indicates an antiferromagnetic interaction.

  16. Mesoporous Fluorinated Metal-Organic Frameworks with Exceptional Adsorption of Fluorocarbons and CFCs.

    PubMed

    Chen, Teng-Hao; Popov, Ilya; Kaveevivitchai, Watchareeya; Chuang, Yu-Chun; Chen, Yu-Sheng; Jacobson, Allan J; Miljanić, Ognjen Š

    2015-11-16

    Two mesoporous fluorinated metal-organic frameworks (MOFs) were synthesized from extensively fluorinated tritopic carboxylate- and tetrazolate-based ligands. The tetrazolate-based framework MOFF-5 has an accessible surface area of 2445 m(2) g(-1), the highest among fluorinated MOFs. Crystals of MOFF-5 adsorb hydrocarbons, fluorocarbons, and chlorofluorocarbons (CFCs)-the latter two being ozone-depleting substances and potent greenhouse species-with weight capacities of up to 225%. The material exhibits an apparent preference for the adsorption of non-spherical molecules, binding unusually low amounts of both tetrafluoromethane and sulfur hexafluoride. PMID:26423312

  17. Metal-organic frameworks for the storage and delivery of biologically active hydrogen sulfide

    SciTech Connect

    Allan, Phoebe K; Wheatley, Paul S; Aldous, David; Mohideen, M Infas; Tang, Chiu; Hriljac, Joseph A; Megson, Ian L; Chapman, Karena W; De Weireld, Guy; Vaesen, Sebastian; Morris, Russell E

    2012-04-02

    Hydrogen sulfide is an extremely toxic gas that is also of great interest for biological applications when delivered in the correct amount and at the desired rate. Here we show that the highly porous metal-organic frameworks with the CPO-27 structure can bind the hydrogen sulfide relatively strongly, allowing the storage of the gas for at least several months. Delivered gas is biologically active in preliminary vasodilation studies of porcine arteries, and the structure of the hydrogen sulfide molecules inside the framework has been elucidated using a combination of powder X-ray diffraction and pair distribution function analysis.

  18. A highly stable zeotype mesoporous zirconium metal-organic framework with ultralarge pores.

    SciTech Connect

    Feng, Dawei; Wang, Kecheng; Su, Jie; Liu, Tian-Fu; Park, Jihye; Wei, Zhangwen; Bosch, Mathieu; Yakovenko, Andrey; Zou, Xiaodong; Zhou, Hong-Cai

    2015-01-02

    Through topological rationalization, a zeotype mesoporous Zr-containing metal-organic framework (MOF), namely PCN-777, has been designed and synthesized. PCN-777 exhibits the largest cage size of 3.8nm and the highest pore volume of 2.8cm(3)g(-1) among reported Zr-MOFs. Moreover, PCN-777 shows excellent stability in aqueous environments, which makes it an ideal candidate as a support to incorporate different functional moieties. Through facile internal surface modification, the interaction between PCN-777 and different guests can be varied to realize efficient immobilization

  19. Highly porous metal-organic framework sustained with 12-connected nanoscopic octahedra.

    PubMed

    Lu, Weigang; Yuan, Daqiang; Makal, Trevor A; Wei, Zhangwen; Li, Jian-Rong; Zhou, Hong-Cai

    2013-02-01

    Two dicopper(II)-paddlewheel-based metal-organic frameworks (PCN-81 and -82) have been synthesized by using tetratopic ligands featuring 90°-carbazole-dicarboxylate moieties. Both adopt 12-connected tfb topology with nanoscopic octahedra as building units. The freeze-dried PCN-82 shows Brunauer-Emmett-Teller (BET) and Langmuir surface areas as high as 4488 and 4859 m(2) g(-1), respectively. It also exhibits high H(2)-adsorption capacity at low pressure (300 cm(3) g(-1) or 2.6 wt% at 77 K and 1 bar), which can be attributed to its high surface area, microporosity, and open metal sites. PMID:23160711

  20. Metal-organic framework with rationally tuned micropores for selective adsorption of water over methanol.

    PubMed

    Chen, Banglin; Ji, Yanyan; Xue, Ming; Fronczek, Frank R; Hurtado, Eric J; Mondal, Jalal U; Liang, Chengdu; Dai, Sheng

    2008-07-01

    A microporous metal-organic framework 1, Cu(R-GLA-Me)(4,4'-Bipy) 0.5.0.55H 2O (R-GLA-Me = R-2-methylglutarate, 4,4'-Bipy = 4,4'-bipyridine), with a primitive cubic net was synthesized and characterized. With pores of about 2.8 x 3.6 A, the activated 1a exhibits exclusive adsorption of water over methanol in a binary water-methanol (1:1) liquid mixture. PMID:18512902

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

    PubMed

    Chen, Banglin; Ma, Shengqian; Hurtado, Eric J; Lobkovsky, Emil B; Zhou, Hong-Cai

    2007-10-15

    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). PMID:17854181

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

    PubMed

    Chen, Banglin; Ma, Shengqian; Zapata, Fatima; Fronczek, Frank R; Lobkovsky, Emil B; Zhou, Hong-Cai

    2007-02-19

    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. PMID:17291116

  3. Alcohol-Mediated Resistance-Switching Behavior in Metal-Organic Framework-Based Electronic Devices.

    PubMed

    Liu, Yaqing; Wang, Hong; Shi, Wenxiong; Zhang, Weina; Yu, Jiancan; Chandran, Bevita K; Cui, Chenlong; Zhu, Bowen; Liu, Zhiyuan; Li, Bin; Xu, Cai; Xu, Zhiling; Li, Shuzhou; Huang, Wei; Huo, Fengwei; Chen, Xiaodong

    2016-07-25

    Metal-organic frameworks (MOFs) have drawn increasing attentions as promising candidates for functional devices. Herein, we present MOF films in constructing memory devices with alcohol mediated resistance switching property, where the resistance state is controlled by applying alcohol vapors to achieve multilevel information storage. The ordered packing mode and the hydrogen bonding system of the guest molecules adsorbed in MOF crystals are shown to be the reason for the alcohol mediated electrical switching. This chemically mediated memory device can be a candidate in achieving environment-responsive devices and exhibits potential applications in wearable information storage systems. PMID:27311703

  4. Effective Detection of Mycotoxins by a Highly Luminescent Metal-Organic Framework.

    PubMed

    Hu, Zhichao; Lustig, William P; Zhang, Jingming; Zheng, Chong; Wang, Hao; Teat, Simon J; Gong, Qihan; Rudd, Nathan D; Li, Jing

    2015-12-30

    We designed and synthesized a new luminescent metal-organic framework (LMOF). LMOF-241 is highly porous and emits strong blue light with high efficiency. We demonstrate for the first time that very fast and extremely sensitive optical detection can be achieved, making use of the fluorescence quenching of an LMOF material. The compound is responsive to Aflatoxin B1 at parts per billion level, which makes it the best performing luminescence-based chemical sensor to date. We studied the electronic properties of LMOF-241 and selected mycotoxins, as well as the extent of mycotoxin-LMOF interactions, employing theoretical methods. Possible electron and energy transfer mechanisms are discussed. PMID:26654703

  5. Switching Kr/Xe Selectivity with Temperature in a Metal-Organic Framework

    SciTech Connect

    Fernandez, Carlos A.; Liu, Jian; Thallapally, Praveen K.; Strachan, Denis M.

    2012-05-16

    Krypton (Kr) and xenon (Xe) adsorption on two partially fluorinated metal-organic frameworks (FMOFCu and FMOFZn) with different cavity size and topologies were reported. FMOFCu shows an inversion in sorption selectivity toward Kr at temperatures below 0 C while FMOFZn does not. The 1D microtubes packed along the (101) direction connected through small bottleneck windows in FMOFCu appear to be the reason for this peculiar behavior. The FMOFCu shows an estimated Kr/Xe selectivity of 36 at 0.1 bar.

  6. Metal-Organic Frameworks for Removal of Xe and Kr from Nuclear Fuel Reprocessing Plants

    SciTech Connect

    Liu, Jian; Thallapally, Praveen K.; Strachan, Denis M.

    2012-08-07

    Removal of Xenon (Xe) and Krypton (Kr) from in parts per million (ppm) levels were demonstrated for the first time using two well known metal-organic frameworks (MOFs), HKUST-1 and Ni/DOBDC. Results of an activated carbon were also included for comparison. Ni/DOBDC has higher Xe/Kr selectivities than those of the activated carbon. Moreover, results show that the Ni/DOBDC and HKUST-1 can selectively adsorb Xe and Kr from air even at 1000 ppm concentration. This shows a promising future for MOFs in a radioactive nuclides separation from spent fuel.

  7. Versatile, High Quality and Scalable Continuous Flow Production of Metal-Organic Frameworks

    PubMed Central

    Rubio-Martinez, Marta; Batten, Michael P.; Polyzos, Anastasios; Carey, Keri-Constanti; Mardel, James I.; Lim, Kok-Seng; Hill, Matthew R.

    2014-01-01

    Further deployment of Metal-Organic Frameworks in applied settings requires their ready preparation at scale. Expansion of typical batch processes can lead to unsuccessful or low quality synthesis for some systems. Here we report how continuous flow chemistry can be adapted as a versatile route to a range of MOFs, by emulating conditions of lab-scale batch synthesis. This delivers ready synthesis of three different MOFs, with surface areas that closely match theoretical maxima, with production rates of 60 g/h at extremely high space-time yields. PMID:24962145

  8. Flux-Pinning Centers In Metal-Organic Deposited YBCO Coated Conductors

    SciTech Connect

    Strickland, N. M.; Long, N. J.; Talantsev, E. F.; Xia, J. A.; Kennedy, J.; Markwitz, A.; Zondervan, A.; Rupich, M. W.; Zhang, W.; Li, X.; Sathyamurthy, S.

    2009-07-23

    We present our recent results in introducing artificial flux-pinning centers in metal-organic deposited YBa{sub 2}Cu{sub 3}O{sub 7} coated conductors. In particular, we describe methods for creating point-like and planar defects through precursor and process modifications, and linear defects using post-process heavy-ion irradiation. We observe these defects through transmission-electron microscopy. Each type of defect contributes a particular critical-current signature and combinations of defects can be used to tailor the superconductor for specific applications.

  9. Photocatalytic CO2 reduction in metal-organic frameworks: A mini review

    NASA Astrophysics Data System (ADS)

    Wang, Chong-Chen; Zhang, Yan-Qiu; Li, Jin; Wang, Peng

    2015-03-01

    Photocatalytic reduction of CO2 for value-added chemicals is an attractive process to address both energy and environmental issues. This mini review paper presents two different conversion processes, namely conversion to organic chemicals (like CH4, CH3OH, HCOOH and so on) and being split into CO, in metal-organic frameworks (MOFs). The reported examples are collected and analyzed; and the reaction mechanism, the influence of various factors on the photocatalytic performance, the involved challenges, and the prospects are discussed and estimated. It is clear that MOFs have a bright prospect in the field of photocatalytic reduction of CO2.

  10. Method of making AlInSb by metal-organic chemical vapor deposition

    DOEpatents

    Biefeld, Robert M.; Allerman, Andrew A.; Baucom, Kevin C.

    2000-01-01

    A method for producing aluminum-indium-antimony materials by metal-organic chemical vapor deposition (MOCVD). This invention provides a method of producing Al.sub.X In.sub.1-x Sb crystalline materials by MOCVD wherein an Al source material, an In source material and an Sb source material are supplied as a gas to a heated substrate in a chamber, said Al source material, In source material, and Sb source material decomposing at least partially below 525.degree. C. to produce Al.sub.x In.sub.1-x Sb crystalline materials wherein x is greater than 0.002 and less than one.

  11. A Zn Metal-Organic Framework with High Stability and Sorption Selectivity for CO2.

    PubMed

    Wang, Rongming; Liu, Xiaobin; Qi, Dongdong; Xu, Yuwen; Zhang, Liangliang; Liu, Xiaoqing; Jiang, Jianzhuang; Dai, Fangna; Xiao, Xin; Sun, Daofeng

    2015-11-16

    A three-dimensional porous Zn metal-organic framework (UPC-12) with high thermal and chemical stability was isolated in high yield and purity from a hydrothermal reaction. UPC-12 exhibits high selectivity for CO2 due to the formation of hydrogen bonds between CO2 molecules and the -COOH groups exposed inside the channels and the effective π-π interactions between CO2 molecules and the pillared bipyridine moieties of the MOF. The adsorption-desorption process was studied, for the first time, by both (13)C CP-TOSS NMR spectroscopy and in situ DRIFTS. PMID:26503174

  12. Ligand Functionalization in Metal-Organic Frameworks for Enhanced Carbon Dioxide Adsorption.

    PubMed

    Wang, Hao; Peng, Junjie; Li, Jing

    2016-06-01

    Ligand functionalization in metal-organic frameworks (MOFs) has been studied extensively and has been demonstrated to enhance gas adsorption and induce interesting gas adsorption phenomena. This account summarizes our recent study of three series of MOFs by ligand functionalization, as well as their carbon dioxide adsorption properties. While ligand functionalization does not change the overall structure of the frameworks, it can influence their gas adsorption behavior. In the first two series, we show how ligand functionalization influences the CO2 affinity and adsorption capacity of MOFs. We also show a special case in which subtle changes in ligand functionality alter the CO2 adsorption profile. PMID:27071491

  13. Metal-organic framework biosensor with high stability and selectivity in a bio-mimic environment.

    PubMed

    Wu, Xiao-Qin; Ma, Jian-Gong; Li, Han; Chen, Di-Ming; Gu, Wen; Yang, Guang-Ming; Cheng, Peng

    2015-06-01

    A water-stable copper metal-organic framework (MOF), {[Cu2(HL)2(μ2-OH)2(H2O)5]·H2O}n (1, H2L = 2,5-dicarboxylic acid-3,4-ethylene dioxythiophene), was applied for the electrochemical detection of ascorbic acid (AA) without further post-modification. A glass carbon electrode covered with 1 was used as a biosensor for the simultaneous detection of AA and L-tryptophan (L-Trp) from both a single-component solution and a bio-mimic environment. PMID:25947336

  14. Diffusion of acetylene inside the Cu-BTC metal organic framework

    NASA Astrophysics Data System (ADS)

    Prabhudesai, S. A.; Sharma, V. K.; Mitra, S.; Mukhopadhyay, R.

    2012-06-01

    Dynamic of acetylene molecule adsorbed in Copper 1, 3, 5-benzenetricarboxylate metal-organic framework as studied using molecular dynamics simulation technique is reported here. The results showed that the translational motion of the guest molecule exist in two different time scales; faster one behave as free particle and other one is found to follow jump diffusion. Rotational motion of acetylene is found to be an order of magnitude faster than translational motion. Intermediate scattering functions corresponding to rotational motion show an unusual dip, which is described by the m-diffusion model.

  15. Design of a humidity-stable metal-organic framework using a phosphonate monoester ligand.

    PubMed

    Gelfand, Benjamin S; Lin, Jian-Bin; Shimizu, George K H

    2015-02-16

    Phosphonate monoesters are atypical linkers for metal-organic frameworks, but they offer potentially added versatility. In this work, a bulky isopropyl ester is used to direct the topology of a copper(II) network from a dense to an open framework, CALF-30. CALF-30 shows no adsorption of N2 or CH4 however, using CO2 sorption, CALF-30 was found to have a Langmuir surface area of over 300 m(2)/g and to be stable to conditions of 90% relative humidity at 353 K owing to kinetic shielding of the framework by the phosphonate ester. PMID:25646642

  16. Transparent Metal-Organic Framework/Polymer Mixed Matrix Membranes as Water Vapor Barriers.

    PubMed

    Bae, Youn Jue; Cho, Eun Seon; Qiu, Fen; Sun, Daniel T; Williams, Teresa E; Urban, Jeffrey J; Queen, Wendy L

    2016-04-27

    Preventing the permeation of reactive molecules into electronic devices or photovoltaic modules is of great importance to ensure their life span and reliability. This work is focused on the formation of highly functioning barrier films based on nanocrystals (NCs) of a water-scavenging metal-organic framework (MOF) and a hydrophobic cyclic olefin copolymer (COC) to overcome the current limitations. Water vapor transmission rates (WVTR) of the films reveal a 10-fold enhancement in the WVTR compared to the substrate while maintaining outstanding transparency over most of the visible and solar spectrum, a necessary condition for integration with optoelectronic devices. PMID:27071544

  17. Recent advances in porous polyoxometalate-based metal-organic framework materials.

    PubMed

    Du, Dong-Ying; Qin, Jun-Sheng; Li, Shun-Li; Su, Zhong-Min; Lan, Ya-Qian

    2014-07-01

    Polyoxometalate (POM)-based metal-organic framework (MOF) materials contain POM units and generally generate MOF materials with open networks. POM-based MOF materials, which utilize the advantages of both POMs and MOFs, have received increasing attention, and much effort has been devoted to their preparation and relevant applications over the past few decades. They have good prospects in catalysis owing to the electronic and physical properties of POMs that are tunable by varying constituent elements. In this review, we present recent developments in porous POM-based MOF materials, including their classification, synthesis strategies, and applications, especially in the field of catalysis. PMID:24676127

  18. Fluorous Metal-Organic Frameworks with Enhanced Stability and High H2/CO2 Storage Capacities

    PubMed Central

    Zhang, Da-Shuai; Chang, Ze; Li, Yi-Fan; Jiang, Zhong-Yi; Xuan, Zhi-Hong; Zhang, Ying-Hui; Li, Jian-Rong; Chen, Qiang; Hu, Tong-Liang; Bu, Xian-He

    2013-01-01

    A new class of metal-organic frameworks (MOFs) has been synthesized by ligand-functionalization strategy. Systematic studies of their adsorption properties were performed at low and high pressure. Importantly, when fluorine was introduced into the framework via the functionalization, both the framework stabilities and adsorption capacities towards H2/CO2 were enhanced significantly. This consequence can be well interpreted by theoretical studies of these MOFs structures. In addition, one of these MOFs TKL-107 was used to fabricate mixed matrix membranes, which exhibit great potential for the application of CO2 separation. PMID:24264725

  19. A porphyrin-based metal-organic framework as a pH-responsive drug carrier

    NASA Astrophysics Data System (ADS)

    Lin, Wenxin; Hu, Quan; Jiang, Ke; Yang, Yanyu; Yang, Yu; Cui, Yuanjing; Qian, Guodong

    2016-05-01

    A low cytotoxic porphyrin-based metal-organic framework (MOF) PCN-221, which exhibited high PC12 cell viability via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay, was selected as an oral drug carrier. Methotrexate (MTX) was chosen as the model drug molecule which was absorbed into inner pores and channels of MOFs by diffusion. PCN-221 showed high drug loading and sustained release behavior under physiological environment without "burst effect". The controlled pH-responsive release of drugs by PCN-221 revealed its promising application in oral drug delivery.

  20. Efficient photocatalytic degradation of rhodamine 6G with a quantum dot-metal organic framework nanocomposite.

    PubMed

    Kaur, Rajnish; Vellingiri, Kowsalya; Kim, Ki-Hyun; Paul, A K; Deep, Akash

    2016-07-01

    The hybrid structures of metal organic frameworks (MOFs) and nanoparticles may offer the realization of effective photocatalytic materials due to combined benefits of the porous and molecular sieving properties of MOF matrix and the functional characteristics of encapsulated nanoparticles. In this study, cadmium telluride (CdTe) quantum dots (QD) are conjugated with a europium-MOF for the synthesis of a novel nanocomposite material with photocatalytic properties. Successful synthesis of a QD/Eu-MOF nanocomposite was characterized with various spectroscopic and microscopic techniques. This QD/Eu-MOF is found to be an effective catalyst to complete the degradation of Rhodamine 6G dye within 50 min. PMID:27101017

  1. Evaluation of Metal-Organic Frameworks and Porous Polymer Networks for CO2 -Capture Applications.

    PubMed

    Verdegaal, Wolfgang M; Wang, Kecheng; Sculley, Julian P; Wriedt, Mario; Zhou, Hong-Cai

    2016-03-21

    This manuscript presents experimental data for 20 adsorption materials (metal-organic frameworks, porous polymer networks, and Zeolite-5A), including CO2 and N2 isotherms and heat capacities. With input from only experimental data, working capacities per energy for each material were calculated. Furthermore, by running seven different carbon-capture scenarios in which the initial flue-gas composition and process temperature was systematically changed, we present a range of performances for each material and quantify how sensitive each is to these varying parameters. The presented calculations provide researchers with a tool to investigate promising carbon-capture materials more easily and completely. PMID:26840979

  2. Carbon dioxide capturing technologies: a review focusing on metal organic framework materials (MOFs).

    PubMed

    Sabouni, Rana; Kazemian, Hossein; Rohani, Sohrab

    2014-04-01

    In this study, a relevant literature has been reviewed focusing on the carbon dioxide capture technologies in general, such as amine-based absorption as conventional carbon dioxide capturing technology, aqueous ammonia-based absorption, membranes, and adsorption material (e.g., zeolites, and activated carbons). In more details, metal organic frameworks (MOFs) as new emerging technologies for carbon dioxide adsorption are discussed. The MOFs section is intended to provide a comprehensive overview of MOFs including material characteristics and synthesis, structural features, CO2 adsorption capacity, heat of adsorption and selectivity of CO2. PMID:24338107

  3. Review of Molecular Simulations of Methane Storage in Metal-Organic Frameworks.

    PubMed

    Lee, Seung-Joon; Bae, Youn-Sang

    2016-05-01

    Methane storage in porous materials is one of the hot issues because it can replace dangerous high-pressure compressed natural gas (CNG) tanks in natural gas vehicles. Among the diverse adsorbents, metal-organic frameworks (MOFs) are considered to be promising due to their extremely high surface areas and low crystal densities. Molecular simulation has been considered as an important tool for finding an appropriate MOF for methane storage. We review several important roles of molecular modeling for the studies of methane adsorption in MOFs. PMID:27483748

  4. Mechanical properties of metal-organic frameworks: An indentation study on epitaxial thin films

    NASA Astrophysics Data System (ADS)

    Bundschuh, S.; Kraft, O.; Arslan, H. K.; Gliemann, H.; Weidler, P. G.; Wöll, C.

    2012-09-01

    We have determined the hardness and Young's modulus of a highly porous metal-organic framework (MOF) using a standard nanoindentation technique. Despite the very low density of these films, 1.22 g cm-3, Young's modulus reaches values of almost 10 GPa for HKUST-1, demonstrating that this porous coordination polymer is substantially stiffer than normal polymers. This progress in characterizing mechanical properties of MOFs has been made possible by the use of high quality, oriented thin films grown using liquid phase epitaxy on modified Au substrates.

  5. An all-atom force field developed for Zn₄O(RCO₂)₆ metal organic frameworks.

    PubMed

    Sun, Yingxin; Sun, Huai

    2014-03-01

    An all-atom force field is developed for metal organic frameworks Zn₄O(RCO₂)₆ by fitting to quantum mechanics data. Molecular simulations are conducted to validate the force field by calculating thermal expansion coefficients, crystal bulk and Young's moduli, power spectra, self-diffusion coefficients, and activation energies of self-diffusions for benzene and n-hexane. The calculated results are in good agreement with available experimental data. The proposed force field is suitable for simulations of adsorption or diffusion of organic molecules with flexible frameworks. PMID:24562858

  6. Metal-organic framework derived hollow polyhedron metal oxide posited graphene oxide for energy storage applications.

    PubMed

    Ramaraju, Bendi; Li, Cheng-Hung; Prakash, Sengodu; Chen, Chia-Chun

    2016-01-18

    A composite made from hollow polyhedron copper oxide and graphene oxide was synthesized by sintering a Cu-based metal-organic framework (Cu-MOF) embedded with exfoliated graphene oxide. As a proof-of-concept application, the obtained Cu(ox)-rGO materials were used in a lithium-ion battery and a sodium-ion battery as anode materials. Overall, the Cu(ox)-rGO composite delivers excellent electrochemical properties with stable cycling when compared to pure CuO-rGO and Cu-MOF. PMID:26587567

  7. Synthesis and characterization of two dimensional metal organic framework of cerium with tetraaza macrocyclic

    SciTech Connect

    Bt Safiin, Nurul Atikah; Yarmo, Ambar; Yamin, Bohari M.

    2013-11-27

    A two dimensional metal organic framework containing cerium sufate layers and ethylenediaminium between layers was obtained by refluxing the mixture of cerium sulphate and 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7, 14-diene bromide. The complex was characterized by infrared spectroscopy and microelemental analysis. X-ray study showed that the complex adopts eleven coordination environments about the central atom. Thermogravimetric study showed the removal of water molecules at about 70°C followed by a gradual mass loss until the whole structure collapsed at about 400°C.

  8. Unprecedented selectivity in molecular recognition of carbohydrates by a metal-organic framework.

    PubMed

    Yabushita, Mizuho; Li, Peng; Bernales, Varinia; Kobayashi, Hirokazu; Fukuoka, Atsushi; Gagliardi, Laura; Farha, Omar K; Katz, Alexander

    2016-06-01

    Metal-organic framework (MOF) material NU-1000 adsorbs dimers cellobiose and lactose from aqueous solution, in amounts exceeding 1250 mg gNU-1000(-1) while completely excluding the adsorption of the monomer glucose, even in a competitive mode with cellobiose. The MOF also discriminates between dimers consisting of α and β linkages, showing no adsorption of maltose. Electronic structure calculations demonstrate that key to this selective molecular recognition is the number of favorable CH-π interactions made by the sugar with pyrene units of the MOF. PMID:27184781

  9. Metal-organic frameworks constructed from crown ether-based 1,4-benzenedicarboxylic acid derivatives.

    PubMed

    Chen, Teng-Hao; Schneemann, Andreas; Fischer, Roland A; Cohen, Seth M

    2016-02-21

    A series of unprecedented crown ether- and thiacrown ether-derivatized benzene dicarboxylic acid (H2bdc) ligands has been synthesized and incorporated into the prototypical isoreticular metal-organic framework (IRMOF) and UiO-66 materials. In the case of UiO-66, only MOFs comprised from a mixed-ligand composition, requiring both unsubstituted bdc and crown ether containing ligands, could be prepared. These are among the few ligand derivatives, and resulting MOFs, that incorporate a macrocyclic group directly on the bdc ligand, providing a new, modular platform for exploring new supramolecular and coordination chemistry within MOFs. PMID:26765588

  10. Joint of REBa2Cu3O7-δ Coated Conductors Using Metal Organic Deposition

    NASA Astrophysics Data System (ADS)

    Hiramatsu, K.; Teranishi, R.; Yamada, K.; Sato, Y.; Kaneko, K.

    Joint techniques connecting REBa2Cu3O7-δ(REBCO) coated conductors (CCs) are required to fabricate long length CCs and to repair locally damaged one. Two pieces of REBCO CC were attempted to be jointed using a metal organic deposition (MOD) method. The starting solution for YBCO layer was coated on GdBCO layer of CCs and calcined to fabricate precursor films, two of which were stuck together in a face to face manner, and then these films were pressurized and crystallized to joint them. Two CCs were successfully jointed together with c-axis oriented YBCO without pores and reacted phases at the joint interface.

  11. Alkali burns from wet cement.

    PubMed Central

    Peters, W. J.

    1984-01-01

    When water is added to the dry materials of Portland cement calcium hydroxide is formed; the wet cement is caustic (with a pH as high as 12.9) and can produce third-degree alkali burns after 2 hours of contact. Unlike professional cement workers, amateurs are usually not aware of any danger and may stand or kneel in the cement for long periods. As illustrated in a case report, general physicians may recognize neither the seriousness of the injury in its early stages nor the significance of a history of prolonged contact with wet cement. All people working with cement should be warned about its dangers and advised to immediately wash and dry the skin if contact does occur. Images Fig. 1 PMID:6561052

  12. Transformation of metal-organic framework to polymer gel by cross-linking the organic ligands preorganized in metal-organic framework.

    PubMed

    Ishiwata, Takumi; Furukawa, Yuki; Sugikawa, Kouta; Kokado, Kenta; Sada, Kazuki

    2013-04-10

    Until now, seamless fusion of metal-organic frameworks (MOFs) and covalently cross-linked polymer gels (PG) at molecular level has been extremely rare, since these two matters have been regarded as opposite, that is, hard versus soft. In this report, we demonstrate transformation of cubic MOF crystals to PG via inner cross-linking of the organic linkers in the void space of MOF, followed by decomposition of the metal coordination. The obtained PG behaved as a polyelectrolyte gel, indicating the high content of ionic groups inside. Metal ions were well adsorbed in the PG due to its densely packed carboxylate groups. A chimera-type hybrid material consisting of MOF and PG was obtained by partial hydrolysis of resulting cross-linked MOF. The shape of resulting PG network well reflected the crystal structure of MOF employed as a template. Our results will connect the two different network materials that have been ever studied in the two different fields to provide new soft and hard hybrid materials, and the unique copolymerization in the large void space of the MOF will open a new horizon toward "ideal network polymers" never prepared before now. PMID:23472763

  13. Facile method to disperse nonporous metal organic frameworks: composite formation with a porous metal organic framework and application in adsorptive desulfurization.

    PubMed

    Hasan, Zubair; Jhung, Sung Hwa

    2015-05-20

    It is generally not easy to utilize nonporous metal organic frameworks (MOFs) with a large crystal size (especially for catalysis or adsorption) because their surface area is low and the majority of the active sites exist inside the MOFs. Composing with porous materials may be one way to disperse the nonporous materials. In this study, a nonporous/nonsoluble MOF (in which the particle size was much larger than the cavity size of the porous MOFs) containing Cu(I) ((Cu2(pyz)2(SO4)(H2O)2)n, denoted as CP) was composed with typical porous MOFs such as MIL100(Fe) (iron-benzenetricarboxylate) and CuBTC (cupper-benzenetricarboxylate). The Cu(I) species of the nonporous MOF was effectively utilized for the adsorptive desulfurization (ADS) of model fuel. Even though the porosities of the composed MOFs decreased as the content of CP increased, the adsorption capacity increased as the content of CP increased (up to a certain content). Considering the negligible capacity of CP for ADS, the enhanced adsorption capacity may be a result of the well-dispersed Cu(I), which is known to be beneficial for ADS via π-complexation. The dispersed CP was also observed by transmission electron microscopy mapping. Therefore, composing a nonporous MOF with porous MOF is a new and facile way to disperse/utilize the active sites of a nonporous MOF. PMID:25912936

  14. Monolithic column incorporated with lanthanide metal-organic framework for capillary electrochromatography.

    PubMed

    Zhang, Li-Shun; Du, Pei-Yao; Gu, Wen; Zhao, Qing-Li; Huang, Yan-Ping; Liu, Zhao-Sheng

    2016-08-26

    A new lanthanide metal-organic frameworks NKU-1 have successfully incorporated into poly (BMA-co-EDMA) monolith and evaluated by capillary electrochromatography (CEC). Lanthanide metal-organic frameworks [Eu2(ABTC)1.5(H2O)3(DMA)] (NKU-1) were synthesized by self-assembly of Eu(III) ions and 3,3',5,5'-azo benzene tetracarboxylic acid ligands have been fabricated into poly(BMA-co-EDMA) monoliths. 1-Butyl-3-methylimidazolium tetrafluoroborate and N,N-dimethylformamide were developed as binary porogen obtaining homogeneous dispersibility for NKU-1 and high permeability for monolithic column. The successful incorporation of NKU-1 into poly(BMA-co-EDMA) was confirmed and characterized by FT-IR spectra, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer area scanning, and transmission electron microscopy. Separation ability of the NKU-1-poly (BMA-co-EDMA) monoliths was demonstrated by separating four groups of analytes in CEC, including alkylbenzenes, polycyclic aromatic hydrocarbon, aniline series and naphthyl substitutes. Compared with bare monolithic (column efficiency of 100,000plates/m), the NKU-1-poly (BMA-co-EDMA) monoliths have displayed greater column efficiency (maximum 210,000plates/m) and higher permeability, as well as less peak tailing. The results showed that the NKU-1-poly (BMA-co-EDMA) monoliths are promising stationary phases for CEC separations. PMID:27432788

  15. Isolation of Renewable Phenolics by Adsorption on Ultrastable Hydrophobic MIL-140 Metal-Organic Frameworks.

    PubMed

    Van de Voorde, Ben; Damasceno Borges, Daiane; Vermoortele, Frederik; Wouters, Robin; Bozbiyik, Belgin; Denayer, Joeri; Taulelle, Francis; Martineau, Charlotte; Serre, Christian; Maurin, Guillaume; De Vos, Dirk

    2015-09-21

    The isolation and separation of phenolic compounds from aqueous backgrounds is challenging and will gain in importance as we become more dependent on phenolics from lignocellulose-derived bio-oil to meet our needs for aromatic compounds. Herein, we show that highly stable and hydrophobic Zr metal-organic frameworks of the MIL-140 type are effective adsorbent materials for the separation of different phenolics and far outperform other classes of porous solids (silica, zeolites, carbons). The mechanism of the hydroquinone-catechol separation on MIL-140C was studied in detail by combining experimental results with computational techniques. Although the differences in adsorption enthalpy between catechol and hydroquinone are negligible, the selective uptake of catechol in MIL-140C is explained by its dense π-π stacking in the pores. The interplay of enthalpic and entropic effects allowed separation of a complex, five-compound phenol mixture through breakthrough over a MIL-140C column. Unlike many other metal-organic frameworks, MIL-140C is remarkably stable and maintained structure, porosity and performance after five adsorption-desorption cycles. PMID:26373364

  16. Made-to-order metal-organic frameworks for trace carbon dioxide removal and air capture

    PubMed Central

    Shekhah, Osama; Belmabkhout, Youssef; Chen, Zhijie; Guillerm, Vincent; Cairns, Amy; Adil, Karim; Eddaoudi, Mohamed

    2014-01-01

    Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting sources, namely stationary power plants and transportation. Here we show that metal-organic framework crystal chemistry permits the construction of an isostructural metal-organic framework (SIFSIX-3-Cu) based on pyrazine/copper(II) two-dimensional periodic 44 square grids pillared by silicon hexafluoride anions and thus allows further contraction of the pore system to 3.5 versus 3.84 Å for the parent zinc(II) derivative. This enhances the adsorption energetics and subsequently displays carbon dioxide uptake and selectivity at very low partial pressures relevant to air capture and trace carbon dioxide removal. The resultant SIFSIX-3-Cu exhibits uniformly distributed adsorption energetics and offers enhanced carbon dioxide physical adsorption properties, uptake and selectivity in highly diluted gas streams, a performance, to the best of our knowledge, unachievable with other classes of porous materials. PMID:24964404

  17. Fabrication of carbon nanorods and graphene nanoribbons from a metal-organic framework.

    PubMed

    Pachfule, Pradip; Shinde, Dhanraj; Majumder, Mainak; Xu, Qiang

    2016-07-01

    One- and two-dimensional carbon nanomaterials are attracting considerable attention because of their extraordinary electrical, mechanical and thermal properties, which could lead to a range of important potential applications. Synthetic processes associated with making these materials can be quite complex and also consume large amounts of energy, so a major challenge is to develop simple and efficient methods to produce them. Here, we present a self-templated, catalyst-free strategy for the synthesis of one-dimensional carbon nanorods by morphology-preserved thermal transformation of rod-shaped metal-organic frameworks. The as-synthesized non-hollow (solid) carbon nanorods can be transformed into two- to six-layered graphene nanoribbons through sonochemical treatment followed by chemical activation. The performance of these metal-organic framework-derived carbon nanorods and graphene nanoribbons in supercapacitor electrodes demonstrates that this synthetic approach can produce functionally useful materials. Moreover, this approach is readily scalable and could be used to produce carbon nanorods and graphene nanoribbons on industrial levels. PMID:27325100

  18. Bi2O3 nanoparticles encapsulated in surface mounted metal-organic framework thin films

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Chen, Zhi; Yang, Chengwu; Neumann, Tobias; Kübel, Christian; Wenzel, Wolfgang; Welle, Alexander; Pfleging, Wilhelm; Shekhah, Osama; Wöll, Christof; Redel, Engelbert

    2016-03-01

    We describe a novel procedure to fabricate a recyclable hybrid-photocatalyst based on Bi2O3@HKUST-1 MOF porous thin films. Bi2O3 nanoparticles (NPs) were synthesized within HKUST-1 (or Cu3(BTC)2) surface-mounted metal-organic frame-works (SURMOFs) and characterized using X-ray diffraction (XRD), a quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). The Bi2O3 semiconductor NPs (diameter 1-3 nm)/SURMOF heterostructures exhibit superior photo-efficiencies compared to NPs synthesized using conventional routes, as demonstrated via the photodegradation of the nuclear fast red (NFR) dye.We describe a novel procedure to fabricate a recyclable hybrid-photocatalyst based on Bi2O3@HKUST-1 MOF porous thin films. Bi2O3 nanoparticles (NPs) were synthesized within HKUST-1 (or Cu3(BTC)2) surface-mounted metal-organic frame-works (SURMOFs) and characterized using X-ray diffraction (XRD), a quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). The Bi2O3 semiconductor NPs (diameter 1-3 nm)/SURMOF heterostructures exhibit superior photo-efficiencies compared to NPs synthesized using conventional routes, as demonstrated via the photodegradation of the nuclear fast red (NFR) dye. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00532b

  19. Metal-organic framework with optimally selective xenon adsorption and separation.

    PubMed

    Banerjee, Debasis; Simon, Cory M; Plonka, Anna M; Motkuri, Radha K; Liu, Jian; Chen, Xianyin; Smit, Berend; Parise, John B; Haranczyk, Maciej; Thallapally, Praveen K

    2016-01-01

    Nuclear energy is among the most viable alternatives to our current fossil fuel-based energy economy. The mass deployment of nuclear energy as a low-emissions source requires the reprocessing of used nuclear fuel to recover fissile materials and mitigate radioactive waste. A major concern with reprocessing used nuclear fuel is the release of volatile radionuclides such as xenon and krypton that evolve into reprocessing facility off-gas in parts per million concentrations. The existing technology to remove these radioactive noble gases is a costly cryogenic distillation; alternatively, porous materials such as metal-organic frameworks have demonstrated the ability to selectively adsorb xenon and krypton at ambient conditions. Here we carry out a high-throughput computational screening of large databases of metal-organic frameworks and identify SBMOF-1 as the most selective for xenon. We affirm this prediction and report that SBMOF-1 exhibits by far the highest reported xenon adsorption capacity and a remarkable Xe/Kr selectivity under conditions pertinent to nuclear fuel reprocessing. PMID:27291101

  20. Gold nanoparticles immobilized on metal-organic frameworks with enhanced catalytic performance for DNA detection.

    PubMed

    Liu, Ya Li; Fu, Wen Liang; Li, Chun Mei; Huang, Cheng Zhi; Li, Yuan Fang

    2015-02-25

    In this work, gold nanoparticles (AuNPs) assembled on the surface of iron based metal-organic frameworks (MOFs), Fe-MIL-88, are facilely prepared through electrostatic interactions using polyethyleneimine (PEI) molecules as linker. The resulting hybrid materials possess synergetic peroxidase-like activity. Because iron based metal-organic frameworks, Fe-MIL-88, exhibits highly peroxidase-like activity, and AuNPs has the distinct adsorption property to single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The peroxidase-like activity of Au@Fe-MIL-88 exhibit excellent switchable in response to specific DNA, ssDNA is easily adsorbed on the surface of the Au@Fe-MIL-88 hybrids, resulting in the reduce of the peroxidase-like activity of the hybrids. While it is recovered by the addition of target DNA, and the recovery degree is proportional to the target DNA concentration over the range of 30-150 nM with a detection limit of 11.4 nM. Based on these unique properties, we develop a label-free colorimetric method for DNA hybridization detection. In control experiment, base-mismatched DNA cannot induce recovery of the peroxidase-like activity. This detection method is simple, cheap, rapid and colorimetric. PMID:25702274

  1. Percolative metal-organic framework/carbon composites for hydrogen storage

    NASA Astrophysics Data System (ADS)

    Xie, Shuqian; Hwang, Jiann-Yang; Sun, Xiang; Shi, Shangzhao; Zhang, Zheng; Peng, Zhiwei; Zhai, Yuchun

    2014-05-01

    Percolative Metal-organic framework/Carbon (MOFAC) composites are synthesized by IRMOF8 (isoreticular metal-organic frameworks) directly depositing on activated carbon via heterogeneous nucleation. Carbon content is calculated by TGA (Thermogravimetric analysis) tests. XRD (X-ray diffraction) and FESEM (Field emission-scanning electron microscope) are carried out to characterize the structures of the samples. BET surface areas and the pore size distribution are measured. The dielectric constant is measured with impedance analyzer and a specially designed sample holder. The dielectric constants of the MOFAC composites rise with increasing the carbon content, and the composites possess the insulator-conductor transition as the carbon content increases from 17.77 wt% to 22.2 wt%. The composites are further tested for hydrogen storage capability under assist of the PMN-PT (single crystal lead magnesium niobate-lead titanate) generated electric field. With help from the PMN-PT, the hydrogen uptake capability is increased about 31.5% over the MOFAC3 (MOF-Carbon composite with 22.2 wt% of carbon) without PMN-PT, which is elucidated by the charge distribution mechanisms. The improved storage is due to a stronger electrostatic interaction between IRMOF8 and hydrogen molecule caused by field polarization. Meanwhile, rapid adsorption/desorption kinetics and total reversibility on the samples are observed in the present or absence of external electric field.

  2. Made-to-order metal-organic frameworks for trace carbon dioxide removal and air capture

    NASA Astrophysics Data System (ADS)

    Shekhah, Osama; Belmabkhout, Youssef; Chen, Zhijie; Guillerm, Vincent; Cairns, Amy; Adil, Karim; Eddaoudi, Mohamed

    2014-06-01

    Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting sources, namely stationary power plants and transportation. Here we show that metal-organic framework crystal chemistry permits the construction of an isostructural metal-organic framework (SIFSIX-3-Cu) based on pyrazine/copper(II) two-dimensional periodic 44 square grids pillared by silicon hexafluoride anions and thus allows further contraction of the pore system to 3.5 versus 3.84 Å for the parent zinc(II) derivative. This enhances the adsorption energetics and subsequently displays carbon dioxide uptake and selectivity at very low partial pressures relevant to air capture and trace carbon dioxide removal. The resultant SIFSIX-3-Cu exhibits uniformly distributed adsorption energetics and offers enhanced carbon dioxide physical adsorption properties, uptake and selectivity in highly diluted gas streams, a performance, to the best of our knowledge, unachievable with other classes of porous materials.

  3. Glass shell manufacturing in space. [residual gases in spherical shells made from metal-organic gels

    NASA Technical Reports Server (NTRS)

    Nolen, R. J.; Ebner, M. A.; Downs, R. L.

    1980-01-01

    Residual gases always found in glass shells are CO2, O2 and N2. In those cases where high water vapor pressure is maintained in the furnace, water is also found in the shells. Other evidence for the existence of water in shells is the presence of water-induced surface weathering of the interior shell surface. Water and CO2 are the predominant volatiles generated by the pyrolysis of both inorganic and hydrolyzed metal-organic gels. The pyrolysates of unhydrolyzed metal-organic gels also contain, in addition to water and CO2, significant levels of organic volatiles, such as ethanol and some hydrocarbons; on complete oxidation, these produce CO2 and water as well. Water is most likely the initial blowing agent, it is produced copiously during the initial stages of heating. In the later stages, CO2 becomes the dominant gas as H2O is lost at increasing rates. Water in the shell arises mainly from gel dehydration, CO2 by sodium bicarbonate/carbonate decomposition and carbon oxidation, and O2 and N2 by permeation of the ambient furnace air through the molten shell wall.

  4. Bulk synthesis of metal-organic hybrid dimers and their propulsion under electric fields.

    PubMed

    Wang, Sijia; Ma, Fuduo; Zhao, Hui; Wu, Ning

    2014-03-26

    Metal-organic hybrid particles have great potential in applications such as colloidal assembly, autonomous microrobots, targeted drug delivery, and colloidal emulsifiers. Existing fabrication methods, however, typically suffer from low throughput, high operation cost, and imprecise property control. Here, we report a facile and bulk synthesis platform that makes a wide range of metal-organic colloidal dimers. Both geometric and interfacial anisotropy on the particles can be tuned independently and conveniently, which represents a key advantage of this method. We further investigate the self-propulsion of platinum-polystyrene dimers under perpendicularly applied electric fields. In 1 × 10(-4) M KCl solution, the dimers exhibit both linear and circular motion with the polystyrene lobes facing toward the moving direction, due to the induced-charge electroosmotic flow surrounding the metal-coated lobes. Surprisingly, in deionized water, the same dimers move in an opposite direction, i.e., the metallic lobes face the forward direction. This is because of the impact of another type of electrokinetic flow: the electrohydrodynamic flow arising from the induced charges on the conducting substrate. The competition between the electrohydrodynamic flow along the substrate and the induced-charge electroosmotic flow along the metallic lobe dictates the propulsion direction of hybrid dimers under electric fields. Our synthetic approach will provide potential opportunities to study the combined impacts of the geometric and interfacial anisotropy on the propulsion, assembly, and other applications of anisotropic particles. PMID:24581149

  5. Post Modification of Metal-Organic Framework and Their Application In Cancer Theranostics

    NASA Astrophysics Data System (ADS)

    Lakkakula, Hima bindu

    The research proposal aims to demonstrate that Metal-Organic Frameworks (MOFs) are mainly used for cancer theranostics which is the combination of both diagnostic and therapeutic functions. The research will emphasis on synthesis of Fe- MOFs by solvothermal nucleation, crystallization, characterization by microscopy and spectroscopy and evaluation with different lattice parameters and its morphology. Nowadays MOFs are used for the novel drug delivery purposes. The current published Fe- MOFs research focus is on the cancer theranostics by Indian medicines which will be impregnated into the MOFs and which will evaluate bioavailability and the chemotherapeutic activity of the drug. Nanotechnology provides the target specificity without affecting the healthy tissues. Other research problems to be addressed are the relationship between metal connectivity and ligand-based luminescence, MOF stability in an aqueous environment and activating it at increased temperature serves as a crucial role. The merits of this research are to increase the surface area and pore size of the drug so that the therapeutic efficacy can be improved. Moreover, the stabilization of metal-organic frameworks can also be enhanced with high surface area.

  6. Two-Dimensional Ketone-Driven Metal-Organic Coordination on Cu(111).

    PubMed

    Della Pia, Ada; Riello, Massimo; Lawrence, James; Stassen, Daphne; Jones, Tim S; Bonifazi, Davide; De Vita, Alessandro; Costantini, Giovanni

    2016-06-01

    Two-dimensional metal-organic nanostructures based on the binding of ketone groups and metal atoms were fabricated by depositing pyrene-4,5,9,10-tetraone (PTO) molecules on a Cu(111) surface. The strongly electronegative ketone moieties bind to either copper adatoms from the substrate or codeposited iron atoms. In the former case, scanning tunnelling microscopy images reveal the development of an extended metal-organic supramolecular structure. Each copper adatom coordinates to two ketone ligands of two neighbouring PTO molecules, forming chains that are linked together into large islands through secondary van der Waals interactions. Deposition of iron atoms leads to a transformation of this assembly resulting from the substitution of the metal centres. Density functional theory calculations reveal that the driving force for the metal substitution is primarily determined by the strength of the ketone-metal bond, which is higher for Fe than for Cu. This second class of nanostructures displays a structural dependence on the rate of iron deposition. PMID:27071489

  7. Integrating Sphere Alkali-Metal Vapor Cells

    NASA Astrophysics Data System (ADS)

    McGuyer, Bart; Ben-Kish, Amit; Jau, Yuan-Yu; Happer, William

    2010-03-01

    An integrating sphere is an optical multi-pass cavity that uses diffuse reflection to increase the optical path length. Typically applied in photometry and radiometry, integrating spheres have previously been used to detect trace gases and to cool and trap alkali-metal atoms. Here, we investigate the potential for integrating spheres to enhance optical absorption in optically thin alkali-metal vapor cells. In particular, we consider the importance of dielectric effects due to a glass container for the alkali-metal vapor. Potential applications include miniature atomic clocks and magnetometers, where multi-passing could reduce the operating temperature and power consumption.

  8. Alkali Silicate Vehicle Forms Durable, Fireproof Paint

    NASA Technical Reports Server (NTRS)

    Schutt, John B.; Seindenberg, Benjamin

    1964-01-01

    The problem: To develop a paint for use on satellites or space vehicles that exhibits high resistance to cracking, peeling, or flaking when subjected to a wide range of temperatures. Organic coatings will partially meet the required specifications but have the inherent disadvantage of combustibility. Alkali-silicate binders, used in some industrial coatings and adhesives, show evidence of forming a fireproof paint, but the problem of high surface-tension, a characteristic of alkali silicates, has not been resolved. The solution: Use of a suitable non-ionic wetting agent combined with a paint incorporating alkali silicate as the binder.

  9. Diode pumped alkali vapor fiber laser

    DOEpatents

    Payne, Stephen A.; Beach, Raymond J.; Dawson, Jay W.; Krupke, William F.

    2007-10-23

    A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

  10. Diode pumped alkali vapor fiber laser

    DOEpatents

    Payne, Stephen A.; Beach, Raymond J.; Dawson, Jay W.; Krupke, William F.

    2006-07-26

    A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

  11. Advancements in flowing diode pumped alkali lasers

    NASA Astrophysics Data System (ADS)

    Pitz, Greg A.; Stalnaker, Donald M.; Guild, Eric M.; Oliker, Benjamin Q.; Moran, Paul J.; Townsend, Steven W.; Hostutler, David A.

    2016-03-01

    Multiple variants of the Diode Pumped Alkali Laser (DPAL) have recently been demonstrated at the Air Force Research Laboratory (AFRL). Highlights of this ongoing research effort include: a) a 571W rubidium (Rb) based Master Oscillator Power Amplifier (MOPA) with a gain (2α) of 0.48 cm-1, b) a rubidium-cesium (Cs) Multi-Alkali Multi-Line (MAML) laser that simultaneously lases at both 795 nm and 895 nm, and c) a 1.5 kW resonantly pumped potassium (K) DPAL with a slope efficiency of 50%. The common factor among these experiments is the use of a flowing alkali test bed.

  12. Structural and Magnetic Diversity in Alkali-Metal Manganate Chemistry: Evaluating Donor and Alkali-Metal Effects in Co-complexation Processes.

    PubMed

    Uzelac, Marina; Borilovic, Ivana; Amores, Marco; Cadenbach, Thomas; Kennedy, Alan R; Aromí, Guillem; Hevia, Eva

    2016-03-24

    By exploring co-complexation reactions between the manganese alkyl Mn(CH2SiMe3)2 and the heavier alkali-metal alkyls M(CH2SiMe3) (M=Na, K) in a benzene/hexane solvent mixture and in some cases adding Lewis donors (bidentate TMEDA, 1,4-dioxane, and 1,4-diazabicyclo[2,2,2] octane (DABCO)) has produced a new family of alkali-metal tris(alkyl) manganates. The influences that the alkali metal and the donor solvent impose on the structures and magnetic properties of these ates have been assessed by a combination of X-ray, SQUID magnetization measurements, and EPR spectroscopy. These studies uncover a diverse structural chemistry ranging from discrete monomers [(TMEDA)2 MMn(CH2SiMe3)3] (M=Na, 3; M=K, 4) to dimers [{KMn(CH2SiMe3)3 ⋅C6 H6}2] (2) and [{NaMn(CH2SiMe3)3}2 (dioxane)7] (5); and to more complex supramolecular networks [{NaMn(CH2SiMe3)3}∞] (1) and [{Na2Mn2 (CH2SiMe3)6 (DABCO)2}∞] (7)). Interestingly, the identity of the alkali metal exerts a significant effect in the reactions of 1 and 2 with 1,4-dioxane, as 1 produces coordination adduct 5, while 2 forms heteroleptic [{(dioxane)6K2Mn2 (CH2SiMe3)4(O(CH2)2OCH=CH2)2}∞] (6) containing two alkoxide-vinyl anions resulting from α-metalation and ring opening of dioxane. Compounds 6 and 7, containing two spin carriers, exhibit antiferromagnetic coupling of their S=5/2 moments with varying intensity depending on the nature of the exchange pathways. PMID:26916525

  13. Alkali metal for ultraviolet band-pass filter

    NASA Technical Reports Server (NTRS)

    Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

    1993-01-01

    An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

  14. NEPTUNIUM SOLVENT EXTRACTION PROCESS

    DOEpatents

    Dawson, L.R.; Fields, P.R.

    1959-10-01

    The separation of neptunium from an aqueous solution by solvent extraction and the extraction of neptunium from the solvent solution are described. Neptunium is separated from an aqueous solution containing tetravalent or hexavalent neptunium nitrate, nitric acid, and a nitrate salting out agent, such as sodium nitrate, by contacting the solution with an organic solvent such as diethyl ether. Subsequently, the neptunium nitrate is extracted from the organic solvent extract phase with water.

  15. Solvent refining process

    SciTech Connect

    Mead, T.C.; Sequeira, A.J.; Smith, B.F.

    1981-10-13

    An improved process is described for solvent refining lubricating oil base stocks from petroleum fractions containing both aromatic and nonaromatic constituents. The process utilizes n-methyl-2-pyrrolidone as a selective solvent for aromatic hydrocarbons wherein the refined oil fraction and the extract fraction are freed of final traces of solvent by stripping with gaseous ammonia. The process has several advantages over conventional processes including a savings in energy required for the solvent refining process, and reduced corrosion of the process equipment.

  16. Alkali Metal Handling Practices at NASA MSFC

    NASA Technical Reports Server (NTRS)

    Salvail, Patrick G.; Carter, Robert R.

    2002-01-01

    NASA Marshall Space Flight Center (MSFC) is NASA s principle propulsion development center. Research and development is coordinated and carried out on not only the existing transportation systems, but also those that may be flown in the near future. Heat pipe cooled fast fission cores are among several concepts being considered for the Nuclear Systems Initiative. Marshall Space Flight Center has developed a capability to handle high-purity alkali metals for use in heat pipes or liquid metal heat transfer loops. This capability is a low budget prototype of an alkali metal handling system that would allow the production of flight qualified heat pipe modules or alkali metal loops. The processing approach used to introduce pure alkali metal into heat pipe modules and other test articles are described in this paper.

  17. Alkali-metal intercalation in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Béguin, F.; Duclaux, L.; Méténier, K.; Frackowiak, E.; Salvetat, J. P.; Conard, J.; Bonnamy, S.; Lauginie, P.

    1999-09-01

    We report on successful intercalation of multiwall (MWNT) and single wall (SWNT) carbon nanotubes with alkali metals by electrochemical and vapor phase reactions. A LiC10 compound was produced by full electrochemical reduction of MWNT. KC8 and CsC8-MWNT first stage derivatives were synthesized in conditions of alkali vapor saturation. Their identity periods and the 2×2 R 0° alkali superlattice are comparable to their parent graphite compounds. The dysonian shape of KC8 EPR line and the temperature-independent Pauli susceptibility are both characteristic of a metallic behavior, which was confirmed by 13C NMR anisotropic shifts. Exposure of SWNT bundles to alkali vapor led to an increase of the pristine triangular lattice from 1.67 nm to 1.85 nm and 1.87 nm for potassium and rubidium, respectively.

  18. Metal-organic frameworks with functional pores for recognition of small molecules.

    PubMed

    Chen, Banglin; Xiang, Shengchang; Qian, Guodong

    2010-08-17

    Molecular recognition, an important process in biological and chemical systems, governs the diverse functions of a variety of enzymes and unique properties of some synthetic receptors. Because molecular recognition is based on weak interactions between receptors and substrates, the design and assembly of synthetic receptors to mimic biological systems and the development of novel materials to discriminate different substrates for selective recognition of specific molecules has proved challenging. The extensive research on synthetic receptors for molecular recognition, particularly on noncovalent complexes self-assembled by hydrogen bonding and metal-organic coordination, has revealed some underlying principles. In particular, these studies have demonstrated that the shapes of the supramolecular receptors play significant roles in their specific and selective recognition of substrates: receptors can offer concave surfaces that complement their convex targets. This Account describes our research to develop a synthetic molecular recognition platform using porous metal-organic frameworks (MOFs). These materials contain functional pores to direct their specific and unique recognition of small molecules through several types of interactions: van der Waals interactions of the framework surface with the substrate, metal-substrate interactions, and hydrogen bonding of the framework surface with the substrate. These materials have potential applications for gas storage, separation, and sensing. We demonstrate a simple strategy to construct a primitive cubic net of interpenetrated microporous MOFs from the self-assembly of the paddle-wheel clusters M(2)(CO(2))(4) (M = Cu(2+), Zn(2+), and Co(2+)) with two types of organic dicarboxylic acid and pillar bidentate linkers. This efficient method allows us to rationally tune the micropores to size-exclusively sort different small gas molecules, leading to the highly selective separation and purification of gases. By optimizing the

  19. Alkali metal intercalates of molybdenum disulfide.

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.

    1973-01-01

    Study of some of the physicochemical properties of compounds obtained by subjecting natural molybdenite and single crystals of molybdenum disulfide grown by chemical vapor transport to intercalation with the alkali group of metals (Li, Na, K, Rb, and Cs) by means of the liquid ammonia technique. Reported data and results include: (1) the intercalation of the entire alkali metal group, (2) stoichiometries and X-ray data on all of the compounds, and (3) superconductivity data for all the intercalation compounds.

  20. Superconductivity in alkali-doped C60

    NASA Astrophysics Data System (ADS)

    Ramirez, Arthur P.

    2015-07-01

    Superconductivity in alkali-doped C60 (A3C60, A = an alkali atom) is well described by an s-wave state produced by phonon mediated pairing. Moderate coupling of electrons to high-frequency shape-changing intra-molecular vibrational modes produces transition temperatures (Tc) up to 33 K in single-phase material. The good understanding of pairing in A3C60 offers a paradigm for the development of new superconducting materials.

  1. Desulfurizing Coal With an Alkali Treatment

    NASA Technical Reports Server (NTRS)

    Ravindram, M.; Kalvinskas, J. J.

    1987-01-01

    Experimental coal-desulfurization process uses alkalies and steam in fluidized-bed reactor. With highly volatile, high-sulfur bituminous coal, process removed 98 percent of pyritic sulfur and 47 percent of organic sulfur. Used in coal liquefaction and in production of clean solid fuels and synthetic liquid fuels. Nitrogen or steam flows through bed of coal in reactor. Alkalies react with sulfur, removing it from coal. Nitrogen flow fluidizes bed while heating or cooling; steam is fluidizing medium during reaction.

  2. Alkali metal crystalline polymer electrolytes.

    PubMed

    Zhang, Chuhong; Gamble, Stephen; Ainsworth, David; Slawin, Alexandra M Z; Andreev, Yuri G; Bruce, Peter G

    2009-07-01

    Polymer electrolytes have been studied extensively because uniquely they combine ionic conductivity with solid yet flexible mechanical properties, rendering them important for all-solid-state devices including batteries, electrochromic displays and smart windows. For some 30 years, ionic conductivity in polymers was considered to occur only in the amorphous state above Tg. Crystalline polymers were believed to be insulators. This changed with the discovery of Li(+) conductivity in crystalline poly(ethylene oxide)(6):LiAsF(6). However, new crystalline polymer electrolytes have proved elusive, questioning whether the 6:1 complex has particular structural features making it a unique exception to the rule that only amorphous polymers conduct. Here, we demonstrate that ionic conductivity in crystalline polymers is not unique to the 6:1 complex by reporting several new crystalline polymer electrolytes containing different alkali metal salts (Na(+), K(+) and Rb(+)), including the best conductor poly(ethylene oxide)(8):NaAsF(6) discovered so far, with a conductivity 1.5 orders of magnitude higher than poly(ethylene oxide)(6):LiAsF(6). These are the first crystalline polymer electrolytes with a different composition and structures to that of the 6:1 Li(+) complex. PMID:19543313

  3. Solvents and sustainable chemistry

    PubMed Central

    Welton, Tom

    2015-01-01

    Solvents are widely recognized to be of great environmental concern. The reduction of their use is one of the most important aims of green chemistry. In addition to this, the appropriate selection of solvent for a process can greatly improve the sustainability of a chemical production process. There has also been extensive research into the application of so-called green solvents, such as ionic liquids and supercritical fluids. However, most examples of solvent technologies that give improved sustainability come from the application of well-established solvents. It is also apparent that the successful implementation of environmentally sustainable processes must be accompanied by improvements in commercial performance. PMID:26730217

  4. Solvent recycle/recovery

    SciTech Connect

    Paffhausen, M.W.; Smith, D.L.; Ugaki, S.N.

    1990-09-01

    This report describes Phase I of the Solvent Recycle/Recovery Task of the DOE Chlorinated Solvent Substitution Program for the US Air Force by the Idaho National Engineering Laboratory, EG G Idaho, Inc., through the US Department of Energy, Idaho Operations Office. The purpose of the task is to identify and test recovery and recycling technologies for proposed substitution solvents identified by the Biodegradable Solvent Substitution Program and the Alternative Solvents/Technologies for Paint Stripping Program with the overall objective of minimizing hazardous wastes. A literature search to identify recycle/recovery technologies and initial distillation studies has been conducted. 4 refs.

  5. Dual solvent refining process

    SciTech Connect

    Woodle, R.A.

    1982-04-20

    A dual solvent refining process is claimed for solvent refining petroleum based lubricating oil stocks with n-methyl-2-pyrrolidone as selective solvent for aromatic oils wherein a highly paraffinic oil having a narrow boiling range approximating the boiling point of n-methyl-2-pyrrolidone is employed as a backwash solvent. The process of the invention results in an increased yield of refined lubricating oil stock of a predetermined quality and simplifies separation of the solvents from the extract and raffinate oil fractions.

  6. A Molecular Artisans Guide to Supramolecular Coordination Complexes and Metal Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Wu, Xialu; Young, David J.; Hor, T. S. Andy

    2015-10-01

    As molecular synthesis advances, we are beginning to learn control of not only the chemical reactivity (and function) of molecules, but also of their interactions with other molecules. It is this basic idea that has led to the current explosion of supramolecular science and engineering. Parallel to this development, chemists have been actively pursuing the design of very large molecules using basic molecular building blocks. Herein, we review the general development of supramolecular chemistry and particularly of two new branches: supramolecular coordination complexes (SCCs) and metal organic frameworks (MOFs). These two fields are discussed in detail with typical examples to illustrate what is now possible and what challenges lie ahead for tomorrow's molecular artisans.

  7. Cobalt-Based Layered Metal-Organic Framework as an Ultrahigh Capacity Supercapacitor Electrode Material.

    PubMed

    Liu, Xiuxiu; Shi, Changdong; Zhai, Changwei; Cheng, Meiling; Liu, Qi; Wang, Guoxiu

    2016-02-24

    Metal-organic frameworks (MOFs) have recently received increasing interest due to their potential application in the energy storage and conversion field. Herein, cobalt-based layered MOF ({[Co(Hmt)(tfbdc)(H2O)2]·(H2O)2}n, Co-LMOF; Hmt = hexamethylenetetramine; H2tfbdc = 2,3,5,6-tetrafluoroterephthalic acid) has been evaluated as an electrode material for supercapacitors. The Co-LMOF electrode exhibits a high specific capacitance and excellent cycling stability. Its maximum specific capacitance is 2474 F g(-1) at a current density of 1 A g(-1), and the specific capacitance retention is about 94.3% after 2000 cycles. The excellent electrochemical property may be ascribed to the intrinsic nature of Co-LMOF, enough space available for the storage and diffusion of the electrolyte, and the particles of nanoscale size. PMID:26829547

  8. Fabrication of the microchannel by metal-organic framework, copper benzenetricarboxylate.

    PubMed

    Lim, Mikyung; Seo, You-Kyong; Park, Hyoun Hyang; Kim, Jin-Ha; Chang, Jong-San; Hwang, Young Kyu; Lee, Seung S

    2013-04-01

    We successfully fabricated the metal-organic framework (MOF), copper benzenetricarboxylate on a microchannel system, which was able to solve the problems created by increased heat dissipation in small electronic equipment. The microchannel system was designed to make an entrance part that can control the reaction temperature, which was predicted through a heat transfer analysis and the finite element method with COMSOL Multiphysics. Synthetic conditions, synthesis time, temperature and microchannel size were systematically tuned for the selective fabrication of copper benzenetricarboxylate on a microchannel surface. Scanning electron microscope (SEM) images, selected area electron diffraction (SAED) pattern and Fourier transform infrared (FT-IR) data clearly demonstrated that copper benzenetricarboxylate was strongly adhered to the bottom surfaces of the microchannels. Moreover, the synthesis of MOF in the microchannel system provided a much faster growth rate and better crystallinity compared to a conventional synthesis method. PMID:23763149

  9. Computational Design of Metal-Organic Frameworks with High Methane Deliverable Capacity

    NASA Astrophysics Data System (ADS)

    Bao, Yi; Martin, Richard; Simon, Cory; Haranczyk, Maciej; Smit, Berend; Deem, Michael; Deem Team; Haranczyk Team; Smit Team

    Metal-organic frameworks (MOFs) are a rapidly emerging class of nanoporous materials with largely tunable chemistry and diverse applications in gas storage, gas purification, catalysis, etc. Intensive efforts are being made to develop new MOFs with desirable properties both experimentally and computationally in the past decades. To guide experimental synthesis with limited throughput, we develop a computational methodology to explore MOFs with high methane deliverable capacity. This de novo design procedure applies known chemical reactions, considers synthesizability and geometric requirements of organic linkers, and evolves a population of MOFs with desirable property efficiently. We identify about 500 MOFs with higher deliverable capacity than MOF-5 in 10 networks. We also investigate the relationship between deliverable capacity and internal surface area of MOFs. This methodology can be extended to MOFs with multiple types of linkers and multiple SBUs. DE-FG02- 12ER16362.

  10. A metal-organic framework-based splitter for separating propylene from propane.

    PubMed

    Cadiau, A; Adil, K; Bhatt, P M; Belmabkhout, Y; Eddaoudi, M

    2016-07-01

    The chemical industry is dependent on the olefin/paraffin separation, which is mainly accomplished by using energy-intensive processes. We report the use of reticular chemistry for the fabrication of a chemically stable fluorinated metal-organic framework (MOF) material (NbOFFIVE-1-Ni, also referred to as KAUST-7). The bridging of Ni(II)-pyrazine square-grid layers with (NbOF5)(2-) pillars afforded the construction of a three-dimensional MOF, enclosing a periodic array of fluoride anions in contracted square-shaped channels. The judiciously selected bulkier (NbOF5)(2-) caused the looked-for hindrance of the previously free-rotating pyrazine moieties, delimiting the pore system and dictating the pore aperture size and its maximum opening. The restricted MOF window resulted in the selective molecular exclusion of propane from propylene at atmospheric pressure, as evidenced through multiple cyclic mixed-gas adsorption and calorimetric studies. PMID:27387945

  11. Size-selective crystallization of homochiral camphorate metal-organic frameworks for lanthanide separation.

    PubMed

    Zhao, Xiang; Wong, Matthew; Mao, Chengyu; Trieu, Thuong Xinh; Zhang, Jian; Feng, Pingyun; Bu, Xianhui

    2014-09-10

    Lanthanides (Ln) are a group of important elements usually found in nature as mixtures. Their separation is essential for technological applications but is made challenging by their subtly different properties. Here we report that crystallization of homochiral camphorate metal-organic frameworks (MOFs) is highly sensitive to ionic radii of lanthanides and can be used to selectively crystallize a lanthanide element into predesigned MOFs. Two series of camphorate MOFs were synthesized with acetate (Type 1 with early lanthanides La-Dy) or formate (Type 2 with late lanthanides Tb-Lu and Y) as the auxiliary ligand, respectively. The Ln coordination environment in each type exhibits selectivity for Ln(3+) of different sizes, which could form the basis for a new cost-effective method for Ln separation. PMID:25164942

  12. Use of metal organic fluors for spectral discrimination of neutrons and gammas.

    SciTech Connect

    Allendorf, Mark D.; Doty, F. Patrick; Feng, Patrick L.

    2010-09-01

    A new method for spectral shape discrimination (SSD) of fast neutrons and gamma rays has been investigated. Gammas interfere with neutron detection, making efficient discrimination necessary for practical applications. Pulse shape discrimination (PSD) in liquid organic scintillators is currently the most effective means of gamma rejection. The hazardous liquids, restrictions on volume, and the need for fast timing are drawbacks to traditional PSD scintillators. In this project we investigated harvesting excited triplet states to increase scintillation yield and provide distinct spectral signatures for gammas and neutrons. Our novel approach relies on metal-organic phosphors to convert a portion of the energy normally lost to the scintillation process into useful luminescence with sub-microsecond lifetimes. The approach enables independent control over delayed luminescence wavelength, intensity, and timing for the first time. We demonstrated that organic scintillators, including plastics, nanoporous framework materials, and oil-based liquids can be engineered for both PSD and SSD.

  13. Adsorption of silver nanoparticles from aqueous solution on copper-based metal organic frameworks (HKUST-1).

    PubMed

    Conde-González, J E; Peña-Méndez, E M; Rybáková, S; Pasán, J; Ruiz-Pérez, C; Havel, J

    2016-05-01

    Silver nanoparticles (AgNP) are emerging pollutants. The use of novel materials such as Cu-(benzene 1,3,5-tricarboxylate, BTC) Metal-Organic Framework (MOFs), for AgNP adsorption and their removal from aqueous solutions has been studied. The effect of different parameters was followed and isotherm model was suggested. MOFs adsorbed fast and efficiently AgNP in the range C0 < 10 mg L(-1), being Freundlich isotherm (R = 0.993) these data fitted to. Among studied parameters a remarkable effect of chloride on sorption was found, thus their possible interactions were considered. The high adsorption efficiency of AgNP was achieved and it was found to be very fast. The feasibility of adsorption on Cu-(BTC) was proved in spiked waters. The results showed the potential interest of new material as adsorbent for removing AgNP from environment. PMID:26879292

  14. Detection of Volatile Organic Compounds by Weight-Detectable Sensors coated with Metal-Organic Frameworks

    PubMed Central

    Yamagiwa, Hiroki; Sato, Seiko; Fukawa, Tadashi; Ikehara, Tsuyoshi; Maeda, Ryutaro; Mihara, Takashi; Kimura, Mutsumi

    2014-01-01

    Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs. PMID:25175808

  15. Imparting biomolecules to a metal-organic framework material by controlled DNA tetrahedron encapsulation

    NASA Astrophysics Data System (ADS)

    Jia, Yongmei; Wei, Benmei; Duan, Ruixue; Zhang, Ying; Wang, Boya; Hakeem, Abdul; Liu, Nannan; Ou, Xiaowen; Xu, Shaofang; Chen, Zhifei; Lou, Xiaoding; Xia, Fan

    2014-08-01

    Recently, the incorporation of biomolecules in Metal-organic frameworks (MOFs) attracts many attentions because of controlling the functions, properties and stability of trapped molecules. Although there are few reports on protein/MOFs composites and their applications, none of DNA/MOFs composite is reported, as far as we know. Here, we report a new composite material which is self-assembled from 3D DNA (guest) and pre-synthesized MOFs (host) by electrostatic interactions and hydrophilic interactions in a well-dispersed fashion. Its biophysical characterization is well analyzed by fluorescence spectroscopy, quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). This new composite material keeps 3D DNA nanostructure more stable than only 3D DNA nanostructure in DI water at room temperature, and stores amounts of genetic information. It will make DNA as a guest for MOFs and MOFs become a new platform for the development of DNA nanotechnology.

  16. Metal-organic chemical vapor deposition of aluminum oxide thin films via pyrolysis of dimethylaluminum isopropoxide

    SciTech Connect

    Schmidt, Benjamin W.; Sweet, William J. III; Rogers, Bridget R.; Bierschenk, Eric J.; Gren, Cameron K.; Hanusa, Timothy P.

    2010-03-15

    Metal-organic chemical vapor deposited aluminum oxide films were produced via pyrolysis of dimethylaluminum isopropoxide in a high vacuum reaction chamber in the 417-659 deg. C temperature range. Deposited films contained aluminum, oxygen, and carbon, and the carbon-to-aluminum ratio increased with increased deposition temperature. Aluminum-carbon bonding was observed in films deposited at 659 deg. C by x-ray photoelectron spectroscopy, but not in films deposited at 417 deg. C. The apparent activation energy in the surface reaction controlled regime was 91 kJ/mol. The O/Al and C/Al ratios in the deposited films were greater and less than, respectively, the ratios predicted by the stoichiometry of the precursor. Flux analysis of the deposition process suggested that the observed film stoichiometries could be explained by the participation of oxygen-containing background gases present in the reactor at its base pressure.

  17. Platinum nanoparticles encapsulated metal-organic frameworks for the electrochemical detection of telomerase activity.

    PubMed

    Ling, Pinghua; Lei, Jianping; Jia, Li; Ju, Huangxian

    2016-01-21

    A simple and rapid electrochemical sensor is constructed for the detection of telomerase activity based on the electrocatalysis of platinum nanoparticle (Pt NP) encapsulated metal-organic frameworks (MOFs), which are synthesized by one-pot encapsulation of Pt NPs into prototypal MOFs, UiO-66-NH2. Integrating with the efficient electrocatalysis of Pt@MOFs towards NaBH4 oxidation, this biosensor shows the wide dynamic correlation of telomerase activity from 5 × 10(2) to 10(7) HeLa cells mL(-1) and the telomerase activity in a single HeLa cell was calculated to be 2.0 × 10(-11) IU, providing a powerful platform for detecting telomerase activity. PMID:26612011

  18. Mechanical tunability via hydrogen bonding in metal-organic frameworks with the perovskite architecture.

    PubMed

    Li, Wei; Thirumurugan, A; Barton, Phillip T; Lin, Zheshuai; Henke, Sebastian; Yeung, Hamish H-M; Wharmby, Michael T; Bithell, Erica G; Howard, Christopher J; Cheetham, Anthony K

    2014-06-01

    Two analogous metal-organic frameworks (MOFs) with the perovskite architecture, [C(NH2)3][Mn(HCOO)3] (1) and [(CH2)3NH2][Mn(HCOO)3] (2), exhibit significantly different mechanical properties. The marked difference is attributed to their distinct modes of hydrogen bonding between the A-site amine cation and the anionic framework. The stronger cross-linking hydrogen bonding in 1 gives rise to Young's moduli and hardnesses that are up to twice those in 2, while the thermal expansion is substantially smaller. This study presents clear evidence that the mechanical properties of MOF materials can be substantially tuned via hydrogen-bonding interactions. PMID:24815319

  19. Iron-Based Metal-Organic Frameworks as Catalysts for Visible Light-Driven Water Oxidation.

    PubMed

    Chi, Le; Xu, Qian; Liang, Xiaoyu; Wang, Jide; Su, Xintai

    2016-03-01

    The development of earth-abundant, active, and stable catalysts is important for solar energy conversion. Metal-organic frameworks (MOFs) have been viewed as a promising class of porous materials, which may have innovative application in photocatalysis. In this paper, three types of Fe-based MOFs and their aminofunctionalized derivatives have been fabricated and systematically studied as water oxidation catalysts (WOCs) for oxygen evolution under visible light irradiation. MIL-101(Fe) possesses a higher current density and earlier onset potential and exhibits excellent visible light-driven oxygen evolution activity than the other Fe-based catalysts. It speeds up the oxygen evolution reaction rate with the higher initial turnover frequencies value of 0.10 s(-1) . Our study demonstrates that Fe-based MOFs as efficient WOCs are promising candidates for photocatalytic water oxidation process. PMID:26756919

  20. Bimetallic Metal-Organic Frameworks for Controlled Catalytic Graphitization of Nanoporous Carbons

    PubMed Central

    Tang, Jing; Salunkhe, Rahul R.; Zhang, Huabin; Malgras, Victor; Ahamad, Tansir; Alshehri, Saad M.; Kobayashi, Naoya; Tominaka, Satoshi; Ide, Yusuke; Kim, Jung Ho; Yamauchi, Yusuke

    2016-01-01

    Single metal-organic frameworks (MOFs), constructed from the coordination between one-fold metal ions and organic linkers, show limited functionalities when used as precursors for nanoporous carbon materials. Herein, we propose to merge the advantages of zinc and cobalt metals ions into one single MOF crystal (i.e., bimetallic MOFs). The organic linkers that coordinate with cobalt ions tend to yield graphitic carbons after carbonization, unlike those bridging with zinc ions, due to the controlled catalytic graphitization by the cobalt nanoparticles. In this work, we demonstrate a feasible method to achieve nanoporous carbon materials with tailored properties, including specific surface area, pore size distribution, degree of graphitization, and content of heteroatoms. The bimetallic-MOF-derived nanoporous carbon are systematically characterized, highlighting the importance of precisely controlling the properties of the carbon materials. This can be done by finely tuning the components in the bimetallic MOF precursors, and thus designing optimal carbon materials for specific applications. PMID:27471193

  1. Interactive Thermal Effects on Metal-Organic Framework Polymer Composite Membranes.

    PubMed

    Cacho-Bailo, Fernando; Téllez, Carlos; Coronas, Joaquín

    2016-07-01

    Polymeric membranes are important tools for intensifying separation processes in chemical industries, concerning strategic tasks such as CO2 sequestration, H2 production, and water supply and disposal. Mixed-matrix and supported membranes have been widely developed; recently many of them have been based on metal-organic frameworks (MOFs). However, most of the impacts MOFs have within the polymer matrix have yet to be determined. The effects related to thermal behavior arising from the combination of MOF ZIF-8 and polysulfone have now been quantified. The catalyzed oxidation of the polymer is strongly affected by the MOF crystal size and distribution inside the membrane. A 16 wt % 140 nm-sized ZIF-8 loading causes a 40 % decrease in the observed activation energy of the polysulfone oxidation that takes place at a temperature (545 °C) 80 °C lower than in the raw polymer (625 °C). PMID:27156113

  2. Heterometallic Metal-Organic Frameworks That Catalyze Two Different Reactions Sequentially.

    PubMed

    Saha, Debraj; Hazra, Dipak K; Maity, Tanmoy; Koner, Subratanath

    2016-06-20

    A series of copper- and alkaline-earth-metal-based multidimensional metal-organic frameworks, {[CuMg(pdc)2(H2O)4]·2H2O}n (1), [CuCa(pdc)2]n (2), [CuSr(pdc)2(H2O)3]n (3), and {[CuBa(pdc)2(H2O)5]·H2O}n (4), where H2Pdc = pyridine-2,5-dicarboxylic acid, were hydrothermally synthesized and characterized. Two different metals act as the active center to catalyze two kinds of reactions, viz., olefin to its epoxide followed by epoxide ring opening to afford the corresponding vicinal diol in a sequential manner. PMID:27232433

  3. Selective Gas Adsorption within a Five-Connected Porous Metal-Organic Framework

    SciTech Connect

    Xue, Ming; Zhang, Zhangjing; Xiang, Shengchang; Zhao, Jin; Liang, Chengdu; Guang-Shan, Zhu; Qiu, Shi-Lun; Chen, Banglin

    2010-01-01

    A metal-organic framework, Zn3(OH)( BDC-2,5-Cl2)2.5(DMF)3(H2O) 1 (BDC-2,5-Cl2 = 1,4-benzenedicarboxylate-2,5-dichloro and DMF = N,N -dimethylformamide) of rare five-connected (44)(66) topology was synthesized and structurally characterized. The framework is thermally stable up to 350 C, thus activation of this new MOF material at different temperature of 150 and 300 C under high vacuum formed two microporous materials 1a and 1b, respectively, exhibiting selective gas adsorption behavior with respect to H2/N2 and O2/N2, and CO2/CH4 and CO2/N2.

  4. Entropy prediction for H2 adsorption in metal-organic frameworks.

    PubMed

    Liu, Yu; Guo, Fangyuan; Hu, Jun; Zhao, Shuangliang; Liu, Honglai; Hu, Ying

    2016-09-14

    Entropy is an important thermodynamic property and serves as a bridge connecting equilibrium and non-equilibrium systems, which provides a basic understanding of various practical phenomena. In this study, classical density functional theory was introduced to efficiently predict entropy. The theory was applied to a high-throughput prediction of entropy and excess entropy for H2 adsorption in metal-organic frameworks. It seems that the entropy screening and uptake screening are generally equivalent at high temperature. Based on the entropy screening, the best hydrogen storage materials have been identified. The correlations between entropy and thermodynamic properties, such as uptake, isosteric heat and adsorption degree, were examined and are explained. The results imply that among the tested thermodynamic properties, the correlation between entropy and isosteric heat is the strongest. PMID:27523720

  5. Metal-Organic Frameworks Modulated by Doping Er(3+) for Up-Conversion Luminescence.

    PubMed

    Zhang, Xindan; Li, Bin; Ma, Heping; Zhang, Liming; Zhao, Haifeng

    2016-07-13

    Here we present metal-organic frameworks prepared by a one-step synthesis method, possessing both architectural properties of MOF building and up-conversion luminescence of rare earth Er(3+) (hereafter denoted as Up-MOFs). Up-MOFs have characteristic up-conversion emissions at 520, 540, and 651 nm under the excitation of 980 nm owing to the multiple photon absorption. The up-conversion mechanism of these Up-MOFs has been discussed, and it can be attributed to the excited state absorption process. The design and synthesis of Up-MOF materials possessing near-infrared region excitation and up-conversion luminescence are fully expected to be candidates for the advancement of applications in bioimaging, sensors, optoelectronics, and energy conversion/storage devices. PMID:27315339

  6. Aromatic Substituent Effects on the Flexibility of Metal-Organic Frameworks.

    PubMed

    Hahm, Hyungwoo; Yoo, Kwangho; Ha, Hyeonbin; Kim, Min

    2016-08-01

    The flexibility (or breathing behavior) of zinc-based metal-organic frameworks (MOFs) has been manipulated by regioisomeric and positional control of organic functionalities. Ten new regioisomeric BDC (ortho- or para-disubstituted benzene-1,4-dicarboxylic acid) ligands have been synthesized and applied to a DMOF (dabco MOF) system, which has a zinc(II) paddle-wheel SBU (secondary building unit). Among the new regioisomeric MOFs, the NH2-OMe combination showed significant flexibility (breathing behavior) changes by simply altering the functional group positions (from 2,3 to 2,5). The electronic density of the benzene ring was considered to be a major factor in the flexibility changes in the regioisomeric MOF system. PMID:27414764

  7. Rational design of metal-organic frameworks with anticipated porosities and functionalities

    SciTech Connect

    Zhang, MW; Bosch, M; Gentle, T; Zhou, HC

    2014-01-01

    Metal-organic frameworks have emerged as a new category of porous materials that have intriguing structures and diverse applications. Even though the early discovery of new MOFs appears to be serendipitous, much effort has been made to reveal their structure-property relationships for the purpose of rationally designing novel frameworks with expected properties. Until now, much progress has been made to rationalize the design and synthesis of MOFs. This highlight review will outline the recent advances on this topic from both our and other groups and provide a systematic overview of different methods for the rational design of MOFs with desired porosities and functionalities. In this review, we will categorize the recent efforts for rational MOF design into two different approaches: a structural approach and a functional approach.

  8. Functionalization and Isoreticulation in a Series of Metal-Organic Frameworks Derived from Pyridinecarboxylates.

    PubMed

    Pachfule, Pradip; Garai, Bikash; Banerjee, Rahul

    2016-08-01

    The partially fluorinated metal-organic frameworks (F-MOFs) have been constructed from 3-fluoro-4-pyridinecarboxylic acid and trans-3-fluoro-4-pyridineacrylic acid linkers using Mn(2+), Co(2+), and Cd(2+) metals via the solvothermal method, which show isostructural isomerism with their nonfluorinated counterparts synthesized using 4-pyridinecarboxylic acid and trans-4-pyridineacrylic acid, respectively. The simultaneous effect of partial fluorination and isoreticulation on structure and H2 adsorption has been studied systematically in isostructural nonfluorinated and partially fluorinated MOFs, which shows that the increment in the hydrogen uptake properties in F-MOFs is not a universal phenomenon but is rather system-specific and changes from one system to another. PMID:27164435

  9. New metal-organic nanomaterials synthesized by laser irradiation of organic liquids

    SciTech Connect

    Kuzmin, Stanislav L.; Wesolowski, Michal J.; Duley, Walter W.

    2014-03-31

    A new type of metal-organic composition consisting of clusters of nanoparticles has been synthesised by laser irradiation of metallocene/benzene solutions. The metallocene molecules in this reaction become the source of the metal. Exposure to high-energy femtosecond laser pulses dehydrogenate benzene molecules and initiate the high-temperature high-pressure conditions that results in the synthesis of new materials. Irradiation experiments have been carried out on ferrocene/benzene and on other solutions. With ferrocene the synthesis of a new compound has been confirmed by X-ray powder diffraction as the peaks detected do not correspond to any known substance in the Crystallography Open Database. Theoretical simulation of the periodic structure of this new carbide predicts that it has hexagonal symmetry and a unit cell with a = 3.2A and c =2.8A. The exact structure is still uncertain but may be determined from scanning tunneling microscope (STM) studies.

  10. Bimetallic Metal-Organic Frameworks for Controlled Catalytic Graphitization of Nanoporous Carbons

    NASA Astrophysics Data System (ADS)

    Tang, Jing; Salunkhe, Rahul R.; Zhang, Huabin; Malgras, Victor; Ahamad, Tansir; Alshehri, Saad M.; Kobayashi, Naoya; Tominaka, Satoshi; Ide, Yusuke; Kim, Jung Ho; Yamauchi, Yusuke

    2016-07-01

    Single metal-organic frameworks (MOFs), constructed from the coordination between one-fold metal ions and organic linkers, show limited functionalities when used as precursors for nanoporous carbon materials. Herein, we propose to merge the advantages of zinc and cobalt metals ions into one single MOF crystal (i.e., bimetallic MOFs). The organic linkers that coordinate with cobalt ions tend to yield graphitic carbons after carbonization, unlike those bridging with zinc ions, due to the controlled catalytic graphitization by the cobalt nanoparticles. In this work, we demonstrate a feasible method to achieve nanoporous carbon materials with tailored properties, including specific surface area, pore size distribution, degree of graphitization, and content of heteroatoms. The bimetallic-MOF-derived nanoporous carbon are systematically characterized, highlighting the importance of precisely controlling the properties of the carbon materials. This can be done by finely tuning the components in the bimetallic MOF precursors, and thus designing optimal carbon materials for specific applications.

  11. Metal organic framework-mediated synthesis of highly active and stable Fischer-Tropsch catalysts.

    PubMed

    Santos, Vera P; Wezendonk, Tim A; Jaén, Juan José Delgado; Dugulan, A Iulian; Nasalevich, Maxim A; Islam, Husn-Ubayda; Chojecki, Adam; Sartipi, Sina; Sun, Xiaohui; Hakeem, Abrar A; Koeken, Ard C J; Ruitenbeek, Matthijs; Davidian, Thomas; Meima, Garry R; Sankar, Gopinathan; Kapteijn, Freek; Makkee, Michiel; Gascon, Jorge

    2015-01-01

    Depletion of crude oil resources and environmental concerns have driven a worldwide research on alternative processes for the production of commodity chemicals. Fischer-Tropsch synthesis is a process for flexible production of key chemicals from synthesis gas originating from non-petroleum-based sources. Although the use of iron-based catalysts would be preferred over the widely used cobalt, manufacturing methods that prevent their fast deactivation because of sintering, carbon deposition and phase changes have proven challenging. Here we present a strategy to produce highly dispersed iron carbides embedded in a matrix of porous carbon. Very high iron loadings (>40 wt %) are achieved while maintaining an optimal dispersion of the active iron carbide phase when a metal organic framework is used as catalyst precursor. The unique iron spatial confinement and the absence of large iron particles in the obtained solids minimize catalyst deactivation, resulting in high active and stable operation. PMID:25740709

  12. Metal organic framework-mediated synthesis of highly active and stable Fischer-Tropsch catalysts

    NASA Astrophysics Data System (ADS)

    Santos, Vera P.; Wezendonk, Tim A.; Jaén, Juan José Delgado; Dugulan, A. Iulian; Nasalevich, Maxim A.; Islam, Husn-Ubayda; Chojecki, Adam; Sartipi, Sina; Sun, Xiaohui; Hakeem, Abrar A.; Koeken, Ard C. J.; Ruitenbeek, Matthijs; Davidian, Thomas; Meima, Garry R.; Sankar, Gopinathan; Kapteijn, Freek; Makkee, Michiel; Gascon, Jorge

    2015-03-01

    Depletion of crude oil resources and environmental concerns have driven a worldwide research on alternative processes for the production of commodity chemicals. Fischer-Tropsch synthesis is a process for flexible production of key chemicals from synthesis gas originating from non-petroleum-based sources. Although the use of iron-based catalysts would be preferred over the widely used cobalt, manufacturing methods that prevent their fast deactivation because of sintering, carbon deposition and phase changes have proven challenging. Here we present a strategy to produce highly dispersed iron carbides embedded in a matrix of porous carbon. Very high iron loadings (>40 wt %) are achieved while maintaining an optimal dispersion of the active iron carbide phase when a metal organic framework is used as catalyst precursor. The unique iron spatial confinement and the absence of large iron particles in the obtained solids minimize catalyst deactivation, resulting in high active and stable operation.

  13. Engineering chiral porous metal-organic frameworks for enantioselective adsorption and separation.

    PubMed

    Peng, Yongwu; Gong, Tengfei; Zhang, Kang; Lin, Xiaochao; Liu, Yan; Jiang, Jianwen; Cui, Yong

    2014-01-01

    The separation of racemic molecules is of substantial significance not only for basic science but also for technical applications, such as fine chemicals and drug development. Here we report two isostructural chiral metal-organic frameworks decorated with chiral dihydroxy or -methoxy auxiliares from enantiopure tetracarboxylate-bridging ligands of 1,1'-biphenol and a manganese carboxylate chain. The framework bearing dihydroxy groups functions as a solid-state host capable of adsorbing and separating mixtures of a range of chiral aromatic and aliphatic amines, with high enantioselectivity. The host material can be readily recycled and reused without any apparent loss of performance. The utility of the present adsorption separation is demonstrated in the large-scale resolution of racemic 1-phenylethylamine. Control experiments and molecular simulations suggest that the chiral recognition and separation are attributed to the different orientations and specific binding energies of the enantiomers in the microenvironment of the framework. PMID:25030529

  14. Engineering chiral porous metal-organic frameworks for enantioselective adsorption and separation

    NASA Astrophysics Data System (ADS)

    Peng, Yongwu; Gong, Tengfei; Zhang, Kang; Lin, Xiaochao; Liu, Yan; Jiang, Jianwen; Cui, Yong

    2014-07-01

    The separation of racemic molecules is of substantial significance not only for basic science but also for technical applications, such as fine chemicals and drug development. Here we report two isostructural chiral metal-organic frameworks decorated with chiral dihydroxy or -methoxy auxiliares from enantiopure tetracarboxylate-bridging ligands of 1,1‧-biphenol and a manganese carboxylate chain. The framework bearing dihydroxy groups functions as a solid-state host capable of adsorbing and separating mixtures of a range of chiral aromatic and aliphatic amines, with high enantioselectivity. The host material can be readily recycled and reused without any apparent loss of performance. The utility of the present adsorption separation is demonstrated in the large-scale resolution of racemic 1-phenylethylamine. Control experiments and molecular simulations suggest that the chiral recognition and separation are attributed to the different orientations and specific binding energies of the enantiomers in the microenvironment of the framework.

  15. A homochiral metal-organic framework as an effective asymmetric catalyst for cyanohydrin synthesis.

    PubMed

    Mo, Ke; Yang, Yuhua; Cui, Yong

    2014-02-01

    A homochiral metal-organic framework (MOF) of an enantiopure 2,2'-dihydroxy-1,1'-biphenyl ligand was constructed. After exchanging one proton of the dihydroxyl group for Li(I) ions, the framework is shown to be a highly efficient and recyclable heterogeneous catalyst for asymmetric cyanation of aldehydes with up to >99% ee. Compared with the homogeneous counterpart, the MOF catalyst exhibits significantly enhanced catalytic activity and enantioselectivity, especially at a low catalyst/substrate ratio, due to that the rigid framework could stabilize the catalytically active monolithium salt of biphenol against its free transformation to catalytically inactive and/or less active assemblies in reactions. The synthetic utility of the cyanation was demonstrated in the synthesis of (S)-bufuralol (a nonselective β-adrenoceptor blocking agent) with 98% ee. PMID:24447241

  16. Constitutional Dynamics of Metal-Organic Motifs on a Au(111) Surface.

    PubMed

    Kong, Huihui; Zhang, Chi; Xie, Lei; Wang, Likun; Xu, Wei

    2016-06-13

    Constitutional dynamic chemistry (CDC), including both dynamic covalent chemistry and dynamic noncovalent chemistry, relies on reversible formation and breakage of bonds to achieve continuous changes in constitution by reorganization of components. In this regard, CDC is considered to be an efficient and appealing strategy for selective fabrication of surface nanostructures by virtue of dynamic diversity. Although constitutional dynamics of monolayered structures has been recently demonstrated at liquid/solid interfaces, most of molecular reorganization/reaction processes were thought to be irreversible under ultrahigh vacuum (UHV) conditions where CDC is therefore a challenge to be achieved. Here, we have successfully constructed a system that presents constitutional dynamics on a solid surface based on dynamic coordination chemistry, in which selective formation of metal-organic motifs is achieved under UHV conditions. The key to making this reversible switching successful is the molecule-substrate interaction as revealed by DFT calculations. PMID:27144822

  17. Remarkable Lattice Shrinkage in Highly Oriented Crystalline Three-Dimensional Metal-Organic Framework Thin Films.

    PubMed

    Haraguchi, Tomoyuki; Otsubo, Kazuya; Sakata, Osami; Fujiwara, Akihiko; Kitagawa, Hiroshi

    2015-12-21

    Highly oriented crystalline thin films of metal-organic frameworks (MOFs) have promising practical applications, such as in gas separation, catalysis, and sensing. We report on the successful fabrication of highly oriented crystalline thin films of three-dimensional porous MOFs, Fe(pz)[M(CN)4] (M = Ni, Pd; pz = pyrazine). Synchrotron X-ray diffraction studies reveal not only the highly oriented crystalline nature but also the remarkable shrunken structure of the thin films (∼3-7% volume shrinkage) compared with bulk samples. Furthermore, because of lattice shrinkage, these films exhibit large lattice expansions upon guest adsorption, in marked contrast to the almost unchanged lattice in the bulk samples. PMID:26641131

  18. Metal-organic framework based highly selective fluorescence turn-on probe for hydrogen sulphide

    PubMed Central

    Nagarkar, Sanjog S.; Saha, Tanmoy; Desai, Aamod V.; Talukdar, Pinaki; Ghosh, Sujit K.

    2014-01-01

    Hydrogen sulphide (H2S) is known to play a vital role in human physiology and pathology which stimulated interest in understanding complex behaviour of H2S. Discerning the pathways of H2S production and its mode of action is still a challenge owing to its volatile and reactive nature. Herein we report azide functionalized metal-organic framework (MOF) as a selective turn-on fluorescent probe for H2S detection. The MOF shows highly selective and fast response towards H2S even in presence of other relevant biomolecules. Low cytotoxicity and H2S detection in live cells, demonstrate the potential of MOF towards monitoring H2S chemistry in biological system. To the best of our knowledge this is the first example of MOF that exhibit fast and highly selective fluorescence turn-on response towards H2S under physiological conditions. PMID:25394493

  19. Mechanized azobenzene-functionalized zirconium metal-organic framework for on-command cargo release.

    PubMed

    Meng, Xiangshi; Gui, Bo; Yuan, Daqiang; Zeller, Matthias; Wang, Cheng

    2016-08-01

    Stimuli-responsive metal-organic frameworks (MOFs) have gained increasing attention recently for their potential applications in many areas. We report the design and synthesis of a water-stable zirconium MOF (Zr-MOF) that bears photoresponsive azobenzene groups. This particular MOF can be used as a reservoir for storage of cargo in water, and the cargo-loaded MOF can be further capped to construct a mechanized MOF through the binding of β-cyclodextrin with the azobenzene stalks on the MOF surface. The resulting mechanized MOF has shown on-command cargo release triggered by ultraviolet irradiation or addition of competitive agents without premature release. This study represents a simple approach to the construction of stimuli-responsive mechanized MOFs, and considering mechanized UiO-68-azo made from biocompatible components, this smart system may provide a unique MOF platform for on-command drug delivery in the future. PMID:27493996

  20. Metal-organic frameworks with high capacity and selectivity for harmful gases

    PubMed Central

    Britt, David; Tranchemontagne, David; Yaghi, Omar M.

    2008-01-01

    Benchmarks have been established for the performance of six metal-organic frameworks (MOFs) and isoreticular MOFs (IRMOFs, which have the same underlying topology as MOF-5), MOF-5, IRMOF-3, MOF-74, MOF-177, MOF-199, and IRMOF-62, as selective adsorbents for eight harmful gases: sulfur dioxide, ammonia, chlorine, tetrahydrothiophene, benzene, dichloromethane, ethylene oxide, and carbon monoxide. Kinetic breakthrough measurements are used to determine the calculated dynamic adsorption capacity of each “benchmark” MOF for each gas. The capacity of each MOF is compared to that of a sample of Calgon BPL activated carbon. We find that pore functionality plays a dominant role in determining the dynamic adsorption performance of MOFs. MOFs featuring reactive functionality outperform BPL carbon in all but one case and exhibit high dynamic adsorption capacities up to 35% by weight. PMID:18711128

  1. Metal-Organic Framework (MOF) Compounds: Photocatalysts for Redox Reactions and Solar Fuel Production.

    PubMed

    Dhakshinamoorthy, Amarajothi; Asiri, Abdullah M; García, Hermenegildo

    2016-04-25

    Metal-organic frameworks (MOFs) are crystalline porous materials formed from bi- or multipodal organic linkers and transition-metal nodes. Some MOFs have high structural stability, combined with large flexibility in design and post-synthetic modification. MOFs can be photoresponsive through light absorption by the organic linker or the metal oxide nodes. Photoexcitation of the light absorbing units in MOFs often generates a ligand-to-metal charge-separation state that can result in photocatalytic activity. In this Review we discuss the advantages and uniqueness that MOFs offer in photocatalysis. We present the best practices to determine photocatalytic activity in MOFs and for the deposition of co-catalysts. In particular we give examples showing the photocatalytic activity of MOFs in H2 evolution, CO2 reduction, photooxygenation, and photoreduction. PMID:26970539

  2. High proton conduction in a chiral ferromagnetic metal-organic quartz-like framework.

    PubMed

    Pardo, Emilio; Train, Cyrille; Gontard, Geoffrey; Boubekeur, Kamal; Fabelo, Oscar; Liu, Hongbo; Dkhil, Brahim; Lloret, Francesc; Nakagawa, Kosuke; Tokoro, Hiroko; Ohkoshi, Shin-ichi; Verdaguer, Michel

    2011-10-01

    A complex-as-ligand strategy to get a multifunctional molecular material led to a metal-organic framework with the formula (NH(4))(4)[MnCr(2)(ox)(6)]·4H(2)O. Single-crystal X-ray diffraction revealed that the anionic bimetallic coordination network adopts a chiral three-dimensional quartz-like architecture. It hosts ammonium cations and water molecules in functionalized channels. In addition to ferromagnetic ordering below T(C) = 3.0 K related to the host network, the material exhibits a very high proton conductivity of 1.1 × 10(-3) S cm(-1) at room temperature due to the guest molecules. PMID:21913689

  3. Controlling nucleation of monolayer WSe2 during metal-organic chemical vapor deposition growth

    NASA Astrophysics Data System (ADS)

    Eichfeld, Sarah M.; Oliveros Colon, Víctor; Nie, Yifan; Cho, Kyeongjae; Robinson, Joshua A.

    2016-06-01

    Tungsten diselenide (WSe2) is a semiconducting, two-dimensional (2D) material that has gained interest in the device community recently due to its electronic properties. The synthesis of atomically thin WSe2, however, is still in its infancy. In this work we elucidate the requirements for large selenium/tungsten precursor ratios and explain the effect of nucleation temperature on the synthesis of WSe2 via metal-organic chemical vapor deposition (MOCVD). The introduction of a nucleation-step prior to growth demonstrates that increasing nucleation temperature leads to a transition from a Volmer–Weber to Frank–van der Merwe growth mode. Additionally, the nucleation step prior to growth leads to an improvement of WSe2 layer coverage on the substrate. Finally, we note that the development of this two-step technique may allow for improved control and quality of 2D layers grown via CVD and MOCVD processes.

  4. Characterization of Adsorption Enthalpy of Novel Water-Stable Zeolites and Metal-Organic Frameworks

    PubMed Central

    Kim, Hyunho; Cho, H. Jeremy; Narayanan, Shankar; Yang, Sungwoo; Furukawa, Hiroyasu; Schiffres, Scott; Li, Xiansen; Zhang, Yue-Biao; Jiang, Juncong; Yaghi, Omar M.; Wang, Evelyn N.

    2016-01-01

    Water adsorption is becoming increasingly important for many applications including thermal energy storage, desalination, and water harvesting. To develop such applications, it is essential to understand both adsorbent-adsorbate and adsorbate-adsorbate interactions, and also the energy required for adsorption/desorption processes of porous material-adsorbate systems, such as zeolites and metal-organic frameworks (MOFs). In this study, we present a technique to characterize the enthalpy of adsorption/desorption of zeolites and MOF-801 with water as an adsorbate by conducting desorption experiments with conventional differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). With this method, the enthalpies of adsorption of previously uncharacterized adsorbents were estimated as a function of both uptake and temperature. Our characterizations indicate that the adsorption enthalpies of type I zeolites can increase to greater than twice the latent heat whereas adsorption enthalpies of MOF-801 are nearly constant for a wide range of vapor uptakes. PMID:26796523

  5. Tetrazole-Viologen-based Flexible Microporous Metal-Organic Framework with High CO2 Selective Uptake.

    PubMed

    Zhao, Ya-Ping; Li, Yan; Cui, Cai-Yan; Xiao, Yu; Li, Rong; Wang, Shuai-Hua; Zheng, Fa-Kun; Guo, Guo-Cong

    2016-08-01

    A flexible metal-organic framework (FMOF) with functionalized pores was hydrothermally synthesized to improve CO2 affinity and selectivity. The obtained FMOF exhibits a reversible shrinking and swelling framework transformation, which is triggered by the adsorption of CO2 rather than by the adsorption of N2 and CH4. At ambient temperature and an atmospheric pressure, this FMOF shows not only a high CO2 uptake (98 cm(3) g(-1), 19.3 wt %) but also a good calculated adsorption selectivity for CO2 over both CH4 and N2 (CO2/CH4 50:50 v/v: 28.6:1, CO2/N2 15:85 v/v: 210.4:1 calculated by ideal adsorbed solution theory), indicating potential applications in the purification of natural gas and industrial flue gas. PMID:27400274

  6. Metal-organic Frameworks as A Tunable Platform for Designing Functional Molecular Materials

    PubMed Central

    Wang, Cheng; Liu, Demin

    2013-01-01

    Metal-organic frameworks (MOFs), also known as coordination polymers, represent an interesting class of crystalline molecular materials that are synthesized by combining metal-connecting points and bridging ligands. The modular nature of and mild conditions for MOF synthesis have permitted the rational structural design of numerous MOFs and the incorporation of various functionalities via constituent building blocks. The resulting designer MOFs have shown promise for applications in a number of areas, including gas storage/separation, nonlinear optics/ferroelectricity, catalysis, energy conversion/storage, chemical sensing, biomedical imaging, and drug delivery. The structure-property relationships of MOFs can also be readily established by taking advantage of the knowledge of their detailed atomic structures, which enables fine-tuning of their functionalities for desired applications. Through the combination of molecular synthesis and crystal engineering MOFs thus present an unprecedented opportunity for the rational and precise design of functional materials. PMID:23944646

  7. Defining the Proton Topology of the Zr6-Based Metal-Organic Framework NU-1000.

    PubMed

    Planas, Nora; Mondloch, Joseph E; Tussupbayev, Samat; Borycz, Joshua; Gagliardi, Laura; Hupp, Joseph T; Farha, Omar K; Cramer, Christopher J

    2014-11-01

    Metal-organic frameworks (MOFs) constructed from Zr6-based nodes have recently received considerable attention given their exceptional thermal, chemical, and mechanical stability. Because of this, the structural diversity of Zr6-based MOFs has expanded considerably and in turn given rise to difficulty in their precise characterization. In particular it has been difficult to assign where protons (needed for charge balance) reside on some Zr6-based nodes. Elucidating the precise proton topologies in Zr6-based MOFs will have wide ranging implications in defining their chemical reactivity, acid/base characteristics, conductivity, and chemical catalysis. Here we have used a combined quantum mechanical and experimental approach to elucidate the precise proton topology of the Zr6-based framework NU-1000. Our data indicate that a mixed node topology, [Zr6(μ3-O)4(μ3-OH)4(OH)4 (OH2)4](8+), is preferred and simultaneously rule out five alternative node topologies. PMID:26278741

  8. Bimetallic Metal-Organic Frameworks for Controlled Catalytic Graphitization of Nanoporous Carbons.

    PubMed

    Tang, Jing; Salunkhe, Rahul R; Zhang, Huabin; Malgras, Victor; Ahamad, Tansir; Alshehri, Saad M; Kobayashi, Naoya; Tominaka, Satoshi; Ide, Yusuke; Kim, Jung Ho; Yamauchi, Yusuke

    2016-01-01

    Single metal-organic frameworks (MOFs), constructed from the coordination between one-fold metal ions and organic linkers, show limited functionalities when used as precursors for nanoporous carbon materials. Herein, we propose to merge the advantages of zinc and cobalt metals ions into one single MOF crystal (i.e., bimetallic MOFs). The organic linkers that coordinate with cobalt ions tend to yield graphitic carbons after carbonization, unlike those bridging with zinc ions, due to the controlled catalytic graphitization by the cobalt nanoparticles. In this work, we demonstrate a feasible method to achieve nanoporous carbon materials with tailored properties, including specific surface area, pore size distribution, degree of graphitization, and content of heteroatoms. The bimetallic-MOF-derived nanoporous carbon are systematically characterized, highlighting the importance of precisely controlling the properties of the carbon materials. This can be done by finely tuning the components in the bimetallic MOF precursors, and thus designing optimal carbon materials for specific applications. PMID:27471193

  9. A new method to position and functionalize metal-organic framework crystals

    PubMed Central

    Falcaro, Paolo; Hill, Anita J.; Nairn, Kate M.; Jasieniak, Jacek; Mardel, James I.; Bastow, Timothy J.; Mayo, Sheridan C.; Gimona, Michele; Gomez, Daniel; Whitfield, Harold J.; Riccò, Raffaele; Patelli, Alessandro; Marmiroli, Benedetta; Amenitsch, Heinz; Colson, Tobias; Villanova, Laura; Buso, Dario

    2011-01-01

    With controlled nanometre-sized pores and surface areas of thousands of square metres per gram, metal-organic frameworks (MOFs) may have an integral role in future catalysis, filtration and sensing applications. In general, for MOF-based device fabrication, well-organized or patterned MOF growth is required, and thus conventional synthetic routes are not suitable. Moreover, to expand their applicability, the introduction of additional functionality into MOFs is desirable. Here, we explore the use of nanostructured poly-hydrate zinc phosphate (α-hopeite) microparticles as nucleation seeds for MOFs that simultaneously address all these issues. Affording spatial control of nucleation and significantly accelerating MOF growth, these α-hopeite microparticles are found to act as nucleation agents both in solution and on solid surfaces. In addition, the introduction of functional nanoparticles (metallic, semiconducting, polymeric) into these nucleating seeds translates directly to the fabrication of functional MOFs suitable for molecular size-selective applications. PMID:21407203

  10. III-nitride quantum cascade detector grown by metal organic chemical vapor deposition

    SciTech Connect

    Song, Yu Huang, Tzu-Yung; Badami, Pranav; Gmachl, Claire; Bhat, Rajaram; Zah, Chung-En

    2014-11-03

    Quantum cascade (QC) detectors in the GaN/Al{sub x}Ga{sub 1−x}N material system grown by metal organic chemical vapor deposition are designed, fabricated, and characterized. Only two material compositions, i.e., GaN as wells and Al{sub 0.5}Ga{sub 0.5}N as barriers are used in the active layers. The QC detectors operates around 4 μm, with a peak responsivity of up to ∼100 μA/W and a detectivity of up to 10{sup 8} Jones at the background limited infrared performance temperature around 140 K.

  11. A novel metal-organic framework for high storage and separation of acetylene at room temperature

    NASA Astrophysics Data System (ADS)

    Duan, Xing; Wang, Huizhen; Ji, Zhenguo; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2016-09-01

    A novel 3D microporous metal-organic framework with NbO topology, [Cu2(L)(H2O)2]•(DMF)6·(H2O)2 (ZJU-10, ZJU = Zhejiang University; H4L =2‧-hydroxy-[1,1‧:4‧,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid; DMF =N,N-dimethylformamide), has been synthesized and structurally characterized. With suitable pore sizes and open Cu2+ sites, ZJU-10a exhibits high BET surface area of 2392 m2/g, as well as moderately high C2H2 volumetric uptake capacity of 132 cm3/cm3. Meanwhile, ZJU-10a is a promising porous material for separation of acetylene from methane and carbon dioxide gas mixtures at room temperature.

  12. Separation of C2 Hydrocarbons by Porous Materials: Metal Organic Frameworks as Platform

    SciTech Connect

    Banerjee, Debasis; Liu, Jun; Thallapally, Praveen K.

    2014-12-22

    The effective separation of small hydrocarbon molecules (C1 – C4) is an important process for petroleum industry, determining the end price of many essential commodities in our daily lives. Current technologies for separation of these molecules rely on energy intensive fractional distillation processes at cryogenic temperature, which is particularly difficult because of their similar volatility. In retrospect, adsorptive separation using solid state adsorbents might be a cost effective alternative. Several types of solid state adsorbents (e.g. zeolite molecular sieves) were tested for separation of small hydrocarbon molecules as a function of pressure, temperature or vacuum. Among different types of plausible adsorbents, metal organic frameworks (MOFs), a class of porous, crystalline, inorganic-organic hybrid materials, is particularly promising. In this brief comment article, we discuss the separation properties of different types of solid state adsorbents, with a particular emphasis on MOF based adsorbents for separation of C2 hydrocarbon molecules.

  13. A scalable synthesis of a mesoporous metal-organic framework called NU-1000.

    SciTech Connect

    Wang, Timothy C.; Vermeulen, Nicolaas A.; Kim, In Soo; Martinson, Alex B. F.; Stoddart, J. Fraser; Hupp, Joseph T.; Farha, Omar K.

    2016-01-01

    The synthesis of NU-1000, a mesoporous metal-organic framework (MOF), can be conducted efficiently on a multigram scale from inexpensive starting materials. NU-1000 has been reported as an excellent candidate for gas separation and catalysis. In particular, it is ideal for the catalytic deactivation of nerve agents and shows great promise as a new generic platform for a wide range of applications. Multiple post-synthetic modification protocols have been developed using NU-1000 as the parent material, making it a potentially useful scaffold for several catalytic applications. The procedure for the preparation of NU-1000 can be scaled up reliably and is suitable for the production of 50 grams of the requisite organic linker and ?? grams of NU-1000. The entire synthesis is performed without purification by column chromatography and can be completed within 10 days.

  14. Observation of Resonant Quantum Magnetoelectric Effect in a Multiferroic Metal-Organic Framework.

    PubMed

    Tian, Ying; Shen, Shipeng; Cong, Junzhuang; Yan, Liqin; Wang, Shouguo; Sun, Young

    2016-01-27

    A resonant quantum magnetoelectric coupling effect has been demonstrated in the multiferroic metal-organic framework of [(CH3)2NH2]Fe(HCOO)3. This material shows a coexistence of a spin-canted antiferromagnetic order and ferroelectricity as well as clear magnetoelectric coupling below TN ≈ 19 K. In addition, a component of single-ion quantum magnets develops below ∼ 8 K because of an intrinsic magnetic phase separation. The stair-shaped magnetic hysteresis loop at 2 K signals resonant quantum tunneling of magnetization. Meanwhile, the magnetic field dependence of dielectric permittivity exhibits sharp peaks just at the critical tunneling fields, evidencing the occurrence of resonant quantum magnetoelectric coupling effect. This resonant effect enables a simple electrical detection of quantum tunneling of magnetization. PMID:26743039

  15. Characterization of Adsorption Enthalpy of Novel Water-Stable Zeolites and Metal-Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Kim, Hyunho; Cho, H. Jeremy; Narayanan, Shankar; Yang, Sungwoo; Furukawa, Hiroyasu; Schiffres, Scott; Li, Xiansen; Zhang, Yue-Biao; Jiang, Juncong; Yaghi, Omar M.; Wang, Evelyn N.

    2016-01-01

    Water adsorption is becoming increasingly important for many applications including thermal energy storage, desalination, and water harvesting. To develop such applications, it is essential to understand both adsorbent-adsorbate and adsorbate-adsorbate interactions, and also the energy required for adsorption/desorption processes of porous material-adsorbate systems, such as zeolites and metal-organic frameworks (MOFs). In this study, we present a technique to characterize the enthalpy of adsorption/desorption of zeolites and MOF-801 with water as an adsorbate by conducting desorption experiments with conventional differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). With this method, the enthalpies of adsorption of previously uncharacterized adsorbents were estimated as a function of both uptake and temperature. Our characterizations indicate that the adsorption enthalpies of type I zeolites can increase to greater than twice the latent heat whereas adsorption enthalpies of MOF-801 are nearly constant for a wide range of vapor uptakes.

  16. Modulation by Amino Acids: Toward Superior Control in the Synthesis of Zirconium Metal-Organic Frameworks.

    PubMed

    Gutov, Oleksii V; Molina, Sonia; Escudero-Adán, Eduardo C; Shafir, Alexandr

    2016-09-12

    The synthesis of zirconium metal-organic frameworks (Zr MOFs) modulated by various amino acids, including l-proline, glycine, and l-phenylalanine, is shown to be a straightforward approach toward functional-group incorporation and particle-size control. High yields in Zr-MOF synthesis are achieved by employing 5 equivalents of the modulator at 120 °C. At lower temperatures, the method provides a series of Zr MOFs with increased particle size, including many suitable for single-crystal X-ray diffraction studies. Furthermore, amino acid modulators can be incorporated at defect sites in Zr MOFs with an amino acid/ligand ratio of up to 1:1, depending on the ligand structure and reaction conditions. The MOFs obtained through amino acid modulation exhibit an improved CO2 -capture capacity relative to nonfunctionalized materials. PMID:27482849

  17. Metal-organic frameworks for electronics: emerging second order nonlinear optical and dielectric materials

    NASA Astrophysics Data System (ADS)

    Mendiratta, Shruti; Lee, Cheng-Hua; Usman, Muhammad; Lu, Kuang-Lieh

    2015-10-01

    Metal-organic frameworks (MOFs) have been intensively studied over the past decade because they represent a new category of hybrid inorganic-organic materials with extensive surface areas, ultrahigh porosity, along with the extraordinary tailorability of structure, shape and dimensions. In this highlight, we summarize the current state of MOF research and report on structure-property relationships for nonlinear optical (NLO) and dielectric applications. We focus on the design principles and structural elements needed to develop potential NLO and low dielectric (low-κ) MOFs with an emphasis on enhancing material performance. In addition, we highlight experimental evidence for the design of devices for low-dielectric applications. These results motivate us to develop better low-dielectric and NLO materials and to perform in-depth studies related to deposition techniques, patterning and the mechanical performance of these materials in the future.

  18. Mechanisms of Heat Transfer in Porous Crystals Containing Adsorbed Gases: Applications to Metal-Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Babaei, Hasan; Wilmer, Christopher E.

    2016-01-01

    We have studied the mechanisms of heat transfer in a porous crystal-gas mixture system, motivated by the not insignificant challenge of quickly dissipating heat generated in metal-organic frameworks (MOFs) due to gas adsorption. Our study reveals that the thermal conductance of the system (crystal and gas) is dominated by lattice thermal conductivity in the crystal, and that conductance is reduced as the concentration of gas in the pores increases. This mechanism was observed from classical molecular simulations of a monatomic gas in an idealized porous crystal structure. We show that the decreased conductivity associated with increased gas concentration is due to phonon scattering in the crystal due to interactions with gas molecules. Calculations of scattering rates for two phonon modes reveal that scattering of the lowest frequency mode scales linearly with gas density. This result suggests that the probability of a phonon-gas collision is simply proportional to the number of gas molecules in the pore.

  19. Metal-organic frameworks: mechanisms of antibacterial action and potential applications.

    PubMed

    Wyszogrodzka, Gabriela; Marszałek, Bartosz; Gil, Barbara; Dorożyński, Przemysław

    2016-06-01

    The growing resistance of pathogens to conventional antibiotics has become a public health problem and raises the need to seek new effective solutions. Metal-organic frameworks (MOFs) are porous, hybrid materials comprising metal ions linked by organic binding ligands. The possibility of using a variety of chemical building components in MOFs enables the formation of structures with desired properties. They can act as a reservoir of metal ions, providing their gradual release and resulting in a sustained antibacterial action analogous to that proposed for metal/metal oxide nanoparticles (NPs) but different to that of antibiotics. These features make MOFs promising candidates for pharmaceutical and biomedical applications, as illustrated by examples discussed in this review. PMID:27091434

  20. Surfactant-thermal method to prepare two new cobalt metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Yu, Xianglin; Toh, Yong Siang; Zhao, Jun; Nie, Lina; Ye, Kaiqi; Wang, Yue; Li, Dongsheng; Zhang, Qichun

    2015-12-01

    Employing surfactants as reaction media, two new metal-organic frameworks (MOFs):(HTEA)3[Co3(BTC)3] (NTU-Z33) and (HTEA)[Co3(HBTC)2(BTC)] (NTU-Z34) (H3BTC=1,3,5-benzenetricarboxylic acid, TEA=trimethylamine, and NTU=Nanyang Technological University), have been successfully synthesized and fully characterized. Note that NTU-Z33 has an unusual trimeric [Co3(COO)9] secondary building unit (SBU). Magnetic characterization suggests that both compounds have weak antiferromagnetic behaviors. Our success in preparing new crystalline Co-BTC based MOFs under different surfactant media could provide a new road to prepare new diverse MOFs through various combinations of surfactants.

  1. Carbonization and oxidation of metal-organic frameworks based on 1,4-naphthalene dicarboxylates

    NASA Astrophysics Data System (ADS)

    Chen, Jiun-Jen; Chen, Ya-Ting; Senthil Raja, Duraisamy; Kang, Yu-Hao; Tseng, Pen-Chang; Lin, Chia-Her

    2015-10-01

    Three new isostructural metal-organic frameworks (MOFs), [V(OH)(NDC)] (1), [Cr(OH)(NDC)] (2), and [Ga(OH)(NDC)] (3) have been synthesized hydrothermally using 1,4-naphthalene dicarboxylate (NDC) as the linker. These MOFs (1, 2 and 3) have been used as a template for the synthesis of metal-oxide-inserted nanoporous carbon materials. The newly synthesized MOFs and the resulting porous carbon hybrid functional materials have been characterized using powder x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy dispersive x-ray spectroscopic analysis. Results show that compounds 2 and 3 form their respective metal oxide nanoparticles on the surface of the carbon materials during carbonization at 800 °C. The gas sorption properties of the new MOFs and their corresponding carbon frameworks have been reported.

  2. Lithium ion battery application of porous composite oxide microcubes prepared via metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Yang, Xia; Tang, Yong-Bing; Huang, Xing; Xue, Hong Tao; Kang, Wen Pei; Li, Wen Yue; Ng, Tsz-Wai; Lee, Chun-Sing

    2015-06-01

    Prussian Blue (PB, Fe4[Fe(CN)6]3) is utilized to synthesize bimetallic metal-organic frameworks (MOFs) (Fe4[Fe(CN)6]3/Mx[Fe(CN)6], M = Cu, Ni, Co, etc.) by cation exchange, driven by differences in solubility product constant (Ksp) of monometallic MOFs. Upon decomposition, the bimetallic MOFs convert to porous composite metal oxides (Fe2O3/MOx, M = Cu, Ni, Co, etc.) while keeping the original cubic morphology. This study demonstrates a general approach for preparing bimetallic MOFs and porous composite oxides. We also demonstrate the good electrochemical performance (specific capacity of 774 mAh g-1 after 120 cycles at 500 mA g-1) of the synthesized porous Fe2O3-CuO composite as an anode material for lithium ion batteries. And according to references, this composite exhibit better or comparable rate capability and cycle stability compared with other hybrid transition metal oxides.

  3. Computational design of metal-organic frameworks with paddlewheel-type secondary building units

    NASA Astrophysics Data System (ADS)

    Schwingenschlogl, Udo; Peskov, Maxim V.; Masghouni, Nejib

    We employ the TOPOS package to study 697 coordination polymers containing paddlewheel-type secondary building units. The underlying nets are analyzed and 3 novel nets are chosen as potential topologies for paddlewheel-type metal organic frameworks (MOFs). Dicarboxylate linkers are used to build basic structures for novel isoreticular MOF series, aiming at relatively compact structures with a low number of atoms per unit cell. The structures are optimized using density functional theory. Afterwards the Grand Canonical Monte Carlo approach is employed to generate adsorption isotherms for CO2, CO, and CH4 molecules. We utilize the universal forcefield for simulating the interaction between the molecules and hosting MOF. The diffusion behavior of the molecules inside the MOFs is analyzed by molecular dynamics simulations.

  4. High-pressure, ambient temperature hydrogen storage in metal-organic frameworks and porous carbon

    NASA Astrophysics Data System (ADS)

    Beckner, Matthew; Dailly, Anne

    2014-03-01

    We investigated hydrogen storage in micro-porous adsorbents at ambient temperature and pressures up to 320 bar. We measured three benchmark adsorbents: two metal-organic frameworks, Cu3(1,3,5-benzenetricarboxylate)2 [Cu3(btc)2; HKUST-1] and Zn4O(1,3,5-benzenetribenzoate)2 [Zn4O(btb)2; MOF-177], and the activated carbon MSC-30. In this talk, we focus on adsorption enthalpy calculations using a single adsorption isotherm. We use the differential form of the Claussius-Clapeyron equation applied to the Dubinin-Astakhov adsorption model to calculate adsorption enthalpies. Calculation of the adsorption enthalpy in this way gives a temperature independent enthalpy of 5-7 kJ/mol at the lowest coverage for the three materials investigated. Additionally, we discuss the assumptions and corrections that must be made when calculating adsorption isotherms at high-pressure and adsorption enthalpies.

  5. Hydrogen storage in Pd nanocrystals covered with a metal-organic framework.

    PubMed

    Li, Guangqin; Kobayashi, Hirokazu; Taylor, Jared M; Ikeda, Ryuichi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Toh, Shoichi; Matsumura, Syo; Kitagawa, Hiroshi

    2014-08-01

    Hydrogen is an essential component in many industrial processes. As a result of the recent increase in the development of shale gas, steam reforming of shale gas has received considerable attention as a major source of H2, and the more efficient use of hydrogen is strongly demanded. Palladium is well known as a hydrogen-storage metal and an effective catalyst for reactions related to hydrogen in a variety of industrial processes. Here, we present remarkably enhanced capacity and speed of hydrogen storage in Pd nanocrystals covered with the metal-organic framework (MOF) HKUST-1 (copper(II) 1,3,5-benzenetricarboxylate). The Pd nanocrystals covered with the MOF have twice the storage capacity of the bare Pd nanocrystals. The significantly enhanced hydrogen storage capacity was confirmed by hydrogen pressure-composition isotherms and solid-state deuterium nuclear magnetic resonance measurements. The speed of hydrogen absorption in the Pd nanocrystals is also enhanced by the MOF coating. PMID:25017188

  6. Cu₃(hexaiminotriphenylene)₂: an electrically conductive 2D metal-organic framework for chemiresistive sensing.

    PubMed

    Campbell, Michael G; Sheberla, Dennis; Liu, Sophie F; Swager, Timothy M; Dincă, Mircea

    2015-03-27

    The utility of metal-organic frameworks (MOFs) as functional materials in electronic devices has been limited to date by a lack of MOFs that display high electrical conductivity. Here, we report the synthesis of a new electrically conductive 2D MOF, Cu3(HITP)2 (HITP=2,3,6,7,10,11-hexaiminotriphenylene), which displays a bulk conductivity of 0.2 S cm(-1) (pellet, two-point-probe). Devices synthesized by simple drop casting of Cu3(HITP)2 dispersions function as reversible chemiresistive sensors, capable of detecting sub-ppm levels of ammonia vapor. Comparison with the isostructural 2D MOF Ni3(HITP)2 shows that the copper sites are critical for ammonia sensing, indicating that rational design/synthesis can be used to tune the functional properties of conductive MOFs. PMID:25678397

  7. A novel series of isoreticular metal organic frameworks: realizing metastable structures by liquid phase epitaxy

    NASA Astrophysics Data System (ADS)

    Liu, Jinxuan; Lukose, Binit; Shekhah, Osama; Arslan, Hasan Kemal; Weidler, Peter; Gliemann, Hartmut; Bräse, Stefan; Grosjean, Sylvain; Godt, Adelheid; Feng, Xinliang; Müllen, Klaus; Magdau, Ioan-Bogdan; Heine, Thomas; Wöll, Christof

    2012-12-01

    A novel class of metal organic frameworks (MOFs) has been synthesized from Cu-acetate and dicarboxylic acids using liquid phase epitaxy. The SURMOF-2 isoreticular series exhibits P4 symmetry, for the longest linker a channel-size of 3 × 3 nm2 is obtained, one of the largest values reported for any MOF so far. High quality, ab-initio electronic structure calculations confirm the stability of a regular packing of (Cu++)2- carboxylate paddle-wheel planes with P4 symmetry and reveal, that the SURMOF-2 structures are in fact metastable, with a fairly large activation barrier for the transition to the bulk MOF-2 structures exhibiting a lower, twofold (P2 or C2) symmetry. The theoretical calculations also allow identifying the mechanism for the low-temperature epitaxial growth process and to explain, why a synthesis of this highly interesting, new class of high-symmetry, metastable MOFs is not possible using the conventional solvothermal process.

  8. A microporous metal-organic framework with butynelene functionality for selective gas sorption

    NASA Astrophysics Data System (ADS)

    Wang, Lifeng; Zhai, Lu; Ren, Xiaoming; Zhang, Wenwei

    2013-08-01

    A porous metal-organic framework {[Cu2(BBTC)(H2O)2]·2DMSO·4H2O}n (Cu-BBTC, BBTC=1, 1‧-butadiynebenzene -3,3‧,5,5‧-tetracarboxylate; DMSO=dimethyl sulfoxide) was solvothermally synthesized from a tetracarboxylate ligand with butynelene functionality and structurally characterized. Cu-BBTC features a three-dimensional fof network with two types of cages, a small cage is about 14 Å in diameter and a large shows an ellipsoidal pore with about 14.2×22.6 Å in axes. The activated sample of Cu-BBTC, with Langmuir surface area of 1569 m2 g-1, exhibits selective gas adsorption behavior with respect to C2H2/CH4 and CO2/CH4 at room temperature.

  9. A Stable Polyoxometalate-Pillared Metal-Organic Framework for Proton-Conducting and Colorimetric Biosensing.

    PubMed

    Zhou, En-Long; Qin, Chao; Huang, Peng; Wang, Xin-Long; Chen, Wei-Chao; Shao, Kui-Zhan; Su, Zhong-Min

    2015-08-10

    A stable metal-organic framework pillared by Keggin-type polyoxometalate, Cu6 (Trz)10 (H2O)4 [H2 SiW12 O40 ]⋅8 H2O (Trz=1,2,4-triazole) (1), has been prepared under hydrothermal condition. The 2D layer structure with a 22-member ring was formed by Cu(2+) ions, which are connected with each other via the Trz ligands on the ab plane. Thus, the 2D layers are further interconnected through Keggin polyoxoanions to generate a 3D porous network with a small 1D channel. Moreover, the presence of polyoxoanions make it exhibit selective adsorption of water and proton-conducting properties. Additionally it showed efficient intrinsic peroxidase-like activity, providing a simple and sensitive colorimetric assay to detect H2O2 . PMID:26179161

  10. 3D porous metal-organic framework as an efficient electrocatalyst for nonenzymatic sensing application.

    PubMed

    Zhang, Daojun; Zhang, Jingchao; Zhang, Renchun; Shi, Huaizhong; Guo, Yuanyuan; Guo, Xiuli; Li, Sujuan; Yuan, Baiqing

    2015-11-01

    Novel electroactive materials with high surface area and stability have great potential for electrochemical sensor. Herein, we demonstrate the exploitation of a porous Cu-based metal-organic framework (Cu-MOF) with large pore size as nonenzymatic sensors for the electrochemical determination of hydrogen peroxide (H2O2) and glucose. The Cu-MOF shows high stability even in NaOH solution. The as-prepared Cu-MOF modified carbon paste electrode (CPE) presents a well-behaved redox event from electroactive metal centers in the MOF at the physiological pH which can be utilized to catalyze the electroreduction of H2O2. It also exhibited excellent electrocatalytic activity towards the oxidation of glucose in alkaline solution. The results showed that the nonenzymatic sensors based on the Cu-MOF display excellent analytical performances, which make it a promising candidate in electrochemical sensor. PMID:26452944

  11. Metal-Organic Framework/PVDF Composite Membranes with High H2 Permselectivity Synthesized by Ammoniation.

    PubMed

    Li, Wanbin; Meng, Qin; Zhang, Congyang; Zhang, Guoliang

    2015-05-01

    Herein we report a new ammoniation-based chemical modification strategy for synthesis of continuous and uniform metal-organic framework (MOF)/polyvinylidene fluoride (PVDF) membranes with attractive performance. Ammoniation can promote the support PVDF membrane to produce amino groups, form a nanoparticle structure, and be well cross-linked; therefore, the high-density heterogeneous nucleation sites for MOFs growth were provided and the thermal stability and chemical resistance of composite membranes can be greatly improved. The high-quality layers of representative Cu-BTC and ZIF-8 were synthesized on the chemically modified PVDF membranes. By ammoniation, ZIF-7 can even be grown under harsh synthetic conditions such as in DMF precursor solutions at 403 K. The fabricated MOF/PVDF composite membranes with excellent hollow fiber structures and enhanced structural stability exhibited high H2 permselectivities for H2 /CO2 and H2 /N2 . PMID:25810142

  12. Luminescent zinc metal-organic framework (ZIF-90) for sensing metal ions, anions and small molecules.

    PubMed

    Liu, Chang; Yan, Bing

    2015-09-26

    We synthesize a zinc zeolite-type metal-organic framework, the zeolitic imidazolate framework (ZIF-90), which exhibits an intense blue luminescence excited under visible light. Luminescent studies indicate that ZIF-90 could be an efficient multifunctional fluorescence material for high sensitivity metal ions, anions and organic small molecules, especially for Cd(2+), Cu(2+), CrO4(2-) and acetone. The luminescence intensity of ZIF-90 increases with the concentration of Cd(2+) and decreases proportionally with the concentration of Cu(2+), while the same quenched experimental phenomena appear in the sensing of CrO4(2-). With the increase of the amount of acetone, the luminescence intensity decreases gradually in the emulsions of ZIF-90. The mechanism of the sensing properties is studied in detail as well. This study shows that ZIF-90 could be a useful luminescent sensor for metal ions, anions and organic small molecules. PMID:26123790

  13. Heterogeneity within a Mesoporous Metal-Organic Framework with Three Distinct Metal-Containing Building Units.

    PubMed

    Tu, Binbin; Pang, Qingqing; Ning, Erlong; Yan, Wenqing; Qi, Yi; Wu, Doufeng; Li, Qiaowei

    2015-10-28

    Materials built from multiple constituents have revealed emerging properties that are beyond linear integration of those from single components. We report a mesoporous metal-organic framework made from three geometrically distinct metal-containing secondary building units (SBUs) as a result of topological induction. The combinations of the Cu-based triangular, Zn-based octahedral, and Zn-based square pyramidal SBUs have created four types of cages in the network, despite that only one organic linker pyrazolecarboxylate was used. The longest distance for molecules maneuvering inside the largest cage is 5.2 nm. Furthermore, the complex and diversified pore environments allow the installation of various new functionalities in the framework as well as the expedited Ag nanoparticle formation in the pores. As presented in the molecule movement diagram, the crystal has provided specific arrangements of cages and apertures with distinct chemical features for guests transporting between the pores. PMID:26335899

  14. Theoretical and experimental analysis of H2 binding in a prototype metal organic framework material

    SciTech Connect

    Kong, Dr. Lingzhu; Cooper, Valentino R; Nijem, Nour; Li, Kunhao; Li, Jing; Chabal, Yves J.; Langreth, David C.

    2009-01-01

    Hydrogen adsorption by the metal organic framework (MOF) structure Zn2(BDC)2(TED) is investigated using a combination of experimental and theoretical methods. By use of the nonempirical van der Waals density-functional (vdW-DF) approach, it is found that the locus of deepest H2 binding positions lies within two types of narrow channel. The energies of the most stable binding sites, as well as the number of such binding sites, are consistent with the values obtained from experimental adsorption isotherms and heat of adsorption data. Calculations of the shift of the H H stretch frequency when adsorbed in the MOF give a value of approximately −30 cm−1 at the strongest binding point in each of the two channels. Ambient temperature infrared absorption spectroscopy measurements give a hydrogen peak centered at 4120 cm−1, implying a shift consistent with the theoretical calculations.

  15. Postsynthetic modification of metal-organic framework for hydrogen sulfide detection

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Zhang, Jianmin; Hu, Quan; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2015-11-01

    Hydrogen sulfide (H2S) has recently been identified as the third biological gaseous messenger (gasotransmitter) that is involved in regulating many important physiological processes. The detection of H2S is thus essential for its roles but remain challenging in living systems. We report herein a novel turn-on fluorescent probe for H2S detection based on azide functionalized metal-organic framework (MOF). The MOF probe displayed high sensitivity (detection limit, 28.3 μM), excellent selectivity, and fast response (<2 min) toward H2S over other biologically relevant species. We envisage that this MOF probe can be employed as a useful tool to further elucidate the biological roles of H2S.

  16. A Chlorin-Based Nanoscale Metal-Organic Framework for Photodynamic Therapy of Colon Cancers.

    PubMed

    Lu, Kuangda; He, Chunbai; Lin, Wenbin

    2015-06-24

    We report here the rational design of the first chlorin-based nanoscale metal-organic framework (NMOF), DBC-UiO, with much improved photophysical properties over the previously reported porphyrin-based NMOF, DBP-UiO. Reduction of the DBP ligands in DBP-UiO to the DBC ligands in DBC-UiO led to a 13 nm red shift and an 11-fold increase in the extinction coefficient of the lowest-energy Q band. While inheriting the crystallinity, stability, porosity, and nanoplate morphology of DBP-UiO, DBC-UiO sensitizes more efficient (1)O2 generation and exhibits significantly enhanced photodynamic therapy (PDT) efficacy on two colon cancer mouse models as a result of its improved photophysical properties. Both apoptosis and immunogenic cell death contributed to killing of cancer cells in DBC-UiO-induced PDT. PMID:26068094

  17. In Silico Discovery of High Deliverable Capacity Metal-Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Bao, Yi; Martin, Richard; Simon, Cory; Haranczyk, Maciej; Smit, Berend; Deem, Michael; Michael W. Deem Team; Maciej Haranczyk Team; Berend Smit Team

    2015-03-01

    Metal organic frameworks (MOFs) are actively being explored as potential adsorbed natural gas storage materials for small vehicles. Experimental exploration of potential materials is limited by the throughput of synthetic chemistry. We here describe a computational methodology to complement and guide these experimental efforts. The method uses known chemical transformations in silico to identify MOFs with high methane deliverable capacity. The procedure explicitly considers synthesizability with geometric requirements on organic linkers. We efficiently search the composition and conformation space of organic linkers for nine MOF networks, finding 48 materials with higher predicted deliverable capacity (at 65 bar storage, 5.8 bar depletion, and 298 K) than MOF-5 in four of the nine networks. The best material has a predicted deliverable capacity 8% higher than that of MOF-5. US Department of Energy.

  18. Digitized charge transfer magnitude determined by metal-organic coordination number.

    PubMed

    Yang, Hung-Hsiang; Chu, Yu-Hsun; Lu, Chun-I; Yang, Tsung-Han; Yang, Kai-Jheng; Kaun, Chao-Cheng; Hoffmann, Germar; Lin, Minn-Tsong

    2013-03-26

    Well-ordered metal-organic nanostructures of Fe-PTCDA (perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride) chains and networks are grown on a Au(111) surface. These structures are investigated by high-resolution scanning tunneling microscopy. Digitized frontier orbital shifts are followed in scanning tunneling spectroscopy. By comparing the frontier energies with the molecular coordination environments, we conclude that the specific coordination affects the magnitude of charge transfer onto each PTCDA in the Fe-PTCDA hybridization system. A basic model is derived, which captures the essential underlying physics and correlates the observed energetic shift of the frontier orbital with the charge transfer. PMID:23451803

  19. Inelastic decay of electrons in Shockley-type metal-organic interface states

    NASA Astrophysics Data System (ADS)

    Tsirkin, S. S.; Zaitsev, N. L.; Nechaev, I. A.; Tonner, R.; Höfer, U.; Chulkov, E. V.

    2015-12-01

    We present a theoretical study of lifetimes of interface states (IS) on metal-organic interfaces PTCDA/Ag(111), NTCDA/Ag(111), PFP/Ag(111), and PTCDA/Ag(100), describing and explaining the recent experimental data. By means of unfolding the band structure of one of the interfaces under study onto the Ag(111) Brillouin zone we demonstrate that the Brillouin zone folding upon organic monolayer deposition plays a minor role in the phase space for electron decay, and hence weakly affects the resulting lifetimes. The presence of the unoccupied molecular states below the IS gives a small contribution to the IS decay rate, which is mostly determined by the change of the phase space of bulk states upon the energy shift of the IS. The calculated lifetimes follow the experimentally observed trends. In particular, we explain the trend of the unusual increase of the IS lifetimes with rising temperature.

  20. Hydrogen storage in Pd nanocrystals covered with a metal-organic framework

    NASA Astrophysics Data System (ADS)

    Li, Guangqin; Kobayashi, Hirokazu; Taylor, Jared M.; Ikeda, Ryuichi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Toh, Shoichi; Matsumura, Syo; Kitagawa, Hiroshi

    2014-08-01

    Hydrogen is an essential component in many industrial processes. As a result of the recent increase in the development of shale gas, steam reforming of shale gas has received considerable attention as a major source of H2, and the more efficient use of hydrogen is strongly demanded. Palladium is well known as a hydrogen-storage metal and an effective catalyst for reactions related to hydrogen in a variety of industrial processes. Here, we present remarkably enhanced capacity and speed of hydrogen storage in Pd nanocrystals covered with the metal-organic framework (MOF) HKUST-1 (copper(II) 1,3,5-benzenetricarboxylate). The Pd nanocrystals covered with the MOF have twice the storage capacity of the bare Pd nanocrystals. The significantly enhanced hydrogen storage capacity was confirmed by hydrogen pressure-composition isotherms and solid-state deuterium nuclear magnetic resonance measurements. The speed of hydrogen absorption in the Pd nanocrystals is also enhanced by the MOF coating.

  1. Enhanced ethylene separation and plasticization resistance in polymer membranes incorporating metal-organic framework nanocrystals.

    PubMed

    Bachman, Jonathan E; Smith, Zachary P; Li, Tao; Xu, Ting; Long, Jeffrey R

    2016-08-01

    The implementation of membrane-based separations in the petrochemical industry has the potential to reduce energy consumption significantly relative to conventional separation processes. Achieving this goal, however, requires the development of new membrane materials with greater selectivity, permeability and stability than available at present. Here, we report composite materials consisting of nanocrystals of metal-organic frameworks dispersed within a high-performance polyimide, which can exhibit enhanced selectivity for ethylene over ethane, greater ethylene permeability and improved membrane stability. Our results suggest that framework-polymer interactions reduce chain mobility of the polymer while simultaneously boosting membrane separation performance. The increased stability, or plasticization resistance, is expected to improve membrane utility under real process conditions for petrochemical separations and natural gas purification. Furthermore, this approach can be broadly applied to numerous polymers that encounter aggressive environments, potentially making gas separations possible that were previously inaccessible to membranes. PMID:27064528

  2. Application of Two Cobalt-Based Metal-Organic Frameworks as Oxidative Desulfurization Catalysts.

    PubMed

    Masoomi, Mohammad Yaser; Bagheri, Minoo; Morsali, Ali

    2015-12-01

    Two new porous cobalt-based metal-organic frameworks, [Co6(oba)5(OH)2(H2O)2(DMF)4]n · 5DMF (TMU-10) and [Co3(oba)3(O) (Py)0.5] n · 4DMF · Py (TMU-12) have been synthesized by solvothermal method using a nonlinear dicarboxylate ligand. Under mild reaction conditions, these compounds exhibited good catalytic activity and reusability in oxidative desulfurization (ODS) reaction of model oil which was prepared by dissolving dibenzothiophene (DBT) in n-hexane. FT-IR and Mass analysis showed that the main product of DBT oxidation is its corresponding sulfone, which was adsorbed on the surfaces of catalysts. The activation energy was obtained as 13.4 kJ/mol. PMID:26571113

  3. Generic postfunctionalization route from amino-derived metal-organic frameworks.

    PubMed

    Savonnet, Marie; Bazer-Bachi, Delphine; Bats, Nicolas; Perez-Pellitero, Javier; Jeanneau, Erwann; Lecocq, Vincent; Pinel, Catherine; Farrusseng, David

    2010-04-01

    This study deals with the development of a soft, generic, one-pot postfunctionalization method for metal-organic frameworks (MOFs) starting from compounds with an amino group on the linker. The first step consists of transforming the amino group into azide (N(3)) by an unconventional route using tBuONO and TMSN(3). In the same vessel, the desired functionalized MOF then is obtained by the Huisgen 1,3-dipolar cycloaddition of azides to alkynes, otherwise known as the "click" reaction. The method was applied to DMOF-NH(2) and MIL-68(In)-NH(2), which represent two distinct and important classes of MOF. For both, the functionalization was complete (>90% grafting) and the crystallinity was maintained. Thanks to the large diversity and availability of cyano- and acetylene-based chemicals, this method opens the door to tailor-made functionalized MOFs. PMID:20232865

  4. Anisotropic elastic properties of flexible metal-organic frameworks: how soft are soft porous crystals?

    PubMed

    Ortiz, Aurélie U; Boutin, Anne; Fuchs, Alain H; Coudert, François-Xavier

    2012-11-01

    We performed ab initio calculations of the elastic constants of five flexible metal-organic frameworks (MOFs): MIL-53(Al), MIL-53(Ga), MIL-47, and the square and lozenge structures of DMOF-1. Tensorial analysis of the elastic constants reveals a highly anisotropic elastic behavior, some deformation directions exhibiting very low Young's modulus and shear modulus. This anisotropy can reach a 400:1 ratio between the most rigid and weakest directions, in stark contrast to the case of nonflexible MOFs such as MOF-5 and ZIF-8. In addition, we show that flexible MOFs can display extremely large negative linear compressibility. These results uncover the microscopic roots of stimuli-induced structural transitions in flexible MOFs, by linking the local elastic behavior of the material and its multistability. PMID:23215398

  5. Metal-Organic Framework Thin Films as Stationary Phases in Microfabricated Gas-Chromatography Columns.

    SciTech Connect

    Read, Douglas; Sillerud, Colin Halliday

    2016-01-01

    The overarching goal of this project is to integrate Sandia's microfabricated gas-chromatography ( GC) columns with a stationary phase material that is capable of retaining high-volatility chemicals and permanent gases. The successful integration of such a material with GCs would dramatically expand the repertoire of detectable compounds for Sandia's various microanalysis systems. One such promising class of candidate materials is metal-organic frameworks (MOFs). In this report we detail our methods for controlled deposition of HKUST-1 MOF stationary phases within GC columns. We demonstrate: the chromatographic separation of natural gas; a method for determining MOF film thickness from chromatography alone; and the first-reported GC x GC separation of natural gas -- in general -- let alone for two disparate MOF stationary phases. In addition we determine the fundamental thermodynamic constant for mass sorption, the partition coefficient, for HKUST-1 and several light hydrocarbons and select toxic industrial chemicals.

  6. Active and Durable Hydrogen Evolution Reaction Catalyst Derived from Pd-Doped Metal-Organic Frameworks.

    PubMed

    Chen, Jitang; Xia, Guoliang; Jiang, Peng; Yang, Yang; Li, Ren; Shi, Ruohong; Su, Jianwei; Chen, Qianwang

    2016-06-01

    The water electrolysis is of critical importance for sustainable hydrogen production. In this work, a highly efficient and stable PdCo alloy catalyst (PdCo@CN) was synthesized by direct annealing of Pd-doped metal-organic frameworks (MOFs) under N2 atmosphere. In 0.5 M H2SO4 solution, PdCo@CN displays remarkable electrocatalytic performance with overpotential of 80 mV, a Tafel slope of 31 mV dec(-1), and excellent stability of 10 000 cycles. Our studies reveal that noble metal doped MOFs are ideal precursors for preparing highly active alloy electrocatalysts with low content of noble metal. PMID:27112733

  7. Direct X-ray observation of trapped CO₂ in a predesigned porphyrinic metal-organic framework.

    PubMed

    Johnson, Jacob A; Chen, Shuang; Reeson, Tyler C; Chen, Yu-Sheng; Zeng, Xiao Cheng; Zhang, Jian

    2014-06-16

    Metal-organic frameworks (MOFs) are emerging microporous materials that are promising for capture and sequestration of CO2 due to their tailorable binding properties. However, it remains a grand challenge to pre-design a MOF with a precise, multivalent binding environment at the molecular level to enhance CO2 capture. Here, we report the design, synthesis, and direct X-ray crystallographic observation of a porphyrinic MOF, UNLPF-2, that contains CO2-specific single molecular traps. Assembled from an octatopic porphyrin ligand with [Co2(COO)4] paddlewheel clusters, UNLPF-2 provides an appropriate distance between the coordinatively unsaturated metal centers, which serve as the ideal binding sites for in situ generated CO2. The coordination of Co(II) in the porphyrin macrocycle is crucial and responsible for the formation of the required topology to trap CO2. By repeatedly releasing and recapturing CO2, UNLPL-2 also exhibits recyclability. PMID:24861568

  8. Cross coupling between electric and magnetic orders in a multiferroic metal-organic framework.

    PubMed

    Tian, Ying; Stroppa, Alessandro; Chai, Yisheng; Yan, Liqin; Wang, Shouguo; Barone, Paolo; Picozzi, Silvia; Sun, Young

    2014-01-01

    The coexistence of both electric and magnetic orders in some metal-organic frameworks (MOFs) has yielded a new class of multiferroics beyond inorganic materials. However, the coupling between two orders in multiferroic MOFs has not been convincingly verified yet. Here we present clear experimental evidences of cross coupling between electric and magnetic orders in a multiferroic MOF [(CH3)2NH2]Fe(HCOO)3 with a perovskite structure. The dielelectric constant exhibit a hump just at the magnetic ordering temperature TN. Moreover, both the direct (magnetic field control of dielectric properties) and converse (electric field control of magnetization) magnetoelectric effects have been observed in the multiferroic state. This work opens up new insights on the origin of ferroelectricity in MOFs and highlights their promise as magnetoelectric multiferroics. PMID:25317819

  9. Two unusual 12-connected metal-organic coordination polymers with fcu net

    NASA Astrophysics Data System (ADS)

    Guo, Sheng-Qi; Tian, Dan; Luo, Yu-Hui; Chen, Xin; Zhang, Hong

    2013-09-01

    Two new three-dimensional 12-connected metal-organic coordination polymers, [Zn2(bptc)(H2O)]·C2H5OH·H2O (1) and [Cd4(bptc)2(bbi)(H2O)]·H2O (2) (H4bptc=biphenyl-2,5,2',5'-tetracarboxylic acid, bbi=1,1'-(1,4-butanediyl)bis(imidazole)), have been solvothermally synthesized and structurally characterized by single crystal X-ray diffraction analyses. All compounds are also characterized by elemental analyses, IR spectra, thermogravimetric (TG) analyses and X-ray powder diffraction (XRD). Topological analysis indicates that both 1 and 2 are 12-connected frameworks with fcu topology, which are based on cuboid cage and rob-like {Cd3} subunit as 12-connected nodes, respectively. Furthermore, the luminescence properties of the two compounds were discussed in detail.

  10. Fluorous Metal Organic Frameworks as Superhydrophobic Adsorbents for Oil Spill Cleanup and Hydrocarbons Storage

    SciTech Connect

    Yang, Chi; Mather, Qian; Wang, Xiaoping; Kaipa, Ushasree; Nesterov, Vladimir; Venero, Augustin; Omary, Mohammad A

    2011-01-01

    We demonstrate that fluorous metal-organic frameworks (FMOFs) are highly hydrophobic porous materials with a high capacity and affinity to C{sub 6}-C{sub 8} hydrocarbons of oil components. FMOF-1 exhibits reversible adsorption with a high capacity for n-hexane, cyclohexane, benzene, toluene, and p-xylene, with no detectable water adsorption even at near 100% relative humidity, drastically outperforming activated carbon and zeolite porous materials. FMOF-2, obtained from annealing FMOF-1, shows enlarged cages and channels with double toluene adsorption vs FMOF-1 based on crystal structures. The results suggest great promise for FMOFs in applications such as removal of organic pollutants from oil spills or ambient humid air, hydrocarbon storage and transportation, water purification, etc. under practical working conditions.

  11. A Water-Stable Cationic Metal-Organic Framework as a Dual Adsorbent of Oxoanion Pollutants.

    PubMed

    Desai, Aamod V; Manna, Biplab; Karmakar, Avishek; Sahu, Amit; Ghosh, Sujit K

    2016-06-27

    A three-dimensional water-stable cationic metal-organic framework (MOF) pillared by a neutral ligand and with Ni(II)  metal nodes has been synthesized employing a rational design approach. Owing to the ordered arrangement of the uncoordinated tetrahedral sulfate (SO4 (2-) ) ions in the channels, the compound has been employed for aqueous-phase ion-exchange applications. The compound exhibits rapid and colorimetric aqueous-phase capture of environmentally toxic oxoanions (with similar geometries) in a selective manner. This system is the first example of a MOF-based system which absorbs both dichromate (Cr2 O7 (2-) ) and permanganate (MnO4 (-) ) ions, with the latter acting as a model for the radioactive contaminant pertechnetate (TcO4 (-) ). PMID:26855323

  12. When hole extraction determines charge transfer across metal-organic-metal structure

    NASA Astrophysics Data System (ADS)

    Govor, L. V.; Reiter, G.; Parisi, J.

    2016-03-01

    We examined the charge transfer in metal-organic-metal structure, where the contact resistance of the extracting interface is larger than the resistance of the organic crystalline material and the resistance of the injecting interface. If direct tunneling (low voltage) and Fowler-Nordheim tunnelling (high voltage) across both interfaces take place, part of the injected holes remains located in the organic crystal because of the blocking action of the extracting interface, but not because of traps within the organic crystalline material (which was negligible). If Fowler-Nordheim tunneling across the injecting interface and direct tunneling across the extracting interface take place for high voltages, the latter leads to the deviation of the total current-voltage characteristic from the power law I∼ Vγ with γ>2 to Ohm's law with γ≃1.0 .

  13. Metal organic vapor phase epitaxy of hexagonal Ge-Sb-Te (GST)

    NASA Astrophysics Data System (ADS)

    Schuck, Martin; Rieß, Sally; Schreiber, Marcel; Mussler, Gregor; Grützmacher, Detlev; Hardtdegen, Hilde

    2015-06-01

    Epitaxial, hexagonal Ge-Sb-Te was grown on Si(111) substrates by Metal Organic Vapor Phase Epitaxy (MOVPE) using the precursor digermane. The effect of reactor pressure, growth temperature and in situ pre-treatment on morphology and Ge-Sb-Te composition was studied. The composition is sensitive to reactor pressure and growth temperature. Compositional control is achieved at a reactor pressure of 50 hPa. Substrate pre-treatment affects film coalescence. The use of hydrogen and a suitable precursor pre-treatment leads to enhanced surface coverage. X-ray diffraction reveals a trigonal structure with lattice parameters close to that reported for Ge1Sb2Te4 crystallizing in the R 3 bar m phase. The composition was confirmed by energy-dispersive X-ray spectroscopy.

  14. Characterization of Adsorption Enthalpy of Novel Water-Stable Zeolites and Metal-Organic Frameworks.

    PubMed

    Kim, Hyunho; Cho, H Jeremy; Narayanan, Shankar; Yang, Sungwoo; Furukawa, Hiroyasu; Schiffres, Scott; Li, Xiansen; Zhang, Yue-Biao; Jiang, Juncong; Yaghi, Omar M; Wang, Evelyn N

    2016-01-01

    Water adsorption is becoming increasingly important for many applications including thermal energy storage, desalination, and water harvesting. To develop such applications, it is essential to understand both adsorbent-adsorbate and adsorbate-adsorbate interactions, and also the energy required for adsorption/desorption processes of porous material-adsorbate systems, such as zeolites and metal-organic frameworks (MOFs). In this study, we present a technique to characterize the enthalpy of adsorption/desorption of zeolites and MOF-801 with water as an adsorbate by conducting desorption experiments with conventional differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). With this method, the enthalpies of adsorption of previously uncharacterized adsorbents were estimated as a function of both uptake and temperature. Our characterizations indicate that the adsorption enthalpies of type I zeolites can increase to greater than twice the latent heat whereas adsorption enthalpies of MOF-801 are nearly constant for a wide range of vapor uptakes. PMID:26796523

  15. System and method for generating and/or screening potential metal-organic frameworks

    DOEpatents

    Wilmer, Christopher E; Leaf, Michael; Snurr, Randall Q; Farha, Omar K; Hupp, Joseph T

    2015-04-21

    A system and method for systematically generating potential metal-organic framework (MOFs) structures given an input library of building blocks is provided herein. One or more material properties of the potential MOFs are evaluated using computational simulations. A range of material properties (surface area, pore volume, pore size distribution, powder x-ray diffraction pattern, methane adsorption capability, and the like) can be estimated, and in doing so, illuminate unidentified structure-property relationships that may only have been recognized by taking a global view of MOF structures. In addition to identifying structure-property relationships, this systematic approach to identify the MOFs of interest is used to identify one or more MOFs that may be useful for high pressure methane storage.

  16. System and method for generating and/or screening potential metal-organic frameworks

    DOEpatents

    Wilmer, Christopher E; Leaf, Michael; Snurr, Randall Q; Farha, Omar K; Hupp, Joseph T

    2014-12-02

    A system and method for systematically generating potential metal-organic framework (MOFs) structures given an input library of building blocks is provided herein. One or more material properties of the potential MOFs are evaluated using computational simulations. A range of material properties (surface area, pore volume, pore size distribution, powder x-ray diffraction pattern, methane adsorption capability, and the like) can be estimated, and in doing so, illuminate unidentified structure-property relationships that may only have been recognized by taking a global view of MOF structures. In addition to identifying structure-property relationships, this systematic approach to identify the MOFs of interest is used to identify one or more MOFs that may be useful for high pressure methane storage.

  17. Novel metal-organic photocatalysts: synthesis, characterization and decomposition of organic dyes.

    PubMed

    Gopal Reddy, N B; Murali Krishna, P; Kottam, Nagaraju

    2015-02-25

    An efficient method for the photocatalytic degradation of methylene blue in an aqueous medium was developed using metal-organic complexes. Two novel complexes were synthesized using, Schiff base ligand, N'-[(E)-(4-ethylphenyl)methylidene]-4-hydroxybenzohydrazide (HL) and Ni(II) (Complex 1)/Co(II) (Complex 2) chloride respectively. These complexes were characterized using microanalysis, various spectral techniques. Spectral studies reveal that the complexes exhibit square planar geometry with ligand coordination through azomethine nitrogen and enolic oxygen. The effects of catalyst dosage, irradiation time and aqueous pH on the photocatalytic activity were studied systematically. The photocatalytic activity was found to be more efficient in the presence of Ni(II) complexes than the Co(II) complex. Possible mechanistic aspects were discussed. PMID:25233028

  18. A Luminescent Metal-Organic Framework Thermometer with Intrinsic Dual Emission from Organic Lumophores.

    PubMed

    Zhang, Hao; Lin, Chensheng; Sheng, Tianlu; Hu, Shengmin; Zhuo, Chao; Fu, Ruibiao; Wen, Yuehong; Li, Haoran; Su, Shaodong; Wu, Xintao

    2016-03-18

    A new mixed-ligand metal-organic framework (MOF), ZnATZ-BTB, has been constructed as a luminescent ratiometric thermometer by making use of the intrinsic dual emission at cryogenic temperatures. Its twofold interpenetrated network promotes the Dexter energy transfer (DET) between the mixed organic lumophores. The temperature-dependent luminescent behavior arises from the thermal equilibrium between two separated excited states coupled by DET, which is confirmed by Boltzmann distribution fitting. The small excited-state energy gap allows ZnATZ-BTB to measure and visualize cryogenic temperatures (30-130 K) with significantly high relative sensitivity (up to 5.29 % K(-1) at 30 K). Moreover, it is the first example of a ratiometric MOF thermometer the dual emitting sources of which are widely applicable mixed organic ligands, opening up new opportunities for designing such devices. PMID:26864609

  19. Little Thermodynamic Penalty for the Synthesis of Ultraporous Metal Organic Frameworks.

    PubMed

    Akimbekov, Zamirbek; Navrotsky, Alexandra

    2016-02-16

    Many metal-organic frameworks (MOFs) of ultrahigh porosity (with molar volumes more than ten times greater than those of the corresponding dense phases) have been synthesized. However, the number of possible structures far exceeds those that have been made. It is logical to ask if there are energetic barriers to the stability of ultraporous MOFs or whether there is little thermodynamic penalty to their formation. Herein, we show that although the molar volumes of MOF-177 and UMCM-1 reach ultrahigh values, their energetic metastability is in the same range (of 7-36 kJ mol(-1)) as that seen previously for other porous materials. These findings suggest that there is little thermodynamic penalty for the synthesis of structures with varying porosity, and hence, ultraporous frameworks are energetically accessible. Therefore, innovative synthesis methods have the possibility to overcome the drawbacks of conventional approaches and greatly extend the number, porosity, and properties of new framework materials. PMID:26670808

  20. Enhanced ethylene separation and plasticization resistance in polymer membranes incorporating metal-organic framework nanocrystals

    NASA Astrophysics Data System (ADS)

    Bachman, Jonathan E.; Smith, Zachary P.; Li, Tao; Xu, Ting; Long, Jeffrey R.

    2016-08-01

    The implementation of membrane-based separations in the petrochemical industry has the potential to reduce energy consumption significantly relative to conventional separation processes. Achieving this goal, however, requires the development of new membrane materials with greater selectivity, permeability and stability than available at present. Here, we report composite materials consisting of nanocrystals of metal-organic frameworks dispersed within a high-performance polyimide, which can exhibit enhanced selectivity for ethylene over ethane, greater ethylene permeability and improved membrane stability. Our results suggest that framework-polymer interactions reduce chain mobility of the polymer while simultaneously boosting membrane separation performance. The increased stability, or plasticization resistance, is expected to improve membrane utility under real process conditions for petrochemical separations and natural gas purification. Furthermore, this approach can be broadly applied to numerous polymers that encounter aggressive environments, potentially making gas separations possible that were previously inaccessible to membranes.