Showing papers by "Omar M. Yaghi published in 2010"

Ultrahigh Porosity in Metal-Organic Frameworks

Abstract: Crystalline solids with extended non-interpenetrating three-dimensional crystal structures were synthesized that support well-defined pores with internal diameters of up to 48 angstroms The Zn4O(CO2)6 unit was joined with either one or two kinds of organic link, 4,4',4''-[benzene-1,3,5-triyl-tris(ethyne-2,1-diyl)]tribenzoate (BTE), 4,4',44''-[benzene-1,3,5-triyl-tris(benzene-4,1-diyl)]tribenzoate (BBC), 4,4',44''-benzene-1,3,5-triyl-tribenzoate (BTB)/2,6-naphthalenedicarboxylate (NDC), and BTE/biphenyl-4,4'-dicarboxylate (BPDC), to give four metal-organic frameworks (MOFs), MOF-180, -200, -205, and -210, respectively Members of this series of MOFs show exceptional porosities and gas (hydrogen, methane, and carbon dioxide) uptake capacities For example, MOF-210 has Brunauer-Emmett-Teller and Langmuir surface areas of 6240 and 10,400 square meters per gram, respectively, and a total carbon dioxide storage capacity of 2870 milligrams per gram The volume-specific internal surface area of MOF-210 (2060 square meters per cubic centimeter) is equivalent to the outer surface of nanoparticles (3-nanometer cubes) and near the ultimate adsorption limit for solid materials

Synthesis, Structure, and Carbon Dioxide Capture Properties of Zeolitic Imidazolate Frameworks

Abstract: Zeolites are one of humanity’s most important synthetic products. These aluminosilicate-based materials represent a large segment of the global economy. Indeed, the value of zeolites used in petroleum refining as catalysts and in detergents as water softeners is estimated at $350 billion per year. A major current goal in zeolite chemistry is to create a structure in which metal ions and functionalizable organic units make up an integral part of the framework. Such a structure, by virtue of the flexibility with which metal ions and organic moieties can be varied, is viewed as a key to further improving zeolite properties and accessing new applications. Recently, it was recognized that the Si−O−Si preferred angle in zeolites (145°) is coincident with that of the bridging angle in the M−Im−M fragment (where M is Zn or Co and Im is imidazolate), and therefore it should be possible to make new zeolitic imidazolate frameworks (ZIFs) with topologies based on those of tetrahedral zeolites. This idea was successfu...

Multiple Functional Groups of Varying Ratios in Metal-Organic Frameworks

Abstract: We show that metal-organic frameworks (MOFs) can incorporate a large number of different functionalities on linking groups in a way that mixes the linker, rather than forming separate domains. We made complex MOFs from 1,4-benzenedicarboxylate (denoted by "A" in this work) and its derivatives -NH2, -Br, -(Cl)2, -NO2, -(CH3)2, -C4H4, -(OC3H5)2, and -(OC7H7)2 (denoted by "B" to "I," respectively) to synthesize 18 multivariate (MTV) MOF-5 type structures that contain up to eight distinct functionalities in one phase. The backbone (zinc oxide and phenylene units) of these structures is ordered, but the distribution of functional groups is disordered. The complex arrangements of several functional groups within the pores can lead to properties that are not simply linear sums of those of the pure components. For example, a member of this series, MTV-MOF-5-EHI, exhibits up to 400% better selectivity for carbon dioxide over carbon monoxide compared with its best same-link counterparts.

Exceptional ammonia uptake by a covalent organic framework

Abstract: Covalent organic frameworks (COFs) are porous crystalline materials composed of light elements linked by strong covalent bonds. A number of these materials contain a high density of Lewis acid boron sites that can strongly interact with Lewis basic guests, which makes them ideal for the storage of corrosive chemicals such as ammonia. We found that a member of the covalent organic framework family, COF-10, shows the highest uptake capacity (15 mol kg⁻¹, 298 K, 1 bar) of any porous material, including microporous 13X zeolite (9 mol kg⁻¹), Amberlyst 15 (11 mol kg⁻¹) and mesoporous silica, MCM-41 (7.9 mol kg⁻¹). Notably, ammonia can be removed from the pores of COF-10 by heating samples at 200°C under vacuum. In addition, repeated adsorption of ammonia into COF-10 causes a shift in the interlayer packing, which reduces its apparent surface area to nitrogen. However, owing to the strong Lewis acid-base interactions, the total uptake capacity of ammonia and the structural integrity of the COF are maintained after several cycles of adsorption/desorption.

Metal insertion in a microporous metal-organic framework lined with 2,2'-bipyridine.

Abstract: Reaction of AlCl3·6H2O with 2,2′-bipyridine-5,5′-dicarboxylic acid (H2bpydc) affords Al(OH)(bpydc) (1, MOF-253), the first metal−organic framework with open 2,2′-bipyridine (bpy) coordination sites. The material displays a BET surface area of 2160 m2/g and readily complexes metals to afford, for example, 1·xPdCl2 (x = 0.08, 0.83) and 1·0.97Cu(BF4)2. EXAFS spectroscopy performed on 1·0.83PdCl2 reveals the expected square planar coordination geometry, matching the structure of the model complex (bpy)PdCl2. Significantly, the selectivity factor for binding CO2 over N2 under typical flue gas conditions is observed to increase from 2.8 in 1 to 12 in 1·0.97Cu(BF4)2.

Metal-organic frameworks from edible natural products.

Abstract: Metal–organic frameworks (MOFs) represent an extensive class of porous crystals in which organic struts link metalcontaining clusters. The success in controlling the functionality and structure of MOFs has led to numerous applications, most notably gas adsorption, storage of clean gas fuels, catalysis, separations, and drug delivery. However, the vast majority of MOFs described to date are composed of organic struts derived from non-renewable petrochemical feedstocks and transition metals. The challenge in preparing MOFs from natural products lies in the inherent asymmetry of the building units, which are not amenable to crystallization in the form of highly porous frameworks. Herein, we report a strategy to overcome this problem using g-cyclodextrin (g-CD), a symmetrical cyclic oligosaccharide that is mass-produced enzymatically from starch and comprised of eight asymmetric a-1,4-linked dglucopyranosyl residues. These g-CD building units are then linked by potassium ions, in aqueous media at ambient temperature and pressure, to form a body-centered cubic structure, termed CD-MOF-1, which has the empirical formula [(C48H80O40)(KOH)2]n. CD-MOFs can be prepared entirely from edible ingredients: combining food-grade g-CD with salt substitute (KCl) or potassium benzoate (food additive E212) in bottled water and Everclear grain spirit (EtOH) yields porous frameworks which constitute edible MOFs. While there have been a few reports of MOFs assembled from amino acids, nucleobases, peptides, magnesium formates, and metal glutarates, examples of these materials are not common despite the rapidly growing desire to fabricate MOFs from naturally available building blocks. We suspect that the key to our success in assembling CD-MOFs lies in the symmetric arrangement (C8) within the g-CD torus of eight asymmetric (C1) a-1,4-linked d-glucopyranosyl residues and the ready availability of g-CD as a chiral molecular building block (Figure 1). CD-MOF-1 was prepared by combining 1.0 equiv of g-CD with 8.0 equiv of KOH in aqueous solution, followed by vapor diffusion of MeOH into the solution during 2–7 days, resulting in colorless, cubic, single crystals, suitable for X-ray crystallography, in approximately 70% yield. Other CD-MOFs were readily obtained using salts of Na, Rb, and Cs, giving rise to an extensive new family of porous materials. A complete list of metal salts employed to form CD-MOFs and the full synthesis of CDMOFs are provided in Section S2 of the Supporting Information. The X-ray crystal structure of CD-MOF-1 reveals that eight-coordinate K ions not only assist in the assembly of (gCD)6 cubes (Figure 2a,b), wherein six g-CD units occupy the faces of a cube, but they also serve to link these cubes together in a three-dimensional array which extends throughout the crystal (Figure 2c). The (g-CD)6 repeating motifs adopt a body-centered cubic packing arrangement wherein each symmetrically equivalent K ion links two contiguous g-CD

A Combined Experimental−Computational Investigation of Carbon Dioxide Capture in a Series of Isoreticular Zeolitic Imidazolate Frameworks

Abstract: A series of five zeolitic imidazolate frameworks (ZIFs) have been synthesized using zinc(II) acetate and five different 4,5-functionalized imidazole units, namely ZIF-25, -71, -93, -96, and -97. These 3-D porous frameworks have the same underlying topology (RHO) with Brunauer−Emmet−Teller surface areas ranging from 564 to 1110 m2/g. The only variation in structure arises from the functional groups that are directed into the pores of these materials, which include −CH3, −OH, −Cl, −CN, −CHO, and −NH2; therefore these 3-D frameworks are ideal for the study of the effect of functionality on CO2 uptake. Experimental results show CO2 uptake at approximately 800 Torr and 298 K ranging from 0.65 mmol g−1 in ZIF-71 to 2.18 mmol g−1 in ZIF-96. Molecular modeling calculations reproduce the pronounced dependence of the equilibrium adsorption on functionalization and suggest that polarizability and symmetry of the functionalization on the imidazolate are key factors leading to high CO2 uptake.

A Metal−Organic Framework with Covalently Bound Organometallic Complexes

Abstract: A procedure for making covalently linked organometallic complexes within the pores of metal−organic frameworks (MOFs) has been described. An N-heterocyclic carbene precursor containing link L0 was prepared and then constructed into a MOF-5-type structure (IRMOF-76). Attempts to produce covalently bound organometallic complexes in IRMOF-76 were unsuccessful. An alternative way of linking the first metalated link, L1, into the desired metalated MOF structure, IRMOF-77, was successful. IRMOF-76 and -77 were characterized by single-crystal X-ray studies. Demonstration of permanent porosity and successful substitution of the pyridine coligand in IRMOF-77 are also described.

Adsorption Mechanism and Uptake of Methane in Covalent Organic Frameworks: Theory and Experiment

Abstract: We determined the methane (CH4) uptake (at 298 K and 1 to 100 bar pressure) for a variety of covalent organic frameworks (COFs), including both two-dimensional (COF-1, COF-5, COF-6, COF-8, and COF-10) and three-dimensional (COF-102, COF-103, COF-105, and COF-108) systems. For all COFs, the CH4 uptake was predicted from grand canonical Monte Carlo (GCMC) simulations based on force fields (FF) developed to fit accurate quantum mechanics (QM) [second order Moller−Plesset (MP2) perturbation theory using doubly polarized quadruple-ζ (QZVPP) basis sets]. This FF was validated by comparison with the equation of state for CH4 and by comparison with the experimental uptake isotherms at 298 K (reported here for COF-5 and COF-8), which agrees well (within 2% for 1−100 bar) with the GCMC simulations. From our simulations we have been able to observe, for the first time, multilayer formation coexisting with a pore filling mechanism. The best COF in terms of total volume of CH4 per unit volume COF absorbent is COF-1, w...

A Catenated Strut in a Catenated Metal-Organic Framework

Abstract: Mechanically interlocked molecules (MIMs), in the form of donor–acceptor [2]catenane-containing struts of exceptional length, have been incorporated into a three-dimensional catenated metal–organic framework (MOF) at precise locations and with uniform relative orientations. Catenation is expressed simultaneously within the struts and the framework.

Ring-opening reactions within porous metal-organic frameworks.

Abstract: Two new metal-organic framework (MOF) structures, IRMOF-3b and -3c, were prepared by ring-opening reaction of 1,3-propanesultone and 2-methylaziridine with an amine functionalized MOF, IRMOF-3. The new structures are permanently functionalized with covalently linked sulfonate and alkyamine units, respectively. The underlying framework structure is retained after reaction as confirmed by powder X-ray diffraction. The high porosity of IRMOF-3 is also maintained, as evidenced by nitrogen adsorption experiments, which yield Brunauer-Emmett-Teller (BET) surface areas of 1380 and 530 m(2) g(-1) compared to 2040 m(2) g(-1) in the parent material. Ring-opening reactions provide a versatile route to irreversible binding of a range of functionalities that are otherwise difficult to access in MOFs.

Reversible ethylene oxide capture in porous frameworks

Abstract: This disclosure relates to porous metal organic frameworks for ethylene oxide separation and recovery.

Positronium formation in porous materials for antihydrogen production

Abstract: Positronium (Ps) formation measurements in several porous materials as: Vycor, germanate Xerogel, Metal-Organic Frameworks MOF-177 and Aerogel with two densities (20 and 150 mg/cm 3 ), were performed by means of a variable energy positron beam provided with a Ge detector and a positron lifetime spectrometer. An efficient formation of cooled Ps atoms is a requisite for the production of antihydrogen, with the aim of a direct measurement of the Earth gravitational acceleration g of antimatter, which is a primary scientific goal of AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Porous materials are necessary to form a high yield of Ps atoms as well as to cool Ps through collisions with the inner walls of the pores. The different materials were characterized and produce Ps into the pores. Lifetime measurements give an estimation of the typical pores dimension of the substances. A comparative study of the positron lifetime and the Ps fraction values in the above mentioned materials indicates that silica Aerogel, with the appropriate density, is an excellent candidate for an efficient formation of cold Ps atoms for the AEGIS project.

Carbon dioxide capture and storage using open frameworks

Abstract: Methods and compositions useful for gas storage and separation are provided. More particularly, compositions and methods for CO 2 storage and separation are provided comprising an open metal organic framework.

Oxidative homo-coupling reactions of aryl boronic acids using a porous copper metal-organic framework as a highly efficient heterogeneous catalyst

Abstract: The disclosure provides methods for the use of open metal frameworks to catalyze coupling reactions.

Conductive organometallic framework

Abstract: The disclosure provides organometallic frameworks, catalysts and sensors. In one aspect, the organometallic framework comprises di-isocyanide group.

Complex mixed ligand open framework materials

Abstract: The disclosure provides multivariate metal organic frameworks comprising different functional ligands.

Metal complex array, method for producing the same and material

Abstract: PROBLEM TO BE SOLVED: To provide a metal complex array or a metal complex array-immobilized solid obtained by immobilizing the array on a solid carrier, to provide a method for producing them, and to provide a material suitably usable for the purpose. SOLUTION: The metal complex array in which two or more metal complex compounds having amino groups and carboxy groups form a multi-combination (the number of bonds is n) through amide bonds associated with the amino groups and the carboxy groups can be produced by using a newly synthesized organic compound and a metal complex thereof, multiply linking the products on a solid carrier by an operation similar to a method of Fmoc solid-phase peptide synthesis, and finally separating the product from the solid carrier. COPYRIGHT: (C)2011,JPO&INPIT

Structures organiques ouvertes en métal avec aire de surface exceptionnelle et grande capacité de stockage de gaz

Abstract: La presente invention concerne des structures organiques en metal qui comportent une porosite exceptionnelle.

Réactions dhomocouplage doxydation dacides boroniques daryle utilisant une structure poreuse organique à base de cuivre comme catalyseur hétérogène extrêmement efficace

Abstract: Cette invention concerne des procedes d’utilisation de structures metalliques ouvertes pour synthetiser des composes biaryle consistant a mettre en contact une structure metallo-organique ou un polyedre metallo-organique avec un compose acide boronique d’aryle dans des conditions ou la structure metallo-organique ou le polyedre metallo-organique catalyse la synthese du biaryle par une reaction d’homocouplage.

Matériaux à structure ouverte à ligand mixte complexe

Abstract: L'invention porte sur des structures organometalliques a multiples variables comprenant differents ligands fonctionnels.