Zeolitic Metal Organic Frameworks Research Articles

Zeolitic metal-organic frameworks based on amino acid.

Two enantiomorphic metal-organic frameworks with zeotype SOD topology have been successfully synthesized from enantiopure L-alanine and D-alanine, respectively, which demonstrates the feasibility of fabricating MOFs that integrate the 4-connected zeotype topologies and homochiral nature by the employment of enantiopure amino acids.

Metal–Organic Framework Supported Bimetallic NiPt Nanoparticles as High‐performance Catalysts for Hydrogen Generation from Hydrazine in Aqueous Solution

AbstractHighly dispersed bimetallic NiPt nanoparticles with different NiPt compositions have been successfully immobilized by the zeolitic metal–organic framework ZIF‐8 by a simple liquid impregnation method. These catalysts show high catalytic activity and durability for hydrogen generation from decomposition of hydrazine (H2NNH2) in aqueous alkaline solution at 323 K. Both transmission electron microscopic (TEM) and high‐angle annular dark‐field scanning TEM measurements (HAADF‐STEM) images showed that the ZIF‐8 immobilized NPs were highly dispersed and controlled in small sizes with an average diameter of 2.2±0.3 nm.

A 4 + 4 strategy for synthesis of zeolitic metal–organic frameworks: an indium-MOF with SOD topology as a light-harvesting antenna

A zeolitic metal-organic framework with a SOD topology, (Et2NH2)[In(BCBAIP)]·4DEF·4EtOH (H4BCBAIP: 5-(bis(4-carboxybenzyl)amino)isophthalic acid) (1), has been constructed by a 4 + 4 synthetic strategy from tetrahedral organic building units and In(3+) ions. Compound 1 could adsorb organic dyes and be used as a light-harvesting antenna.

ZIF-8 immobilized nickel nanoparticles: highly effective catalysts for hydrogen generation from hydrolysis of ammonia borane

Highly dispersed Ni nanoparticles have been successfully immobilized by the zeolitic metal-organic framework ZIF-8 via sequential deposition-reduction methods, which show high catalytic activity and long durability for hydrogen generation from hydrolysis of aqueous ammonia borane (NH(3)BH(3)) at room temperature.

ChemInform Abstract: MOFs, MILs and More: Concepts, Properties and Applications for Porous Coordination Networks (PCNs)

AbstractReview: 235 refs.

Molecular Understanding for the Adsorption of Water and Alcohols in Hydrophilic and Hydrophobic Zeolitic Metal−Organic Frameworks

A molecular simulation study is reported for the adsorption of water and alcohols (methanol and ethanol) in two metal−organic frameworks (MOFs) topologically similar to rho-zeolite; one is a hydrophilic Na+-exchanged rho-zeolite-like MOF (Na-rho-ZMOF), and the other is a hydrophobic zeolitic−imidazolate framework-71 (ZIF-71). The adsorption isotherms in Na-rho-ZMOF are type I as a consequence of the high affinity of the nonframework Na+ ions and ionic framework. The adsorption capacity decreases in the order of water > methanol > ethanol. Water is adsorbed more closely in the window region, whereas methanol and ethanol are populated in the α cage due to steric effect. In water/methanol and water/ethanol mixtures, water adsorption increases continuously with increasing pressure and replaces alcohols competitively at high pressures. In ZIF-71, the framework−adsorbate affinity is relatively weaker and type V adsorption is observed. Water has vanishingly small adsorption at low pressures and a sharp increase in adsorption at 22 kPa due to capillary condensation. Methanol and ethanol exhibit cluster-growth adsorption, followed by continuous pore filling. The adsorption in ZIF-71 increases in the order of water < methanol < ethanol at low pressures; however, the opposite order is observed at high pressures because of entropy effect. In water/alcohol mixtures, alcohols are selectively more adsorbed at low pressures but surpassed by water with increasing pressure. The framework charges have a substantial effect on adsorption in Na-rho-ZMOF, but not in ZIF-71. This study provides a molecular understanding for the adsorption of water and alcohols in two zeolitic MOFs with the identical topology and reveals the significantly different adsorption mechanisms.

MOFs, MILs and more: concepts, properties and applications for porous coordination networks (PCNs)

This review (over 380 references) summarizes metal–organic frameworks (MOFs), Materials Institute Lavoisier (MILs), iso-reticular metal–organic frameworks (IR-MOFs), porous coordination networks (PCNs), zeolitic metal–organic frameworks (ZMOFs) and porous coordination polymers (PCPs) with selected examples of their structures, concepts for linkers, syntheses, post-synthesis modifications, metal nanoparticle formations in MOFs, porosity and zeolitic behavior for applications in gas storage for hydrogen, carbon dioxide, methane and applications in conductivity, luminescence and catalysis.

Zeolitic polyoxometalates metal organic frameworks (Z-POMOF) with imidazole ligands and ε-Keggin ions as building blocks; computational evaluation of hypothetical polymorphs and a synthesis approach

We investigate here a new family of zeolitic Metal Organic Frameworks (MOFs) based on imidazole (im) as the ligand and epsilon-type Keggin PolyOxoMetalates (POMs) as building units. The POM used in this study is the epsilon-{PMo(12)O(40)} Keggin isomer capped by four Zn(ii) ions (noted epsilon-Zn) in tetrahedral coordination. We describe here our methods to first construct and then evaluate the stability of hypothetical 3-D POMOFs possessing a tetrahedral network, typified by dense silica polymorphs and zeotypes and referred here to as Z-POMOFs. We use the analogy between the connectivity of silicon ion in dense minerals or zeolites and the epsilon-Zn, using imidazolate ligands to mimic the role of oxygen atoms in zeolites. Handling the epsilon-Keggin and imidazole as the constitutive building-blocks, a selection of 40 polymorphs were constructed and their relative stabilities computed. Among these Z-POMOFs, the cristobalite-like and zni-structure were identified as the most stable candidates. In parallel, we have attempted to synthesize Z-POMOF structures with epsilon-Zn POMs, synthesized in situ under hydrothermal conditions, and imidazole ligands. We present our first experimental result, the extended material [NBu(4)][PMo(V)(8)Mo(VI)(4)O(37)(OH)(3)Zn(4)(im)(Him)], named epsilon(im)(2). The structure of the hybrid framework is built by the connection of dimerized epsilon-Zn POMs to imidazole ligands in two directions. The obtaining of the first POMOF based on imidazole ligand is an encouraging step towards the synthesis of a new family of POMOFs.

Zeolitic Polyoxometalate-Based Metal−Organic Frameworks (Z-POMOFs): Computational Evaluation of Hypothetical Polymorphs and the Successful Targeted Synthesis of the Redox-Active Z-POMOF1

The targeted design and simulation of a new family of zeolitic metal-organic frameworks (MOFs) based on benzenedicarboxylate (BDC) as the ligand and epsilon-type Keggin polyoxometalates (POMs) as building units, named here Z-POMOFs, have been performed. A key feature is the use of the analogy between the connectivity of silicon in dense minerals and zeolites with that of the epsilon-type Keggin POMs capped with Zn(II) ions. Handling the epsilon-Keggin as a building block, a selection of 21 zeotype structures, together with a series of dense minerals were constructed and their relative stabilities computed. Among these Z-POMOFs, the cristobalite-like structure was predicted to be the most stable structure. This prediction has been experimentally validated by the targeted synthesis of the first experimental Z-POMOF structure, which was strikingly found to possess the cristobalite topology, with three interpenetrated networks. Crystals of [NBu(4)](3)[PMo(V)(8)Mo(VI)(4)O(36)(OH)(4)Zn(4)(BDC)(2)].2H(2)O (Z-POMOF1) have been isolated under hydrothermal conditions from the reduction of ammonium heptamolybdate in the presence of phosphorous acid and Zn(II) ions. Tetrabutylammonium cations play the role of counterions and space-filling agents in this tridimensional interpenetrated framework. Moreover, the electrochemistry of the epsilon-Keggin POM is maintained and can be exploited in the insoluble Z-POMOF1 framework, as demonstrated by the electrocatalytic reduction of bromate.

Design and Generation of Extended Zeolitic Metal–Organic Frameworks (ZMOFs): Synthesis and Crystal Structures of Zinc(II) Imidazolate Polymers with Zeolitic Topologies

Attempts to create metal-organic frameworks (MOFs) with zeolitic topologies, metal (zinc(II) and cobalt(II)) imidazolates have repeatedly been used as the metal-organic motifs of inorganic silicate analogues. By modulating the synthetic strategy based on the solvothermal and liquid diffusion method, seven further MOFs (including at least three zeolitic MOFs) of zinc(II) imidazolates, [Zn(im)2.x G] (G=guest molecule, x=0.2-1) 1 a-7 a, have been successfully synthesized. Of these, 1 a-3 a are isostructural with the previously reported cobalt analogues 1 b-3 b, respectively, while 4 a-7 a are new members of the metal imidazolate MOF family. Complex 4 a exhibits a structure related to silicate CaAl2Si2O8 of CrB4 topology, but with a higher network symmetry; complex 5 a has a structure with zeolitic DFT topology that was discovered in zeolite-related materials of DAF-2, UCSB-3, and UCSB-3GaGe; complex 6 a demonstrates an unprecedented zeolite-like topology with one dimensional channels with 10-rings; and 7 a displays a structure of natural zeolite GIS (gismondine) topology. All of these polymorphous MOFs were created only by using certain solvents as structure-directing agents (SDAs). Further extensive metal-organic frameworks with zeolitic topologies can be envisaged if other solvents were to be used.