Large-Pore Apertures in a Series of Metal-Organic Frameworks
25 May 2012-Science (American Association for the Advancement of Science)-Vol. 336, Iss: 6084, pp 1018-1023
TL;DR: A strategy to expand the pore aperture of metal-organic frameworks (MOFs) into a previously unattained size regime (>32 angstroms) is reported, as evidenced by their permanent porosity and high thermal stability (up to 300°C).
Abstract: We report a strategy to expand the pore aperture of metal-organic frameworks (MOFs) into a previously unattained size regime (>32 angstroms). Specifically, the systematic expansion of a well-known MOF structure, MOF-74, from its original link of one phenylene ring (I) to two, three, four, five, six, seven, nine, and eleven (II to XI, respectively), afforded an isoreticular series of MOF-74 structures (termed IRMOF-74-I to XI) with pore apertures ranging from 14 to 98 angstroms. All members of this series have noninterpenetrating structures and exhibit robust architectures, as evidenced by their permanent porosity and high thermal stability (up to 300°C). The pore apertures of an oligoethylene glycol–functionalized IRMOF-74-VII and IRMOF-74-IX are large enough for natural proteins to enter the pores.
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TL;DR: Metal-organic frameworks are porous materials that have potential for applications such as gas storage and separation, as well as catalysis, and methods are being developed for making nanocrystals and supercrystals of MOFs for their incorporation into devices.
Abstract: Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.
10,934 citations
Cites background from "Large-Pore Apertures in a Series of..."
...Pore aperture IRMOF-74-XI 98 Å (22) Number of organic linkers MTV-MOF-5 8 (7)...
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...More important, the large pore aperture is of benefit to the surface modification of the pores with various functionalities without sacrificing the porosity (22)....
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TL;DR: This review provides an overview of the significant advances in the development of diverse MOF composites reported till now with special emphases on the synergistic effects and applications of the composites.
Abstract: Metal–organic frameworks (MOFs), also known as porous coordination polymers (PCPs), synthesized by assembling metal ions with organic ligands have recently emerged as a new class of crystalline porous materials. The amenability to design as well as fine-tunable and uniform pore structures makes them promising materials for a variety of applications. Controllable integration of MOFs and functional materials is leading to the creation of new multifunctional composites/hybrids, which exhibit new properties that are superior to those of the individual components through the collective behavior of the functional units. This is a rapidly developing interdisciplinary research area. This review provides an overview of the significant advances in the development of diverse MOF composites reported till now with special emphases on the synergistic effects and applications of the composites. The most widely used and successful strategies for composite synthesis are also presented.
1,738 citations
TL;DR: Advances in Zr-MOFs since 2008 are summarized and reviewed from three aspects: design and synthesis, structure, and applications to provide guidance for the in-depth investigation of MOFs towards practical applications.
Abstract: Among the large family of metal–organic frameworks (MOFs), Zr-based MOFs, which exhibit rich structure types, outstanding stability, intriguing properties and functions, are foreseen as one of the most promising MOF materials for practical applications. Although this specific type of MOF is still in its early stage of development, significant progress has been made in recent years. Herein, advances in Zr-MOFs since 2008 are summarized and reviewed from three aspects: design and synthesis, structure, and applications. Four synthesis strategies implemented in building and/or modifying Zr-MOFs as well as their scale-up preparation under green and industrially feasible conditions are illustrated first. Zr-MOFs with various structural types are then classified and discussed in terms of different Zr-based secondary building units and organic ligands. Finally, applications of Zr-MOFs in catalysis, molecule adsorption and separation, drug delivery, and fluorescence sensing, and as porous carriers are highlighted. Such a review based on a specific type of MOF is expected to provide guidance for the in-depth investigation of MOFs towards practical applications.
1,692 citations
TL;DR: This critical review of metal-organic frameworks (MOFs) highlights advances in MOF synthesis focusing on linker design and examples of building MOFs to reach unique properties, such as unprecedented surface area, pore aperture, molecular recognition, stability, and catalysis, through linkers are described.
Abstract: Metal–organic frameworks (MOFs) are constructed from metal ions/clusters coordinated by organic linkers (or bridging-ligands). The hallmark of MOFs is their permanent porosity, which is frequently found in MOFs constructed from metal-clusters. These clusters are often formed in situ, whereas the linkers are generally pre-formed. The geometry and connectivity of a linker dictate the structure of the resulting MOF. Adjustments of linker geometry, length, ratio, and functional-group can tune the size, shape, and internal surface property of a MOF for a targeted application. In this critical review, we highlight advances in MOF synthesis focusing on linker design. Examples of building MOFs to reach unique properties, such as unprecedented surface area, pore aperture, molecular recognition, stability, and catalysis, through linker design are described. Further search for application-oriented MOFs through judicious selection of metal clusters and organic linkers is desirable. In this review, linkers are categorized as ditopic (Section 1), tritopic (Section 2), tetratopic (Section 3), hexatopic (Section 4), octatopic (Section 5), mixed (Section 6), desymmetrized (Section 7), metallo (Section 8), and N-heterocyclic linkers (Section 9).
1,647 citations
References
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TL;DR: Use of amphiphilic triblock copolymers to direct the organization of polymerizing silica species has resulted in the preparation of well-ordered hexagonal mesoporous silica structures (SBA-15) with uniform pore sizes up to approximately 300 angstroms.
Abstract: Use of amphiphilic triblock copolymers to direct the organization of polymerizing silica species has resulted in the preparation of well-ordered hexagonal mesoporous silica structures (SBA-15) with uniform pore sizes up to approximately 300 angstroms. The SBA-15 materials are synthesized in acidic media to produce highly ordered, two-dimensional hexagonal (space group p6mm) silica-block copolymer mesophases. Calcination at 500°C gives porous structures with unusually large interlattice d spacings of 74.5 to 320 angstroms between the (100) planes, pore sizes from 46 to 300 angstroms, pore volume fractions up to 0.85, and silica wall thicknesses of 31 to 64 angstroms. SBA-15 can be readily prepared over a wide range of uniform pore sizes and pore wall thicknesses at low temperature (35° to 80°C), using a variety of poly(alkylene oxide) triblock copolymers and by the addition of cosolvent organic molecules. The block copolymer species can be recovered for reuse by solvent extraction with ethanol or removed by heating at 140°C for 3 hours, in both cases, yielding a product that is thermally stable in boiling water.
10,807 citations
TL;DR: The aim is to present the state of the art chemistry and physics of and in the micropores of porous coordination polymers, and the next generation of porous functions based on dynamic crystal transformations caused by guest molecules or physical stimuli.
Abstract: The chemistry of the coordination polymers has in recent years advanced extensively, affording various architectures, which are constructed from a variety of molecular building blocks with different interactions between them. The next challenge is the chemical and physical functionalization of these architectures, through the porous properties of the frameworks. This review concentrates on three aspects of coordination polymers: 1). the use of crystal engineering to construct porous frameworks from connectors and linkers ("nanospace engineering"), 2). characterizing and cataloging the porous properties by functions for storage, exchange, separation, etc., and 3). the next generation of porous functions based on dynamic crystal transformations caused by guest molecules or physical stimuli. Our aim is to present the state of the art chemistry and physics of and in the micropores of porous coordination polymers.
9,661 citations
TL;DR: This work has shown that highly porous frameworks held together by strong metal–oxygen–carbon bonds and with exceptionally large surface area and capacity for gas storage have been prepared and their pore metrics systematically varied and functionalized.
Abstract: The long-standing challenge of designing and constructing new crystalline solid-state materials from molecular building blocks is just beginning to be addressed with success. A conceptual approach that requires the use of secondary building units to direct the assembly of ordered frameworks epitomizes this process: we call this approach reticular synthesis. This chemistry has yielded materials designed to have predetermined structures, compositions and properties. In particular, highly porous frameworks held together by strong metal-oxygen-carbon bonds and with exceptionally large surface area and capacity for gas storage have been prepared and their pore metrics systematically varied and functionalized.
8,013 citations
TL;DR: Metal-organic framework (MOF-5), a prototype of a new class of porous materials and one that is constructed from octahedral Zn-O-C clusters and benzene links, was used to demonstrate that its three-dimensional porous system can be functionalized with the organic groups and can be expanded with the long molecular struts biphenyl, tetrahydropyrene, pyrene, and terphenyl.
Abstract: A strategy based on reticulating metal ions and organic carboxylate links into extended networks has been advanced to a point that allowed the design of porous structures in which pore size and functionality could be varied systematically. Metal-organic framework (MOF-5), a prototype of a new class of porous materials and one that is constructed from octahedral Zn-O-C clusters and benzene links, was used to demonstrate that its three-dimensional porous system can be functionalized with the organic groups –Br, –NH2, –OC3H7, –OC5H11, –C2H4, and –C4H4 and that its pore size can be expanded with the long molecular struts biphenyl, tetrahydropyrene, pyrene, and terphenyl. We synthesized an isoreticular series (one that has the same framework topology) of 16 highly crystalline materials whose open space represented up to 91.1% of the crystal volume, as well as homogeneous periodic pores that can be incrementally varied from 3.8 to 28.8 angstroms. One member of this series exhibited a high capacity for methane storage (240 cubic centimeters at standard temperature and pressure per gram at 36 atmospheres and ambient temperature), and others the lowest densities (0.41 to 0.21 gram per cubic centimeter) for a crystalline material at room temperature.
6,922 citations
TL;DR: 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 is reported.
Abstract: 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.
3,598 citations