Open-Framework Inorganic Materials

Cheetham, Anthony K.; Férey, Gérard; Loiseau, Thierry

doi:10.1002/(sici)1521-3773(19991115)38:22<3268::aid-anie3268>3.0.co;2-u

Cited by 2,368 publications

(435 citation statements)

References 180 publications

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“…However, the discovery of large families of naturally occurring and synthetic zeolites with massive internal void spaces quickly overturned that belief 11 and established that kinetic stability dominates over thermodynamic stability in these types of metastable open framework solids. 12 Over half a century of research on template-directed synthesis of zeolites had created the impression that obtaining pore sizes beyond the microporous limit of 2 nm would be impossible. However, this also proved to be wrong with the discovery that periodic mesoporous silicas (PMS) with pore sizes in the 2À50 nm range could be synthesized with supramolecular templates comprised of surfactant or block copolymer assemblies.…”

Section: The Utilization Of the Inherently Unstable Multiplymentioning

confidence: 99%

Periodic Mesoporous Hydridosilica − Synthesis of an “Impossible” Material and Its Thermal Transformation into Brightly Photoluminescent Periodic Mesoporous Nanocrystal Silicon-Silica Composite

et al. 2011

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There has always been a fascination with “impossible” compounds, ones that do not break any rules of chemical bonding or valence but whose structures are unstable and do not exist. This instability can usually be rationalized in terms of chemical or physical restrictions associated with valence electron shells, multiple bonding, oxidation states, catenation, and the inert pair effect. In the pursuit of these “impossible” materials, appropriate conditions have sometimes been found to overcome these instabilities and synthesize missing compounds, yet for others these tricks have yet to be uncovered and the materials remain elusive. In the scientifically and technologically important field of periodic mesoporous silicas (PMS), one such “impossible” material is periodic mesoporous hydridosilica (meso-HSiO1.5). It is the archetype of a completely interrupted silica open framework material: its pore walls are comprised of a three-connected three-dimensional network that should be so thermodynamically unstable that any mesopores present would immediately collapse upon removal of the mesopore template. In this study we show that meso-HSiO1.5 can be synthesized by template-directed self-assembly of HSi(OEt)3 under aqueous acid-catalyzed conditions and after template extraction remains stable to 300 °C. Above this temperature, bond redistribution reactions initiate a metamorphic transformation which eventually yields periodic mesoporous nanocrystalline silicon-silica, meso-ncSi/SiO2, a nanocomposite material in which brightly photoluminescent silicon nanocrystallites are embedded within a silica matrix throughout the mesostructure. The integration of the properties of silicon nanocrystallinity with silica mesoporosity provides a wealth of new opportunities for emerging nanotechnologies.

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Section: The Utilization Of the Inherently Unstable Multiplymentioning

confidence: 99%

Periodic Mesoporous Hydridosilica − Synthesis of an “Impossible” Material and Its Thermal Transformation into Brightly Photoluminescent Periodic Mesoporous Nanocrystal Silicon-Silica Composite

et al. 2011

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“…1 This has been achieved in crystalline zeolites 2 and in other extended networks and frameworks, such as metalorganic frameworks (MOFs), [3][4][5][6] covalent organic frameworks (COFs), 7,8 and organic polymer networks. [9][10][11] There is also growing interest in porous materials composed of discrete organic [12][13][14][15][16][17][18][19] or metal-organic [20][21][22][23] molecules.…”

Section: Introductionmentioning

confidence: 99%

Controlling the Crystallization of Porous Organic Cages: Molecular Analogs of Isoreticular Frameworks Using Shape-Specific Directing Solvents

et al. 2014

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Small structural changes in organic molecules can have a large influence on solid-state crystal packing, and this often thwarts attempts to produce isostructural series of crystalline solids. For metal-organic frameworks and covalent organic frameworks, this has been addressed by using strong, directional intermolecular bonding to create families of isoreticular solids. Here we show that an organic directing solvent, 1,4-dioxane, has a dominant effect on the lattice energy for a series of organic cage molecules. Inclusion of dioxane directs the crystal packing for these cages away from their lowest-energy polymorphs to form isostructural, 3-dimensional diamondoid pore channels. This is a unique function of the size, chemical function, and geometry of 1,4-dioxane, and hence a non-covalent auxiliary interaction assumes the role of directional coordination bonding or covalent bonding in extended crystalline frameworks. For a new cage, CC13, a dual, interpenetrating pore structure is formed which doubles the gas uptake and the surface area in the resulting dioxanedirected crystals.

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“…In addition to diverse metal phosphates, germanates, and borates, there are sulfates, arsenates, or phosphonates as well as organicÀinorganic hybrid compounds with porous networks. 1,2 However, many microporous structures are thermally and chemically not sufficiently stable to make their way toward advanced materials. Consequently, it is worthwhile to synthesize novel open-framework materials that exhibit three-dimensional, rigid framework structures based on vertex-sharing tetrahedra.…”

Section: ' Introductionmentioning

confidence: 99%

Unprecedented Zeolite-Like Framework Topology Constructed from Cages with 3-Rings in a Barium Oxonitridophosphate

et al. 2011

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Classical zeolites, such as aluminosilicates and aluminophosphates, are well-established in fundamental industrial processes, e.g., substance separation, air and water conditioning, or catalysis. As they have the potential for further applications in future technologies (e.g., sensors, electronic, or optical systems), inorganic open-framework materials emerged as a research area with a multitude of compound classes in the last decades. In addition to diverse metal phosphates, germanates, and borates, there are sulfates, arsenates, or phosphonates as well as organicÀinorganic hybrid compounds with porous networks. 1,2 However, many microporous structures are thermally and chemically not sufficiently stable to make their way toward advanced materials. Consequently, it is worthwhile to synthesize novel open-framework materials that exhibit three-dimensional, rigid framework structures based on vertex-sharing tetrahedra. Since the discovery of the aluminophosphates by Flanigen et al. 3 in the 1980s, it has been attempted with great creativity and effort to access new stable frameworks with different pore sizes and shapes combined with varying chemical and physical properties. Different synthesis conditions (temperature, reaction time, pH), many different structure-directing agents (SDA), as well as a broad spectrum of solvents, including ionic liquids, were employed. The fluoride route 4 has been utilized, and other tetrahedra centers (e.g., B, Ga, Zn) were included, resulting in new zeotypes in compound classes like silicoaluminophosphates (SAPOs) and metal-containing versions (e.g., MeAPO, MeAPSO) thereof. 2,5 Thus, the field of zeolite chemistry seems quite mature which means that the search for new framework types becomes increasingly challenging.The exchange of oxygen by nitrogen in the anionic substructure is an innovative but rarely realized expansion of zeolite chemistry. Nitrido-zeolites promise beneficial chemical and physical properties (e.g., higher thermal stability or adjustable acidity/basicity) and a huge structural diversity. As compared with oxygen, nitrogen atoms are more common in three-binding situations, and they provide more flexibility as bridging atoms in networks by occasionally realizing smaller angles TÀXÀT (X = O, N). Consequently, both large rings as well as rare 3-rings can be stabilized so that novel zeolite-like frameworks become possible.This nitride concept became reality in (oxo-)nitridosilicates and (oxo-)nitridophosphates. After the proof of concept with nitridosodalites 6 and related oxonitridosodalites, 7 the benefits of nitrogen in zeolite-like framework structures have been demonstrated only for very few examples. Besides a zeolite-like SiÀN framework in Ba 2 Nd 7 Si 11 N 23 with a notable thermal stability up to 1600°C, 8 the flexibility of N bridging resulted in Li x H 12ÀxÀy+z - [P 12 O y N 24Ày ]X z for X = Cl, Br with a new zeolite topology, namely, NPO (nitridophosphate one). 9 The typical (ring-)strain Received: March 20, 2011 ABSTRACT: A novel oxonitridophospha...

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Open-Framework Inorganic Materials

Cited by 2,368 publications

References 180 publications

Periodic Mesoporous Hydridosilica − Synthesis of an “Impossible” Material and Its Thermal Transformation into Brightly Photoluminescent Periodic Mesoporous Nanocrystal Silicon-Silica Composite

Periodic Mesoporous Hydridosilica − Synthesis of an “Impossible” Material and Its Thermal Transformation into Brightly Photoluminescent Periodic Mesoporous Nanocrystal Silicon-Silica Composite

Controlling the Crystallization of Porous Organic Cages: Molecular Analogs of Isoreticular Frameworks Using Shape-Specific Directing Solvents

Unprecedented Zeolite-Like Framework Topology Constructed from Cages with 3-Rings in a Barium Oxonitridophosphate

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