To date, only several microporous, and even fewer nanoporous, glasses have been produced, always via post synthesis acid treatment of phase separated dense materials, e.g. Vycor glass. In comparison, high internal surface areas are readily achieved in crystalline materials, such as metal-organic frameworks (MOFs). It has recently been discovered that a new family of melt quenched glasses can be produced from MOFs, though they have thus far have lacked the accessible and intrinsic porosity of their crystalline precursors. Here, we report the first glasses that are permanently, and reversibly porous toward incoming gases, without post synthetic treatment. We characterized the structure of these glasses using a range of experimental techniques, and demonstrate pores in the 4-8 angstrom range. The discovery of MOF-glasses with permanent accessible porosity reveals a new category of porous glass materials, that are potentially elevated beyond conventional inorganic and organic porous glasses, by their diversity and tunability.

Lichtsammelnde MOFs: Ein neues Porphyrin‐haltiges Metall‐organisches Gerüst (MOF; siehe Bild) wurde durch Hydrothermalsynthese erhalten. Die chemische und thermische Stabilität des Materials ermöglicht es, Zink nachträglich in das Porphyrin‐Zentrum einzuführen. Die photokatalytische Aktivität dieses Porphyrin‐basierten Materials im sichtbaren Bereich wird anhand der Entwicklung von Wasserstoff aus Wasser gezeigt.

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Amorphous metal–organic frameworks (MOFs) are an emerging class of materials. However, their structural characterisation represents a significant challenge. Fe‑BTC, and the commercial equivalent Basolite® F300, are MOFs with incredibly diverse catalytic ability, yet their disordered structures remain poorly understood. Here, we use advanced electron microscopy to identify a nanocomposite structure of Fe‑BTC where nanocrystalline domains are embedded within an amorphous matrix, whilst synchrotron total scattering measurements reveal the extent of local atomic order within Fe‑BTC. We use a polymerisation-based algorithm to generate an atomistic structure for Fe-BTC, the first example of this methodology applied to the amorphous MOF field outside the well-studied zeolitic imidazolate framework family. This demonstrates the applicability of this computational approach towards the modelling of other amorphous MOF systems with potential generality towards all MOF chemistries and connectivities. We find that the structures of Fe-BTC and Basolite® F300 can be represented by models containing a mixture of short- and medium-range order with a greater proportion of medium-range order in Basolite® F300 than in Fe-BTC. We conclude by discussing how our approach may allow for high-throughput computational discovery of functional, amorphous MOFs.

The majority of research into metal-organic frameworks (MOFs) focuses on their crystalline nature. Recent research has revealed solid-liquid transitions within the family, which we use here to create a class of functional, stable and porous composite materials. Described herein is the design, synthesis, and characterisation of MOF crystal-glass composites, formed by dispersing crystalline MOFs within a MOF-glass matrix. The coordinative bonding and chemical structure of a MIL-53 crystalline phase are preserved within the ZIF-62 glass matrix. Whilst separated phases, the interfacial interactions between the closely contacted microdomains improve the mechanical properties of the composite glass. More significantly, the high temperature open pore phase of MIL-53, which spontaneously transforms to a narrow pore upon cooling in the presence of water, is stabilised at room temperature in the crystalglass composite. This leads to a significant improvement of CO 2 adsorption capacity.

The majority of research into metal-organic frameworks (MOFs) focuses on their crystalline nature. However, in recent research the vitrification of a number of MOFs has been revealed. We propose that the solid-liquid phase transitions involved in MOF-glass formation can provide unique opportunities for the creation of a new class of functional, stable and porous composite materials. Described herein is the design, synthesis, and characterisation of novel metal-organic framework (MOF) crystal-glass composites, formed by dispersing crystalline MOFs within a MOF-glass matrix. We demonstrate using structural characterisation and analytical electron tomography, that the coordinative bonding and chemical structure of a MIL-53 crystalline phase are preserved within the ZIF-62 glass matrix. Whilst separated phases, the microdomains of each lie close to one another and possess interfacial interactions which improve the mechanical properties of the composite glass. More significantly, the high temperature open pore phase of MIL-53, which spontaneously transforms to a narrow pore upon cooling, is stabilized at room temperature in the crystal-glass composite. This leads to a significantly higher gas adsorption capacity for the crystal-glass composite than for either constituent phase.

Metal-organic framework crystal-glass composites (MOF-CGCs) are materials in which a crystalline MOF is dispersed within a MOF glass. In this work, we explore the room temperature stabilisation of the open-pore form of MIL-53(Al), usually observed at high-temperature, which occurs upon encapsulation within a ZIF-62(Zn) MOF glass matrix. A series of MOF-CGCs containing different loadings of MIL-53 were synthesised and characterised using X-ray diffraction and nuclear magnetic resonance spectroscopy. An upper limit of MIL-53 that can be stabilised in the composite was determined. The nanostructure of the composites was probed using pair distribution function analysis and scanning transmission electron microscopy. The distribution and integrity of the crystalline component was determined, and these findings related to the MOF-CGC gas adsorption capacity in order to identify the optimal loading necessary for maximum CO₂ sorption capacity.

<div><div><div><p>Stimuli-responsive flexible metal-organic frameworks (MOFs) remain at the forefront of porous materials research due to their enormous potential for various technological applications. Here, we introduce the concept of frustrated flexibility in MOFs, which arises from an incompatibility of intra-framework dispersion forces with the geometrical constraints of the inorganic building units. Controlled by appropriate linker functionalization with dispersion energy donating alkoxy groups, this approach results in a series of MOFs exhibiting a new type of guest- and temperature-responsive structural flexibility characterized by reversible loss and recovery of crystalline order under full retention of framework connectivity and topology. The stimuli-dependent phase change of the frustrated MOFs involves non-correlated deformations of their inorganic building unit, as probed by a combination of global and local structure techniques together with computer simulations. Frustrated flexibility may be a common phenomenon in MOF structures, which are commonly regarded as rigid, and thus may be of crucial importance for the performance of these materials in various applications.</p></div></div></div>