High Ammonia Adsorption in MFM-300 Materials: Dynamics and Charge Transfer in Host-Guest Binding.

Ammonia (NH) is a promising energy resource owing to its high hydrogen density. However, its widespread application is restricted by the lack of efficient and corrosion-resistant storage materials. Here, we report high NH adsorption in a series of robust metal-organic framework (MOF) materials, MFM-300(M) (M = Fe, V, Cr, In).

Long-Term Stability of MFM-300(Al) toward Toxic Air Pollutants.

Temperature- or pressure-swing sorption in porous metal-organic framework (MOF) materials has been proposed for new gas separation technologies. The high tunability of MOFs toward particular adsorbates and the relatively low energy penalty for system regeneration indicate that reversible physisorption in MOFs has the potential to create economic and environmental benefits compared with state-of-the-art chemisorption systems. However, for MOF-based sorbents to be commercialized, they have to show long-term stability under the conditions imposed by the application.

Reversible coordinative binding and separation of sulfur dioxide in a robust metal-organic framework with open copper sites.

Emissions of SO from flue gas and marine transport have detrimental impacts on the environment and human health, but SO is also an important industrial feedstock if it can be recovered, stored and transported efficiently. Here we report the exceptional adsorption and separation of SO in a porous material, [Cu(L)] (HL = 4',4‴-(pyridine-3,5-diyl)bis([1,1'-biphenyl]-3,5-dicarboxylic acid)), MFM-170. MFM-170 exhibits fully reversible SO uptake of 17.

Post-synthetic modulation of the charge distribution in a metal-organic framework for optimal binding of carbon dioxide and sulfur dioxide.

Modulation of pore environment is an effective strategy to optimize guest binding in porous materials. We report the post-synthetic modification of the charge distribution in a charged metal-organic framework, MFM-305-CH, [Al(OH)(L)]Cl, [(HL)Cl = 3,5-dicarboxy-1-methylpyridinium chloride] and its effect on guest binding. MFM-305-CH shows a distribution of cationic (methylpyridinium) and anionic (chloride) centers and can be modified to release free pyridyl N-centres by thermal demethylation of the 1-methylpyridinium moiety to give the neutral isostructural MFM-305.

Exceptional Adsorption and Binding of Sulfur Dioxide in a Robust Zirconium-Based Metal-Organic Framework.

We report a record-high SO adsorption capacity of 12.3 mmol g in a robust porous material, MFM-601, at 298 K and 1.0 bar.

Optimal Binding of Acetylene to a Nitro-Decorated Metal-Organic Framework.

We report the first example of crystallographic observation of acetylene binding to -NO groups in a metal-organic framework (MOF). Functionalization of MFM-102 with -NO groups on phenyl groups leads to a 15% reduction in BET surface area in MFM-102-NO. However, this is coupled to a 28% increase in acetylene adsorption to 192 cm g at 298 K and 1 bar, comparable to other leading porous materials.

Ammonia Storage by Reversible Host-Guest Site Exchange in a Robust Metal-Organic Framework.

MFM-300(Al) shows reversible uptake of NH (15.7 mmol g at 273 K and 1.0 bar) over 50 cycles with an exceptional packing density of 0.

Reversible adsorption of nitrogen dioxide within a robust porous metal-organic framework.

Nitrogen dioxide (NO) is a major air pollutant causing significant environmental and health problems. We report reversible adsorption of NO in a robust metal-organic framework. Under ambient conditions, MFM-300(Al) exhibits a reversible NO isotherm uptake of 14.

Direct observation of supramolecular binding of light hydrocarbons in vanadium(iii) and (iv) metal-organic framework materials.

Fine tuning of host-guest supramolecular interactions in porous systems enables direct control over the properties of functional materials. We report here a modification of hydrogen bonding and its effect on guest binding in a pair of redox-active metal-organic frameworks (MOFs). Oxidation of MFM-300(V) {[VIII2(OH)(L)], LH = biphenyl-3,3',5,5'-tetracarboxylic acid} is accompanied by deprotonation of the bridging hydroxyl groups to afford isostructural MFM-300(V), [VIV2O(L)].

Locating the binding domains in a highly selective mixed matrix membrane via synchrotron IR microspectroscopy.

The binding domains within a mixed matrix membrane (MMM) that is selective for CO comprising MFM-300(Al) and the polymer 6FDA-Durene-DABA have been established via in situ synchrotron IR microspectroscopy. The MOF crystals are fully accessible and play a critical role in the binding of CO, creating a selective pathway to promote permeation of CO within and through the MMM. This study reveals directly the molecular mechanism for the overall enhanced performance of this MMM in terms of permeability, solubility and selectivity for CO.

Confinement of Iodine Molecules into Triple-Helical Chains within Robust Metal-Organic Frameworks.

During nuclear waste disposal process, radioactive iodine as a fission product can be released. The widespread implementation of sustainable nuclear energy thus requires the development of efficient iodine stores that have simultaneously high capacity, stability and more importantly, storage density (and hence minimized system volume). Here, we report high I adsorption in a series of robust porous metal-organic materials, MFM-300(M) (M = Al, Sc, Fe, In).

Stepwise observation and quantification and mixed matrix membrane separation of CO within a hydroxy-decorated porous host.

The identification of preferred binding domains within a host structure provides important insights into the function of materials. State-of-the-art reports mostly focus on crystallographic studies of empty and single component guest-loaded host structures to determine the location of guests. However, measurements of material properties (, adsorption and breakthrough of substrates) are usually performed for a wide range of pressure (guest coverage) and/or using multi-component gas mixtures.

Binding CO by a Cr Metallacrown.

The {Cr } metallacrown [CrF(O C Bu) ] , containing a F-lined internal cavity, shows high selectivity for CO over N . DFT calculations and absorption studies support the multiple binding of F-groups to the C-center of CO (C⋅⋅⋅F 3.190(9)-3.

Modulating supramolecular binding of carbon dioxide in a redox-active porous metal-organic framework.

Hydrogen bonds dominate many chemical and biological processes, and chemical modification enables control and modulation of host-guest systems. Here we report a targeted modification of hydrogen bonding and its effect on guest binding in redox-active materials. MFM-300(V) {[V(OH)(L)], LH=biphenyl-3,3',5,5'-tetracarboxylic acid} can be oxidized to isostructural MFM-300(V), [VO(L)], in which deprotonation of the bridging hydroxyl groups occurs.

Unravelling exceptional acetylene and carbon dioxide adsorption within a tetra-amide functionalized metal-organic framework.

Understanding the mechanism of gas-sorbent interactions is of fundamental importance for the design of improved gas storage materials. Here we report the binding domains of carbon dioxide and acetylene in a tetra-amide functionalized metal-organic framework, MFM-188, at crystallographic resolution. Although exhibiting moderate porosity, desolvated MFM-188a exhibits exceptionally high carbon dioxide and acetylene adsorption uptakes with the latter (232 cm g at 295 K and 1 bar) being the highest value observed for porous solids under these conditions to the best of our knowledge.

Amides Do Not Always Work: Observation of Guest Binding in an Amide-Functionalized Porous Metal-Organic Framework.

An amide-functionalized metal organic framework (MOF) material, MFM-136, shows a high CO uptake of 12.6 mmol g at 20 bar and 298 K. MFM-136 is the first example of an acylamide pyrimidyl isophthalate MOF without open metal sites and, thus, provides a unique platform to study guest binding, particularly the role of free amides.