A Flexible Phosphonate Metal-Organic Framework for Enhanced Cooperative Ammonia Capture.

Ammonia (NH) production in 2023 reached 150 million tons and is associated with potential concomitant production of up to 500 million tons of CO each year. Efforts to produce green NH are compromised since it is difficult to separate using conventional condensation chillers, but in situ separation with minimal cooling is challenging. While metal-organic framework materials offer some potential, they are often unstable and decompose in the presence of caustic and corrosive NH.

Trace benzene capture by decoration of structural defects in metal-organic framework materials.

Capture of trace benzene is an important and challenging task. Metal-organic framework materials are promising sorbents for a variety of gases, but their limited capacity towards benzene at low concentration remains unresolved. Here we report the adsorption of trace benzene by decorating a structural defect in MIL-125-defect with single-atom metal centres to afford MIL-125-X (X = Mn, Fe, Co, Ni, Cu, Zn; MIL-125, TiO(OH)(BDC) where HBDC is 1,4-benzenedicarboxylic acid).

High adsorption of ammonia in a titanium-based metal-organic framework.

We report the high adsorption of NH in a titanium-based metal-organic framework, MFM-300(Ti), comprising extended [TiO] chains linked by biphenyl-3,3',5,5'-tetracarboxylate ligands. At 273 K and 1 bar, MFM-300(Ti) shows an exceptional NH uptake of 23.4 mmol g with a record-high packing density of 0.

Comprehensive Analysis of Methyl-β-D-ribofuranoside: A Multifaceted Spectroscopic and Theoretical Approach.

This study presents a comprehensive analysis of the vibrational spectra of methyl-β-D-ribofuranoside. Employing a combination of inelastic neutron scattering, Raman, and infrared spectroscopy allows for the observation of all modes regardless of the selection rules. The experimental techniques were complemented by density functional theory computational methods using both gas-phase () and solid-state (, ) approaches to provide an unambiguous assignment of the defining vibrational features.

Control of H-Related Defects in γ-MnO in a Hydrothermal Synthesis.

Manganese dioxide is a good candidate for effective energy storage and conversion as it possesses rich electrochemistry. The compound also shows a wide polymorphism. The γ-variety, an intergrowth of β- and R-MnO, has been extensively studied in several types of batteries (e.

Understanding the ZIF-L to ZIF-8 transformation from fundamentals to fully costed kilogram-scale production.

The production of MOFs at large scale in a sustainable way is key if these materials are to be exploited for their promised widespread application. Much of the published literature has focused on demonstrations of preparation routes using difficult or expensive methodologies to scale. One such MOF is nano-zeolitic imidazolate framework-8 (ZIF-8) - a material of interest for a range of possible applications.

From PEF to PBF: What difference does the longer alkyl chain make a computational spectroscopy study of poly(butylene 2,5-furandicarboxylate).

This work explores the conformational preferences and the structure-property correlations of poly(butylene 2,5-furandicarboxylate) (PBF), a longer chain analogue of the most well-known biobased polyester from the furan family, poly(ethylene 2,5-furandicarboxylate) (PEF). A thorough computational spectroscopic study-including infrared, Raman and inelastic neutron scattering spectroscopy, combined with discrete and periodic density functional theory calculations-allowed the identification of dominant structural motifs in the amorphous and crystalline regions. Discrete calculations and vibrational spectroscopy of semi-crystalline and amorphous samples strongly support the predominance of conformations of the butylene glycol fragment in both the crystalline and amorphous domains.

Direct Visualization of Supramolecular Binding and Separation of Light Hydrocarbons in MFM-300(In).

The purification of light olefins is one of the most important chemical separations globally and consumes large amounts of energy. Porous materials have the capability to improve the efficiency of this process by acting as solid, regenerable adsorbents. However, to develop translational systems, the underlying mechanisms of adsorption in porous materials must be fully understood.

High capacity ammonia adsorption in a robust metal-organic framework mediated by reversible host-guest interactions.

To understand the exceptional adsorption of ammonia (NH) in MFM-300(Sc) (19.5 mmol g at 273 K and 1 bar without hysteresis), we report a systematic investigation of the mechanism of adsorption by a combination of neutron powder diffraction, inelastic neutron scattering, synchrotron infrared microspectroscopy, and solid-state Sc NMR spectroscopy. These complementary techniques reveal the formation of reversible host-guest supramolecular interactions, which explains directly the observed excellent reversibility of this material over 90 adsorption-desorption cycles.

Spectroscopic Signatures of Hydrogen-Bonding Motifs in Protonic Ionic Liquid Systems: Insights from Diethylammonium Nitrate in the Solid State.

Diethylammonium nitrate, [N][NO], and its perdeuterated analogue, [N ] [NO], were structurally characterized and studied by infrared, Raman, and inelastic neutron scattering (INS) spectroscopy. Using these experimental data along with state-of-the-art computational materials modeling, we report unambiguous spectroscopic signatures of hydrogen-bonding interactions between the two counterions. An exhaustive assignment of the spectral features observed with each technique has been provided, and a number of distinct modes related to NH···O dynamics have been identified.

Pore Distortion in a Metal-Organic Framework for Regulated Separation of Propane and Propylene.

The development of porous solids for adsorptive separation of propylene and propane remains an important and challenging line of research. State-of-the-art sorbent materials often suffer from the trade-off between adsorption capacity and selectivity. Here, we report the regulated separation of propylene and propane in a metal-organic framework designed pore distortion.

Predicting the impact sensitivity of a polymorphic high explosive: the curious case of FOX-7.

The impact sensitivity (IS) of FOX-7 polymorphs is predicted by phonon up-pumping to decrease as layers of FOX-7 molecules flatten. Experimental validation proved anomalous owing to a phase transition during testing, raising questions regarding impact sensitivity measurement and highlighting the need for models to predict IS of polymorphic energetic materials.

Atomically Dispersed Copper Sites in a Metal-Organic Framework for Reduction of Nitrogen Dioxide.

Metal-organic framework (MOF) materials provide an excellent platform to fabricate single-atom catalysts due to their structural diversity, intrinsic porosity, and designable functionality. However, the unambiguous identification of atomically dispersed metal sites and the elucidation of their role in catalysis are challenging due to limited methods of characterization and lack of direct structural information. Here, we report a comprehensive investigation of the structure and the role of atomically dispersed copper sites in UiO-66 for the catalytic reduction of NO at ambient temperature.

Metallodrug-protein interaction probed by synchrotron terahertz and neutron scattering spectroscopy.

This experimental work applied coherent synchrotron-radiation terahertz spectroscopy and inelastic neutron scattering to address two processes directly associated with the mode of action of metal-based anticancer agents that can severely undermine chemotherapeutic treatment: drug binding to human serum albumin, occurring during intravenous drug transport, and intracellular coordination to thiol-containing biomolecules (such as metallothioneins) associated with acquired drug resistance. Cisplatin and two dinuclear platinum (Pt)- and palladium (Pd)-polyamine agents developed by this research group, which have yielded promising results toward some types of human cancers, were investigated. Complementary synchrotron-radiation-terahertz and inelastic neutron scattering data revealed protein metalation, through S- and N-donor ligands from cysteine, methionine, and histidine residues.

Purification of Propylene and Ethylene by a Robust Metal-Organic Framework Mediated by Host-Guest Interactions.

Industrial purification of propylene and ethylene requires cryogenic distillation and selective hydrogenation over palladium catalysts to remove propane, ethane and/or trace amounts of acetylene. Here, we report the excellent separation of equimolar mixtures of propylene/propane and ethylene/ethane, and of a 1/100 mixture of acetylene/ethylene by a highly robust microporous material, MFM-520, under dynamic conditions. In situ synchrotron single crystal X-ray diffraction, inelastic neutron scattering and analysis of adsorption thermodynamic parameters reveal that a series of synergistic host-guest interactions involving hydrogen bonding and π⋅⋅⋅π stacking interactions underpin the cooperative binding of alkenes within the pore.

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).

Control of zeolite microenvironment for propene synthesis from methanol.

Optimising the balance between propene selectivity, propene/ethene ratio and catalytic stability and unravelling the explicit mechanism on formation of the first carbon-carbon bond are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the nature of active sites within the pores of commercial MFI-zeolites by incorporating tantalum(V) and aluminium(III) centres into the framework. The resultant TaAlS-1 zeolite exhibits simultaneously remarkable propene selectivity (51%), propene/ethene ratio (8.

Ammonia Storage in Hydrogen Bond-Rich Microporous Polymers.

The fascinating structural flexibility of porous polymers is highly attractive because it can result in optimized materials with specific host-guest interactions. Nevertheless, the fundamental mechanisms responsible for controlling the weak interactions of these hydrogen bond-rich networks-essential for developing smart task-specific materials used in recognition, capture, and sequestration processes-remain unexplored. Herein, by systematically comparing performance changes between poly(amic acid) ()- and polycyclic imide ()-based porous polymers before and after NH adsorption, the role of hydrogen bonds in conformational lability and responsiveness toward guest molecules is highlighted.

Guest-Controlled Incommensurate Modulation in a Meta-Rigid Metal-Organic Framework Material.

Structural transitions of host systems in response to guest binding dominate many chemical processes. We report an unprecedented type of structural flexibility within a meta-rigid material, MFM-520, which exhibits a reversible periodic-to-aperiodic structural transition resulting from a drastic distortion of a [ZnON] node controlled by the specific host-guest interactions. The aperiodic crystal structure of MFM-520 has no three-dimensional (3D) lattice periodicity but shows translational symmetry in higher-dimensional (3 + 2)D space.