Structural and magnetic studies of the frustratedS = 1 kagome magnet NH4Ni2Mo2O10H3

The strong geometric frustration of the kagome antiferromagnets (KAFMs) can destabilise conventional magnetic order and lead to exotic electronic states, such as the quantum spin-liquid state observed in someS=12KAFM materials. However, the ground state ofS = 1 KAFM systems are less well understood. Spin nematic phases and valence bond solid ground states have been predicted to form but a paucity of experimental realisations restricts understanding. Here, theS = 1 KAFM NH4Ni2Mo2O10H3is presented, which has the 3-fold symmetry of the kagome lattice but significant site depletion, with∼64%site occupancy. Frustration and a competition between exchange interactions are evidenced through the suppression of order below the Weiss temperature|θW|and observation of ferromagnetic and antiferromagnetic characteristics in the magnetisation data. A semi spin glass ground state is predicted based on the ac-field frequency dependence of the magnetic transition and ferromagnetic signal.

Monitoring the Formation of Nickel-Poor and Nickel-Rich Oxide Cathode Materials for Lithium-Ion Batteries with Synchrotron Radiation

The syntheses of Ni-poor (NCM111, LiNi_1/3Co_1/3Mn_1/3O₂) and Ni-rich (NCM811 LiNi_0.8Co_0.1Mn_0.1O₂) lithium transition-metal oxides (space group R3̅m) from hydroxide precursors (Ni_1/3Co_1/3Mn_1/3(OH)₂, Ni_0.8Co_0.1Mn_0.1(OH)₂) are investigated using in situ synchrotron powder diffraction and near-edge X-ray absorption fine structure spectroscopy. The development of the layered structure of these two cathode materials proceeds via two utterly different reaction mechanisms. While the synthesis of NCM811 involves a rock salt-type intermediate phase, NCM111 reveals a layered structure throughout the entire synthesis. Moreover, the necessity and the impact of a preannealing step and a high-temperature holding step are discussed.

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. Herein, we report the adsorption and dynamic separation of C₂ and C₃ hydrocarbons in the metal-organic framework MFM-300(In), which exhibits excellent performance in the separation of mixtures of ethane/ethylene and propyne/propylene. Unusually selective adsorption of ethane over ethylene at low pressure is observed, resulting in selective retention of ethane from a mixture of ethylene/ethane, thus demonstrating its potential for a one-step purification of ethylene (purity > 99.9%). In situ neutron powder diffraction and inelastic neutron scattering reveal the preferred adsorption domains and host-guest binding dynamics of adsorption of C₂ and C₃ hydrocarbons in MFM-300(In).

Spatially Resolved Operando Synchrotron-Based X-Ray Diffraction Measurements of Ni-Rich Cathodes for Li-Ion Batteries

Understanding the performance of commercially relevant cathode materials for lithium-ion (Li-ion) batteries is vital to realize the potential of high-capacity materials for automotive applications. Of particular interest is the spatial variation of crystallographic behavior across (what can be) highly inhomogeneous electrodes. In this work, a high-resolution X-ray diffraction technique was used to obtain operando transmission measurements of Li-ion pouch cells to measure the spatial variances in the cell during electrochemical cycling. Through spatially resolved investigations of the crystallographic structures, the distribution of states of charge has been elucidated. A larger portion of the charging is accounted for by the central parts, with the edges and corners delithiating to a lesser extent for a given average electrode voltage. The cells were cycled to different upper cutoff voltages (4.2 and 4.3 V vs. graphite) and C-rates (0.5, 1, and 3C) to study the effect on the structure of the NMC811 cathode. By combining this rapid data collection method with a detailed Rietveld refinement of degraded NMC811, the spatial dependence of the degradation caused by long-term cycling (900 cycles) has also been shown. The variance shown in the pristine measurements is exaggerated in the aged cells with the edges and corners offering an even lower percentage of the charge. Measurements collected at the very edge of the cell have also highlighted the importance of electrode alignment, with a misalignment of less than 0.5 mm leading to significantly reduced electrochemical activity in that area.

1138 Complete Cycle Audit of Adults with Incapacity Documentation

Aim

The Adults with Incapacity (Scotland) Act 2000 sets out the framework for regulating intervention in the affairs of adults who have impaired capacity. A certificate of incapacity should be completed for those deem incapable to decide on their medical treatment. We aim to improve the accuracy of adults with incapacity documentation to 90% over 6 months period and

Method

Data was collected over three months, focusing on 3 domains:

The results of first cycle were discussed on the departmental meeting. Education flyers were sent to everyone in the department and put up in the doctors’ room. Data was collected again after 6 months with the same inclusion criteria.

Results

The percentage of patients with a patient with incapacity certificate has dropped to 34% from 50%. Completion of capacity assessment remained 100%. Attempt to contact relevant others has increased from 52% to 92%. Accuracy of documentation has improved to 77% from 44%.

Conclusions

The proportion of patients with a patient with incapacity certificate is in keeping with the prevalence of delirium in surgical wards. Interactive discussion and flyers improve compliances with completion of adult with incapacity certificate. Routine training should be included in departmental teaching to ensure future compliances.

Structural Features in Some Layered Hybrid Copper Chloride Perovskites: ACuCl4 or A2CuCl4

We present three new hybrid copper(II) chloride layered perovskites of generic composition ACuCl₄ or A₂CuCl₄, which exhibit three distinct structure types. (m-PdH₂)CuCl₄ (m-PdH₂²⁺ = protonated m-phenylenediamine) adopts a Dion-Jacobson (DJ)-like layered perovskite structure type and exhibits a very large axial thermal contraction effect upon heating, as revealed via variable-temperature synchrotron X-ray powder diffraction (SXRD). This can be attributed to the contraction of an interlayer block, via a slight repositioning of the m-PdH₂²⁺ moiety. (3-AbaH)₂CuCl₄ (3-AbaH⁺ = protonated 3-aminobenzoic acid) and (4-AbaH)₂CuCl₄ (4-AbaH⁺ = protonated 4-aminobenzoic acid) possess the same generic formula as Ruddlesden-Popper (RP) layered perovskites, A₂BX₄, but adopt different structures. (4-AbaH)₂CuCl₄ adopts a near-staggered structure type, whereas (3-AbaH)₂CuCl₄ adopts a near-eclipsed structure type, which resembles the DJ rather than the RP family. (3-AbaH)₂CuCl₄ also displays static disorder of the [CuCl₄]_∞ layers. The crystal structures of each are discussed in terms of the differing nature of the templating molecular species, and these are compared to related layered perovskites. Preliminary magnetic measurements are reported, suggesting dominant ferromagnetic interactions.

The Origin of Catalytic Benzylic C-H Oxidation over a Redox-Active Metal-Organic Framework

Selective oxidation of benzylic C-H compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metal catalysts. Herein, we report the efficient oxidation of benzylic C-H groups in a broad range of substrates under mild conditions over a robust metal-organic framework material, MFM-170, incorporating redox-active [Cu2 II (O2 CR)4 ] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X-ray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant t BuOOH (tert-butyl hydroperoxide) via partial reduction to [CuII CuI (O2 CR)4 ] species.

Induced Active Sites by Adsorbate in Zeotype Materials

There has been a long debate on how and where active sites are created for molecular adsorption and catalysis in zeolites, which underpin many important industrial applications. It is well accepted that Lewis acidic sites (LASs) and basic sites (LBSs) as active sites in pristine zeolites are generally believed to be the extra-framework Al species and residue anion (OH^-) species formed at fixed crystallographic positions after their synthesis. However, the dynamic interactions of adsorbates/reactants with pristine zeotype materials to "create" sites during real conditions remain largely unexplored. Herein, direct experimental observation of the establishment of induced active sites in silicoaluminophosphate (SAPO) by an adsorbate is for the first time made, which contradicts the traditional view of the fixed active sites in zeotype materials. Evidence shows that an induced frustrated Lewis pair (FLP, three-coordinated framework Al as LAS and SiO (H) as LBS) can be transiently favored for heterolytic molecular binding/reactions of competitive polar adsorbates due to their ineffective orbital overlap in the rigid framework. High-resolution magic-angle-spinning solid-state NMR, synchrotron X-ray diffraction, neutron powder diffraction, in situ diffuse reflectance infrared Fourier transform spectroscopy, and ab initio molecular dynamics demonstrate the transformation of a typical Brønsted acid site (Al(OH)Si) in SAPO zeolites to new induced FLP structure for hetereolytic binding upon adsorption of a strong polar adsorbate. Our unprecedented finding opens up a new avenue to understanding the dynamic establishment of active sites for adsorption or chemical reactions under molecular bombardment of zeolitic structures.

The Electrophilicity of Surface Carbon Species in the Redox Reactions of CuO-CeO2 Catalysts

Electronic metal–support interactions (EMSI) describe the electron flow between metal sites and a metal oxide support. It is generally used to follow the mechanism of redox reactions. In this study of CuO‐CeO₂ redox, an additional flow of electrons from metallic Cu to surface carbon species is observed via a combination of operando X‐ray absorption spectroscopy, synchrotron X‐ray powder diffraction, near ambient pressure near edge X‐ray absorption fine structure spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. An electronic metal–support–carbon interaction (EMSCI) is proposed to explain the reaction pathway of CO oxidation. The EMSCI provides a complete picture of the mass and electron flow, which will help predict and improve the catalytic performance in the selective activation of CO₂, carbonate, or carbonyl species in C1 chemistry.

[Effects of remote ischemic preconditioning on contrast-induced acute kidney injury after percutaneous coronary intervention in patients with chronic total occlusion]

Objective: To investigate the effect of remote ischemic preconditioning (RIPC) on contrast-induced acute kidney injury (CI-AKI) in patients with chronic total occlusion (CTO) after percutaneous coronary intervention (PCI). Methods: A total of 282 patients undergoing PCI at Zhongda Hospital Affiliated to Southeast University between June 2017 and January 2019 were prospectively enrolled. The patients were randomly divided into RIPC group (n=142) and control group (n=140). CI-AKI was defined as an increase in level of cystatin C (CysC)≥10% above baseline at 24 h after contrast administration. Baseline characteristics and the incidence of CI-AKI were compared between the two groups. The multivariate logistic regression analysis was further used to analyze the independent risk factors of CI-AKI. Results: There were no significant differences in age, gender, smoking, hypertension, diabetes, stroke and old myocardial infarction, coronary artery bypass graft surgery, previous PCI history and laboratory test indicators, target vessel and pathological characteristics of CTO lesions, contrast agent dosage, J-CTO (Multicenter CTO Registry in Japan) score, SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score, PCI success rate and stent number between the two groups (P>0.05). The incidence of CI-AKI was significantly lower (18.3% vs 29.3%, P=0.036) in RIPC group than that of control group. Multivariate logistic analysis found that creatinine [odds ratio (OR)=1.018,95%CI: 1.006-1.030, P=0.003], CysC (OR=5.200, 95%CI:2.714-9.963, P<0.001),contrast agent dosage (OR=1.013,95%CI: 1.007-1.019, P<0.001) and J-CTO score (OR=1.834, 95%CI: 1.145-2.939, P=0.012) were independent risk factors of CI-AKI. However, RIPC was an independent protective factor of CI-AKI (OR=0.391, 95%CI: 0.199-0.765, P=0.006). Conclusion: RIPC before contrast agent administration prevents CI-AKI in CTO patients undergoing PCI.

Responses of Defect-Rich Zr-Based Metal-Organic Frameworks toward NH3 Adsorption

Understanding structural responses of metal-organic frameworks (MOFs) to external stimuli such as the inclusion of guest molecules and temperature/pressure has gained increasing attention in many applications, for example, manipulation and manifesto smart materials for gas storage, energy storage, controlled drug delivery, tunable mechanical properties, and molecular sensing, to name but a few. Herein, neutron and synchrotron diffractions along with Rietveld refinement and density functional theory calculations have been used to elucidate the responsive adsorption behaviors of defect-rich Zr-based MOFs upon the progressive incorporation of ammonia (NH₃) and variable temperature. UiO-67 and UiO-bpydc containing biphenyl dicarboxylate and bipyridine dicarboxylate linkers, respectively, were selected, and the results establish the paramount influence of the functional linkers on their NH₃ affinity, which leads to stimulus-tailoring properties such as gate-controlled porosity by dynamic linker flipping, disorder, and structural rigidity. Despite their structural similarities, we show for the first time the dramatic alteration of NH₃ adsorption profiles when the phenyl groups are replaced by the bipyridine in the organic linker. These molecular controls stem from controlling the degree of H-bonding networks/distortions between the bipyridine scaffold and the adsorbed NH₃ without significant change in pore volume and unit cell parameters. Temperature-dependent neutron diffraction also reveals the NH₃-induced rotational motions of the organic linkers. We also demonstrate that the degree of structural flexibility of the functional linkers can critically be affected by the type and quantity of the small guest molecules. This strikes a delicate control in material properties at the molecular level.

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 (8.3) and catalytic stability (>50 h) at full methanol conversion. In situ synchrotron X-ray powder diffraction, X-ray absorption spectroscopy and inelastic neutron scattering coupled with DFT calculations reveal that the first carbon–carbon bond is formed between an activated methanol molecule and a trimethyloxonium intermediate. The unprecedented cooperativity between tantalum(V) and Brønsted acid sites creates an optimal microenvironment for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins.

Lower olefins are mainly produced from fossil resources and the methanol-to-olefins process offers a new sustainable pathway. Here, the authors show a new zeolite containing tantalum and aluminium centres which shows simultaneously high propene selectivity, catalytic activity, and stability for the synthesis of propene.

Crystallisation studies of sodium acetate trihydrate – suppression of incongruent melting and sub-cooling to produce a reliable, high-performance phase-change material

Polymer additives reliably prevent incongruent melting of sodium acetate trihydrate when temperature-cycled over multiple thousands of melting and freezing cycles.

Enhanced proton conductivity in a flexible metal–organic framework promoted by single-crystal-to-single-crystal transformation

Transformation of MFM-722(Pb)-DMA to MFM-722(Pb)-H₂O leads to an increase in proton conductivity linked to a structural transition.

Bulk fatigue induced by surface reconstruction in layered Ni-rich cathodes for Li-ion batteries

Ni-rich layered cathode materials are among the most promising candidates for high-energy-density Li-ion batteries, yet their degradation mechanisms are still poorly understood. We report a structure-driven degradation mechanism for NMC811 (LiNi_0.8Mn_0.1Co_0.1O₂), in which a proportion of the material exhibits a lowered accessible state of charge at the end of charging after repetitive cycling and becomes fatigued. Operando synchrotron long-duration X-ray diffraction enabled by a laser-thinned coin cell shows the emergence and growth in the concentration of this fatigued phase with cycle number. This degradation is structure driven and is not solely due to kinetic limitations or intergranular cracking: no bulk phase transformations, no increase in Li/Ni antisite mixing and no notable changes in the local structure or Li-ion mobility of the bulk are seen in aged NMCs. Instead, we propose that this degradation stems from the high interfacial lattice strain between the reconstructed surface and the bulk layered structure that develops when the latter is at states of charge above a distinct threshold of approximately 75%. This mechanism is expected to be universal in Ni-rich layered cathodes. Our findings provide fundamental insights into strategies to help mitigate this degradation process.

A rational study on the geometric and electronic properties of single-atom catalysts for enhanced catalytic performance

We investigate the geometric and electronic properties of single-atom catalysts (SACs) within metal-organic frameworks (MOFs) with respect to electrocatalytic CO2 reduction as a model reaction. A series of mid-to-late 3d transition metals have been immobilised within the microporous cavity of UiO-66-NH2. By employing Rietveld refinement of new-generation synchrotron diffraction, we not only identified the crystallographic and atomic parameters of the SACs that are stabilised with a robust MN(MOF) bonding of ca. 2.0 Å, but also elucidated the end-on coordination geometry with CO2. A volcano trend in the FEs of CO has been observed. In particular, the confinement effect within the rigid MOF can greatly facilitate redox hopping between the Cu SACs, rendering high FEs of CH4 and C2H4 at a current density of -100 mA cm-2. Although only demonstrated in selected SACs within UiO-66-NH2, this study sheds light on the rational engineering of molecular interactions(s) with SACs for the sustainable provision of fine chemicals.

Porous Metal-Organic Polyhedra: Morphology, Porosity, and Guest Binding

Designing porous materials which can selectively adsorb CO₂ or CH₄ is an important environmental and industrial goal which requires an understanding of the host–guest interactions involved at the atomic scale. Metal–organic polyhedra (MOPs) showing permanent porosity upon desolvation are rarely observed. We report a family of MOPs (Cu-1a, Cu-1b, Cu-2), which derive their permanent porosity from cavities between packed cages rather than from within the polyhedra. Thus, for Cu-1a, the void fraction outside the cages totals 56% with only 2% within. The relative stabilities of these MOP structures are rationalized by considering their weak nondirectional packing interactions using Hirshfeld surface analyses. The exceptional stability of Cu-1a enables a detailed structural investigation into the adsorption of CO₂ and CH₄ using in situ X-ray and neutron diffraction, coupled with DFT calculations. The primary binding sites for adsorbed CO₂ and CH₄ in Cu-1a are found to be the open metal sites and pockets defined by the faces of phenyl rings. More importantly, the structural analysis of a hydrated sample of Cu-1a reveals a strong hydrogen bond between the adsorbed CO₂ molecule and the Cu(II)-bound water molecule, shedding light on previous empirical and theoretical observations that partial hydration of metal−organic framework (MOF) materials containing open metal sites increases their uptake of CO₂. The results of the crystallographic study on MOP–gas binding have been rationalized using DFT calculations, yielding individual binding energies for the various pore environments of Cu-1a.

We report a family of metal−organic polyhedra (MOP), which derive their permanent porosity from cavities between packed cages rather than from within the polyhedra. The relative stabilities of these MOP structures are rationalized by considering their weak nondirectional packing interactions using Hirshfeld surface analysis. A detailed structural investigation into the adsorption of CO₂ and CH₄ is reported using in situ X-ray and neutron diffraction, coupled with DFT calculations.

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. Here, we demonstrate the structural stability of MFM-300(Al) in the presence of a series of industrially relevant toxic and corrosive gases, including SO₂, NO₂, and NH₃, over 4 years using long-duration synchrotron X-ray powder diffraction. Full structural analysis of gas-loaded MFM-300(Al) confirms the retention of these toxic gas molecules within the porous framework for up to 200 weeks, and cycling adsorption experiments verified the reusability of MFM-300(Al) for the capture of these toxic air pollutants.

Enantiospecificity in achiral zeolites for asymmetric catalysis

This article highlights the recent fundamental study in using achiral and chiral porous materials for the potential applications in asymmetric catalysis. Thanks to the new-generation synchrotron X-ray powder diffraction (SXRD) facilities, we reveal the presence of the unique 'chiral region' in achiral zeolites with the MFI topology. Both the inherent site-isolation effect of the active sites and internal confinement restraints in zeolites are critical for creating 'chiral regions' that can aid the design of more enantioselective catalytic reactions. We also offer an outlook on the challenges and opportunities of this research area.

Refinement of pore size at sub-angstrom precision in robust metal-organic frameworks for separation of xylenes

The demand for xylenes is projected to increase over the coming decades. The separation of xylene isomers, particularly p- and m-xylenes, is vital for the production of numerous polymers and materials. However, current state-of-the-art separation is based upon fractional crystallisation at 220 K which is highly energy intensive. Here, we report the discrimination of xylene isomers via refinement of the pore size in a series of porous metal-organic frameworks, MFM-300, at sub-angstrom precision leading to the optimal kinetic separation of all three xylene isomers at room temperature. The exceptional performance of MFM-300 for xylene separation is confirmed by dynamic ternary breakthrough experiments. In-depth structural and vibrational investigations using synchrotron X-ray diffraction and terahertz spectroscopy define the underlying host-guest interactions that give rise to the observed selectivity (p-xylene < o-xylene < m-xylene) and separation factors of 4.6-18 for p- and m-xylenes.

Evaluation of microflow configurations for scale inhibition and serial X-ray diffraction analysis of crystallization processes

The clean and reproducible conditions provided by microfluidic devices are ideal sample environments for in situ analyses of chemical and biochemical reactions and assembly processes. However, the small size of microchannels makes investigating the crystallization of poorly soluble materials on-chip challenging due to crystal nucleation and growth that result in channel fouling and blockage. Here, we demonstrate a reusable insert-based microfluidic platform for serial X-ray diffraction analysis and examine scale formation in response to continuous and segmented flow configurations across a range of temperatures. Under continuous flow, scale formation on the reactor walls begins almost immediately on mixing of the crystallizing species, which over time results in occlusion of the channel. Depletion of ions at the start of the channel results in reduced crystallization towards the end of the channel. Conversely, segmented flow can control crystallization, so it occurs entirely within the droplet. Consequently, the spatial location within the channel represents a temporal point in the crystallization process. Whilst each method can provide useful crystallographic information, time-resolved information is lost when reactor fouling occurs and changes the solution conditions with time. The flow within a single device can be manipulated to give a broad range of information addressing surface interaction or solution crystallization.

Amino Acid Residues Determine the Response of Flexible Metal-Organic Frameworks to Guests

Flexible metal-organic frameworks (MOFs) undergo structural transformations in response to physical and chemical stimuli. This is hard to control because of feedback between guest uptake and host structure change. We report a family of flexible MOFs based on derivatized amino acid linkers. Their porosity consists of a one-dimensional channel connected to three peripheral pockets. This network structure amplifies small local changes in linker conformation, which are strongly coupled to the guest packing in and the shape of the peripheral pockets, to afford large changes in the global pore geometry that can, for example, segment the pore into four isolated components. The synergy among pore volume, guest packing, and linker conformation that characterizes this family of structures can be determined by the amino acid side chain, because it is repositioned by linker torsion. The resulting control optimizes noncovalent interactions to differentiate the uptake and structure response of host-guest pairs with similar chemistries.

Dynamic Crystallization Pathways of Polymorphic Pharmaceuticals Revealed in Segmented Flow with Inline Powder X-ray Diffraction

Understanding the transitions between polymorphs is essential in the development of strategies for manufacturing and maximizing the efficiency of pharmaceuticals. However, this can be extremely challenging: crystallization can be influenced by subtle changes in environment, such as temperature and mixing intensity or even imperfections in the crystallizer walls. Here, we highlight the importance of in situ measurements in understanding crystallization mechanisms, where a segmented flow crystallizer was used to study the crystallization of the pharmaceuticals urea: barbituric acid (UBA) and carbamazepine (CBZ). The reactor provides highly reproducible reaction conditions, while in situ synchrotron powder X-ray diffraction (PXRD) enables us to monitor the evolution of this system. UBA has two polymorphs of almost equivalent free-energy and so is typically obtained as a polymorphic mixture. In situ PXRD analysis uncovered a progression of polymorphs from UBA III to the thermodynamic polymorph UBA I, where different positions along the length of the tubular flow crystallizer correspond to different reaction times. Addition of UBA I seed crystals modified this pathway such that only UBA I was observed throughout, while transformation from UBA III into UBA I still occurred in the presence of UBA III seeds. Information regarding the mixing-dependent kinetics of the CBZ form II to III transformation was also uncovered in a series of seeded and unseeded flow crystallization runs, despite atypical habit expression. These results illustrate the importance of coupling controlled reaction environments with in situ XRD to study the phase relationships in polymorphic materials.

Quantitative production of butenes from biomass-derived γ-valerolactone catalysed by hetero-atomic MFI zeolite

The efficient production of light olefins from renewable biomass is a vital and challenging target to achieve future sustainable chemical processes. Here we report a hetero-atomic MFI-type zeolite (NbAlS-1), over which aqueous solutions of γ-valerolactone (GVL), obtained from biomass-derived carbohydrates, can be quantitatively converted into butenes with a yield of >99% at ambient pressure under continuous flow conditions. NbAlS-1 incorporates simultaneously niobium(V) and aluminium(III) centres into the framework and thus has a desirable distribution of Lewis and Brønsted acid sites with optimal strength. Synchrotron X-ray diffraction and absorption spectroscopy show that there is cooperativity between Nb(V) and the Brønsted acid sites on the confined adsorption of GVL, whereas the catalytic mechanism for the conversion of the confined GVL into butenes is revealed by in situ inelastic neutron scattering, coupled with modelling. This study offers a prospect for the sustainable production of butene as a platform chemical for the manufacture of renewable materials.

Hydroxyl-rich macromolecules enable the bio-inspired synthesis of single crystal nanocomposites

Acidic macromolecules are traditionally considered key to calcium carbonate biomineralisation and have long been first choice in the bio-inspired synthesis of crystalline materials. Here, we challenge this view and demonstrate that low-charge macromolecules can vastly outperform their acidic counterparts in the synthesis of nanocomposites. Using gold nanoparticles functionalised with low charge, hydroxyl-rich proteins and homopolymers as growth additives, we show that extremely high concentrations of nanoparticles can be incorporated within calcite single crystals, while maintaining the continuity of the lattice and the original rhombohedral morphologies of the crystals. The nanoparticles are perfectly dispersed within the host crystal and at high concentrations are so closely apposed that they exhibit plasmon coupling and induce an unexpected contraction of the crystal lattice. The versatility of this strategy is then demonstrated by extension to alternative host crystals. This simple and scalable occlusion approach opens the door to a novel class of single crystal nanocomposites.

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

Emissions of SO₂ from flue gas and marine transport have detrimental impacts on the environment and human health, but SO₂ is also an important industrial feedstock if it can be recovered, stored and transported efficiently. Here we report the exceptional adsorption and separation of SO₂ in a porous material, [Cu₂(L)] (H₄L = 4',4‴-(pyridine-3,5-diyl)bis([1,1'-biphenyl]-3,5-dicarboxylic acid)), MFM-170. MFM-170 exhibits fully reversible SO₂ uptake of 17.5 mmol g^-1 at 298 K and 1.0 bar, and the SO₂ binding domains for trapped molecules within MFM-170 have been determined. We report the reversible coordination of SO₂ to open Cu(II) sites, which contributes to excellent adsorption thermodynamics and selectivities for SO₂ binding and facile regeneration of MFM-170 after desorption. MFM-170 is stable to water, acid and base and shows great promise for the dynamic separation of SO₂ from simulated flue gas mixtures, as confirmed by breakthrough experiments.

Accelerated diversification correlated with functional traits shapes extant diversity of the early divergent angiosperm family Annonaceae

A major goal of phylogenetic systematics is to understand both the patterns of diversification and the processes by which these patterns are formed. Few studies have focused on the ancient, species-rich Magnoliales clade and its diversification pattern. Within Magnoliales, the pantropically distributed Annonaceae are by far the most genus-rich and species-rich family-level clade, with c. 110 genera and c. 2,400 species. We investigated the diversification patterns across Annonaceae and identified traits that show varied associations with diversification rates using a time-calibrated phylogeny of 835 species (34.6% sampling) and 11,211 aligned bases from eight regions of the plastid genome (rbcL, matK, ndhF, psbA-trnH, trnL-F, atpB-rbcL, trnS-G, and ycf1). Twelve rate shifts were identified using BAMM: in Annona, Artabotrys, Asimina, Drepananthus, Duguetia, Goniothalamus, Guatteria, Uvaria, Xylopia, the tribes Miliuseae and Malmeeae, and the Desmos-Dasymaschalon-Friesodielsia-Monanthotaxis clade. TurboMEDUSA and method-of-moments estimator analyses showed largely congruent results. A positive relationship between species richness and diversification rate is revealed using PGLS. Our results show that the high species richness in Annonaceae is likely the result of recent increased diversification rather than the steady accumulation of species via the 'museum model'. We further explore the possible role of selected traits (habit, pollinator trapping, floral sex expression, pollen dispersal unit, anther septation, and seed dispersal unit) in shaping diversification patterns, based on inferences of BiSSE, MuSSE, HiSSE, and FiSSE analyses. Our results suggest that the liana habit, the presence of circadian pollinator trapping, androdioecy, and the dispersal of seeds as single-seeded monocarp fragments are closely correlated with higher diversification rates; pollen aggregation and anther septation, in contrast, are associated with lower diversification rates.

Visualization of the effect of additives on the nanostructures of individual bio-inspired calcite crystals

Soluble additives provide a versatile strategy for controlling crystallization processes, enabling selection of properties including crystal sizes, morphologies, and structures. The additive species can also be incorporated within the crystal lattice, leading for example to enhanced mechanical properties. However, while many techniques are available for analyzing particle shape and structure, it remains challenging to characterize the structural inhomogeneities and defects introduced into individual crystals by these additives, where these govern many important material properties. Here, we exploit Bragg coherent diffraction imaging to visualize the effects of soluble additives on the internal structures of individual crystals on the nanoscale. Investigation of bio-inspired calcite crystals grown in the presence of lysine or magnesium ions reveals that while a single dislocation is observed in calcite crystals grown in the presence of lysine, magnesium ions generate complex strain patterns. Indeed, in addition to the expected homogeneous solid solution of Mg ions in the calcite lattice, we observe two zones comprising alternating lattice contractions and relaxation, where comparable alternating layers of high magnesium calcite have been observed in many magnesium calcite biominerals. Such insight into the structures of nanocomposite crystals will ultimately enable us to understand and control their properties.

Inorganic co-crystal formation and thermal disproportionation in a dicyanometallate ‘superperovskite’

The dicyanometallate superperovskite co-crystal [NBu₄]Mn[Au(CN)₂]₃·[NBu₄]ClO₄ illustrates a new type of structural and phase complexity accessible to dicyanometallate perovskites.

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

We report a record-high SO₂ adsorption capacity of 12.3 mmol g^–1 in a robust porous material, MFM-601, at 298 K and 1.0 bar. SO₂ adsorption in MFM-601 is fully reversible and highly selective over CO₂ and N₂. The binding domains for adsorbed SO₂ and CO₂ molecules in MFM-601 have been determined by in situ synchrotron X-ray diffraction experiments, giving insights at the molecular level to the basis of the observed high selectivity.

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

MFM-300(Al) shows reversible uptake of NH3 (15.7 mmol g-1 at 273 K and 1.0 bar) over 50 cycles with an exceptional packing density of 0.62 g cm-3 at 293 K. In situ neutron powder diffraction and synchrotron FTIR micro-spectroscopy on ND3 @MFM-300(Al) confirms reversible H/D site exchange between the adsorbent and adsorbate, representing a new type of adsorption interaction.

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-CH₃, [Al(OH)(L)]Cl, [(H₂L)Cl = 3,5-dicarboxy-1-methylpyridinium chloride] and its effect on guest binding. MFM-305-CH₃ 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. This leads simultaneously to enhanced adsorption capacities and selectivities (two parameters that often change in opposite directions) for CO₂ and SO₂ in MFM-305. The host-guest binding has been comprehensively investigated by in situ synchrotron X-ray and neutron powder diffraction, inelastic neutron scattering, synchrotron infrared and ²H NMR spectroscopy and theoretical modelling to reveal the binding domains of CO₂ and SO₂ in these materials. CO₂ and SO₂ binding in MFM-305-CH₃ is shown to occur via hydrogen bonding to the methyl and aromatic-CH groups, with a long range interaction to chloride for CO₂. In MFM-305 the hydroxyl, pyridyl and aromatic C-H groups bind CO₂ and SO₂ more effectively via hydrogen bonds and dipole interactions. Post-synthetic modification via dealkylation of the as-synthesised metal-organic framework is a powerful route to the synthesis of materials incorporating active polar groups that cannot be prepared directly.

A slow-cooling-rate in situ cell for long-duration studies of mineral precipitation in cold aqueous environments on Earth and other planetary bodies

Liquid oceans and ice caps, along with ice crusts, have long been considered defining features of the Earth, but space missions and observations have shown that they are in fact common features among many of the solar system's outer planets and their satellites. Interactions with rock-forming materials have produced saline oceans not dissimilar in many respects to those on Earth, where mineral precipitation within frozen seawater plays a significant role in both determining global properties and regulating the environment in which a complex ecosystem of extremophiles exists. Since water is considered an essential ingredient for life, the presence of oceans and ice on other solar system bodies is of great astrobiological interest. However, the details surrounding mineral precipitation in freezing environments are still poorly constrained, owing to the difficulties of sampling and ex situ preservation for laboratory analysis, meaning that predictive models have limited empirical underpinnings. To address this, the design and performance characterization of a transmission-geometry sample cell for use in long-duration synchrotron X-ray powder diffraction studies of in situ mineral precipitation from aqueous ice-brine systems are presented. The cell is capable of very slow cooling rates (e.g. 0.3°C per day or less), and its performance is demonstrated with the results from a year-long study of the precipitation of the hydrated magnesium sulfate phase meridianiite (MgSO4·11H2O) from the MgSO4-H2O system. Evidence from the Mars Rover mission suggests that this hydrated phase is widespread on the present-day surface of Mars. However, as well as the predicted hexagonal ice and meridianiite phases, an additional hydrated sulfate phase and a disordered phase are observed.

Recyclable switching between nonporous and porous phases of a square lattice (sql) topology coordination network

A 2D switching material holds great potential for exceptional working capacity of gas storage.

Impact of partial interpenetration in a hybrid ultramicroporous material on C2H2/C2H4 separation performance

Phases of a 2-fold pcu hybrid ultramicroporous material (HUM), SIFSIX-14-Cu-i, exhibiting 99%, 93%, 89%, and 70% partial interpenetration have been obtained.

A gel aging effect in the synthesis of open-framework gallium phosphates: structure solution and solid-state NMR of a large-pore, open-framework material

The templated zeolite-analogue GaPO-34 (CHA structure type) crystallises from a gel precursor Ga2O3 : 2H3PO4 : 1HF : 1.7SDA : 70H2O (where SDA = structure directing agent), treated hydrothermally for 24 hours at 170 °C using either pyridine or 1-methylimizadole as SDA and one of either poorly crystalline ε-Ga2O3 or γ-Ga2O3 as gallium precursor. If the same gels are stirred for periods shorter than 2 hours but treated under identical hydrothermal conditions, then a second phase crystallises, free of GaPO-34. If β-Ga2O3 is used as a reagent only the second phase is found to crystallise, irrespective of gel aging time. The competing phase, which we denote GaPO-34A, has been structurally characterised using synchrotron powder X-ray diffraction for the pyridine material, GaPO-34A(pyr), and using single-crystal X-ray diffraction for the 1-methylimiazole material, GaPO-34A(mim). The structure of GaPO-34A(pyr), P1[combining macron], a = 10.22682(6) Å, b = 12.09585(7) Å, c = 13.86713(8) Å, α = 104.6531(4)°, β = 100.8111(6)°, γ = 102.5228(6)°, contains 7 unique gallium sites and 6 phosphorus sites, with empirical formula [Ga7P6O24(OH)2F3(H2O)2]·2(C5NH6). GaPO-34A(mim) is isostructural but is modelled as a half volume unit cell, P1[combining macron], a = 5.0991(2) Å, b = 12.0631(6) Å, c = 13.8405(9) Å, α = 104.626(5)°, β = 100.346(5)°, γ = 101.936(4)°, with a gallium and a bridging fluoride partially occupied and two partially occupied SDA sites. Solid-state 31P and 71Ga NMR spectroscopy confirms the structural complexity of GaPO-34A with signals resulting from overlapping lineshapes from multiple Ga and P sites, while 1H and 13C solid-state NMR spectra confirm the presence of the protonated SDA and provide evidence for disorder in the SDA. The protonated SDA is located in 14-ring one-dimensional channels with hydrogen bonding deduced from the SDA nitrogens to framework oxygen distances. Upon thermal treatment to investigate SDA removal, structure collapse occurs, which may be due the large number of bridging hydroxides and fluorides in the as-made material, and the unequal amounts of gallium and phosphorus present.