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Adsorption‐based cooling is an energy‐efficient renewable‐energy technology that can be driven using low‐grade industrial waste heat and/or solar heat. Here, we report the first exploration of fluorocarbon adsorption using porous covalent organic polymers (COPs) for this cooling application. High fluorocarbon R134a equilibrium capacities and unique overall linear‐shaped isotherms are revealed for the materials, namely COP‐2 and COP‐3. The key role of mesoporous defects on this unusual adsorption behavior was demonstrated by molecular simulations based on atomistic defect‐containing models built for both porous COPs. Analysis of simulated R134a adsorption isotherms for various defect‐containing atomistic models of the COPs shows a direct correlation between higher fluorocarbon adsorption capacities and increasing pore volumes induced by defects. Combined with their high porosities, excellent reversibility, fast kinetics, and large operating window, these defect‐containing porous COPs are promising for adsorption‐based cooling applications. [ABSTRACT FROM AUTHOR]

Adsorption‐based cooling is an energy‐efficient renewable‐energy technology that can be driven using low‐grade industrial waste heat and/or solar heat. Here, we report the first exploration of fluorocarbon adsorption using porous covalent organic polymers (COPs) for this cooling application. High fluorocarbon R134a equilibrium capacities and unique overall linear‐shaped isotherms are revealed for the materials, namely COP‐2 and COP‐3. The key role of mesoporous defects on this unusual adsorption behavior was demonstrated by molecular simulations based on atomistic defect‐containing models built for both porous COPs. Analysis of simulated R134a adsorption isotherms for various defect‐containing atomistic models of the COPs shows a direct correlation between higher fluorocarbon adsorption capacities and increasing pore volumes induced by defects. Combined with their high porosities, excellent reversibility, fast kinetics, and large operating window, these defect‐containing porous COPs are promising for adsorption‐based cooling applications. [ABSTRACT FROM AUTHOR]

The role of nuclear quantum effects on the adsorption of molecular hydrogen in metal-organic frameworks (MOFs) has been investigated on grounds of Grand-Canonical Quantized Liquid Density- Functional Theory (GC-QLDFT) calculations. For this purpose, we have carefully validated classical H2-host interaction potentials that are obtained by fitting Born-Oppenheimer ab initio reference data. The hydrogen adsorption has first been assessed classically using Liquid Density-Functional Theory and the Grand-Canonical Monte Carlo methods. The results have been compared against the semi-classical treatment of quantum effects by applying the Feynman-Hibbs correction to the Born-Oppenheimer-derived potentials, and by explicit treatment within the GC-QLDFT. The results are compared with experimental data and indicate pronounced quantum and possibly many-particle effects. After validation calculations have been carried out for IRMOF-1 (MOF-5), GC-QLDFT is applied to study the adsorption of H2 in a series of MOFs, including IRMOF-4, -6, -8, -9, -10, -12, -14, - 16,-18, and MOF-177. Finally, we discuss the evolution of the H2 quantum fluid with increasing pressure and lowering temperature. [ABSTRACT FROM AUTHOR]

The discovery of naturally occurring linker‐based zirconium MOFs with permanent porosity and accessible functional groups remains a challenge. Using trans‐aconitic acid to assemble with Zr6 oxoclusters under green and scalable conditions, a novel microporous Zr‐aconitate framework has been prepared successfully with a high space‐time yield. This MOF is isostructural to the previously reported Zr‐fumarate, however with a smaller pore size and an abundant concentration of free acetic acid functional groups. This MOF shows an excellent chemical stability under various conditions, including boiling water, concentrated acids, and basic solution with pH below 12. Furthermore, this compound not only shows a higher carbon dioxide uptake compared to the Zr‐fumarate analogue but also exhibits a notably enhanced adsorptive selectivity for carbon dioxide over nitrogen in the entire pressure range. [ABSTRACT FROM AUTHOR]

Finding appropriate stimuli for controlling the breathing behavior of flexible metal–organic frameworks (MOFs) is highly challenging. Herein, we report the solvent‐induced changes in the particle size and stability of different breathing phases of the MIL‐53 series, a group of flexible MOFs. A water/dimethylformamide (DMF) ratio is tuned to synthesize members of the MIL‐53 series which have different behaviors. The breathing is explored by high‐pressure methane sorption tests. Increasing DMF concentration decreases MOF particle size and increases the stability of the porous phases, boosting the 5.8–65 bar sorption difference of methane, which is required for natural‐gas delivery. [ABSTRACT FROM AUTHOR]

Finding appropriate stimuli for controlling the breathing behavior of flexible metal–organic frameworks (MOFs) is highly challenging. Herein, we report the solvent‐induced changes in the particle size and stability of different breathing phases of the MIL‐53 series, a group of flexible MOFs. A water/dimethylformamide (DMF) ratio is tuned to synthesize members of the MIL‐53 series which have different behaviors. The breathing is explored by high‐pressure methane sorption tests. Increasing DMF concentration decreases MOF particle size and increases the stability of the porous phases, boosting the 5.8–65 bar sorption difference of methane, which is required for natural‐gas delivery. [ABSTRACT FROM AUTHOR]

The functionalization of the metal–organic framework MIL-47(VIV) with ligands bearing bulky functional groups (–Br or –CF3) has been envisaged as a possible route to enhance the mechanical energy storage performances of this family of hybrid porous materials. This exploratory work was carried out by coupling advanced experimental techniques (mercury intrusion and X-ray powder diffraction) supported by density functional theory calculations. MIL-47(VIV)-BDC-CF3 was demonstrated to be one of the most promising porous materials for mechanical energy-related applications with performance in terms of work energy which surpasses that of any porous solids reported so far. [ABSTRACT FROM AUTHOR]

Graphical abstract Al-MIL-53-TDC (TDC = 2,5-thiophenedicarboxylate) posses the highest value of work energy compared to the one determined for the Metal-Organic Frameworks of the MIL-53's family (MIL stands for Materials of Institut Lavoisier) revealing the influence of the organic linker on the mechanical behavior of these solids. Abstract The mechanical behavior of the recently synthesized flexible metal organic framework [Al(OH)(TDC)] with the well-known MIL-53 topology, built of 2,5-thiophenedicarboxylate (TDC2−) , OH– and Al3+ ions, named Al-MIL-53-TDC, has been explored using a combination of advanced characterization tools including mercury intrusion and high-pressure synchrotron X-ray powder diffraction, supported by Density Functional Theory calculations. This hybrid porous material was shown to exhibit a pressure-induced reversible structural contraction at ∼275 MPa associated with a unit cell volume change of ∼28.1% and a hysteresis loop once the pressure is released. This leads to an unprecedented energy work of 79 J g−1 that can be stored during one compression/decompression cycle for such a class of porous solids presenting a large-pore form ↔ closed-pore form phase transition. As such Al-MIL-53-TDC is at this time the best candidate of the MIL-53's family for a future potential application where a nano-damper is required. [ABSTRACT FROM AUTHOR]

A structure prediction tool has been developed to guide the discovery of MOF materials. This computational strategy has been trained over a series of existing MOFs and further successfully applied in tandem with an experimental effort to produce novel Zr MOFs based on naturally occurring carboxylic acids. [ABSTRACT FROM AUTHOR]

The porous metal‐organic framework (MOF) MIL‐160 [Al(OH)(O2C‐C4H2O‐CO2)] was investigated by means of high‐resolution powder X‐ray diffraction experiments using synchrotron radiation. The structures of the dehydrated, hydrated and nitrogen loaded forms of MIL‐160 are refined by the Rietveld method. The structure of the hydrated form, as postulated from solid state NMR and DFT calculations, is confirmed. The host–guest and thermal responses of this compound are also investigated. Adsorption of water is found to induce a phase transition from I41/amd (the dehydrated structure) to I41md (the hydrated structure), mediated by flexibility of the MOF framework. Water molecules were observed to arrange themselves with an ice‐like geometry. Conversely, adsorption of more weakly interacting N2 into the structure or thermal treatment (cooling the sample from 400 to 80 K) leads to no phase transition, indicating that the phase transition is induced by the strong interactions of H2O with the framework. The accuracy of the refined structures is investigated by DFT calculations, which show very small deviations in optimised atomic positions and lattice parameters. [ABSTRACT FROM AUTHOR]

Extensive damage and loss of life can be caused by tropical cyclones (TCs) that make landfall. Modelling of TC landfall probability is beneficial to insurance/re-insurance companies, decision makers, government policy and planning, and residents in coastal areas. In this study, we develop a climatological model of tropical cyclone genesis, tracks and landfall for North Indian Ocean (NIO) rim countries based on kernel density estimation, a generalised additive model (GAM) including an Euler integration step, and landfall detection using a country mask approach. Using a 35-year record (1979-2013) of tropical cyclone track observations from the Joint Typhoon Warning Centre (part of the International Best Track Archive Climate Stewardship Version 6), the GAM is fitted to the observed cyclone track velocities as a smooth function of location in each season. The distribution of cyclone genesis points is approximated by kernel density estimation. The model simulated TCs are randomly selected from the fitted kernel (TC genesis), and the cyclone paths (TC tracks), represented by the GAM together with the application of stochastic innovations at each step, are simulated to generate a suite of NIO rim landfall statistics. Three hindcast validation methods are applied to evaluate the integrity of the model. First, leave-one-out cross validation is applied whereby the country of landfall is determined by the majority vote (considering the location by only highest percentage of landfall) from the simulated tracks. Second, the probability distribution of simulated landfall is evaluated against the observed landfall. Third, the distances between the point of observed landfall and simulated landfall are compared and quantified. Overall, the model shows very good cross-validated hindcast skill of modelled landfalling cyclones against observations in each of the NIO tropical cyclone seasons and for most NIO rim countries, with only a relatively small difference in the percentage of predicted landfall locations compared with observations. [ABSTRACT FROM AUTHOR]

Hydrogenation reactions catalyzed by transition-metal-containing nanoparticles represent an important type of reaction in chemical industry. However, the modeling of these reactions in their working conditions requires much longer simulation times than what could usually be achieved with ab initio or first-principle methods. To address this problem, in this work, the density-functional-based tight-binding (DFTB) method was parameterized for hydrogenation reactions on molybdenum carbide catalysts, involving the elements C, H, Mo, O and Si. The overall quality of the DFTB parameters was tested with band structure/molecular orbital energies, molecular/crystal structures, chemisorption bond strengths, hydrogen adsorption energies, hydrogenation reaction energies, molecular vibrational frequencies, energy barriers and the structures of the transition states for systems of interest. The parameterized DFTB method gave errors of <1.45 % for bond distances of hydrocarbons and 4.86 % for non-hydrocarbons. It could reproduce the structure and vibrational frequencies (with errors of about 100 cm−1) of selected hydrocarbon–molybdenum carbide complexes obtained from DFT calculations. Good agreement was reached between DFTB and DFT on the dissociative adsorption of hydrogen on the α-Mo2C (0001) surface. For most of the hydrogenation reactions examined, DFTB showed errors of ~2 kcal/mol compared to DFT/PBE, with a few exceptions of ~5 kcal/mol. It could also describe the reaction energies, the forward and reverse energy barriers and the transition-state structures for the benzene hydrogenation reaction on a Mo38C19 cluster. [ABSTRACT FROM AUTHOR]

The solution chemistry of aluminum is highly complex and various polyoxocations are known. Here we report on the facile synthesis of a cationic Al24 cluster that forms porous salts of composition [Al24(OH)56(CH3COO)12]X4, denoted CAU‐55‐X, with X=Cl−, Br−, I−, HSO4−. Three‐dimensional electron diffraction was employed to determine the crystal structures. Various robust and mild synthesis routes for the chloride salt [Al24(OH)56(CH3COO)12]Cl4 in water were established resulting in high yields (>95 %, 215 g per batch) within minutes. Specific surface areas and H2O capacities with maximum values of up to 930 m2 g−1 and 430 mg g−1 are observed. The particle size of CAU‐55‐X can be tuned between 140 nm and 1250 nm, permitting its synthesis as stable dispersions or as highly crystalline powders. The positive surface charge of the particles, allow fast and effective adsorption of anionic dye molecules and adsorption of poly‐ and perfluoroalkyl substances (PFAS). [ABSTRACT FROM AUTHOR]

Die Chemie von Al3+‐Ionen in wässriger Lösung ist sehr komplex und führte bereits zu verschiedenen Polyoxokationen. In diesem Artikel wird die einfache Synthese von porösen Salzen der Zusammensetzung [Al24(OH)56(CH3COO)12]X4 (CAU‐55‐X, mit X=Cl−, Br−, I−, HSO4−) beschrieben, welche einen kationischen Al24‐Cluster enthalten. Die Kristallstrukturen wurden aus Elektronenbeugungsdaten bestimmt. Verschiedene Synthesewege wurden für das Chloridsalz [Al24(OH)56(CH3COO)12]Cl4 in Wasser entwickelt, die innerhalb von Minuten zu hohen Ausbeuten (>95 %, und bis zu 215 g pro Ansatz) führten. Die Verbindungen weisen spezifische Oberflächen und H2O‐Kapazitäten mit Maximalwerten von bis zu 930 m2 g−1 bzw. 430 mg g−1 auf. Die Partikelgröße von CAU‐55‐X kann zwischen 140 nm und 1250 nm eingestellt werden, wodurch die Herstellung stabiler Dispersionen oder hochkristalliner Pulver möglich ist. Die positive Oberflächenladung der Partikel ermöglicht eine schnelle und effektive Adsorption anionischer Farbstoffmoleküle und die Adsorption von per‐ und polyfluorierten Alkylverbindungen (PFAS). [ABSTRACT FROM AUTHOR]

Numerical study is performed to investigate the Non-isothermal flow in a rotating straight duct under various flow conditions. Spectral method is applied as a main tool for the numerical technique, where the Chebyshev polynomial, the Collocation methods, the Arc-length method and the Newton-Raphson method are also used as secondary tools. The characteristics of the flow mentioned above are described here. The incompressible viscous steady Non-isothermal flow through a straight duct of rectangular cross-section rotating at a constant angular velocity about the center of the duct cross-section is investigated numerically to examine the combined effects of Rotation parameter (Coriolis force), Grashof number (parameter which is used in heat, transfer studies involving free, forced or natural convection and is equql to $$\frac{{L^3 g\beta \Delta {\rm T}}} {{v^2 }}$$, where L is the characteristic length, ρ the density, g the acceleration due to gravity, β the thermal expansion coefficient, Δ T the temperature difference, μ the viscosity and ν the kinematic viscosity of the fluid. The expansion coefficient β is a measure of the rate at which the volume V of the fluid changes with temperature at a given pressure P), Prandtl number, aspect ratio and Pressure-driven parameter (centrifugal force) on the flow. We examine the structures in case of rotation of the duct axis and the Pressure-driven parameter with large aspect ratio where other parameters are fixed. The calculations are carried out for 0 ≤ T ≤ 300, 2 ≤ γ ≤ 6, G = 100, P = 7.0 and 0 ≤ P ≤ 800 by applying the Spectral method. When Ω > 0 and the rotation is in the same direction as the Coriolis force enforces the centrifugal force, multiple solutions of Non-symmetric the secondary flow patterns with 10-vortex (maximum) are obtained in case of T = 100 and 150 with large aspect ratio. The intense of the temperature field is very strong near the heated wall in all cases. Finally, the overall solutions of the problems considered in conclusion. [ABSTRACT FROM AUTHOR]

This work has been numerically studied the fluid flow structure in the presence of magnetic field through a rotating rectangular straight duct under various flow conditions. Spectral method is applied as a main tool for the numerical calculation technique, where the Chebyshev polynomial, the Collocation method and the Newton-Raphson method are also used as secondary tools. The Magnetohydrodynamics incompressible viscous steady fluid flows in a straight duct of rectangular cross-section rotating at a constant angular velocity about the center of the duct of the cross-section is numerically investigated to examine the combined effects of Magnetic parameter (M_g), Rotational Parameter (T_r), Pressure driven parameter (D_n) and aspect ratio (γ)=b/a whereas a is the half width and b is the half height of the duct cross-section, Ω is the angular velocity, μ is the viscosity, ν is the kinematic viscosity. One of the interesting phenomena of the flow is the solution curve and the flow structure. The flow structures in case of small rotation of the duct axis and the pressure gradient with small Magnetic parameter as well as large Rotational Parameter and Large Magnetic Parameter have been considered while other parameters are remain constant. The calculations are carried out for 0.1&les; M_g &les; 32000, 5&les; T_r &les; 32000, D_n = 500, 1000, 1500, 2000,9000,10000,11000,12000 and 12500 where the aspect ratio γ =1.0. [ABSTRACT FROM AUTHOR]

In their Research Article on page 18037, Guillaume Maurin, Radha Kishan Motkuri, and co-workers present experimental and computational evidence that mesoporous defects in the framework play a key role for the unique overall linear-shaped R134a adsorption isotherm and the exceptional adsorption uptake. Inside Cover: Porous Covalent Organic Polymers for Efficient Fluorocarbon-Based Adsorption Cooling (Angew. Keywords: adsorption cooling; structure defects; fluorocarbon refrigerants; porous covalent organic polymers EN adsorption cooling structure defects fluorocarbon refrigerants porous covalent organic polymers 17750 17750 1 08/05/21 20210809 NES 210809 B Defective covalent organic polymers b are promising for adsorption-based cooling applications. [Extracted from the article]

Adsorption cooling, structure defects, fluorocarbon refrigerants, porous covalent organic polymers Keywords: adsorption cooling; structure defects; fluorocarbon refrigerants; porous covalent organic polymers EN adsorption cooling structure defects fluorocarbon refrigerants porous covalent organic polymers 17894 17894 1 08/05/21 20210809 NES 210809 B Defekthaltige kovalente organische Polymere b sind vielversprechend für adsorptionsbasierte Kühlanwendungen. Innentitelbild: Porous Covalent Organic Polymers for Efficient Fluorocarbon-Based Adsorption Cooling (Angew. [Extracted from the article]

Zeolites and metal‐organic frameworks (MOFs) are considered as "competitors" for new separation processes. The production of high‐quality gasoline is currently achieved through the total isomerization process that separates pentane and hexane isomers while not reaching the ultimate goal of a research octane number (RON) higher than 92. This work demonstrates how a synergistic action of the zeolite 5A and the MIL‐160(Al) MOF leads to a novel adsorptive process for octane upgrading of gasoline through an efficient separation of isomers. This innovative mixed‐bed adsorbent strategy encompasses a thermodynamically driven separation of hexane isomers according to the degree of branching by MIL‐160(Al) coupled to a steric rejection of linear isomers by the molecular sieve zeolite 5A. Their adsorptive separation ability is further evaluated under real conditions by sorption breakthrough and continuous cyclic experiments with a mixed bed of shaped adsorbents. Remarkably, at the industrially relevant temperature of 423 K, an ideal sorption hierarchy of low RON over high RON alkanes is achieved, i.e., n‐hexane ≫ n‐pentane ≫ 2‐methylpentane > 3‐methylpentane ⋙ 2,3‐dimethylbutane > isopentane ≈ 2,2‐dimethylbutane, together with a productivity of 1.14 mol dm−3 and a high RON of 92, which is a leap‐forward compared with existing processes. [ABSTRACT FROM AUTHOR]

Zeolites and metal‐organic frameworks (MOFs) are considered as "competitors" for new separation processes. The production of high‐quality gasoline is currently achieved through the total isomerization process that separates pentane and hexane isomers while not reaching the ultimate goal of a research octane number (RON) higher than 92. This work demonstrates how a synergistic action of the zeolite 5A and the MIL‐160(Al) MOF leads to a novel adsorptive process for octane upgrading of gasoline through an efficient separation of isomers. This innovative mixed‐bed adsorbent strategy encompasses a thermodynamically driven separation of hexane isomers according to the degree of branching by MIL‐160(Al) coupled to a steric rejection of linear isomers by the molecular sieve zeolite 5A. Their adsorptive separation ability is further evaluated under real conditions by sorption breakthrough and continuous cyclic experiments with a mixed bed of shaped adsorbents. Remarkably, at the industrially relevant temperature of 423 K, an ideal sorption hierarchy of low RON over high RON alkanes is achieved, i.e., n‐hexane ≫ n‐pentane ≫ 2‐methylpentane > 3‐methylpentane ⋙ 2,3‐dimethylbutane > isopentane ≈ 2,2‐dimethylbutane, together with a productivity of 1.14 mol dm−3 and a high RON of 92, which is a leap‐forward compared with existing processes. [ABSTRACT FROM AUTHOR]

The improvement of the Total Isomerization Process (TIP) for the production of high‐quality gasoline with the ultimate goal of reaching a Research Octane Number (RON) higher than 92 requires the use of specific sorbents to separate pentane and hexane isomers into classes of linear, mono‐ and di‐branched isomers. Herein we report the design of a new multi‐cage microporous Fe(III)‐MOF (referred to as MIP‐214, MIP stands for materials of the Institute of Porous Materials of Paris) with a flu‐e topology, incorporating an asymmetric heterofunctional ditopic ligand, 4‐pyrazolecarboxylic acid, that exhibits an appropriate microporous structure for a thermodynamic‐controlled separation of hydrocarbon isomers. This MOF produced via a direct, scalable, and mild synthesis route was proven to encompass a unique separation of C5/C6 isomers by classes of low RON over high RON alkanes with a sorption hierarchy: (n‐hexane≫n‐pentane≈2‐methylpentane>3‐methylpentane)low RON≫(2,3‐dimethylbutane≈i‐pentane≈2,2‐dimethylbutane)high RON following the adsorption enthalpy sequence. We reveal for the first time that a single sorbent can efficiently separate such a complex mixture of high RON di‐branched hexane and mono‐branched pentane isomers from their low RON counterparts, which is a major achievement reported so far. [ABSTRACT FROM AUTHOR]

The improvement of the Total Isomerization Process (TIP) for the production of high‐quality gasoline with the ultimate goal of reaching a Research Octane Number (RON) higher than 92 requires the use of specific sorbents to separate pentane and hexane isomers into classes of linear, mono‐ and di‐branched isomers. Herein we report the design of a new multi‐cage microporous Fe(III)‐MOF (referred to as MIP‐214, MIP stands for materials of the Institute of Porous Materials of Paris) with a flu‐e topology, incorporating an asymmetric heterofunctional ditopic ligand, 4‐pyrazolecarboxylic acid, that exhibits an appropriate microporous structure for a thermodynamic‐controlled separation of hydrocarbon isomers. This MOF produced via a direct, scalable, and mild synthesis route was proven to encompass a unique separation of C5/C6 isomers by classes of low RON over high RON alkanes with a sorption hierarchy: (n‐hexane≫n‐pentane≈2‐methylpentane>3‐methylpentane)low RON≫(2,3‐dimethylbutane≈i‐pentane≈2,2‐dimethylbutane)high RON following the adsorption enthalpy sequence. We reveal for the first time that a single sorbent can efficiently separate such a complex mixture of high RON di‐branched hexane and mono‐branched pentane isomers from their low RON counterparts, which is a major achievement reported so far. [ABSTRACT FROM AUTHOR]

Correction for ‘Modulation of the mechanical energy storage performance of the MIL-47(VIV) metal organic framework by ligand functionalization’ by Pascal G. Yot et al., Dalton Trans., 2019, DOI: 10.1039/c8dt04214d. [ABSTRACT FROM AUTHOR]

Water adsorption/desorption isotherms of Cr-soc-MOF-1 were monitored electrically, with the translation of proton conductivity measurements to physisorption isotherms in terms of S-shape and hysteresis features revealed by volumetry. Molecular modelling further established the relationship between the evolutive water–hydrogen bonded network and the "electrical" isotherm for this water-mediated proton conducting MOF. [ABSTRACT FROM AUTHOR]

The transition-metal dichalcogenides (TMD) MoS2 and WS2 show remarkable electromechanical properties. Strain modifies the direct band gap into an indirect one, and substantial strain even induces an semiconductor-metal transition. Providing strain through mechanical contacts is difficult for TMD monolayers, but state-of-the-art for TMD nanotubes. We show using density-functional theory that similar electromechanical properties as in monolayer and bulk TMDs are found for large diameter TMD single- (SWNT) and multi-walled nanotubes (MWNTs). The semiconductor-metal transition occurs at elongations of 16%. We show that Raman signals of the in-plane and out-of-plane lattice vibrations depend significantly and linearly on the strain, showing that Raman spectroscopy is an excellent tool to determine the strain of the individual nanotubes and hence monitor the progress of nanoelectromechanical experiments in situ. TMD MWNTs show twice the electric conductance compared to SWNTs, and each wall of the MWNTs contributes to the conductance proportional to its diameter. [ABSTRACT FROM AUTHOR]

The reaction of the V‐shaped linker molecule 5‐hydroxyisophthalic acid (H2L0), with Al or Ga nitrate under almost identical reaction conditions leads to the nitration of the linker and subsequent formation of metal–organic frameworks (MOFs) with CAU‐10 or MIL‐53 type structure of composition [Al(OH)(L)], denoted as Al‐CAU‐10‐L0, 2, 4, 6 or [Ga(OH)(L)], denoted as Ga‐MIL‐53‐L2. The Al‐MOF contains the original linker L0 as well as three different nitration products (L2, L4 and L4/6), whereas the Ga‐MOF mainly incorporates the linker L2. The compositions were deduced by 1H NMR spectroscopy and confirmed by Rietveld refinement. In situ and ex situ studies were carried out to follow the nitration and crystallization, as well as the composition of the MOFs. The crystal structures were refined against powder X‐ray diffraction (PXRD) data. As anticipated, the use of the V‐shaped linker results in the formation of the CAU‐10 type structure in the Al‐MOF. Unexpectedly, the Ga‐MOF crystallizes in a MIL‐53 type structure, which is usually observed with linear or slightly bent linker molecules. To study the structure directing effect of the in situ nitrated linker, pure 2‐nitrobenzene‐1,3‐dicarboxylic acid (m‐H2BDC‐NO2) was employed which exclusively led to the formation of [Ga(OH)(C8H3NO6)] (Ga‐MIL‐53‐m‐BDC‐NO2), which is isoreticular to Ga‐MIL‐53‐L2. Density Functional Theory (DFT) calculations confirmed the higher stability of Ga‐MIL‐53‐L2 compared to Ga‐CAU‐10‐L2 and grand canonical Monte Carlo simulations (GCMC) are in agreement with the observed water adsorption isotherms of Ga‐MIL‐53‐L2. [ABSTRACT FROM AUTHOR]

Aluminium, framework flexibility, gallium, molecular simulations, water adsorption Keywords: aluminium; framework flexibility; gallium; molecular simulations; water adsorption EN aluminium framework flexibility gallium molecular simulations water adsorption 7591 7591 1 05/20/21 20210517 NES 210517 B Starting from 5-hydroxyisophthalic acid b (not shown), in situ nitration leads to different nitrated linker molecules that selectively react with Ga SP 3+ sp or Al SP 3+ sp ions to Ga-MIL-53 and Al-CAU-10 type frameworks, respectively. Cover Feature: Metal-Dependent and Selective Crystallization of CAU-10 and MIL-53 Frameworks through Linker Nitration (Chem. Eur. J. 28/2021). [Extracted from the article]