Search

Crystalline porous materials such as covalent organic frameworks (COFs), metal-organic frameworks (MOFs) and porous organic cages (POCs) have been widely applied in various fields with outstanding performances. However, the lack of general and effective methodology for large-scale production limits their further industrial applications. In this work, we developed a general approach comprising high pressure homogenization (HPH), which can realize large-scale synthesis of crystalline porous materials including COFs, MOFs, and POCs under benign conditions. This universal strategy, as illustrated in the proof of principle studies, has prepared 4 COFs, 4 MOFs, and 2 POCs. It can circumvent some drawbacks of existing approaches including low yield, high energy consumption, low efficiency, weak mass/thermal transfer, tedious procedures, poor reproducibility, and high cost. On the basis of this approach, an industrial homogenizer can produce 0.96 ~ 580.48 ton of high-performance COFs, MOFs, and POCs per day, which is unachievable via other methods. The large-scale production of crystalline porous materials remains a challenge. Here the authors report a general approach of high-pressure homogenization that can realize large-scale synthesis of crystalline porous materials under benign conditions. [ABSTRACT FROM AUTHOR]

Developing adsorptive separation processes based on C2H6‐selective sorbents to replace energy‐intensive cryogenic distillation is a promising alternative for C2H4 purification from C2H4/C2H6 mixtures, which however remains challenging. During our studies on two isostructural metal–organic frameworks (Ni‐MOF 1 and Ni‐MOF 2), we found that Ni‐MOF 2 exhibited significantly higher performance for C2H6/C2H4 separation than Ni‐MOF‐1, as clearly established by gas sorption isotherms and breakthrough experiments. Density‐Functional Theory (DFT) studies showed that the unblocked unique aromatic pore surfaces within Ni‐MOF 2 induce more and stronger C−H⋅⋅⋅π with C2H6 over C2H4 while the suitable pore spaces enforce its high C2H6 uptake capacity, featuring Ni‐MOF 2 as one of the best porous materials for this very important gas separation. It generates 12 L kg−1 of polymer‐grade C2H4 product from equimolar C2H6/C2H4 mixtures at ambient conditions. [ABSTRACT FROM AUTHOR]

Water pollution is a growing threat to humanity due to the pervasiveness of contaminants in water bodies. Significant efforts have been made to separate these hazardous components to purify polluted water through various methods. However, conventional remediation methods suffer from limitations such as low uptake capacity or selectivity, and current water quality standards cannot be met. Recently, advanced porous materials (APMs) have shown promise in improved segregation of contaminants compared to traditional porous materials in uptake capacity and selectivity. These materials feature merits of high surface area and versatile functionality, rendering them ideal platforms for the design of novel adsorbents. This Review summarizes the development and employment of APMs in a variety of water treatments accompanied by assessments of task‐specific adsorption performance. Finally, we discuss our perspectives on future opportunities for APMs in water purification. [ABSTRACT FROM AUTHOR]

Immobilization of biomolecules into porous materials could lead to significantly enhanced performance in terms of stability towards harsh reaction conditions and easier separation for their reuse. Metal-Organic Frameworks (MOFs), offering unique structural features, have emerged as a promising platform for immobilizing large biomolecules. Although many indirect methods have been used to investigate the immobilized biomolecules for diverse applications, understanding their spatial arrangement in the pores of MOFs is still preliminary due to the difficulties in directly monitoring their conformations. To gain insights into the spatial arrangement of biomolecules within the nanopores. We used in situ small-angle neutron scattering (SANS) to probe deuterated green fluorescent protein (d-GFP) entrapped in a mesoporous MOF. Our work revealed that GFP molecules are spatially arranged in adjacent nanosized cavities of MOF-919 to form "assembly" through adsorbate-adsorbate interactions across pore apertures. Our findings, therefore, lay a crucial foundation for the identification of proteins structural basics under confinement environment of MOFs. Immobilization of biomolecules into porous materials could lead to enhanced performance in terms of stability and easier separation for their reuse. Here authors gain insights into the spatial arrangement of green fluorescent protein entrapped in a mesoporous MOF by situ small-angle neutron scattering. [ABSTRACT FROM AUTHOR]

The capture of the xenon and krypton from nuclear reprocessing off‐gas is essential to the treatment of radioactive waste. Although various porous materials have been employed to capture Xe and Kr, the development of high‐performance adsorbents capable of trapping Xe/Kr at very low partial pressure as in the nuclear reprocessing off‐gas conditions remains challenging. Herein, we report a self‐adjusting metal‐organic framework based on multiple weak binding interactions to capture trace Xe and Kr from the nuclear reprocessing off‐gas. The self‐adjusting behavior of ATC‐Cu and its mechanism have been visualized by the in‐situ single‐crystal X‐ray diffraction studies and theoretical calculations. The self‐adjusting behavior endows ATC‐Cu unprecedented uptake capacities of 2.65 and 0.52 mmol g−1 for Xe and Kr respectively at 0.1 bar and 298 K, as well as the record Xe capture capability from the nuclear reprocessing off‐gas. Our work not only provides a benchmark Xe adsorbent but proposes a new route to construct smart materials for efficient separations. [ABSTRACT FROM AUTHOR]

The enantioselective separation of racemic mixtures is highly important in the pharmaceutical, food and agrochemical sector. Metal‐organic frameworks, as a class of highly porous materials are emerging as highly efficient and selective platforms for chiral recognition and separation owing to their ultrahigh porosities, functionalized pore walls, controllable pore chemistry and presence of highly ordered chiral recognition sites. In this review, we summarize the progress made in the synthesis of chiral MOFs via direct and indirect methods, followed by their applications in some important chiral separations of alcohols, drugs, amino acids, biologically relevant molecules and important chiral organic mixtures. The developments in chiral MOF membranes as thin films for practical industrial use are also explored. Finally, the outlook for the MOFs as emerging platforms for enantioseparation and the future directions are discussed. [ABSTRACT FROM AUTHOR]

Acetylene is an important precursor in the petrochemical, plastics and electronic industries, as well as the prominent fuel for welding and metal cutting. The high flammability and explosive nature of acetylene, however hinder its safe storage and transportation. Porous materials are highly promising for acetylene storage and as they can provide strong binding interactions and an optimal pore environment. Furthermore, high selectivity and separation can be achieved for acetylene over other gases such as CO2 and small hydrocarbons. In this review, we divulge into the recent advancements and paradigms in acetylene storage and separation with a focus on porous metal‐organic frameworks (MOFs). An overview of the benchmark materials for acetylene storage and separation, along with some recent developments in the strategies to balance the trade‐off between the uptake capacity and selectivity is provided. The approaches of designing small pores and highly functionalized pore environments for strong binding with the acetylene adsorbate; along with the pore space partition, window space directed assembly and inverse CO2/C2H2 adsorption for the separation of acetylene from CO2, CH4, C2H4 and other hydrocarbons are reviewed to provide a summary and help further augment the research in this direction. [ABSTRACT FROM AUTHOR]

Porous materials with open metal sites have been investigated to separate various gas mixtures. However, open metal sites show the limitation in the separation of some challenging gas mixtures, such as C2H2/CO2. Herein, we propose a new type of ultra‐strong C2H2 nano‐trap based on multiple binding interactions to efficiently capture C2H2 molecules and separate C2H2/CO2 mixture. The ultra‐strong acetylene nano‐trap shows a benchmark Qst of 79.1 kJ mol−1 for C2H2, a record high pure C2H2 uptake of 2.54 mmol g−1 at 1×10−2 bar, and the highest C2H2/CO2 selectivity (53.6), making it as a new benchmark material for the capture of C2H2 and the separation of C2H2/CO2. The locations of C2H2 molecules within the MOF‐based nanotrap have been visualized by the in situ single‐crystal X‐ray diffraction studies, which also identify the multiple binding sites accountable for the strong interactions with C2H2. [ABSTRACT FROM AUTHOR]

The strong coordination between metal ions and binding moieties in functional porous materials is central to the design and advancement of heterogeneous catalysis. In this study, we have successfully immobilized catalytically active iridium ions on a two-dimensional covalent organic framework (COF) having bipyridine moieties using a programmed synthetic procedure. The iridium immobilized framework, Ircod(I)@Py-2,2′-BPyPh COF, had high porosity, good stability, and exhibited excellent catalytic activity for C—H borylation, as compared with the pristine framework. Additionally, Ircod(I)@Py-2,2′-BPyPh COF was found to be an efficient catalyst for a series of electronically and sterically substituted substrates. The immobilized COF possessed excellent reusability, recyclability, and retention of crystallinity. This report highlights the role of porous materials as an ideal decorating platform for conducting a wide range of potent chemical conversions. [ABSTRACT FROM AUTHOR]

Abstract: Herein, we report that a new flexible coordination network, NiL2 (L=4‐(4‐pyridyl)‐biphenyl‐4‐carboxylic acid), with diamondoid topology switches between non‐porous (closed) and several porous (open) phases at specific CO2 and CH4 pressures. These phases are manifested by multi‐step low‐pressure isotherms for CO2 or a single‐step high‐pressure isotherm for CH4. The potential methane working capacity of NiL2 approaches that of compressed natural gas but at much lower pressures. The guest‐induced phase transitions of NiL2 were studied by single‐crystal XRD, in situ variable pressure powder XRD, synchrotron powder XRD, pressure‐gradient differential scanning calorimetry (P‐DSC), and molecular modeling. The detailed structural information provides insight into the extreme flexibility of NiL2. Specifically, the extended linker ligand, L, undergoes ligand contortion and interactions between interpenetrated networks or sorbate–sorbent interactions enable the observed switching. [ABSTRACT FROM AUTHOR]

The energy costs associated with the separation and purification of industrial commodities, such as gases, fine chemicals and fresh water, currently represent around 15 per cent of global energy production, and the demand for such commodities is projected to triple by 2050 (ref. 1). The challenge of developing effective separation and purification technologies that have much smaller energy footprints is greater for carbon dioxide (CO2) than for other gases; in addition to its involvement in climate change, CO2 is an impurity in natural gas, biogas (natural gas produced from biomass), syngas (CO/H2, the main source of hydrogen in refineries) and many other gas streams. In the context of porous crystalline materials that can exploit both equilibrium and kinetic selectivity, size selectivity and targeted molecular recognition are attractive characteristics for CO2 separation and capture, as exemplified by zeolites 5A and 13X (ref. 2), as well as metal-organic materials (MOMs). Here we report that a crystal engineering or reticular chemistry strategy that controls pore functionality and size in a series of MOMs with coordinately saturated metal centres and periodically arrayed hexafluorosilicate (SiF62−) anions enables a 'sweet spot' of kinetics and thermodynamics that offers high volumetric uptake at low CO2 partial pressure (less than 0.15 bar). Most importantly, such MOMs offer an unprecedented CO2 sorption selectivity over N2, H2 and CH4, even in the presence of moisture. These MOMs are therefore relevant to CO2 separation in the context of post-combustion (flue gas, CO2/N2), pre-combustion (shifted synthesis gas stream, CO2/H2) and natural gas upgrading (natural gas clean-up, CO2/CH4). [ABSTRACT FROM AUTHOR]

Microporous metal-organic frameworks (MOFs) based on lanthanide metal ions or clusters represent a group of porous materials, featuring interesting coordination, electronic, and optical properties. These attractive properties in combination with the porosity make microporous lanthanide MOFs (Ln-MOFs) hold the promise for various applications. This review is to provide an overview of the current status of the research in microporous Ln-MOFs, and highlight their potential as types of multifunctional materials for applications in gas/solvent adsorption and separation, luminescence and chemical sensing and catalysis. [ABSTRACT FROM AUTHOR]

Three isomorphous porous metal-organic frameworks (MOFs; PCN-9 (Co/Fe/Mn)) with entatic metal centers have been constructed on the basis of the trigonal planar H[sub3]TATB ligand and a novel square-planar secondary building unit. N[sub2] adsorption isotherms at 77 K confirmed the permanent porosities of the three porous MOFs. Variable-temperature adsorption measurements of H[sub2] revealed that the H[sub2] affinities of the three porous MOFs are related to the nature of entatic metal centers, which reversely affect their H[sub2] uptake capacities. [ABSTRACT FROM AUTHOR]

Front Cover: New Paradigms in Porous Framework Materials for Acetylene Storage and Separation (Eur. J. Inorg. Acetylene separation, Acetylene storage, Binding interactions, Metal-organic frameworks, Selectivity Keywords: Acetylene separation; Acetylene storage; Binding interactions; Metal-organic frameworks; Selectivity EN Acetylene separation Acetylene storage Binding interactions Metal-organic frameworks Selectivity 4496 4496 1 11/29/21 20211125 NES 211125 B The Front Cover b shows how humans may benefit from acetylene naturally present in the solar system during astronavigation. [Extracted from the article]

Herein, we firstly develop porous organic cage (POC) as an efficient platform for highly effective radioactive iodine capture under industrial operating conditions (typically ≥150 °C), ≤150 ppmv of I2). Due to the highly dispersed and readily accessible binding sites as well as sufficient accommodating space, the constructed NKPOC‐DT‐(I−) (NKPOC=Nankai porous organic cage) demonstrates a record‐high I2 uptake capacity of 48.35 wt % and extraordinary adsorption capacity of unit ionic site (~1.62) at 150 °C and 150 ppmv of I2. The I2 capacity is 3.5, 1.6, and 1.3 times higher than industrial silver‐based adsorbents Ag@MOR and benchmark materials of TGDM and 4F‐iCOF‐TpBpy‐I− under the same conditions. Furthermore, NKPOC‐DT‐(I−)Me exhibits remarkable adsorption kinetics (k1=0.013 min−1), which is 1.2 and 1.6 times higher than TGDM and 4F‐iCOF‐TpBpy‐I− under the identical conditions. NKPOC‐DT‐(I−)Me thus sets a new benchmark for industrial radioactive I2 adsorbents. This work not only provides a new insight for effectively enhancing the adsorption capacity of unit functional sites, but also advances POC as an efficient platform for radioiodine capture in industry. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are an emerging class of functional nanostructures with intriguing properties, due to their unprecedented combination of high crystallinity, tunable pore size, large surface area, and unique molecular architecture. The range of properties characterized in COFs has rapidly expanded to include those of interest for numerous applications ranging from energy to environment. Here, a background overview is provided, consisting of a brief introduction of porous materials and the design feature of COFs. Then, recent advancements of COFs as a designer platform for a plethora of applications are emphasized together with discussions about the strategies and principles involved. Finally, challenges remaining for this type material for real applications are outlined. Covalent organic frameworks (COFs) are porous crystalline polymers with tunable composition and structural architecture, enabling precise control over functionality, density, and spatial arrangement. This universal control makes them a particularly promising platform for task‐led design. Recent advancements of COFs for numerous applications are reviewed and the challenges and opportunities associated with processing and large‐scale synthesis are discussed. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are an emerging class of functional nanostructures with intriguing properties, due to their unprecedented combination of high crystallinity, tunable pore size, large surface area, and unique molecular architecture. The enormous possible design space available within COFs provides virtually unlimited room for imagination, allowing designed incorporation of different functionalities. In article number 1801410, Qi Sun, Shengqian Ma, and co‐workers review the recent advancements of COFs for numerous applications. [ABSTRACT FROM AUTHOR]