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The structures and properties of nano-XNH2 (X = C, Si, Ge, and Sn) are explored using Density Functional Theory (DFT). Elastic strain and width are introduced to investigate the nano-XNH2 nanosheets and nanoribbons. First, their structural parameters and lattice constants are investigated by using quadratic curve fitting methods. Second, the regulation of bandgap with the change in the elastic strain and width is investigated. The theoretical calculations show that the bandgaps of these materials can be easily modulated. Therefore, nano-XNH2 has great potential applications in stress sensors and electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this special issue, M. El-Kaderi and co-workers reported the synthesis of a redox-active pyrene-containing polyimide COF (PICOF-1) by linker exchange using an imine-linked COFs as a template (article 2200782). In order to improve the production efficiency of COFs, He and co-workers reported a "thermally promoted homogenous-floating-concentrating" strategy for the rapid synthesis of highly crystalline triazine/hydroxyl-rich COFs under mild conditions (article 2200786). Covalent organic frameworks (COFs) are a class of crystalline, porous polymers formed from the reversible covalent reactions between organic building blocks, resulting in ordered structure, permanent porosity, and topologically diversed. [Extracted from the article]

Orthogonal signal-division multiplexing (OSDM) is an attractive alternative to conventional orthogonal frequency-division multiplexing (OFDM) due to its enhanced ability in peak-to-average power ratio (PAPR) reduction. Combining OSDM with multiple-input multiple-output (MIMO) signaling has the potential to achieve high spectral and power efficiency. However, a direct channel equalization in this case incurs a cubic complexity, which may be expensive for practical use. To solve the problem, low-complexity per-vector and block equalization algorithms of MIMO-OSDM are proposed in this paper for time-invariant and time-varying channels, respectively. By exploiting the channel matrix structures, these algorithms have only a linear complexity in the transformed domain. Simulation results demonstrate their validity and the related performance comparisons. [ABSTRACT FROM AUTHOR]

Noninterpenetrating chiral porous cobalt metal-organic framework built from the coplanar triangular H3TATB ligands has been synthesized under solvothermal conditions. X-ray analysis revealed the compound crystallized in the chiral space group either P4132 or P4332, and adopted a trimetallic “hourglass” secondary building unit, in which there are two terminal Td-Co atoms and one central Oh-Co with Td-Co and Oh-Co distance about 3.604 Å. Paramagnetic behavior is observed throughout the measured temperature range of 2–300 K. Assuming a uniform isotropic interaction between the nearest neighbor Co atoms, susceptibility of the trinuclear Co2+ linear chain has been calculated by following Van Vleck’s quantum model for spin-spin couplings. The resultant fit to the data indicates an antiferromagnetic Co–Co interaction in the molecule, with coupling strength J∼-6.2×10-16 erg, θ∼-16 K. [ABSTRACT FROM AUTHOR]

Polyazamacrocycles and its functionalized derivatives have been employed recently as organic building blocks in the construction of extended metal–organic frameworks (MOFs). Incorporating azamacrocycles into the MOF architectures not only merges the chemistry of MOFs with supramolecular chemistry of the macrocycles, but also brings out novel properties from the hybrid frameworks produced. In this review, we describe recent advances of the fabrication of azamacrocycles into MOF structures along with the most prominent applications based upon azamacrocycle-containing MOFs, which include molecular recognition and separation, template synthesis, gas adsorption, and heterogenous catalysis. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have attracted great attention as a new type of prospective material with various merits and functionalities. MOFs can either act as biomimetic catalysts to mimic enzymatic activities or serve as hosts to encapsulate bio-active species for biomimetic catalysis. However, in comparison with the dramatic development of MOFs in other catalytic fields, MOF-based biomimetic catalysis is still in its infancy and is yet to be systematically and comprehensively explored. Herein, the principles and strategies for the design and synthesis of MOF-based biomimetic catalysts, especially the structural features of representative MOFs that are related to biomimetic catalysis, are summarized and reviewed. In addition, recent advances in biomimetic catalysis of MOFs and the relationships between their catalytic performances and the structural specificities are discussed in detail as well. [ABSTRACT FROM AUTHOR]

The theoretical calculations indicate that the metal-doped boron nitride (BN) sheets are potential materials to store the hydrogen and tune the bandgap. It is all known that the BN sheet is a nonmagnetic wide-bandgap semiconductor. Using density function theory (DFT), the lattice parameters of Cr-doped BN sheets are optimized, which are still kept on two-dimensional (2D) planar geometry, and the bandgap and storage are studied. The simulation results show that the molecule can be easily absorbed by Cr-doped N in BN sheet. As the adsorption energy was greatly decreasing with the increasing number of Cr-doped N, B had an affinity for adsorption of . With the increase of Cr doping, the bandgap of Cr-doped BN sheet is decreasing. The bandgap decreases from 4.705 eV to 0.08 eV. So Cr-doped BN sheet is a promising material in storing and tuning the bandgap. [ABSTRACT FROM AUTHOR]

In this review, we systematically summarize our recent work on how metal-organic frameworks (MOFs) are constructed via custom design of organic ligands and beyond. Following a brief introduction of basic concepts and general background of MOFs, we explain how to fine-tune MOFs' structures via the design strategy of network, secondary building unit (SBU), and ligand. Amongst these, the custom design of organic ligands plays a fundamental yet important role in this field. In addition, the custom-designed ligands, which feature certain functional motifs, can further enrich the performances of targeted MOFs owing to the primary functionalities bestowed on the frameworks by the ligands. Therefore, the custom design of organic ligands and beyond can be a useful approach to task-specifical functionalizing of the frameworks. [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]

The theoretical calculations indicate that the metal doped BN sheets are potential materials to store the hydrogen and tune the band gap. The BN sheet is a nonmagnetic wide-band-gap semiconductor. We predict that 2D h-BN-like sheet material (h-ScN sheet) has special properties, above all, strong adsorption H 2 , tuning the band gap and others potential properties. Using Density Functional Theory (DFT), the lattice parameters of Al/Cr doped ScN sheets are optimized, which are still kept on 2D planar geometry, and the band gap and H 2 storage are studied. The simulation results show that the ScN sheet is a nonmagnetic narrow-band-gap semiconductor, in which the band gap is only 1.130 eV. We find that the H 2 molecule can be easily absorbed by Al/Cr doped N in ScN sheet, and the band gap is very easy to be tuned by Al/Cr doped ScN sheet. The band gap decreases from 1.130 eV to 0.041 eV. So Al/Cr doped ScN sheet is a promising material in storage H 2 and tuning the band gap. [ABSTRACT FROM AUTHOR]

Solvothermal reactions of Cu(NO3)2 with azoxybenzene-3,3′,5,5′-tetracarboxylic acid (H4aobtc) or trans-stilbene-3,3′,5,5′-tetracarboxylic acid (H4sbtc) give rise to two isostructural microporous metal−organic frameworks, Cu2(abtc)(H2O)2·3DMA (PCN-10, abtc = azobenzene-3,3′,5,5′-tetracarboxylate) and Cu2(sbtc)(H2O)2·3DMA (PCN-11, sbtc = trans-stilbene-3,3′,5,5′-tetracarboxylate), respectively. Both PCN-10 and PCN-11 possess significant enduring porosity with Langmuir surface areas of 1779 and 2442 m2/g (corresponding to BET surface areas of 1407 or 1931 m2/g, respectively) and contain nanoscopic cages and coordinatively unsaturated metal centers. At 77 K, 760 Torr, the excess gravimetric (volumetric) hydrogen uptake of PCN-10 is 2.34 wt % (18.0 g/L) and that of PCN-11 can reach 2.55 wt % (19.1 g/L). Gas-adsorption studies also suggest that MOFs containing CC double bonds are more favorable than those with NN double bond in retaining enduring porosity after thermal activation, although NN has slightly higher H2 affinity. The excess gravimetric (volumetric) adsorption at 77 K saturates around 20 atm and reaches values of 4.33% (33.2 g/L) and 5.05% (37.8 g/L) for PCN-10 and PCN-11, respectively. In addition to its appreciable hydrogen uptake, PCN-11 has an excess methane uptake of 171 cm3(STP)/cm3 at 298 K and 35 bar, approaching the DOE target of 180 v(STP)/v for methane storage at ambient temperature. Thus, PCN-11 represents one of the few materials that is applicable to both hydrogen and methane storage applications. Two isostructural MOFs based on two predesigned double-bond-coupled bis(isophthalate) ligands, PCN-10 and PCN-11, were synthesized and structurally characterized. One of the MOFs, PCN-11 shows an excess volumetric (gravimetric) hydrogen uptake of 37.8 g/L (5.05 wt %) at 77 K and 50 bar, and an excess methane storage capacity of 171 cm3(STP)/cm3 at 298 K and 35 bar. Thus, PCN-11 represents one of the few materials that is applicable to both hydrogen and methane storage applications. [ABSTRACT FROM AUTHOR]

Cavities up to 4 nm have been introduced into a hierarchically-assembled metal–organic framework by adopting an angular, semi-flexible tetratopic ligand. The resulting MOF possesses permanent porosity and exhibits stepwise sorption isotherms for O2and N2gases. [ABSTRACT FROM AUTHOR]

A nanotubular metal–organic framework, PCN-19, was constructed based on a μ3-oxo-trinickel basic carboxylate secondary building unit (SBU) and the 9,10-anthracenedicarboxylate ligand; its permanent porosity was confirmed by N2adsorption isotherms, and its H2storage performances were evaluated under both low and high pressures at 77 K. [ABSTRACT FROM AUTHOR]

A three-dimensional porous metal-organic framework (PCN-18) was constructed through interdigitating two-dimensional grid sheets composed of 4,4'-(anthracene-9, 10-diyl)dibenzoate and copper paddIewheel secondary building units, and its dynamic features were evidenced by gas sorption isotherms. [ABSTRACT FROM AUTHOR]

Abstract: A magnesium metal–organic framework with a distorted (10,3)-a-net topology has been synthesized under solvothermal conditions, and characterized by X-ray structure determination, thermogravimetric analysis, X-ray powder diffraction, IR, and nonlinear optical studies. [Copyright &y& Elsevier]

The design and synthesis of polyhedra using coordination‐driven self‐assembly has been an intriguing research area for synthetic chemists. Metal‐organic polyhedra are a class of intricate molecular architectures that have garnered significant attention in the literature due to their diverse structures and potential applications. Hereby, we report Cu‐MOP, a bifunctional metal‐organic cuboctahedra built using 2,6‐dimethylpyridine‐3,5‐dicarboxylic acid and copper acetate at room temperature. The presence of both Lewis basic pyridine groups and Lewis acidic copper sites imparts catalytic activity to Cu‐MOP for the tandem one‐pot deacetalization‐Knoevenagel/Henry reactions. The effect of solvent system and time duration on the yields of the reactions was studied, and the results illustrate the promising potential of these metal‐organic cuboctahedra, also known as nanoballs for applications in catalysis. [ABSTRACT FROM AUTHOR]

Six novel lanthanide complexes ([Nd2(L)(H2O)6]n·4.58n(H2O) (1), [Ln(H3L)(H2O)]n·0.5n(H2O), Ln = Sm (2), Eu (3), Gd (4), Tb (5), Eu0.18Gd0.62Tb0.20 (6)) have been hydrothermally synthesized based on the ligand 4,5-di(3,5-dicarboxylphenoxy)phthalic acid (H6L). Single crystal X-ray diffraction reveals that complexes 1–6 are 2D structures, where 2–6 are isomorphic. Complexes 3 and 5 exhibit the characteristic fluorescence of Eu(III) and Tb(III) ions respectively, while complex 4 shows blue-green light emission based on the ligand. In particular, the ternary Eu/Gd/Tb complex 6 shows white light emission with a CIE (Commission International del'Eclairage) chromaticity coordinate of (0.330, 0.339) and hence close to pure white light emission. Moreover, complexes 3 and 5 display specific fluorescence-enhanced detection performance for Pb2+ ions: The interaction between Pb2+ ions and the ligand enhances the charge transfer efficiency between the ligand and the Eu(III) and Tb(III) ions and thus leads to fluorescence enhancement of complexes 3 and 5. More importantly, complex 3 exhibits the lowest detection limit of 4.72 nM for Pb2+ ions among the existing complex fluorescent probes. In addition, both complexes 3 and 5 show good performance for recycling and for the detection of Pb2+ in real water samples. [ABSTRACT FROM AUTHOR]

Chlorhexidine dodecyl sulfate (CHX-DS) was synthesized and characterized via single-crystal X-ray diffraction (SC-XRD), 1H nuclear magnetic resonance (NMR) spectroscopy, 1H nuclear Overhauser effect spectroscopy (NOESY), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). The solid-state structure, comprising a 1 : 2 stoichiometric ratio of chlorhexidine cations [C22H30Cl2N10]2+ to dodecyl sulfate anions [C12H25SO4]−, is the first report of chlorhexidine isolated with a surfactant. CHX-DS exhibits broad-spectrum antibacterial activity and demonstrates superior efficacy for reducing bacteria-generated volatile sulfur compounds (VSCs) as compared to chlorhexidine gluconate (CHG). The minimum inhibitory concentrations (MICs) of CHX-DS were 7.5, 2.5, 2.5, and 10 μM for S. enterica, E. coli, S. aureus, and S. mutans, respectively. Furthermore, MIC assays for E. coli and S. mutans demonstrate that CHX-DS and CHX exhibit a statistically significant efficacy enhancement in 2.5 μM treatment as compared to CHG. CHX-DS was incorporated into SBA-15, a mesoporous silica nanoparticle (MSN) framework, and its release was qualitatively measured via UV-vis in aqueous media, which suggests its potential as an advanced functional material for drug delivery applications. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are man-made environmental contaminants causing increasing global concern due to their adverse effect on environmental and human health. Conventional treatment methods are ineffective in removing short-chain PFAS because they are persistent and recalcitrant to treatment. This study evaluated the performance of a structurally-tunable and chemically-stable porous organic polymer (POP) for PFAS removal under realistic environmental conditions. The POP demonstrated an exceptionally high removal efficiency (>95%) within 15 min when the initial PFAS concentration was approximately 400 ng/L. The adsorption of PFAS on the POP was not significantly affected by changes in solution pH within the range of 5–9. The common co-contaminants in water competed with short-chain PFAS for active sites during the adsorption process following the order of natural organic matter (NOM), long-chain PFAS, and Cl−. The Freundlich-type model could predict the multicomponent interactions well with a R2 value above 0.91. The spent POP was effectively regenerated using a mixture of the 10% NaCl and 30% methanol solution and the PFAS removal maintained at 90% through five adsorption and desorption cycles. The characteristics of the designed POP make it a highly promising and stable absorbent. It enables fast and effective removal of short-chain PFAS. [Display omitted] • Cationic POP shows a fast adsorption rate and a high capacity for PFAS removal. • The designed POP maintained above 85% removal for PFBA at a pH range of 5–9. • The effect of the co-contaminants on PFBA removal followed the order of HA > PFOS > Cl−. • PFAS removal maintained at 90% in five consecutive adsorption/regeneration cycles. [ABSTRACT FROM AUTHOR]

Nature has long been a dominant source of inspiration in the area of chemistry, serving as prototypes for the design of materials with proficient performance. In this Feature article, we present our efforts to explore porous organic polymers (POPs) as a platform for the construction of biomimetic materials to enable new technologies to achieve efficient conversions and molecular recognition. For each aspect, we first present the chemical basis of nature, followed by depicting the principles and design strategies involved for functionalizing POPs along with a summary of critical requirements for materials, culminating in a demonstration of unique features of POPs. Our endeavours in using POPs to address the fundamental scientific problems related to biomimetic catalysis and adsorption are then illustrated to show their enormous potential and capabilities for applications ranging from concerted catalysis to radionuclide sequestration. To conclude, we present a personal perspective on the challenges and opportunities in this emerging field. [ABSTRACT FROM AUTHOR]

Zn 1-x Fe x Se thin films are synthesized for photoelectrochemical cell application using the simple and cost-effective potentiostatic electrodeposition method. The Fe2+ ions are varied from 10 to 40% concerning Zn. The Zn2+ atoms in ZnSe crystals replaced by Fe2+ ions and studied the optical, morphological, structural, photoluminescence and photoelectrochemical cell characteristics of the Zn 1-x Fe x Se based composite. The different analytical tools are used to investigate the properties of Zn 1-x Fe x Se based composite. Wettability studies of thin films are investigated using contact angle meter. The EIS technique is used to study the electrochemical properties. Photoelectrochemical cell properties are investigated using the J-V characteristic study. The variation in Fe2+ ions is responsible for the change in crystal size and morphology. Hence differences are observed in corresponding photoluminescence and photoelectrochemical cell performance. [ABSTRACT FROM AUTHOR]

The selective removal of the β‐emitting pertechnetate ion (99TcO4−) from nuclear waste streams is technically challenging. Herein, a practical approach is proposed for the selective removal of 99TcO4− (or its surrogate ReO4−) under extreme conditions of high acidity, alkalinity, ionic strength, and radiation field. Hollow porous N‐doped carbon capsules loaded with ruthenium clusters (Ru@HNCC) are first prepared, then modified with a cationic polymeric network (R) containing imidazolium‐N+ units (Ru@HNCC‐R) for selective 99TcO4− and ReO4− binding. The Ru@HNCC‐R capsules offer high binding affinities for 99TcO4−/ReO4− under wide‐ranging conditions. An electrochemical redox process then transforms adsorbed ReO4− to bulk ReO3, delivering record‐high removal capacities, fast kinetics, and excellent long‐term durability for removing ReO4− (as a proxy for 99TcO4−) in a 3 m HNO3, simulated nuclear waste‐Hanford melter recycle stream and an alkaline high‐level waste stream (HLW) at the U.S. Savannah River Site (SRS). In situ Raman and X‐ray absorption spectroscopy (XAS) analyses showed that adsorbed Re(VII) is electrocatalytically reduced on Ru sites to a Re(IV)O2 intermediate, which can then be re‐oxidized to insoluble Re(VI)O3 for facile collection. This approach overcomes many of the challenges associated with the selective separation and removal of 99TcO4−/ReO4− under extreme conditions, offering new vistas for nuclear waste management and environmental remediation. [ABSTRACT FROM AUTHOR]

An inorganic–organic hybrid probe MP-ZIF-90 was synthesized via a simple condensation reaction based on the free CHO groups of zeolitic imidazolate framework-90 (ZIF-90) and 4-methyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)pyridinium bromide (MP). This probe exhibited intense green emission, which was selectively quenched by the addition of ClO− anions. The response of probe MP-ZIF-90 toward ClO− was rapid (within 20 s) and sensitive, with a limit of detection (LOD) of 0.612 μM. Importantly, the utilization of the probe in the fluorescence imaging of ClO− anions in the mitochondria of living cells and zebrafish was demonstrated. [ABSTRACT FROM AUTHOR]

Review: 52 refs. [ABSTRACT FROM AUTHOR]

Optimizing the electronic structure of covalent organic framework (COF) photocatalysts is essential for maximizing photocatalytic activity. Herein, we report an isoreticular family of multivariate COFs containing chromenoquinoline rings in the COF structure and electron‐donating or withdrawing groups in the pores. Intramolecular donor‐acceptor (D‐A) interactions in the COFs allowed tuning of local charge distributions and charge carrier separation under visible light irradiation, resulting in enhanced photocatalytic performance. By optimizing the optoelectronic properties of the COFs, a photocatalytic uranium extraction efficiency of 8.02 mg/g/day was achieved using a nitro‐functionalized multicomponent COF in natural seawater, exceeding the performance of all COFs reported to date. Results demonstrate an effective design strategy towards high‐activity COF photocatalysts with intramolecular D‐A structures not easily accessible using traditional synthetic approaches. [ABSTRACT FROM AUTHOR]

Optimizing the electronic structure of covalent organic framework (COF) photocatalysts is essential for maximizing photocatalytic activity. Herein, we report an isoreticular family of multivariate COFs containing chromenoquinoline rings in the COF structure and electron‐donating or withdrawing groups in the pores. Intramolecular donor‐acceptor (D‐A) interactions in the COFs allowed tuning of local charge distributions and charge carrier separation under visible light irradiation, resulting in enhanced photocatalytic performance. By optimizing the optoelectronic properties of the COFs, a photocatalytic uranium extraction efficiency of 8.02 mg/g/day was achieved using a nitro‐functionalized multicomponent COF in natural seawater, exceeding the performance of all COFs reported to date. Results demonstrate an effective design strategy towards high‐activity COF photocatalysts with intramolecular D‐A structures not easily accessible using traditional synthetic approaches. [ABSTRACT FROM AUTHOR]

One striking feature of enzyme is its controllable ability to trap substrates via synergistic or cooperative binding in the enzymatic pocket, which renders the shape‐selectivity of product by the confined spatial environment. The success of shape‐selective catalysis relies on the ability of enzyme to tune the thermodynamics and kinetics for chemical reactions. In emulation of enzyme's ability, we showcase herein a targeting strategy with the substrate being anchored on the internal pore wall of metal‐organic frameworks (MOFs), taking full advantage of the sterically kinetic control to achieve shape‐selectivity for the reactions. For this purpose, a series of binding site‐accessible metal metalloporphyrin‐frameworks (MMPFs) have been investigated to shed light on the nature of enzyme‐mimic catalysis. They exhibit a different density of binding sites that are well arranged into the nanospace with corresponding distances of opposite binding sites. Such a structural specificity results in a facile switch in selectivity from an exclusive formation of the thermodynamically stable product to the kinetic product. Thus, the proposed targeting strategy, based on the combination of porous materials and binding events, paves a new way to develop highly efficient heterogeneous catalysts for shifting selectivity. [ABSTRACT FROM AUTHOR]

One striking feature of enzyme is its controllable ability to trap substrates via synergistic or cooperative binding in the enzymatic pocket, which renders the shape‐selectivity of product by the confined spatial environment. The success of shape‐selective catalysis relies on the ability of enzyme to tune the thermodynamics and kinetics for chemical reactions. In emulation of enzyme's ability, we showcase herein a targeting strategy with the substrate being anchored on the internal pore wall of metal‐organic frameworks (MOFs), taking full advantage of the sterically kinetic control to achieve shape‐selectivity for the reactions. For this purpose, a series of binding site‐accessible metal metalloporphyrin‐frameworks (MMPFs) have been investigated to shed light on the nature of enzyme‐mimic catalysis. They exhibit a different density of binding sites that are well arranged into the nanospace with corresponding distances of opposite binding sites. Such a structural specificity results in a facile switch in selectivity from an exclusive formation of the thermodynamically stable product to the kinetic product. Thus, the proposed targeting strategy, based on the combination of porous materials and binding events, paves a new way to develop highly efficient heterogeneous catalysts for shifting selectivity. [ABSTRACT FROM AUTHOR]

Tuning catalytic centers in heterogeneous catalyst, both in a chemical and a spatial manner, is a powerful approach to improve the stability and the efficiency of catalysts. While the chemical aspects are largely understood, the spatial interactions around active sites, comprised of non‐covalent interactions, are difficult to maintain and challenging to study. Herein, the unique properties of covalent organic frameworks (COFs) are utilized to establish an ideal reaction environment for the hydrolysis of cellobiose and other common disaccharides in mild, metal‐free, and neutral aqueous conditions. The chosen COF, HCl‐PSA‐IM‐COF‐OMe ("HCl" for hydrochloric acid, "PSA" for propyl sulfonic acid, "IM" for imidazole, and "OMe" for methoxy), is modified to be ultra‐stable in aqueous conditions and possesses sulfonic acid groups for general acid catalysis and for enhanced hydrogen bonding with reactants as well as intraporous chloride anions for oxocarbenium intermediate stabilization. In addition, the system also relies on the differences in adsorptive binding behavior, Kads, of the reactants and the products to the functionalized framework and benefits from a separate physical, kinetic process to boost the catalytic cycle. Due to its stability in aqueous conditions, HCl‐PSA‐IM‐COF‐OMe can be recycled and maintains its hydrolytic properties for five cycles before regeneration is needed. [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]

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]

A Zn-based porphyrin containing metal–organic material (porphMOM-1) was transformed into a novel Cu-based porphyrin-encapsulating metal–organic material (porph@HKUST-1-β) via a one-pot post-synthetic modification (PSM) process involving both metal ion exchange and linker installation of trimesic acid. HKUST-1-β is the first example of yao topology and is to our knowledge the first supramolecular isomer of the archetypal coordination network HKUST-1. [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]

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]

Asymmetric hydrogenation, a seminal strategy for the synthesis of chiral molecules, remains largely unmet in terms of activation by non‐metal sites of heterogeneous catalysts. Herein, as demonstrated by combined computational and experimental studies, we present a general strategy for integrating rationally designed molecular chiral frustrated Lewis pair (CFLP) with porous metal–organic framework (MOF) to construct the catalyst CFLP@MOF that can efficiently promote the asymmetric hydrogenation in a heterogeneous manner, which for the first time extends the concept of chiral frustrated Lewis pair from homogeneous system to heterogeneous catalysis. Significantly, the developed CFLP@MOF, inherits the merits of both homogeneous and heterogeneous catalysts, with high activity/enantio‐selectivity and excellent recyclability/regenerability. Our work not only advances CFLP@MOF as a new platform for heterogeneous asymmetric hydrogenation, but also opens a new avenue for the design and preparation of advanced catalysts for asymmetric catalysis. [ABSTRACT FROM AUTHOR]

Asymmetric hydrogenation, a seminal strategy for the synthesis of chiral molecules, remains largely unmet in terms of activation by non‐metal sites of heterogeneous catalysts. Herein, as demonstrated by combined computational and experimental studies, we present a general strategy for integrating rationally designed molecular chiral frustrated Lewis pair (CFLP) with porous metal–organic framework (MOF) to construct the catalyst CFLP@MOF that can efficiently promote the asymmetric hydrogenation in a heterogeneous manner, which for the first time extends the concept of chiral frustrated Lewis pair from homogeneous system to heterogeneous catalysis. Significantly, the developed CFLP@MOF, inherits the merits of both homogeneous and heterogeneous catalysts, with high activity/enantio‐selectivity and excellent recyclability/regenerability. Our work not only advances CFLP@MOF as a new platform for heterogeneous asymmetric hydrogenation, but also opens a new avenue for the design and preparation of advanced catalysts for asymmetric catalysis. [ABSTRACT FROM AUTHOR]

Uranium extraction from seawater (UES), a potential approach to securing the long-term uranium supply and sustainability of nuclear energy, has experienced significant progress in the past decade. Promising adsorbents with record-high capacities have been developed by diverse innovative synthetic strategies, and scale-up marine field tests have been put forward by several countries. However, significant challenges remain in terms of the adsorbents' properties in complex marine environments, deployment methods, and the economic viability of current UES systems. This review presents an up-to-date overview of the latest advancements in the UES field, highlighting new insights into the mechanistic basis of UES and the methodologies towards the function-oriented development of uranium adsorbents with high adsorption capacity, selectivity, biofouling resistance, and durability. A distinctive emphasis is placed on emerging electrochemical and photochemical strategies that have been employed to develop efficient UES systems. The most recent achievements in marine tests by the major countries are summarized. Challenges and perspectives related to the fundamental, technical, and engineering aspects of UES are discussed. This review is envisaged to inspire innovative ideas and bring technical solutions towards the development of technically and economically viable UES systems. [ABSTRACT FROM AUTHOR]

Seawater contains uranium at a concentration of ≈3.3 ppb, thus representing a rich and sustainable nuclear fuel source. Herein, an adsorption–electrocatalytic platform is developed for uranium extraction from seawater, comprising atomically dispersed indium anchored on hollow nitrogen‐doped carbon capsules functionalized with flexible amidoxime moieties (In–Nx–C–R, where R denotes amidoxime groups). In–Nx–C–R exhibits excellent uranyl capture properties, enabling a uranium removal rate of 6.35 mg g−1 in 24 h, representing one of the best uranium extractants reported to date. Importantly, In–Nx–C–R demonstrates exceptional selectivity for uranium extraction relative to vanadium in seawater (8.75 times more selective for the former). X‐ray absorption spectroscopy (XAS) reveals that the amidoxime groups serve as uranyl chelating sites, thus allowing selective adsorption over other ions. XAS and in situ Raman results directly indicate that the absorbed uranyl can be electrocatalytically reduced to an unstable U(V) intermediate, then re‐oxidizes to U(VI) in the form of insoluble Na2O(UO3·H2O)x for collection, through reversible single electron transfer processes involving InNx sites. These results provide detailed mechanistic understanding of the uranium extraction process at a molecular level. This work provides a roadmap for the adsorption–electrocatalytic extraction of uranium from seawater, adding to the growing suite of technologies for harvesting valuable metals from the earth's oceans. [ABSTRACT FROM AUTHOR]

Removal of radioactive technetium‐99 (99TcO4−) from water by effective adsorbents is highly desired but remains a challenge. The currently used resin adsorbents possess several obstacles, such as slow adsorption kinetics and low adsorption capacity. To address these issues, herein a type of fibrous adsorbent with porosity and hyper‐branched quaternary ammonium groups, namely porous cationic electrospun fibers (PCE fibers), is successfully prepared. PCE fibers can remove 97% of 99TcO4− within 1 min and the equilibrium time of 99% removal is 20 min. The predicted maximum adsorption capacity toward the surrogate ReO4− can reach 826 mg g−1, which is higher than the state of art anion‐exchange resins and most of the other reported adsorbents. Furthermore, PCE fibers have good selectivity for ReO4− in the presence of competitive anions, and can retain ReO4− uptake under extreme conditions including high acid–base and gamma irradiation. Importantly, PCE fibrous adsorptive membrane is employed for dynamic ReO4− removal from simulated Hanford LAW stream with a processing capacity of 600 kg simulated stream per kilogram PCE fibers. The excellent performance highlights the advantages of PCE fibers over traditional resins in technetium removal. [ABSTRACT FROM AUTHOR]

A cationic pyridinium salt-based COF was synthesized and structurally characterized. PS-COF-1 showed the highest experimental BET surface area (2702.7 m2 g−1) reported to date for any cationic COF material. Endowed by unique structural features, PS-COF-1 showed outstanding performance for the selective adsorption of 99TcO 4 − (and ReO 4 −), suggesting great potential for 99TcO 4 − removal from nuclear wastes and in environmental remediation. [Display omitted] Ionic covalent organic framework (COF) materials with high specific surface areas and well-defined pore structures are desired for many applications yet seldom reported. Herein, we report a cationic pyridinium salt-based COF (PS-COF-1) with a Brunauer-Emmett-Teller (BET) surface area of 2703 m2 g−1, state-of-the-art for an ionic COF. Aided by its ordered pore structure, chemical stability, and radiation resistance, PS-COF-1 showed exceptional adsorption properties toward aqueous ReO 4 − (1262 mg g−1) and 99TcO 4 −. Its adsorption performance surpassed its corresponding amorphous analogue. Importantly, PS-COF-1 exhibited fast adsorption kinetics, high adsorption capacities, and selectivity for 99TcO 4 − and ReO 4 − at high ionic strengths, leading to the successful removal of 99TcO 4 − under conditions relevant to low-activity waste streams at US legacy Hanford nuclear sites. In addition, PS-COF-1 can rapidly decontaminate ReO 4 −/99TcO 4 − polluted potable water (∼10 ppb) to drinking water level (0 ppb, part per billion) within 10 min. Density functional theory (DFT) calculations revealed PS-COF-1 has a strong affinity for ReO 4 − and 99TcO 4 −, thereby favoring adsorption of these low charge density anions over other common anions (e.g., Cl−, NO 3 −, SO 4 2−, CO 3 2−). Our work demonstrates a novel cationic COF sorbent for selective radionuclide capture and legacy nuclear waste management. [ABSTRACT FROM AUTHOR]

A vast amount of energy can be extracted from the untapped low‐grade heat from sources below 100 °C and the Gibbs free energy from salinity gradients. Therefore, a process for simultaneous and direct conversion of these energies into electricity using permselective membranes was developed in this study. These membranes screen charges of ion flux driven by the combined salinity and temperature gradients to achieve thermo‐osmotic energy conversion. Increasing the charge density in the pore channels enhanced the permselectivity and ion conductance, leading to a larger osmotic voltage and current. A 14‐fold increase in power density was achieved by adjusting the ionic site population of covalent organic framework (COF) membranes. The optimal COF membrane was operated under simulated estuary conditions at a temperature difference of 60 K, which yielded a power density of ≈231 W m−2, placing it among the best performing upscaled membranes. The developed system can pave the way to the utilization of the enormous supply of untapped osmotic power and low‐grade heat energy, indicating the tremendous potential of using COF membranes for energy conversion applications. [ABSTRACT FROM AUTHOR]

A vast amount of energy can be extracted from the untapped low‐grade heat from sources below 100 °C and the Gibbs free energy from salinity gradients. Therefore, a process for simultaneous and direct conversion of these energies into electricity using permselective membranes was developed in this study. These membranes screen charges of ion flux driven by the combined salinity and temperature gradients to achieve thermo‐osmotic energy conversion. Increasing the charge density in the pore channels enhanced the permselectivity and ion conductance, leading to a larger osmotic voltage and current. A 14‐fold increase in power density was achieved by adjusting the ionic site population of covalent organic framework (COF) membranes. The optimal COF membrane was operated under simulated estuary conditions at a temperature difference of 60 K, which yielded a power density of ≈231 W m−2, placing it among the best performing upscaled membranes. The developed system can pave the way to the utilization of the enormous supply of untapped osmotic power and low‐grade heat energy, indicating the tremendous potential of using COF membranes for energy conversion applications. [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 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]

Uncontrolled mixing remains the primary hurdle impeding the practical application of reverse electrodialysis (RED) to harvest Gibbs free energy in the form of salinity gradients. Improving the permselectivity of membranes is therefore essential, with ionic density being one of the most critical factors. Herein, it is systematically investigated how the charge population in nanofluidic membranes affects the ionic charge separation and consequently the accompanying power density. To establish this relationship, the effect of the ionic density is decoupled from the impact of pore structure using a multivariate strategy to construct covalent‐organic‐framework‐based membranes, in which the content of ionic sites can be precisely manipulated from 0 to 0.18 C m−2, a range that has rarely been experimentally explored. Beyond the region reported (0.002–0.06 C m−2), wherein increasing pore surface charge density of the membrane enhances permselectivity and leads to a greater osmotic voltage, a sharp volcano‐like curve is observed. The optimal membrane affords record‐high power outputs among membrane systems, one order of magnitude higher than the value set for commercialization. The study provides insights into the impact of ionic density of the membrane on osmotic energy harvesting that can guide RED stack design to advance sustainable energy generation from natural salinity gradients. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Zr(IV)-based MOF with high-density free carboxylic groups was constructed. • The MOF demonstrates high stability and excellent uranium removal performance. • Dynamic sorption tests highlight its potential for treating radioactive wastewater. • The mechanism for its excellent ability to adsorb U(VI) was investigated. The extraction of uranium from aqueous environments, including the ocean and radioactive wastewater, represents a significant challenge with profound implications for energy resources and environmental remediation. This work presents the design and synthesis of a novel highly stable carboxylated metal–organic framework, BUT-12-3COOH, which achieves excellent U(VI) extraction ability from water. BUT-12-3COOH features high-density free carboxylic groups, exceptional chemical stability, fast kinetics, and high adsorption capacity for U(VI). Dynamic sorption experiments further demonstrated the potential of BUT-12-3COOH in treating real radioactive wastewater. The mechanisms for the U(VI) capture of BUT-12-3COOH are investigated through the combination of EDS, FT-IR, and XPS analysis. The results of this study underscore the promising utility of BUT-12-3COOH as an effective sorbent for extracting radionuclides from environmental specimens and liquid nuclear waste streams. [ABSTRACT FROM AUTHOR]

Titanium metal–organic frameworks (Ti‐MOFs), as an appealing type of artificial photocatalyst, have shown great potential in the field of solar energy conversion due to their well‐studied photoredox activity (similar to TiO2) and good optical responsiveness of linkers, which serve as the antenna to absorb visible‐light. Although much effort has been dedicated to developing Ti‐MOFs with high photocatalytic activity, their solar energy conversion performances are still poor. Herein, we have implemented a covalent‐integration strategy to construct a series of multivariate Ti‐MOF/COF hybrid materials PdTCPP⊂PCN‐415(NH2)/TpPa (composites 1, 2, and 3), featuring excellent visible‐light utilization, a suitable band gap, and high surface area for photocatalytic H2 production. Notably, the resulting composites demonstrated remarkably enhanced visible‐light‐driven photocatalytic H2 evolution performance, especially for the composite 2 with a maximum H2 evolution rate of 13.98 mmol g−1 h−1 (turnover frequency (TOF)=227 h−1), which is much higher than that of PdTCPP⊂PCN‐415(NH2) (0.21 mmol g−1 h−1) and TpPa (6.51 mmol g−1 h−1). Our work thereby suggests a new approach to highly efficient photocatalysts for H2 evolution and beyond. [ABSTRACT FROM AUTHOR]

Titanium metal–organic frameworks (Ti‐MOFs), as an appealing type of artificial photocatalyst, have shown great potential in the field of solar energy conversion due to their well‐studied photoredox activity (similar to TiO2) and good optical responsiveness of linkers, which serve as the antenna to absorb visible‐light. Although much effort has been dedicated to developing Ti‐MOFs with high photocatalytic activity, their solar energy conversion performances are still poor. Herein, we have implemented a covalent‐integration strategy to construct a series of multivariate Ti‐MOF/COF hybrid materials PdTCPP⊂PCN‐415(NH2)/TpPa (composites 1, 2, and 3), featuring excellent visible‐light utilization, a suitable band gap, and high surface area for photocatalytic H2 production. Notably, the resulting composites demonstrated remarkably enhanced visible‐light‐driven photocatalytic H2 evolution performance, especially for the composite 2 with a maximum H2 evolution rate of 13.98 mmol g−1 h−1 (turnover frequency (TOF)=227 h−1), which is much higher than that of PdTCPP⊂PCN‐415(NH2) (0.21 mmol g−1 h−1) and TpPa (6.51 mmol g−1 h−1). Our work thereby suggests a new approach to highly efficient photocatalysts for H2 evolution and beyond. [ABSTRACT FROM AUTHOR]