Band gap regulation of MIL-101(Fe) via pyrazine-based ligands substitution for enhanced visible-light adsorption and its photo-Fenton-like application

Regulating the photo-response region of iron metal-organic frameworks (Fe-MOFs) is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process. This study developed a novel pyrazine-based Fe-MOFs (MIL-101(Fe)-Pz) by substituting the 1,4-dicarboxybenzene acid ligands in typical MIL-101(Fe) with 2,5-pyrazinedicarboxylic acid (PzDC), in which sodium acetate was used as coordinative modulator to control the crystal size (2-3 µm). The incorporation of Fe-pyridine N coordination structures originated from PzDC ligands gave MIL-101(Fe)-Pz narrowed band gap (1.45 eV) than MIL-101(Fe) (2.54 eV) resulting in improved visible-light adsorption capacity (λ > 420 nm), and also increased the proportion of Fe(II) in the Fe-clusters. Thus MIL-101(Fe)-Pz exhibited a synergistic enhanced photo-Fenton-like catalytic performance under visible-light irradiation. The MIL-101(Fe)-Pz/H2O2/Vis system could degrade 99% of sulfamethoxazole within 30 min, which was 10-fold faster than that of the pristine MIL-101(Fe), it also effectively removed other organic micropollutants with high durability and stability. Mechanistic analysis revealed that the PzDC ligands substitution decreased the band gap of MIL-101(Fe), giving MIL-101(Fe)-Pz appropriate band structure (-0.40∼1.05 V vs. NHE) which can cover several light-driven process for the generation of reactive oxygen species, including Fe(III) reduction and H2O2 activation for accelerating •OH generation, as well as oxygen reduction reaction for generating H2O2, O2•- and 1O2. This study highlights the role of pyridine-N containing ligands in regulating the band structure of Fe-MOFs, providing valuable guidance for the design of Fe-MOFs photocatalysts.

Fabrication and evaluation of stationary phases with different morphology from two imidazole-based ligands for nonchiral and chiral electrochromatographic separation

In this work, two metal-organic porous materials from the two imidazole-based ligands (4-methylimidazole-5-carbaldehyde (aImeIm) and histidine (His)) and the same metal source (Zn(CH3COO)2·2H2O), namely His-ZIF-93 with a crystal zeolite imidazolate framework and His/aImeIm@Zn with an amorphous networks, were first designed and synthesized by the one-pot method. They were used as the stationary phases (SPs) of open-tubular capillary electrochromatography (OT-CEC) to evaluate and compare their separation performance for the nonchiral and chiral compounds. His-ZIF-93-bonded OT-CEC column successfully separated five families of nonchiral analytes due to the synergistic effect of His and the crystal framework. The separation mechanism included electrostatic interaction, molecular sieve effect, π-π interaction, electrophoretic mobility, hydrogen bonding interaction, and so on. His/aImeIm@Zn-bonded OT-CEC column exhibited a more superior enantioseparation capability for seven chiral compounds with an ultrahigh column efficiency of 7.6 × 105 plates/m due to a large number of chiral sites and the porous networks. Enantioseparation were attributed to the difference of adsorption and selectivity between the SPs and the two enantiomers through the adsorption experiments and the binding constants tests. Thus, both His-ZIF-93-bonded OT-CEC column and His/aImeIm@Zn-bonded OT-CEC column demonstrated the universality for the analytes, as well as excellent reproducibility, satisfactory stability and long lifetime.

Nanochannel functionalization using POFs: Progress and prospects

Biomimetic nanochannels, inspired by natural ion channels found in living organisms, are synthetic systems designed to replicate the highly selective and efficient ion/molecule transport processes essential for various biological functions. These artificial channels mimic the structural and functional properties of their biological counterparts, offering precise control over ion and molecular transport. Porous organic framework materials (POFs), including metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), have emerged as promising materials for functionalizing nanochannels due to their unique structures and exceptional properties. This functionalization strategy not only enhances the performance of synthetic nanochannels but also broadens their application potential across various fields. This review comprehensively examines the recent progress in the preparation and application of POFs stereoscopic-functionalized solid nanochannels. Special emphasis is placed on their practical applications, including proton conduction, ion-selective membranes, photo-responsive materials, sensing and detection, chiral separation, and catalysis. Finally, the future development prospects and challenges in this research area are discussed, highlighting opportunities for advancing the design and application of biomimetic nanochannels.

Manganese dioxide coupled metal-organic framework as mitophagy regulator alleviates periodontitis through SIRT1-FOXO3-BNIP3 signaling axis

Periodontitis is a prevalent chronic inflammatory disease characterized by alveolar bone resorption. Its progression is closely linked to oxidative stress where reactive oxygen species (ROS) generated by mitochondria exacerbate inflammation in positive feedback loops. Strategies for mitochondrial regulation hold potential for therapeutic advances. Metal-organic frameworks (MOFs) have shown promise as nanozymes for ROS scavenging. However, inability to directly regulate cellular processes to prevent further ROS production from damaged mitochondria during persistent inflammation makes MOFs insufficient in treating periodontitis. This study synthesizes MnO2@UiO-66(Ce) by introducing MnO2 within nanoscale mesoporous UiO-66 type MOFs. MnO2 coupled with Ce clusters in MOF channels, forms a superoxide dismutase/catalase cascade catalytic system. More importantnly, manganese endows the MOFs with bioactive effects which enhances mitophagy, facilitating the removal of damaged mitochondria, thereby restoring long-term cellular homeostasis. The results demonstrate that this synergistic antioxidant solution MnO2@UiO-66 restores mitochondrial homeostasis and osteogenic activity of periodontal ligament cells in vitro and alleviates inflammatory bone resorption in a ligature-induced periodontitis model in vivo. The SIRT1-FOXO3-BNIP3 signaling axis plays a key role in this process. This study may provide a design strategy that combines a highly efficient cascade catalytic system with long-term regulation of cellular homeostasis to combat oxidative stress in chronic inflammation.

Tannic acid-based bio-MOFs with antibacterial and antioxidant properties acquiring non-hemolytic and non-cytotoxic characteristics

Tannic acid (TA) based bio-metal phenolic networks (bio-MPNs) were prepared by using Cu(II), Zn(II), Bi(III), Ce(III), La(III), and Ti(IV) metal ions. TA-based bio-MPNs exhibited wedge-shaped pores between 16.4 and 25.8 nm pore size ranges. The higher gravimetric yield% was achieved for TA-Bi(III), and TA-Ti(IV) bio-MPNs with more than 90 %, and higher surface area was observed for TA-La(IIII) bio-MPNs as 56.2 m2/g with 17.3 nm average pore sizes. All TA-based MPNs are non-hemolytic with less than 5 % hemolysis ratio, whereas TA-based Bio-MPNs do not affect blood clotting with > 90 % blood clotting indexes except for TA-Cu(II) Bio-MPNs at 0.1 mg/mL concentration. Moreover, TA-Bi(III) and TA-Ce(III) Bio-MPNs were found to be safer materials showing no significant toxicity on L929 fibroblast cells at 100 μg/mL concentration, along with TA-based Bio-MPNs prepared with Cu(II), Zn(II), La(III), and Ti(IV) metal ions that could be safely used in in vivo applications at 1 μg/mL concentration. It has been proven by 2 different antioxidant tests that the prepared TA-based Bio-MPNs show antioxidant properties even if their TA-derived antioxidant properties decrease. Furthermore, all types of TA-based Bio-MPNs show great antimicrobial activity depending on the metal ion or microorganism types and the highest antibacterial/antifungal effect was determined for TA-Cu(II), and TA-Zn(II) Bio-MPNs with the lowest MBC/MFC values against Pseudomonas aeruginosa ATCC 10145, Bacillus subtilis ATCC 6633, and Candida albicans ATCC 10231.

Incorporating nickel-substituted polyoxometalate into a photoactive metal-organic framework for efficient photodegradation of thiamethoxam insecticide

Hydrogen bonding enhances the interactions between host and guest molecules and facilitates electron transfer between them. In this study, a series of hydrogen-bonded Z-scheme photocatalysts were prepared via impregnation. Nickel (Ni)-substituted polyoxometalate (POM) Na6K4[Ni4(H2O)2(PW9O34)2]∙32H2O (Ni4P2) was anchored within the pores of Zr6(μ3-OH)8(-OH)8(TBAPy)2 (NU-1000) via hydrogen bonding interactions (H4TBAPy = 1,3,6,8-tetrakis(p-benzoic acid)pyrene). Hydrogen bonding not only effectively prevented the leakage of Ni4P2 from NU-1000 pores but also facilitated electron transfer from Ni4P2 to NU-1000. The optimized 0.3-Ni4P2@NU-1000 photocatalyst delivered remarkable performance toward thiamethoxam (TMX) photodegradation, achieving a degradation efficiency of 75.1 % after 120 min. The effects of the photocatalyst dose, pH, coexisting ions, and water sample on TMX degradation were investigated. Radical scavenging experiments and electron spin resonance data revealed that superoxide radicals and holes are the primary species responsible for photodegradation. Moreover, the reaction mechanism and degradation pathways of TMX were thoroughly investigated. Density functional theory calculations confirmed that TMX is adsorbed onto Ni4P2 via hydrogen bonding, structurally changing TMX and increasing its susceptibility to degradation. Chia seed growth experiments and Toxicity Estimation Software Tool analysis indicated that the aquatic toxicities of TMX intermediates and final products are lower than that of the undegraded TMX. This study advances the application of substituted POM-modified NU-1000 for treating TMX-contaminated wastewater.

Breaking the conventional: Ligand-triggered Zn-MOF nanozyme with unusual oxidase activity for dual-channel sensing of benfuracarb

The activity of MOF-based nanozyme mainly relies on the metal sites, the development of organic ligands with intrinsic enzymatic-activity is of great significance for nanozyme-mediated sensors but it remains a huge challenge. Herein, the oxidase-like activity of an azo ligand, 4,4'-azodipyridine (AZPY), was first discovered by rational screening. A new Zn-MOF (JLU-MOF221) was successfully constructed based on the pillar-layered strategy to achieve well-isolated AZPY ligand and robust framework. JLU-MOF221 exhibited excellent affinity for 3,3',5,5'-tetramethylbenzidine (TMB) (Km: 0.180 mM; Kcat: 5.72 s-1), as well as a rapid response time (60 s) and high storage stability (87 % activity over 8 months). The study revealed the unique four-electron O2-to-H2O reaction pathway without relying on active oxygen species. Moreover, combining the hydrolysis behavior of benfuracarb and nanozyme inhibition strategy, a colorimetry and fluorescent dual-channel sensor was firstly developed towards benfuracarb, reaching a low limit of detection of 130 ng/mL and 76 ng/mL, respectively. The breakthrough in enzyme activity of organic ligands not only provides an efficient alternative for the traditional assay to detect benfuracarb, but also greatly promotes nanozyme-mediated sensors to a new stage.

Luminescent nanomaterials based covert tags for anti-counterfeiting applications: A review

Counterfeiting has emerged as a new global threat that challenges companies, securities, governments, and customers. Because of the banal advancements in technology, it is extremely prevalent. Ultimately have a more concerning effect than terrorism in terms of the standard of goods, organizations, banks' financial standing, people's health, the nation's financial situation, etc. Thus, it requires an urgent high-tech solution to combat counterfeiting. The present review surveys the anti-counterfeiting technologies that have been applied to combat and discourage counterfeiting. It presents the photoluminescence properties of quantum dots, metal-organic-framework, and lanthanide-doped nanomaterials and their applications in anti-counterfeiting. Recently, lanthanide-doped nanomaterials have emerged as potential candidates that provide strong security for the products due to their excellent color tunable luminescence properties under the wide range (UV to NIR) of excitation. Therefore, the present review mainly focused on the strategies of luminescence features of lanthanide-doped downconversion/downshifting and upconversion nanomaterials and their potential uses in fighting counterfeiting. Moreover, the key barriers and opportunities to combat counterfeiting advances are discussed. In addition, the crucial factors, such as the fabrication of luminescent ink, various printing techniques employed for printing different kinds of fluorescent security labels, patterns, and codes, etc., have been highlighted. This review will provide detailed information to the readers to design the security labels based on the lanthanide-doped luminescent nanomaterials for high-tech security against counterfeiting.

Ratiometric fluorescence sensor based on bimetallic organic frameworks for anthrax biomarker detection

It is of great significance to construct ratiometric fluorescence sensors with simple operation and desirable anti-interference ability. In this study, a bimetallic organic framework was prepared for the first time by a one-pot solvothermal method, using 4,4'-biphenyl dicarboxylic acid as ligand, lanthanide metal terbium ions (Tb3+) and transition metal zirconium ions (Zr4+) as central metal ions. This preparation method was easy to carry out. On this basis, a novel ratiometric fluorescence sensor Tb-Zr-MOF was constructed successfully for the detection of anthrax biomarker (2,6-pyridinedicarboxylic acid (DPA)). When DPA was added into the detection system, the fluorescence of Tb3+ was enhanced due to the energy transfer from DPA to Tb3+. Therefore, under the single excitation at 285 nm, the fluorescence emission intensity of Tb-Zr-MOF at 402 nm remained unchanged and the fluorescence emission intensity at 546 nm increased. As a ratiometric fluorescence sensor, Tb-Zr-MOF showed good linear response to DPA in the range of 5∼100 μM and the limit of detection was 1.72 μM. This sensor reduces the interference of environmental factors and achieves high sensitivity detection, which is superior to the traditional single emission peak fluorescence sensor. In addition, the developed Tb-Zr-MOF sensor was used to detect DPA in Bauhinia bark samples successfully. The recovery rate was 98.80%∼104.8%, which proved the practical application of Tb-Zr-MOF in complex environment. It is expected to provide a reliable method for the detection of biomarkers of Bacillus anthracis.

In Situ Coupling of MHz Acoustic Waves for the Synthesis of Hierarchical UiO-66 Metal-Organic Frameworks

Engineering the physical properties of metal-organic frameworks (MOFs) to improve their performance has been a key focus area for establishing their use in a variety of applications. While some synthesis strategies have shown promise in this regard, a method that can simultaneously give rise to unique properties in the MOF structure across multiple dimensions (e.g., the nano-, meso-, and macro-scales), which can be critical for a number of practical applications, has never been reported. Herein, we report an acoustomicrofluidic platform that concurrently facilitates such multiscale manipulation of the MOFs' physical properties. In just several minutes at room temperature, large (O(10-100 μm)) monolithic superstructures of UiO-66 MOFs (a MOF model with excellent stability) can be synthesized with highly desirable properties. These properties include hierarchical (micro- and meso-scale) porosity and nanoscale framework-level defects, all of which are absent in conventional-prepared UiO-66 with solvothermal synthesis. We show (as examples of the benefits of simultaneously enhancing the MOF properties on multiple dimensional levels) their practical application for simultaneous capture and degradation of large dye molecules, and for UV photodetection with superior responsivity.

Flexible Metal-Organic Frameworks for Adsorptive Separation of Liquid Hydrocarbons

ConspectusThe separation and purification of liquid hydrocarbons are vital for producing various petrochemical feedstocks. However, the structural and chemical similarities among these hydrocarbons make conventional separation methods such as distillation and extraction both challenging and energy intensive. Adsorptive separation using porous solid adsorbents presents a promising and energy-efficient alternative. Among these, flexible metal-organic frameworks (FMOFs) as a subgroup of MOFs have emerged as an unparalleled class of porous materials for highly selective adsorption-based separation and purification of liquid hydrocarbons. Having intrinsically dynamic structures, FMOFs exhibit very different adsorption behaviors compared to rigid MOFs (RMOFs), those that do not involve structure transformations upon activation, and molecular adsorption.In recent years, we have focused on developing high-performance FMOFs with different dimensionalities, spanning from one-dimensional (1D) chains to two-dimensional (2D) layers and to three-dimensional (3D) networks. Their structural flexibility arises from either local rotation and vibration of organic linkers or global structural changes, enabling stimuli-responsive molecular adsorption. By leveraging their distinct temperature- and adsorbate-dependent adsorption behaviors, we have achieved highly efficient separation of numerous important liquid hydrocarbons through molecular sieving, the mechanism that offers the highest selectivity. The unique dynamic structures and adsorption properties allow FMOFs to have high adsorption capacity, exceptional selectivity, and fast kinetics simultaneously, overcoming the trade-offs typically encountered by conventional adsorbents including RMOFs.In this Account, we summarize our recent advances using FMOFs for the adsorptive separations of three key groups of liquid hydrocarbons: C6 alkane isomers, C8 alkylaromatic isomers, and C6 cyclic hydrocarbons. We highlight the interplay between FMOF structures and sorbate properties, focusing on their unique temperature- and adsorbate-dependent adsorption behaviors and molecular sieving mechanism responsible for high selectivity. We also discuss their inverse size-selective adsorption phenomena stemmed from adsorbate-induced structural transformations─a phenomena not possible in conventional RMOFs, which typically exhibit size-exclusion selectivity. Representative FMOFs with superior separation performance are discussed, along with their underlying working principles. Finally, we address the existing challenges and propose potential strategies to enhance their performance aiming for applications in petrochemical industry. Overall, our studies not only unveil a new dimension of flexible porous crystals but also provide a strategic framework for their design and implementation in highly selective, sieving-based molecular separation. By deepening the understanding of structure-property relationships, our findings offer valuable insights that can inspire future advancements in adsorptive separation technologies, with significant implications for the petrochemical industry and beyond.

Simple Strategies to Quantify and Control Polymer Threading into Micropores

Blends of polymers with microporous particles are essential to many modern technologies, including membranes, catalysts, nanocomposites, and porous liquids. However, the design space and performance of these technologies are substantially limited because it is difficult to quantify and control how polymers thread into the particles' sub-2 nm micropores. Here, we address these issues with two new strategies. First, we show that traditional solution-state NMR can be used to directly monitor polymer chains and quantify their diffusivities as they thread into microporous particles from the surrounding solvent. This label-free, high-resolution, in situ monitoring is possible because once a polymer chain enters the particles, its NMR signal becomes invisible due to excessively slow molecular tumbling. Second, we show that threading rates can be tuned across at least 6 orders of magnitude─without changing the particle size, micropore topology, or polymer chain length─by rationally modifying the particles' external surface with different coatings that form via noncovalent self-assembly after simple mixing. The strategies described here to quantify and control polymer threading are simple and generalizable to a wide range of polymer/particle combinations, solvents, temperatures, and concentrations; thus, they may spark advances in diverse technological and fundamental areas that rely on blends of polymers with microporous particles.

A Rigid, Stable, and Scalable Aliphatic MOF Adsorbent for Efficient C2H2/CO2 Separation with Record Acetylene Packing Density

Integrating separation parameters such as high adsorption capacity and selectivity, moderate adsorption enthalpy (Qst), along with industrial factors including cyclic stability, cost-effectiveness, and scalability into a single adsorbent remains highly challenging due to inherent trade-offs among these properties. Herein, we strategically leverage the coordination modes of aliphatic ligands to significantly enhance C2H2/CO2 separation performance. The structure flexibility and pore metrics are finely modulated by hydroxylated aliphatic acid (DLmal). As a result, the rigid Zn-bpy-DLmal exhibits an exceptional C2H2 adsorption capacity of 1.4 mmol g-1 at 0.01 bar, high C2H2/CO2 selectivity (49), and moderate C2H2 Qst value (38.4 kJ mol-1). Notably, it achieves record-high C2H2 packing densities of 347 g L-1 at 0.01 bar and 747 g L-1 at 0.5 bar. Furthermore, the scale-up production of Zn-bpy-DLmal to kilogram quantities has been successfully achieved at an estimated cost of $74 per kilogram. Dynamic breakthrough experiments confirm its practical C2H2/CO2 separation performance with excellent cyclability under high flow rates and both dry and humid conditions. Moreover, two-bed pressure swing adsorption simulations demonstrate a high-purity C2H2 (>99%) yield of 14.64 mol with a recovery of 88.2% per cycle.

MOF composites for revolutionizing blue energy harvesting and next-gen soft electronics

Metal-organic frameworks (MOFs) are porous materials with highly ordered and crystalline structures, which have earned tremendous attention in the academic community in recent years owing to their high tunability in porosity and pore structure. By integrating MOFs with soft colloids or polymers to form MOF composites, the rigidity and brittle nature of MOFs can be compensated for, thus achieving synergistic effects for a wide variety of applications. In particular, the past decade has seen the advancement of MOF composites in the budding fields of blue energy harvesting and soft electronics, which have received growing interest in the past 5 years. This review focuses on the applications of MOF composites in these two fields, and starts by examining the nanoarchitectures of MOFs, followed by the fabrication of MOF composites. Furthermore, topical advances of MOF composites in blue energy harvesting and soft electronics are reviewed and summarized, and their challenges and future opportunities are discussed as the final touch. This article provides comprehensive review and valuable insights into the development of MOF composites, which may open up new avenues for blue energy harvesting and soft electronics to solve the imminent energy crisis and to advance the wearable technology in healthcare.

Optimizing the pore environment in biological metal-organic frameworks through the incorporation of hydrogen bond acceptors for inverse ethane/ethylene separation

The development of efficient adsorbents for the selective separation of ethane (C2H6) and ethylene (C2H4) is essential for the cost-effective production of high-purity ethylene. Here, we employ a pore engineering strategy to optimize the pore environment of biological metal-organic frameworks (MOFs) by incorporating hydrogen bond receptors to enhance the inverse separation efficiency of C2H6 and C2H4. Compared to the isomorphic Cu-AD-SA, the methyl-functionalized Cu-AD-MSA and Cu-AD-DMSA not only provide suitable pore confinement but also offer additional binding sites, thus creating an optimal environment for strong interactions with C2H6 (AD = adenine, SA = succinic acid, MSA = 2-methylsuccinic acid, and DMSA = 2,2-dimethylsuccinic acid). Adsorption results show that Cu-AD-DMSA exhibits remarkable C2H6/C2H4 selectivity (up to 2.4) as well as outstanding C2H6 adsorption capacity (3.63 mmol g-1), surpassing most reported C2H6-selective MOFs. Theoretical calculations combined with in situ infrared spectroscopy reveal that the synergetic effect of suitable pore confinement, amino groups, and functional surfaces decorated with multiple methyl binding sites provides strong and multipoint interactions for C2H6. Breakthrough experiments demonstrate that Cu-AD-DMSA exhibits exceptional performance in separating binary C2H6/C2H4 gas mixtures. The high chemical and thermal stability, scalable synthesis, and economic viability of Cu-AD-DMSA illustrate its potential as a candidate for C2H6/C2H4 separation application.

Electrochemical detection of tetracycline using Cu-MOF functionalised screen-printed electrodes

This study offers a novel approach to fabricating an electrochemical sensor based on a screen-printed electrode (SPE) modified with a monometallic copper metal-organic framework (Cu-MOF) for detecting tetracycline. Despite tetracycline is an antibiotic used extensively in both human and animal healthcare, overuse of the drug has polluted the environment and caused antibiotic resistance. To protect the public's health and stop the development of resistant bacterial strains, it is essential to detect tetracycline in the supply of food and water. Furthermore, Cu-MOF was synthesized by a solvothermal technique utilizing terephthalic acid as the building block. Several characterization examinations verified the synthesis of the MOF. Because of the metal synergism between Cu ions, the monometallic Cu-MOF showed strong tetracycline adsorption and electrocatalytic capabilities. For the tetracycline electro-determination, it was therefore used as the electrode material. Differential Pulse Voltammetry was employed in the electroanalysis, with a linearity range of 0.0001-100 µmol L-1 and a detection limit as low as 1.007 µmol L-1. The sensor was successfully applied to real-sample matrices, including tap water and RO water, demonstrating good recovery values ranging from 97.05 to 105.71%; the suggested sensor showed good recovery of the antibiotic that had been spiked.

Dual-mode visual fluorescent/colorimetric ratio sensing of alkaline phosphatase in milk based on porphyrinic MOF photonanozyme fibers

The detection of alkaline phosphatase (ALP) in milk is crucial for determining the safety of dairy products, but single mode detection may result in false positives or false negatives. This work presents a dual-mode visual fluorescent/colorimetric ratio sensor for highly sensitive detection of ALP. Zinc meso-tetra(4-carboxyphenyl) porphyrin (ZnTCPP) metal-organic frameworks (MOFs) were grown on polyacrylonitrile with Al2O3 layers (Al-ZnTCPP@PAN). It exhibited enhanced photoresponsive oxidase-like activity, catalyzing 3,3',5,5'-tetramethylbenzidine (TMB) to amplify the colorimetric signal. ALP hydrolyzes l-Ascorbic acid 2-phosphate sesquimagnesium salt hydrate (AA2P) to produce phosphate ions (PO43-), which attack the Al node of Al-ZnTCPP@PAN and cause ZnTCPP to detach from the material surface. It results in weakened colorimetric signals of Al-ZnTCPP@PAN and enhanced fluorescent signals of the reaction solution. A smartphone-integrated platform enabled dual-mode visual fluorescent/colorimetric ratio detection of ALP with the limit of detection as low as 0.039 mU/mL, successfully applied to milk, highlighting its potential in food safety.

Multinetwork Aerogels with In-situ Grown UiO-66: Efficient Adsorption of Diclofenac Sodium and Mechanism Decoding

Diclofenac sodium (DCF) is a novel pollutant that poses a significant environmental threat. Aerogels effectively adsorb diclofenac sodium, but their low density and high porosity exhibit poor adsorption and mechanical properties during adsorption. To overcome the limitations of traditional aerogels, specifically their poor structural integrity and inadequate adsorption performance, multinetwork aerogels were fabricated through successive integration of sodium alginate (SA) with Ca2+, chitosan (CS) with SA, and polyethyleneimine (PEI) with CS, followed by in situ formation of UiO-66@SA/CS/PEI. The results show that the multinetwork structure in the material dramatically enhances the aerogel's stability, which has been greatly improved. After amino modification, the maximum adsorption capacity reached 775.9 mg/L, 2.6 times that of the single network aerogel. A combination of adsorption modeling, molecular simulation and material structure characterization was used to analyze the adsorption mechanism in depth. Analysis revealed that the adsorption mechanism involved a heterogeneous endothermic process, predominantly governed by chemisorption accompanied by synergistic physicochemical interactions. The π-π EDA interaction, metal (Zr)-π interaction, electrostatic interaction, coordination of Zr with O and Cl, and hydrogen bonding were identified. Interference experiments show that UiO-66@SA/CS/PEI has good stability in different environments. This study provides new ideas for the synthesis and adsorption mechanism research of MOF-based poly-network aerogels, as well as theoretical support for the direction of material structure optimization and selective adsorption of DCF.

β-cyclodextrin cross-linked metal organic frameworks as a new sensing candidate for donepezil hydrochloride potentiometric sensors

Screen-printing is a well-established promising technology for large scale production of planner disposable electrochemical sensors. The present study aims to fabricate a novel donepezil hydrochloride (DPH) screen-printed sensor integrated with the cross-linked β-cyclodextrin-functionalized aluminum metal organic framework-multiwall carbon nanotubes nanocomposites (β-CD/MOF/MWCNTs) as a novel sensing element. The fabricated disposable sensors exhibit theoretical Nernstian compliance value of 60.7 ± 1.5 mV decade-1 within a linear dynamic concentration range from 10-6 to 10-2 mol L-1 and limit of detection 7.0 × 10 -7 molL-1. The DPH disposable sensors show high potential stability with a prolonged operational lifetime and the fast response time of 6 s. The presented electrochemical sensors represent an efficient analytical tool for fast and sensitive assay of DPH residues in the marketed pharmaceutical tablets and biological samples with acceptable average recoveries under direct potentiometric measurements, flow injection analysis (FIA), and potentiometric titration. Moreover, the dissolution and degradation studies of DPH can be monitored by the presented disposable sensors.

Anti-biopassivated Reticular Micromotors for Bladder Cancer Therapy

The limited lifespan of enzyme-powered micro/nanomotors (MNMs) hinders their biomedical applications due to the easy deactivation in tumor microenvironments. In this study, by taking advantage of hydrogen bond-rich metal-organic frameworks (MOFs), we design anti-biopassivated urease-powered MOF motors (Ur-MOFtors) with sustained motility for bladder cancer therapy. Such reticular Ur-MOFtors exhibited an exceptionally long locomotion lifespan exceeding 90 min in highly concentrated urea, which was an 18-fold enhancement compared with urease-adsorbed MOFs, resulting in excellent anti-biopassivation of MOFtors. The underlying molecular mechanism of persistent motion involves hydrogen bonding interaction between the MOF skeleton and the catalytic product, as identified by in situ infrared spectroscopy and density functional theory. Based on the preserved enzymatic activity comparable to native urease, the self-propulsion pathway of Ur-MOFtors is driven by ionic self-diffusiophoresis with the positive chemotactic motion toward urea. Benefiting from the persistent motion of Ur-MOFtors in physiological urea, a rapid bladder cancer therapy was achieved with few instillation sessions and short treatment cycles during intravesical administration. This hydrogen bond-rich framework presents a promising anti-biopassivated approach to overcoming the short lifespan and easy deactivation of enzymatic motors for advanced therapeutic robotics.

Two-Dimensional Metal-Organic Framework with High-Performance Single-Molecule Magnets as Nodes Showing Magnetic Coercivity Photomodulation

Addressing the spatial organization of high-performance single-molecule magnets (SMMs) and achieving stimuli-responsive switching of their magnetic bistability are pivotal challenges in molecular memory technologies, paving the way for advanced opto-magnetic devices. Herein, we utilize the photosensitive ligand 4,4'-bipyridine (BPy) as a linker to incorporate typical pentagonal-bipyramidal SMMs as nodes into a two-dimensional metal-organic framework (MOF), formulated as {[Dy1.5(OPh)2Cl(BPy)3(THF)1.5][(BPh4)1.5]·0.5THF}n (1). The precise synthesis facilitates axial coordination of PhO- and equatorial alignment of BPy, enforcing perpendicular orientations of the principal magnetic axes of Dy3+ ions across all Kagomé layers. Compound 1 exhibits photochromic behavior upon exposure to ultraviolet irradiation at room temperature, driven by a photoinduced electron transfer process that generates radicals. The resulting 1uv displays overall faster relaxation dynamics compared to 1, characterized by shorter relaxation times at identical temperatures within the 12-70 K range, a lower diverging temperature in field-cooled and zero-field-cooled curves (9 K for 1 vs. 6 K for 1uv), and reduced energy barriers from 1048(17)/822(46) K for 1 to 1000(9)/641(34) K for 1uv. Notably, the coercive field decreases dramatically from 4500 Oe for 1 to 1300 Oe for 1uv at 2 K, while the hysteresis loop opening temperature decreases from 20 K for 1 to 14 K for 1uv. These photoinduced changes are due to the formation of photogenerated radicals and alterations in crystal packing. This work achieves an MOF that integrate high-performance SMM behavior with magnetic coercive photomodulation, providing a design paradigm for engineering advanced SMM-MOFs with tailored photomagnetic switching.

In Situ ZIF-8-Coated Copper Laminate System for Fluid-Phase Adsorptive Separation

The use of structured adsorbents is emerging as a promising approach for adsorptive separation processes, and several ex situ structuring routes like extrusion, three-dimensional (3D) printing, and coating over substrates have been extensively investigated. However, in situ growth of adsorbents such as metal-organic frameworks (MOFs) on metal laminates remains underexplored. This study introduces a novel laminate system, where aluminum pieces, inspired by the "LEGO" concept, were designed through CNC milling and used to fabricate embossed/dented copper laminates. These laminates were then coated with ZIF-8 crystals (ZIF-8@Cu) via a direct in situ coating method at room temperature, resulting in a 100 μm coating. The system was assembled, packed in a custom-designed column, and evaluated for alcohol recovery from methanol/water and n-butanol/water mixtures. The ZIF-8@Cu laminates exhibited high adsorption capacities: 0.19 gMeOH/gZIF-8, 0.26 gn-BuOH/gZIF-8, and excellent selectivity toward alcohols (αMeOH/H2O = 8.5; αn-BuOH/H2O = 68). Vapor-phase experiments showed dispersive effects in the elution curve, attributed to the intrinsic properties of ZIF-8 (S-shaped equilibrium isotherm) and mass transfer limitation caused by channel nonuniformities and inlet flow maldistribution. For both separation mixtures, the laminate system was regenerated within 2 h via thermal swing adsorption (TSA), thereby exhibiting the combined benefits of microporosity, low-pressure drop, mechanical stability, and efficient heat transfer. The adsorptive properties were further highlighted in liquid-phase separation, where the laminates selectively captured n-butanol from 2.0 wt % aqueous solution and were successfully regenerated via TSA. This study provides proof of concept for the application of MOF-coated metal laminates in multiple adsorption-desorption cycles, thus highlighting their potential for process intensification.

Crystallographic Visualization of Distinct Iodic Aggregations in Isostructural Metal-Organic Frameworks

Precisely determining the location of adsorbed molecules is essential for illuminating the mechanisms underlying molecular confinement within porous metal-organic frameworks (MOFs). Here, we present the pore-filling and reactive adsorption of iodine in ALP-MOF-1 and its isostructural redox-active ALP-MOF-2. The adsorbed iodine molecules (I2) are unaffected by Zn(II) in ALP-MOF-1 and are exclusively confined into an unusual three-dimensional (3D) iodine aggregation due to the 3D cross-linked pore topology and multiple I2-framework interactions. Conversely, in ALP-MOF-2, the adsorbed I2 enables the oxidation of Co(II) to Co(III), which is accompanied by the reduction of I2 to I3- and the formation of I5- and I2 during continuous I2 loading. Identification of distinct iodine adsorption processes in ALP-MOF-1 and -2 motivated tuning of the metal ion composition to adjust the adsorption mechanism. The iodic aggregations in both MOFs are unambiguously confirmed by the combination of single crystal X-ray diffraction and spectroscopic characterization. The presence of multiple adsorption sites facilitate rapid iodine uptake of ∼179 wt % in ALP-MOF-1 and ∼150 wt % in ALP-MOF-2 within ∼5 h, which could be advantageous for applications requiring rapid and energy-efficient iodine capture.

Optimizing Printed Quasi-2D Luminescent Perovskite Films via Delaminated Metal-Organic Framework Modulation

Microelectronic printing technology has recently emerged as a key approach in advancing pixel-array perovskite films, particularly quasi-2D perovskite films, to meet current scientific and technological demands. However, its further development remains hindered by the uncontrollable crystallization of perovskite during the printing process. Herein, a novel in situ heterogeneous nucleation growth approach for obtaining quasi-2D perovskite films is demonstrated, utilizing delaminated metal-organic frameworks (i.e., layered Cd-MOF) with an ordered structure as modulators. The inosculation of phenylethylammonium (PEA+) with layered Cd-MOF serves as crystal nuclei, facilitating heterogeneous crystal nucleation and growth while regulating the distribution of the n-phase. Moreover, the intercalation of the layered Cd-MOF alleviates rigid stress, thereby eliminating defects in the printed films. The resulting quasi-2D perovskite films exhibit an impressive photoluminescence quantum yield of 37.40% along with exceptional luminescent stability, making them promising candidates for various optoelectronic applications. Overall, this study highlights the significant potential of MOF-assisted synthesis in advancing high-performance perovskite materials through microelectronic printing technology, offering a promising pathway for the development of future optoelectronic devices.

A facile two-step synthesis of hollow MOF-74 for enhanced dynamic Xe/Kr separation

Metal-organic frameworks (MOFs) with high-density uncoordinated open metal sites have been intensively investigated in Xe/Kr separation because of their strong and selective interaction with Xe. However, the dynamic Xe/Kr separation behavior of these MOFs is often unsatisfactory in practical applications due to slow diffusion kinetics. This work presents a facile two-step method to synthesize hollow Ni-MOF-74 particles with short diffusion lengths to enhance dynamic Xe/Kr separation. Unlike conventional sacrificial template approaches, where a crystalline MOF layer is directly grown on to the template surface, this method first rapidly deposits a metal-ligand complex layer under mild reaction conditions while the template undergoes simultaneous degradation. These poorly crystalline yet well-faceted hollow capsules are then reconstructed into crystalline hollow Ni-MOF-74 particles of the same morphology. Xe adsorption kinetics analyses show that the Xe diffusion rate of hollow Ni-MOF-74 was 1.5 times faster than that of solid Ni-MOF-74 despite their identical Xe and Kr adsorption capacity and selectivity. As a result, the enhanced diffusion kinetics of the hollow structure resulted in a steeper breakthrough curve and a 17% increase in breakthrough time than its solid counterpart during column separation of a Xe/Kr mixture.

Crystal Engineering of Cyanoborate-Bridged Cubane-Type Tetranuclear Ru Complex: Synthesis, Pseudopolymorphism, and Coordination Polymer Formation

Cyanoborate anions are versatile bridging ligands that lead to structurally diverse compounds from a crystal engineering perspective. Herein, we report the synthesis of a cubane-type tetranuclear Ru complex, [Ru4(Cp)4{B(CN)4}4] (1, Cp = C5H5), obtained by photoirradiation of [Ru(Cp)(C6H6)]B(CN)4 in solution or by the reaction of [CpRu(MeCN)3]+ with KB(CN)4. This complex served as a host for various solvents, generating different pseudopolymorphs, including 1·nCH2Cl2 (n = 1, 2, 3), 1·0.5C6H6, 1·C6H5Me, and 1·3THF upon recrystallization. Moreover, the four free cyano groups in 1 allow it to act as a bridging ligand, facilitating the formation of 1D and 2D coordination polymers through reactions with transition metal complexes.

Solvent-free photochemical formation of cubane-type Ru complexes from organometallic ionic liquids with cyanoborate anions

Coordination compounds, including cage compounds, are typically synthesized via solution reactions. Here, we report the solvent-free, quantitative conversion of organometallic ionic liquids (ILs) containing alkyltricyanoborate anions into solid tetraalkyl cubane-type tetranuclear Ru complexes upon UV irradiation. Furthermore, we elucidated the diverse packing structures of the octyl derivative.

Tunable Self-Assembly of Decanuclear Ni(II) Carbonato Clusters with a Hydroxyquinolinato Shell: Robust Porous Networks with Reversible Solvent-/Temperature-Driven Phase Transitions and Selective Gas Separation

The utilization of molecular metal clusters as building units of noncovalent porous materials (NPMs) is a promising strategy, combining the versatile functionality of organic and inorganic subunits with the softness and flexibility of molecular solids controlled by noncovalent interactions. However, the development of robust porous functional frameworks based on self-assembly driven by noncovalent forces is still highly challenging. Herein, we report the synthesis and characterization of a discrete decanuclear Ni(II) hydroxyquinolinato-carbonato cluster, [Ni10(μ6-CO3)4(L)12], which, depending on the crystallization conditions, self-assembles into either of two microporous frameworks: diamondoid WUT-1(Ni) and pyrite WUT-2(Ni). The transitions between both polymorphs can also be selectively triggered by temperature or exposure to vapors of a particular organic solvent, which is accompanied by the easy recovery of crystallinity by the materials from the noncrystalline phase. Moreover, both materials show excellent robustness toward various chemical environments, including air/moisture and water stability, and demonstrate interesting gas adsorption properties. Remarkably, WUT-1(Ni) exhibits significant enhancement in gas uptake compared to the previously reported isostructural Zn(II) analogue, WUT-1(Zn), representing one of the highest H2 uptakes among NPMs. In turn, tighter voids of the ultramicroporous WUT-2(Ni) framework facilitate selective interactions with gas molecules, resulting in outstanding selectivity in the adsorption of CO2 over CH4 and N2. The presented studies demonstrate the profound role of the character of metal centers on the self-assembly of isostructural nanoclusters as well as properties of the resulting microporous frameworks.

Competitive Host-Guest and Guest-Guest Interaction Dependent Flexibility of Crystal-Size-Engineered ZIF-8: An Inelastic Neutron Scattering Study

Metal-organic frameworks (MOFs) exhibit remarkable structural flexibility, influenced by factors such as crystal size and guest molecule interactions. Here, we investigate the crystal-size-dependent flexibility of ZIF-8 by using inelastic neutron scattering (INS). Our study provides direct experimental evidence of reduced flexibility in small ZIF-8 crystals, underscoring the importance of crystal-size-engineering in modulating MOF properties. The enhanced stiffness observed in smaller ZIF-8 crystals can be attributed to the reduction in the unit cell size, which leads to increased rotational hindrance of the framework. While gas-adsorption-induced flexibility in MOFs is widely reported, the influence of competitive host-guest and guest-guest interactions on framework flexibility remains poorly understood. Through INS experiments, we uncovered a nonmonotonic flexibility behavior in nanosized ZIF-8 upon CO2 exposure, indicating intricate molecular dynamics. We observed a hindrance of methyl rotation (40 cm-1) at low CO2 dosing, attributed to host-guest interactions, followed by a resurgence at higher dosing levels, suggesting enhanced guest-guest interactions. Density functional theory calculations and Grand Canonical Monte Carlo simulations provided mechanistic insights, revealing an enhancement in guest-guest interaction energy and a reduction in host-guest interaction energy with dosing. Phonon calculations for both pure and CO2-adsorbed ZIF-8 were performed by using density functional perturbation theory. This approach allowed for a detailed analysis of vibrational properties and the impact of CO2 adsorption on the framework dynamics. In the minimum energy structure, CO2 was found to adsorb near the cavity opening, where it can interact with three methyl groups through its oxygen atom. The INS and DFT data confirmed that the suppressed mode at ∼40 cm-1 in INS spectra at low CO2 dosing in nanosized ZIF-8-s was caused by blocking of methyl rotation due to its strong affinity for the CO2 molecule. Our findings shed light on the complex interplay between crystal size, guest molecule interactions, and framework flexibility in MOFs, offering valuable insights in designing tailored porous materials for different applications.

Advancements in MOF-based resistive gas sensors: synthesis methods and applications for toxic gas detection

Gas sensors are essential tools for safeguarding public health and safety because they allow the detection of hazardous gases. To advance gas-sensing technologies, novel sensing materials with distinct properties are needed. Metal-organic frameworks (MOFs) hold great potential because of their extensive surface areas, high porosity, unique chemical properties, and capabilities for preconcentration and molecular sieving. These attributes make MOFs highly suitable for designing and creating innovative resistive gas sensors. This review article examines resistive gas sensors made from pristine, doped, decorated, and composite MOFs. The first part of the review focuses on the synthesis strategies of MOFs, while the second part discusses MOF-based resistive gas sensors that operate based on changes in resistance.

Single-Cell Nanoencapsulation: Chemical Synthesis of Artificial Cell-in-Shell Spores

Nature has evolved adaptive strategies to protect living cells and enhance their resilience against hostile environments, exemplified by bacterial and fungal spores. Inspired by cryptobiosis in nature, chemists have designed and synthesized artificial "cell-in-shell" structures, endowed with the protective and functional capabilities of nanoshells. The cell-in-shells hold the potential to overcome the inherent limitations of biologically naı̈ve cells, enabling the acquisition of exogenous phenotypic traits through the chemical process known as single-cell nanoencapsulation (SCNE). This review highlights recent advancements in the development of artificial spores, with sections organized based on the categorization of material types utilized in SCNE, specifically organic, hybrid, and inorganic types. Particular emphasis is placed on the cytoprotective and multifunctional roles of nanoshells, demonstrating potential applications of SCNEd cells across diverse fields, including synthetic biology, biochemistry, materials science, and biomedical engineering. Furthermore, the perspectives outlined in this review propose future research directions in SCNE, with the goal of achieving fine-tuned precision in chemical modulation at both intracellular and pericellular levels, paving the way for the design and construction of customized artificial spores tailored to meet specific functional needs.

Enhanced ethanol-driven carboxylate chain elongation by MOF-808 from waste activated sludge: Process and mechanism

Carboxylate chain elongation can create value-added bioproducts from waste activated sludge (WAS). The bioconversion of WAS during anaerobic fermentation is often constrained by inefficient hydrolysis. The addition of MOF-808 (200 mg MOF-808/g volatile solids (VS)) increased caproate production and selectivity by approximately 38.9 % and 28.9 %, respectively. MOF-808 significantly promoted the hydrolysis of WAS, accelerated the degradation of extracellular polymeric substances, and enhanced acetate accumulation. Absolute quantitative metagenomics conducted during the acidification and chain elongation phases demonstrated that MOF-808 markedly improved enzymatic hydrolysis. The absolute gene abundance of protease and α-glucosidase increased by 168.9 % and 191.2 %, respectively, compared to the control trial. Furthermore, the reverse β-oxidation (RBO) pathway, the primary route for chain elongation, exhibited a 19.2 %-76.1 % increase in gene abundance for enzymes involved in this pathway in the presence of MOF-808. Notably, the absolute gene abundance of electron-bifurcating enzyme complexes, including butyryl-CoA dehydrogenase-electron transferring flavoprotein complex (Bcd-EtfAB), proton-translocating NAD(P)+ transhydrogenase, ATPase (subunits A-I), and NAD oxidoreductase (RnfA-E), was significantly elevated in the MOF-808 trial. These findings provide valuable insights into enhancing the efficiency of chain elongation fermentation of WAS using MOF-like materials.

Tailored engineering of primary catalytic sites and secondary coordination spheres in metalloenzyme-mimetic MOF catalysts for boosting efficient CO2 conversion

The fabrication of metalloenzyme-mimetic artificial catalyst is a promising approach to achieve maximum catalytic efficiency, but the rational integration of sophisticatedly optimized primary catalytic sites (PCS) and secondary coordination spheres (SCS) for specific transformation poses a grand challenge. Here in this work, we report the tailored engineering of Cu PCS and perfluoroalkyl SCS onto a zirconium-based framework [UiO-67-(BPY-Cu)-F x (x = 3, 5, 7, 11)] [BPY = 2,2'-bipyridine-5,5'-dicarboxylate] that can be utilized in the highly efficient carboxylic cyclization reaction between propargylamines and flue gas CO2. The perfluoroalkyl groups act as tunable SCS that can facilely adjust the surface electronegativity, hydrophobicity, as well as the CO2 affinity and water vapor-resistance by simply varying the chain length. Meanwhile, the synergy between the Cu PCS and perfluoroalkyl SCS significantly facilitated the cyclization step by stabilizing the critical transition state, leading to the fast cyclization to the oxazolidinone ring. Owing to these features, UiO-67-(BPY-Cu)-F7 exhibited remarkable metalloenzyme-mimetic catalytic behavior by greatly facilitating the binding of propargylamines and CO2, promoting the stabilization of the critical transition state to cyclization, and boosting the releasing of oxazolidinones, which have been systematically investigated by the combination of substrate adsorption tests, in situ Fourier transform infrared spectra, grand canonical Monte Carlo simulations, density functional theory calculations, etc. Consequently, UiO-67-(BPY-Cu)-F7 showed outstanding catalytic performance in the carboxylic cyclization of propargylamines and flue gas CO2 under ambient conditions, exhibiting 64 times higher turnover frequency (TOF) than that of homogeneous or other MOF catalysts, and exhibiting the highest TOF under similar conditions. The present work not only provides an alternative strategy for the construction of advanced carboxylic cyclization systems, but also paves a new direction in the development of CO2 conversion with exceptional activity through the tailored engineering of PCS and SCS in metalloenzyme-mimetic artificial catalysts.

A new type of C2H2 binding site in a cis-bridging hexafluorosilicate ultramicroporous material that offers trace C2H2 capture

Hybrid ultramicroporous materials (HUMs) comprising hexafluorosilicate (SiF6 2-, SIFSIX) and their variants are promising physisorbents for trace acetylene (C2H2) capture and separation, where the inorganic anions serve as trans-bridging pillars. Herein, for the first time, we report a strategy of fluorine binding engineering in these HUMs via switching the coordination mode of SIFSIX from traditional trans to rarely explored cis. The first example of a rigid HUM involving cis-bridging SIFSIX, SIFSIX-bidmb-Cu (bidmb = 1,4-bis(1-imidazolyl)-2,5-dimethylbenzene), is reported. The resulting self-interpenetrated network is found to be water stable and exhibits strong binding to C2H2 but weak binding to C2H4 and CO2, affording a high Q st of 55.7 kJ mol-1 for C2H2, a high C2H2 uptake of 1.86 mmol g-1 at 0.01 bar and high ΔQ st values. Breakthrough experiments comprehensively demonstrate that SIFSIX-bidmb-Cu can efficiently capture and recover C2H2 from 50/50 or 1/99 C2H2/CO2 and C2H2/C2H4 binary mixtures. In situ single crystal X-ray diffraction (SCXRD) combined with dispersion-corrected density functional theory (DFT-D) calculations reveals that the C2H2 binding site involves two cis-SiF6 2- anions in close proximity (F⋯F distance of 7.16 Å), creating a new type of molecular trap that affords six uncoordinated fluoro moieties to chelate each C2H2 via sixfold C-H⋯F hydrogen bonds. This work therefore provides a new strategy for binding site engineering with selective C2H2 affinity to enable trace C2H2 capture.

Nanoscale Flexing Mechanism of a Metal-Organic Framework Determined by Atomic Force Microscopy

Flexible metal-organic frameworks (MOFs) are a unique set of compounds with applications in diverse areas. The nanoscale mechanism through which they flex is unproven. Herein, we use in situ atomic force microscopy to observe the crystal surface of Ga-MIL-53 MOF, [Ga(OH)(BDC)] (1) (BDC - 1, 4-benzenedicarboxylate) as it undergoes flexing transformations during the guest exchange between N,N-dimethylformamide (DMF) and ethanol (EtOH)-containing 1. 1·0.96DMF undergoes a flexing expansion transformation on guest exchange to form 1·xEtOH through the passage of wavefronts of cooperatively transforming, consecutive rows of unit cells parallel to the (011) plane, resulting in whole (011) layers of unit cells transforming by a layer-by-layer shear mechanism. The reverse process involves 1·xEtOH undergoing a flexing contraction transformation on guest exchange to form 1·0.96DMF through a layer-by-layer shear mechanism involving layers of unit cells parallel to the (011̅) plane transforming in a cooperative manner. This proves a nanoscale mechanism through which a MOF can flex and the coexistence of phases with different degrees of expansion within a crystal, thus providing a missing link in the multilength scale understanding of MOF flexing transformations, which will support future design and application of flexible MOFs and other extended crystalline solids.

Simultaneous Capture of N2O and CO2 from a N2O/N2/CO2/O2 Mixture with a Ni(II)-Pyrazolecarboxylate Framework

Nitrous oxide (N2O) is a potent greenhouse gas and a major contributor to ozone depletion. Its primary industrial emission source is tail gas from adipic acid production, which typically comprises a mixture of N2O, CO2, N2, and O2. Current technologies for the removal of N2O and CO2 from tail gas are energy-intensive and operationally complex. Herein, for the first time, simultaneous capture of N2O and CO2 from the quaternary mixture is achieved using a Ni(II)-pyrazolecarboxylate framework, BUT-167. This material demonstrated an exceptional adsorption capacity (135.8 cm3 cm-3 at 40 kPa) and a high packing density (790 mg cm-3) for N2O, outperforming reported sorbents. Moreover, BUT-167 also exhibits a remarkable CO2 adsorption capacity (101.5 cm3 cm-3 at 4 kPa), achieving simultaneously high selectivity values of 257.6 for CO2/N2 (4:96, v/v) and 135.7 for N2O/N2 (40/60). Importantly, BUT-167 exhibits robust and outstanding dual-gas removal performance across multiple adsorption-desorption breakthrough cycles under both dry and humid conditions. The strong affinity toward CO2 and N2O could be attributed to multiple hydrogen bonding interactions facilitated by its highly confined channel structure, as confirmed through single-crystal X-ray diffraction analysis.

Construction of Four 3D Isostructural Rare Earth-Tetrabromoterephthalate Frameworks with stp Topology: Synthesis, Crystal Structure, and CO2 Sorption Properties

The 3D rare earth metal-organic frameworks containing tetrabromoterephthalate (Br4tp) linkers with square trigonal prism (stp) topological network, [RE(Br4tp)1.5]·3H2O (RE-MOF; RE = Er, Tm, Yb, and Lu), were synthesized through the covalently linking geometrically matching molecular building blocks and cooperative intermolecular interactions. The stp type network exhibits 1D microporous structures that are capable of accommodating hexameric tubular water (H2O)6 clusters. The adsorption-desorption isotherms of CO2, CH4, and N2 gases on a typical sample of RE-MOF were analyzed. The binding mechanism of CO2 with the MOF frameworks was analyzed utilizing density functional theory (DFT) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).

Zero- to One-Dimensional Transformation in a Highly Porous Metal-Organic Framework to Enhance Physicochemical Properties

The dynamic behaviors of metal-organic frameworks (MOFs) continue to expand the accessible architectures and properties within this material class. However, the dynamic behaviors that can be studied in MOFs are limited to the transitions, preserving their high crystallinity. For this reason, their significant structural changes involving coordination bond breakage and rearrangement remain largely underexplored. Herein, we report a three-step single-crystal-to-single-crystal (SCSC) phase transition in a new cerium-based MOF, HKU-9 [Ce2PET(DMF)2(H2O)2], transforming zero-dimensional (0D) secondary building units (SBUs) into one-dimensional (1D) chain SBUs in HKU-90 [Ce2(μ-H2O)PET(H2O)2]. Single-crystal X-ray diffraction studies unambiguously delineate the structural evolution at each stage of this multistep transition, revealing multiple coordination bond dissociations/associations and a significant lattice contraction─all while preserving single-crystal integrity. This dimensional transformation endows HKU-90 with enhanced chemical stability (pH 1-10) and a record-high Brunauer-Emmett-Teller (BET) surface area of 2660 m2 g-1 among reported Ce-based MOFs. Further, HKU-90 exhibits exceptional gas sorption performance, with one of the highest reported C2H2 storage capacities (184 cc g-1 at 273 K, 1 bar) and outstanding C2H2/CO2 selectivity (2.16) under these conditions. Notably, the formation of 1D chain SBUs, a structural motif found in many high-performance MOFs, highlights the potential of using the solid-state fusion of multinuclear metal clusters to tailor the properties of the framework.

Catalysis-Assisted Synthesis of Two-Dimensional Conductive Metal-Organic Framework Films with Controllable Orientation

The facile preparation of two-dimensional (2D) conductive metal-organic framework (MOF) films with controllable orientation and thickness greatly facilitates the further structure-property investigation and performance optimization in their applications. Here, we report a catalysis-assisted synthesis strategy to the rapid production of oriented films of catechol-based (Cu3(HHTP)2, Zn3(HHTP)2, and Cu2TBA) and diamine-based (Ni3(HITP)2) 2D conductive MOFs with thicknesses adjustable from tens of nanometers to several micrometers. Relying on the utilization of a 0.3 nm Pt layer, which can be conveniently predecorated on a substrate surface via evaporating deposition or sputtering, as a catalyst for the aerobic oxidation of the redox-active ligands to trigger the formation of 2D conductive MOFs, this strategy is compatible with a majority of commonly used substrates and capable of producing patterned films with feature sizes ranging from micrometers to centimeters. Investigation on the growth kinetics of Cu3(HHTP)2 indicates that the preferential growth along the c-axis or in the ab-basal plane of its crystallites can be flexibly tuned by the formation reaction kinetics to guide the evolution of films with the face-on or edge-on orientation. The chemiresistive device incorporating the face-on Cu3(HHTP)2 film presents a high response (197%) and a fast respond speed (27 s) toward NH3 (30 ppm) at room temperature, which are superior not only to its edge-on counterpart (90% and 69 s, correspondingly) but also to other reported Cu3(HHTP)2-based sensors.

Inversed Benzene/Cyclohexene/Cyclohexane Adsorption Selectivities for One-Step Purification of Cyclohexene and Beyond

Separation of benzene/cyclohexene/cyclohexane (Bz/Cye/Cya) mixtures, especially purification of Cye, is crucial but challenging in the petrochemical industry. Here, we report two new metal-organic frameworks with opposite adsorption selectivities for on-demand separation/purification of Bz/Cye/Cya mixtures. Although they possess similar frameworks and pore structures, their pore surfaces are functionalized by hydrophobic ethyl and hydrophilic hydroxymethyl groups, which interact conversely with Bz/Cye/Cya, giving a record-high Bz selectivity (129) and the first example of Cya/Cye/Bz selectivity (18.6), respectively. Equimolar ternary mixture breakthrough experiments showed that they could directly produce high-purity Cya (99.5%+, 0.39 mmol g-1) or Bz (99.5%+, 0.25 mmol g-1), and the tandem connection of two adsorbents enabled direct production of high-purity Cye (99.5%+, 0.37 mmol g-1) in a one-step adsorption process. Further, a bypass-tandem strategy is proposed to not only greatly improve Cye productivity (99.5%+, 0.57 mmol g-1) but also simultaneously produce high-purity Cya (99.5%+, 0.36 mmol g-1).

Uncovering the Role of Critical Bonds in the Thermomechanical Response of Zn2(1,4-benzenedicarboxylate)2(1,4-diazabicyclo[2,2,2]octane) Using Ab Initio Simulations and Physics-Constrained Neural Networks

Metal-organic frameworks (MOFs) are susceptible to harsh conditions involving high temperatures, mechanical loading, host/guest chemical interactions, or a combination thereof due to the disruption of underlying bonds. Here, we probed the thermomechanical response of Zn2(BDC)2(DABCO) (BDC = 1,4-benzenedicarboxylate and DABCO = 1,4-diazabicyclo[2,2,2]octane) MOF or Zn-DMOF, whose metal nodes are connected to two BDC and DABCO linkers via Zn-O and N-Zn bonds, respectively. We have examined the relative contributions of such bonds toward Zn-MOF's thermomechanical response at 200 and 300 K, by training a physics-constrained neural network with ab initio molecular dynamics (AIMD)-derived interatomic vibration data, and quantitatively estimated interatomic bond strengths within a local environment in the MOF body. We quantitatively show that N-Zn and Zn-O bonds near the Zn-based metal nodes are weaker than their surroundings. These findings were followed up by separately annealing Zn-DMOF at 920 K-AIMD (above its thermal decomposition temperature), mechanically straining it to failure using 0 K-DFT, and examining host/guest interactions in aqueous and acidic environments with 300 K-AIMD. Together, they indicated that structural instability in Zn-DMOF was initiated by the disruption of N-Zn and Zn-O bonds under harsh conditions and that Zn-O bonds are weaker than N-Zn bonds at T ≥ 300 K. Broadly, we show that bond strength estimates are a reasonable indicator of Zn2(BDC)2(DABCO)'s performance at high temperatures and mechanical loading, and demonstrate the viability of employing AIMD simulations and physics-constrained neural networks to quantify interatomic bond strengths of hybrid organic-inorganic materials.

Reticular Structural Diversification of Zirconium Metal-Organic Frameworks Through Angular Ligand Configuration Control

Reticular chemistry offers practical guidelines for enlarging and enriching the arsenal of metal-organic frameworks (MOFs). However, reticular expansion to access mesoporous structures remains challenging due to limitations in achieving precise control over both the size and configuration during building units' extension. Herein, we combine ligand isomerization and functionalization strategies to regulate the ligand configuration by systematically replacing aryl C-H groups with N atoms, resulting in angular dicarboxylate ligands with various symmetries. The assembly between a 4,4'-(pyridine-2,6-diyl)dibenzoic acid ligand (1N, C2 symmetry) and 12-connected Zr6 cluster leads to the formation of a pseudo ftw topology framework (NU-2611), where one pair of nose-to-nose 1N ligands resembles a tetra-topic ligand. When a 6,6'-(1,3-phenylene)dinicotinic acid ligand (2N, CS symmetry) was used, another pseudo ftw network NU-2612 was obtained with a 2-fold framework interpenetration. Interestingly, the planar [2,2':6',2″-terpyridine]-5,5″-dicarboxylic acid ligand (3N, C2V symmetry) yielded an intriguing mesoporous Zr-MOF with kag topology. NU-2613 represents the first example of kag Zr-MOF designed to include large, well-defined mesopores. The diversity of these MOFs was further enhanced through post-synthetic metalation of linkers. Particularly, metalation of the chelating 3N ligand with Fe3+ in NU-2613 enables efficient catalytic transformation within the functionalized channels. This work contributes insight into the reticular expansion of Zr-MOFs by finely-tuning the ligand planarity, advancing the structure diversification of mesoporous frameworks for specific applications.

Introducing Functional Groups Into B←N Organic Frameworks with Permanent Porosity

Crystalline organic frameworks incorporating dative B←N and reversible B─O bonds (BNOFs) have garnered increasing interest on account of their crystallinity, porosity, and processability. However, strategies for introducing functions into BNOFs remain largely unexplored. In this work, a series of functionalized BNOFs, named BNOF-n (n = 2-9), have been designed and synthesized using a mixed-monomer assembly strategy. The obtained materials share structural similarities but reveal distinct functional groups, demonstrating excellent chemical stability, high surface areas, and remarkable regenerability. Notably, BNOF-5, functionalized with abundant carboxyl groups, achieves exceptional reversible NH3 adsorption capacity (up to 10.0 mmol g-1 at 1 bar and 298 K), significantly surpassing that of the nonfunctionalized BNOF-1 (5.6 mmol g-1) and the less-functionalized BNOF-7 (7.9 mmol g-1), thereby clearly demonstrating the effectiveness of the functionalization strategy. Remarkably, the damaged BNOF-5 can be efficiently repaired through facile regeneration, highlighting its outstanding recyclability. This work demonstrates the first attempt at functionalization methodology in BNOFs, extending their potential toward diverse applications.

Insights into the surface chemistry of N-heterocyclic carbenes

N-heterocyclic carbenes (NHCs) have emerged as a versatile and powerful class of ligands in surface chemistry, offering remarkable stability and tunability when bound to surfaces, including metals, metal oxides, and semiconductors. Understanding their surface and interfacial mechanisms at the atomic-level is essential for precise control of molecule-surface interaction, as well as intermolecular interactions, which directly influence material performance and functionalities. Research in surface chemistry focusing on molecular binding modes, self-assembly, on-surface reactions, and electronic properties is crucial for the rational design of efficient catalysts, customized materials, and high-performance devices. This review highlights these critical aspects of NHCs on surfaces, beginning with their robust and multiple binding modes, which underpin their stability and versatility. The covalent NHC-surface bonds allow NHCs to form stable attachments, often surpassing the strength of traditional thiol-based modifiers, promoting robust anchoring across diverse materials. Another focus is the self-assembly of NHCs into highly ordered monolayers, which facilitates the design of functional nanostructures. Emerging topics also include on-surface reactions, surface electronic properties, and interfacial charge transfer of NHCs, emphasizing their dependence on the substrate and NHC molecular structure. By consolidating recent advancements in the study of NHCs on surfaces, we aim to provide a comprehensive overview of their transformative potential in surface chemistry at the atomic scale, while also identifying key challenges and future directions in the field.

Making and Breaking Supramolecular Synthons for Modular Protein Frameworks

Anionic calixarenes are useful mediators of protein assembly. In some cases, protein - calixarene cocrystallization yields multiple polymorphs. Ralstonia solanacearum lectin (RSL) cocrystallizes with p-sulfonato-calix[8]arene (sclx8) in at least four distinct pH-dependent arrangements. One of these polymorphs, occurring at pH ≤ 4, is a cubic framework in which RSL nodes are connected by sclx8 dimers. These dimers are supramolecular synthons that occur in distinct crystal structures. Now, we show that the discus-shaped dimer of p-phosphonato-calix[6]arene (pclx6), can replace the sclx8 dimer yielding a new assembly of RSL. Remarkably, just one type of RSL - pclx6 cocrystal was formed, irrespective of pH or crystallization condition. These results with pclx6 contrast starkly with sclx8 and suggest that the calixarene type (e.g., phosphonate versus sulfonate) dictates the synthon durability, which in turn exerts control over protein assembly and polymorph selection. Breaking the pclx6 dimer required a mutant of RSL with an affinity tag for macrocycle binding. This highly accessible, dicationic site resulted in a significantly altered and porous framework with pclx6 (but not with sclx8). Experiments with ternary mixtures of RSL, pclx6, and sclx8 provide evidence of pH-driven self-sorting. Thus, the "mix-and-match" of protein and supramolecular synthons is a promising approach to protein crystal engineering.

Identification of Adsorption Sites for CO2 in a Series of Rare-Earth and Zr-Based Metal-Organic Frameworks

The adsorption ofCO 2 ${{\rm{CO}}_2 }$ in MOF-808, NU-1000 and a series of rare-earth CU-10 analogues has been studied with first principles DFT and classical Monte-Carlo methods. DFT calculations describe the interaction ofCO 2 ${{\rm{CO}}_2 }$ with the different metal-organic frameworks (MOFs) as physisorption, but where we can distinguish several adsorption sites in the vicinity of the metal nodes. Beyond the identification of adsorption sites, the MOFs were synthesized, activated, and characterized to evaluate their experimentalN 2 ${{\rm{N}}_2 }$ andCO 2 ${{\rm{CO}}_2 }$ adsorption capacity. Classical Grand Canonical Monte-Carlo (GCMC) simulations for the adsorption ofCO 2 ${{\rm{CO}}_2 }$ are in very good agreement with DFT results for identifying the most favored adsorption sites in the MOFs. In contrast, a rather mixed agreement between GCMC simulations and experimental results is found for the estimation of adsorption capacity of several MOFs studied towardN 2 ${{\rm{N}}_2 }$ andCO 2 ${{\rm{CO}}_2 }$ .

Use of gold/iron metal-organic framework nanoparticles (AuNPs/FeMOF)-modified glassy carbon electrode as an electrochemical sensor for the quantification of risperidone in patient plasma samples

Risperidone (RIS) is one of the most prescribed atypical antipsychotics approved for the treatment of various neuropsychiatric diseases. For the correlation of serum concentration and pharmacological effects of RIS, therapeutic drug monitoring is considered a fundamental concept for clinical application. This paper is provided to develop an electrochemical probe for the determination of RIS in biological samples by modification of glassy carbon electrode (GCE) using gold nanoparticles (AuNPs) and iron metal-organic-frameworks (FeMOFs). This probe fabrication process was characterized with various techniques including Fourier transform infrared (FTIR), emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM), and dynamic light scattering (DLS) to confirm the proper synthesis of materials and the sensors designing. The developed probe square-wave voltammetry (SWV) signal was linear upon RIS concentration from 0.02 to 50 µg/mL with a low limit of quantification (LOQ) of 0.02 µg/mL. Based on the validated method, high accuracy and precision, good specificity, and suitable stability of fabricated probes were achieved. As the ultimate step, this method was successfully applied for the quantification of RIS in patients' plasma samples with regular RIS consumption. The fabricated electrochemical demonstrates favorable clinical applicability due to its simplicity, high sensitivity, low sample pretreatment time, and rapid analysis time, making it a promising probe as an alternative to current separation-based methods. Also, the developed probe is cost-effective, as it uses a low amount of materials, decreases sample processing time, and utilizes inexpensive materials, which could remarkably reduce the overall cost of RIS concentration detection in clinical samples. The obtained results showed the potential of the developed probe for fast and reliable detection of RIS in plasma samples.

Photo-responsive antibacterial metal organic frameworks

The misuse and overuse of antibiotics have caused the emergence of antibiotic-resistant bacteria, making bacterial infections more challenging. The increasing prevalence of multidrug-resistant pathogens has driven researchers to explore novel therapeutic strategies. Phototherapy strategies that utilize photo-responsive biomaterials for their antibacterial properties have gained widespread attention due to their capability of precisely controlling bacterial inactivation with minimal side effects. Despite their potential, photodynamic therapies suffer from phototoxicity and low efficiency of photosensitizers, while photothermal therapy risks overheating, which may harm healthy tissues, thus restricting its broader application. Metal organic frameworks (MOFs) have unique physicochemical properties, which provide a promising way to deal with these challenges. MOFs can function as reservoirs, loading and releasing antibacterial agents, such as antibiotics or metal ions, upon light illumination by virtue of their metastable coordination bonds. Their porous structures enable controlled drug release and encapsulation of photosensitizers. Furthermore, MOFs' tunable composition and pore structure allow for the light-triggered generation of heat and reactive oxygen species, enhancing their antibacterial effectiveness. By doping MOFs with functional materials, it is possible to achieve multi-mode antibacterial effects. In this review, we will outline recent advancements of photo-responsive antibacterial MOFs, categorize their underlying mechanisms of action and highlight their prospects in addressing bacterial resistance.

A novel separated OPECT aptasensor based on MOF-derived BiVO4/Bi2S3 type-II heterojunction for rapid detection of bacterial quorum sensing signal molecules

Quorum sensing signal molecules released by microorganisms serve as critical biomarkers regulating the attachment and aggregation of marine microbes on engineered surfaces. Hence, the development of efficient and convenient methods for detecting quorum sensing signal molecules is crucial for monitoring and controlling the formation and development of marine biofouling. Advanced optoelectronic technologies offer increased opportunities and methods for detecting quorum sensing signal molecules, thereby enhancing the accuracy and efficiency of detection. This study proposes a CAU-17-derived BiVO4/Bi2S3 gated organic photoelectrochemical transistor (OPECT), and applies it to the detection of a typical quorum sensing signal molecule, N-(3-oxodecanoyl)-l-homoserine lactone (3-O-C10-HL). A strategy of signal amplification and separate detection process was employed. Specifically, BiVO4/Bi2S3 type-II heterojunction photoanode was fabricated and successfully utilized for effective gating of the poly (ethylene dioxythiophene): poly (styrene sulfonate) channel. Using the previously screened 3-O-C10-HL adaptor, rapid and sensitive recognition of 3-O-C10-HL was achieved by effectively enhancing the response of the photoanode and regulating the overall performance of the device. The designed device demonstrated excellent specificity and sensitivity with a detection limit of 2.85 pM. This work not only provides an effective OPECT biosensing approach for detecting 3-O-C10-HL, but also reveals the application potential of semiconductor MOFs-derived materials in future optoelectronics.

Mannitol in direct compression: Production, functionality, critical material attributes and co-processed excipients

In recent years, mannitol has been widely used in the pharmaceutical industry as a substitute for lactose. Mannitol is widely available and can be produced by a variety of methods. Due to its water solubility, low hygroscopicity and chemical inertness, it is commonly added to various formulations, especially tablet formulations. A better understanding of the Critical Material Attributes (CMAs) of raw materials can help guide tablet quality improvement and mannitol development based on quality by design. In addition, co-processing of mannitol can introduce more desirable properties to the resulting particles. In this review, we focused specifically on the recent advances and development of mannitol on direct compression (DC) tableting, including the functions in tablet formulations, potential CMAs, and mannitol-based co-processed excipients, therefore providing a reference for further studies.