Stable Metal-Organic Frameworks: Design, Synthesis, and Applications

Triazine-Based Hexacarboxylate Metal-Organic Framework Crystalline Materials: Synthesis, Structural Characterization, and Fluorescence Response toward NACs and Small Drug Molecules

A new triazine-based polycarboxylate metal-organic framework with a three-dimensional microporous structure, (H3O)2·[Eu2(TDPAT)4/3(μ-H2O)]·7H2O·EtOH·5DMA (complex 1), was constructed by the reaction of the ligand 2,4,6-tris(3,5-dicarboxyaniline)-1,3,5-triazine (H6TDPAT) and EuCl3·6H2O under solvothermal conditions. It was characterized by infrared spectroscopy (IR), ultraviolet-visible (UV-vis) spectra, fluorescence spectra, powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis, etc. Structural analysis shows that the three-dimensional microporous structure is constructed by a binuclear structural unit [Eu2(COO)2(μ-H2O)] and a TDPAT ligand. Fluorescence sensing exploration was conducted for complex 1, and experiments found that various drug molecules and phenolic compounds are responsible for the observed fluorescence quenching. Among them, the fluorescence quenching constant KSV of complex 1 for the drug molecule moxifloxacin hydrochloride is as high as 1.57 × 105 M-1. In addition, it was found that the detection effect of complex 1 for nitrophenols is superior to that of chlorinated phenols. Therefore, complex 1 is expected to become a multifunctional fluorescent sensor in the future.

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.

A metal-organic framework-derived α-MnS/MWCNT composite as a promising pseudocapacitive material for a flexible quasi-solid-state asymmetric supercapacitor device

The low conductivity of traditionally used pseudocapacitive materials like transition metal oxides has forced researchers to look for alternative materials. Transition metal sulfides are being investigated as viable alternative materials and have shown promising results. In this work, an α-MnS/MWCNT composite is selected as the active material for supercapacitor application. α-MnS has better conductivity than many transition metal oxides but has an extremely low specific surface area (10.5 m2 g-1), which reduces its specific capacitance. Metal-organic framework (MOF)-derived materials are known to possess higher specific surface area and favorable pore size distribution. Herein, α-MnS/MWCNT composites are synthesized via two routes: the conventional solvothermal technique and the MOF route, and their performance is compared. It is proved that the α-MnS/MWCNT composite synthesized through the MOF route shows a favorable porous structure and better performance than the composite synthesized through the conventional route. It shows a specific surface area of 47.6 m2 g-1 and a specific capacitance of 546.3 F g-1 at 1 A g-1 with a mass loading of 1.5 mg cm-2 in 3 M KOH under a 3-electrode configuration. A flexible quasi-solid-state asymmetric supercapacitor device is fabricated with MOF-derived α-MnS/MWCNT as the positive electrode material, and the device achieved a potential window of 1.4 V, a specific capacitance of 82.5 F g-1 at 1 A g-1 and a capacitance retention of 90.1% after 5000 cycles at 10 A g-1. The results clearly indicate that transition metal sulfides like MOF-derived α-MnS can be a viable alternative to traditional materials like transition metal oxides. The assembled device has the potential to power flexible, wearable electronics.

C2H2/CO2 Separation by a Carborane Hybrid 2D Metal-Organic Framework

The separation of acetylene (C2H2) from carbon dioxide (CO2) is important in industry but challenging due to their similar physical properties. Herein, a boron-rich 2D metal-organic framework ZNU-14 based on the carborane backbone was readily prepared by the supramolecular assembly of Zn2+, p-C2B10H10-(COOH)2, and di(pyridin-4-yl) amine under mild conditions for C2H2/CO2 separation. ZNU-14 displays a straight 1D channel (7.6 × 12.5 Å2) with an electronegative pore surface. Gas adsorption isotherms show that ZNU-14 has a good C2H2 adsorption capacity of 43.6 cm3 g-1, 181% of the CO2 uptake capacity. The calculated ideal adsorbed solution theory (IAST) selectivity is as high as 6.3-9.7, outperforming many popular materials. The moderate C2H2 adsorption heat of 34.3 kJ mol-1 facilitates the straightforward desorption and regeneration of ZNU-14. Furthermore, the theoretical study confirmed the stronger binding of C2H2 compared to that of CO2. The practical C2H2/CO2 separation performance was fully demonstrated by breakthrough experiments with excellent dynamic selectivity and recyclability under various conditions.

pH-Dependent Structural Engineering of Sulfonate-Carboxylate Cu-MOFs for High Proton Conductivity

Metal-organic frameworks (MOFs) with free carboxylic acid (COOH) groups are promising for solid-state proton-conducting materials, owing to the Brønsted acidity, polarity, and the hydrogen-bonding ability of COOH groups. In this work, two Cu-MOFs with different dimensions were synthesized by adjusting the pH of the reaction solution using disodium-2,2'-disulfonate-4,4'-oxidibenzoic acid (Na2H2DSOA) and 4,4'-bipyridine (4,4'-bpy) as ligands to coordinate with Cu(II). The resulting compounds, CuDSOA-1 (([Cu(4,4'-bpy)2(H2O)2][Cu(H2DSOA)2(4,4'-bpy)(H2O)2]·12H2O)) and CuDSOA-2 ([Cu2(DSOA)(4,4'-bpy)2(H2O)2]·4H2O), have distinct dimensionalities and structures, mainly due to the pH's effect on carboxylic acid deprotonation. Notably, CuDSOA-1 with abundant COOH groups, uncoordinated sulfonate groups, and water molecules shows a significantly enhanced proton conductivity of 2.46 × 10-2 S cm-1 at 95 °C and 98% RH, surpassing CuDSOA-2 (3.40 × 10-5 S cm-1 at 85 °C and 98% RH). The conductivity mechanism was found to be a Grotthuss mechanism, confirmed by deuterium-hydrogen isotopic effects. This study offers a method to control the coordination of sulfonic-carboxylic acid ligands with Cu(II) by pH adjustment, aiming to create MOFs with ultrahigh proton conductivity.

Advanced Solid Lubrication with COK-47: Mechanistic Insights on the Role of Water and Performance Evaluation

Metal-organic framework (MOF) nanoparticles have attracted widespread attention as lubrication additives due to their tunable structures and surface effects. However, their solid lubrication properties have been rarely explored. This work introduces the positive role of moisture in solid lubrication in the case of a newly described Ti-based MOF (COK-47) powder. COK-47 achieves an 8.5-fold friction reduction compared to AISI 304 steel-on-steel sliding under room air. In addition, COK-47 maintains a similarly low coefficient of friction (0.1-0.2) on various counterbodies, including Al2O3, ZrO2, SiC, and Si3N4. Notably, compared to other widely studied MOFs (ZIF-8, ZIF-67) and 2D materials powder (MXene, TMD, rGO), COK-47 exhibits the lowest friction (≈0.1) under the same experimental settings. Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscope, and transmission electron microscopy indicate that the tribofilm is an amorphous film obtained by hydrolysis of COK-47 in the air with moisture. Density functional theory further confirms that water catalyzes the decomposition of COK-47, a crucial step in forming the tribofilm. This study demonstrates the idea of utilizing MOF and water-assisted lubrication mechanisms. It provides new insights into MOF applications in tribology and highlights interdisciplinary contributions of mechanical engineering and chemistry.

Synthesis and Characterisation of Multivariate Metal-Organic Frameworks for Controlled Doxorubicin Absorption and Release

The development of drug carriers with efficient absorption and controlled delivery properties is crucial for advancing medical treatments. Metal-organic frameworks (MOFs) with tunable porosity and a large surface area represent a promising class of materials for this application. Among them, NUIG4 stands out as a biocompatible MOF that exhibits exceptionally high doxorubicin (Dox) absorption (1995 mg dox/g NUIG4) and pH-controlled release properties. In this study, we report the synthesis and characterisation of multivariate MOFs (MV-NUIG4), which are analogues of NUIG4 that maintain the same topology while incorporating different functional groups within their framework. Eight new MV-NUIG4 MOFs have been synthesised through in situ reactions of the corresponding 4-aminobenzoic acid derivative with 4-formylbenzoic acid. The compounds were thoroughly characterised using a range of techniques, including powder X-ray diffraction, infrared spectroscopy, 1H-NMR, and single-crystal X-ray crystallography. The experimental ratio of the reagents and ligand precursors for the synthesis of MV-NUIG4 MOFs matched the ratio of the linkers in the final products. These structures incorporate additional functional groups, such as methyl and hydroxyl, in varying ratios. Computational modelling was used to provide further insight into the crystal structure of the MOFs, revealing a random distribution of the functional groups in the framework. The Dox absorption and release capacity of all analogues were studied, and the results revealed that all analogues displayed high drug absorption in the range of 1234-1995 mg Dox/g MOF. Furthermore, the absorption and release rates of the drug are modulated by the ratio of functional groups, providing a promising approach for controlling drug delivery properties in MOFs.

Pushing the Frontiers: Artificial Intelligence (AI)-Guided Programmable Concepts in Binary Self-Assembly of Colloidal Nanoparticles

Colloidal nanoparticle self-assembly is a key area in nanomaterials science, renowned for its ability to design metamaterials with tailored functionalities through a bottom-up approach. Over the past three decades, advancements in nanoparticle synthesis and assembly control methods have propelled the transition from single-component to binary assemblies. While binary assembly has been recognized as a significant concept in materials design, its potential for intelligent and customized assembly has often been overlooked. It is argued that the future trend in the assembly of binary nanocrystalline superlattices (BNLSs) can be analogous to the '0s' and '1s' in computer programming, and customizing their assembly through precise control of these basic units could significantly expand their application scope. This review briefly recaps the developmental trajectory of nanoparticle assembly, tracing its evolution from simple single-component assemblies to complex binary co-assemblies and the unique property changes they induce. Of particular significance, this review explores the future prospects of binary co-assembly, viewed through the lens of 'AI-guided programmable assembly'. Such an approach has the potential to shift the paradigm from passive assembly to active, intelligent design, leading to the creation of new materials with disruptive properties and functionalities and driving profound changes across multiple high-tech fields.

Direct Photopatterning of Zeolitic Imidazolate Frameworks via Photoinduced Fluorination

Precise and effective patterning strategies are essential for integrating metal-organic frameworks (MOFs) into microelectronics, photonics, sensors, and other solid-state devices. Direct lithography of MOFs with light and other irradiation sources has emerged as a promising patterning strategy. However, existing direct lithography methods often rely on the irradiation-induced amorphization of the MOFs structures and the breaking of strong covalent bonds in their organic linkers. High-energy sources (such as X-rays or electron beams) and large irradiation doses - conditions unfavorable for scalable patterning - are thus required. Here, we report a photoinduced fluorination chemistry for patterning various zeolitic imidazolate frameworks (ZIFs) under mild UV irradiation. Using UV doses as low as 10 mJ cm-2, light-sensitive fluorine-containing molecules covalently bond to ZIFs and enhance their stability in water. This creates a water-stability contrast between ZIFs in exposed and unexposed regions, enabling scalable direct photolithography of ZIFs with high resolution (2 μm) on 4-inch wafers and flexible substrates. The patterned ZIFs preserve their original crystallinity and porous properties while gaining increased hydrophobicity. This allows for the demonstration of a water-responsive fluorescent MOFs array with implications in sensing and multicolor information encryption.

In situ generated hydrogen-bonding microenvironment in functionalized MOF nanosheets for enhanced CO2 electroreduction

The microenvironment around catalytic sites plays crucial roles in enzymatic catalysis while its precise control in heterogeneous catalysts remains challenging. Herein, the coordinatively unsaturated metal nodes of Hf-based metal-organic framework nanosheets are simultaneously codecorated with catalytically active Co(salen) units and adjacent pyridyl-substituted alkyl carboxylic acids via a post modification route. By varying pyridyl-substituted alkyl carboxylic acids, the spatial positioning of the N atom in pyridine group relative to adjacent Co(salen) can be precisely controlled. Notably, the 3-(pyridin-4-yl)propionic acid, with para-position pyridine N atom, maximally improves the electrocatalytic CO2 reduction performance of Co(salen) unit, far superior to other counterparts. Mechanism investigations reveal that the pyridine unit of 3-(pyridin-4-yl)propionic acid is optimally positioned relative to Co(salen) and undergoes in situ reduction to pyridinyl radical under working potentials. This greatly facilitates the stabilization of *COOH intermediate via hydrogen-bonding interaction, lowering the formation energy barrier of *COOH and therefore boosting CO2 electroreduction.

Metal pyrazolate frameworks: crystal engineering access to stable functional materials

As the focus evolves from structure discovery/characterization (what it is) to property/performance exploration (what it is for), the pursuit of stable functional metal-organic frameworks (MOFs) has been ongoing in terms of both fundamental research and industrial implementation. Under the guidance of crystal engineering principles, a plethora of research has developed pyrazolate MOFs (metal pyrazaolate frameworks, MPFs) featuring strong coordination M-N bonding. This attribution helps them retain their structures and functions under the alkaline conditions required for practical use. Based on poly-topic pyrazolate ligands, various classic MOFs, such as Co(bdp), Fe2(BDP)3, Ni8L6, PCN-601, and BUT-55, to name a few, have revealed fascinating architectures, intriguing properties, and record-breaking performances in applications during the past decade. This review will present the full scope of MPFs to date: (1) the superiority and significance of constructing MPFs through the crystal engineering approach, (2) synthetic strategies adopted in building and/or modifying MPFs, (3) structural features and stability of the MPF community, and (4) potential applications in energy and environmental related fields. The future opportunities of MPFs are also discussed for designing the next-generation of smart materials. Overall, this review attempts to provide insights and guidelines for the customization of pyrazolate-based MOFs for specific purposes, which would also promote the development of stable functional porous materials for addressing societal challenges.

Tailoring of Unsaturated Metal Sites in Metal-Organic Frameworks to Promote the Conversion of CO2 into High-Value-Added Products

Well-defined metal-organic frameworks (MOFs) provide an attractive platform for catalysis. Understanding the intrinsic structure-activity relationship of MOFs helps guide the design of novel catalysts. In this work, a new three-dimensional (3D) MnII(salen)-based MOF (1) with strong adsorption capacity and high selectivity for CO2 was synthesized. Through sequential demetallization and remetallization, the flexible tailoring of the metal centers was realized to obtain a series of remetallized MOFs (r1M; M = Mn, Co, Cu, Ni, V). Among them, r1Co was proved to be the most active catalyst for the cycloaddition of CO2 and epoxides. Mechanistic studies reveal that r1Co displays a high CO2 affinity and Lewis acidity. In addition, kinetic studies suggest that r1Co has a lower activation energy than the original MOF (1) and demetallized MOF (d1). Remarkably, r1Co could be reused five times without affecting its catalytic activity.

Water-Stable MIL-MOFs Developed Through a Novel Sacrifice-Protection Strategy Inspired by Butterfly Wings' Scales for Long-Term Turn-On Fluorescence Sensing of H2S

Metal-organic frameworks, which are the desired candidates for biosensing application due to their tunable properties, are significantly hindered by their rapid degradation in aqueous solutions, as well as the loss of their inherent fluorescence. Most studies aim to improve the hydrophobicity of materials by modifying their contact angle, thereby enhancing water stability. However, water droplets poorly adhere to the surface of hydrophobic materials, limiting their application for direct contact and detection in aqueous environments. Drawing inspiration from the sacrificial protection mechanism of butterfly wings used to evade predation and entanglement, a universal approach is successfully developed to protect water-sensitive MIL-MOFs from water molecule attack while preserving good hydrophilicity. Using the organic ligand 2,2'-bipyridine-5,5'-dicarboxylic acid (bpydc) as sacrificial protection scales, the MIL-125-NH2-bpydc demonstrated broad pH structural stability (pH 2-12) and fluorescence stability increased by 10.17 time in aqueous solutions, achieving the highest performance in MILMOFs. The MIL-125-NH2-bpydc is biocompatible enabling it to perform long-term fluorescence imaging in living cells and zebrafish, further detecting hydrogen sulfide (H2S) in the aqueous and biological systems via turn-on fluorescence emission. This study offers a novel and universal sacrifice-protection strategy for the design and development of the luminescent biocompatible MOFs tailored for biosensing applications.

Engineered Metal-Organic Frameworks for Targeted CRISPR/Cas9 Gene Editing

The development of precise and efficient delivery systems is pivotal for advancing CRISPR/Cas9 gene-editing technologies, particularly for therapeutic applications. Engineered metal-organic frameworks (MOFs) have emerged as a promising class of inorganic nonviral vectors, offering unique advantages such as tunable porosity, high cargo-loading capacity, and biocompatibility. This review explores the design and application of MOF-based nanoplatforms tailored for the targeted delivery of CRISPR/Cas9 components, aiming to enhance gene-editing precision and efficiency. By incorporating stimuli-responsive linkers and bioactive ligands, these MOFs enable controlled release of CRISPR/Cas9 payloads at the target site. Comparative discussions demonstrate superior performance of MOFs over conventional nonviral systems in terms of stability, transfection efficiency, and reduced off-target effects. Additionally, the intracellular trafficking mechanisms and the therapeutic potential of these platforms in preclinical models are discussed. These findings highlight the transformative potential of MOF-based delivery systems in overcoming the challenges associated with gene-editing technologies, such as immunogenicity and cytotoxicity, paving the way for their application in precision medicine. This review provides a blueprint for the integration of nanotechnology and genome editing, advancing the frontier of nonviral therapeutic delivery systems.

Strategic Secondary Ligand Selection for Enhanced Pore-Type Construction and Water Purification Capacity in Zeolitic Imidazolate Frameworks

Selective ligand removal (SeLiRe) is a powerful strategy for constructing novel pore-type and ligand-defective structures in metal-organic frameworks (MOFs), but few studies have focused on the effect of secondary ligands with different functional groups on this process. We synthesized versions of zeolitic imidazolate framework-8 with six different secondary ligands and comprehensively investigated their pore-type structures after SeLiRe treatment. Their pore volume, size, and distribution are closely related to the respective organic functional groups on the secondary ligands. NH2-functionalized ligands tend to form larger domains and have weaker Zn-Nβ covalent bonds, which facilitate the removal process and the construction of larger cavities. Among the six secondary ligands, 5-bromo-1H-benzo[d]imidazol-2-amine exhibits the composite pore-type structure with hierarchical micro- and mesopores, achieving the highest methylene blue adsorption capacity of 28.1 mg g-1. Compared to traditional sodalite-type ZIFs, this results in a 53-fold increase in water pollutant adsorption. This work highlights the crucial role of the secondary ligand in the SeLiRe strategy and provides valuable insights for designing other hierarchical porous hybrid structures.

High-Performance Overall Water Splitting Dominated by Direct Ligand-to-Cluster Photoexcitation in Metal-Organic Frameworks

Expanding the spectral response of photocatalysts to facilitate overall water splitting (OWS) represents an effective approach for improving solar spectrum utilization efficiency. However, the majority of single-phase photocatalysts designed for OWS primarily respond to the ultraviolet region, which accounts for a small proportion of sunlight. Herein, we present a versatile strategy to achieve broad visible-light-responsive OWS photocatalysis dominated by direct ligand-to-cluster charge transfer (LCCT) within metal-organic frameworks (MOFs). Three synthesized OWS MOFs, namely Fe2MCbz (M2+ = Mn2+, Co2+, Ni2+), exhibited intrinsic OWS capability without the requirement for extra photosensitizer or sacrificial agent or cocatalyst. Among these, Fe2NiCbz was identified as the superior performer, and when dispersed with polyacrylonitrile nanofibers using electrospinning technology, it achieved the highest OWS rates of 170.2 and 85.1 μmol g-1 h-1 for H2 and O2 evolution, surpassing all previously documented MOF-based photocatalysts. Experimental and theoretical analyses revealed that direct LCCT played a crucial role in enhancing the photocatalytic efficiency, with exceptional performance of Fe2NiCbz attributed to its well-optimized energy level structures and highly efficient charge transfer mechanism. This work not only sets a benchmark in OWS MOF photocatalysts but also paves the way for maximizing solar spectrum utilization, thereby advancing renewable hydrogen production strategy.

Hydroxyl-induced structural defects in metal-organic frameworks for improved photocatalytic decontamination: Accelerated exciton dissociation and hydrogen bonding interaction

The introduction of structural defects can improve the charge separation efficiency of metal-organic frameworks (MOFs)-based photocatalysts, which however come with suboptimal decontamination performance, due to steric hindrance and limited binding capacity of the involved modulators. In this work, hydroxyl group capturing the advantages of both worlds was utilized as new modulator to improve the photocatalytic performance of Fe-based defective MOFs. Benefited from its low steric effect and strong coordination bonding capability, hydroxyl-induced defects in Fe-MOF contributed to a nearly 8-fold increase of rate constant for the photocatalytic removal of hexavalent chromium (Cr(VI)) compared to that of pristine one, which also exceeded the defective one induced by acetic acid as modulator. A combination of characterizations and theoretical calculations suggests that hydroxyl-induced structural defects fostered faster kinetics of exciton dissociation and optimal charge separation. The higher electron utilization through hydrogen bonding interaction between these hydroxyl-induced structural defects and contaminant was further confirmed by ab initio molecular dynamics (AIMD) simulations. This work presents a simple yet robust strategy for the generation of defective MOFs, upon which efficient photoreduction systems toward Cr(VI) removal are anticipated.

An ecofriendly iron MOF-based immunosensor for sensitive detection of vascular endothelial growth factor in the serum of cancer patients

This work demonstrates the potential of an iron-based metal-organic framework, MIL-100(Fe), to effectively modify a multi-wall carbon nanotube (MWCNT) screen-printed electrode (SPE) for enhanced electrochemical immunosensing of vascular endothelial growth factor (VEGF), which has been recently considered a promising tumor biomarker. MIL-100(Fe) has been synthesized using an ecofriendly, sustainable, heatless water-based technique at various synthesis reaction times. The morphological, structural and electrochemical properties of the different samples of MIL-100(Fe) were evaluated using several physical and electrochemical techniques. MIL-100(Fe) after 48 h has a crystalline microporous-mesoporous structure, with superior properties, that is a larger BET surface area of 1082 ± 18 m2 g-1, a larger pore volume of 0.696 cm3 g-1 and better electroconductivity. After optimizing the experimental conditions, the MIL-100(Fe) 48 h/MWCNTs/SPE-based immunosensor showed a linear range between 100 and 480 pg mL-1, a LOD of 50 pg mL-1 (3σ/S), a sensitivity of 0.017 mA mL pg-1, good reproducibility and high selectivity. In addition, the developed immunosensor was used to satisfactorily detect VEGF in human serum samples of cancer patients, compared to the traditional ELISA method. Considering the sustainable and easy fabrication of the proposed platform, it may provide a promising application as a point-of-care (PoC) device for VEGF detection for diagnosis of cancer.

Bimetallic NiCu-MOF Protects DOX-Induced Myocardial Injury and Cardiac Dysfunction by Suppressing Ferroptosis and Inflammation

Doxorubicin (DOX), a potent anthracycline chemotherapeutic agent, is widely used in cancer treatment but is associated with significant adverse effects, particularly DOX-induced cardiomyopathy (DIC). DIC pathogenesis involves the generation of reactive oxygen species (ROS) and ferroptosis induction. Novel therapeutic strategies targeting antioxidant defenses and ferroptosis inhibition are essential for mitigating DIC. An innovative bimetallic metal-organic framework (MOF), NiCu-MOF (NCM), is developed, exhibiting multifaceted antioxidant enzyme-mimicking activities that effectively scavenge a broad spectrum of ROS. Additionally, the bimetallic NCM exhibits excellent iron-chelating ability. In vitro experiments demonstrate that NCM significantly reduces cardiomyocyte death by attenuating ROS levels and inhibiting ferroptosis. Furthermore, in a mouse model of DIC, NCM treatment results in substantial myocardial protection, evidenced by improved cardiac function and structural integrity. This protective effect is attributed to suppression of ferroptosis, preservation of mitochondrial function, and attenuation of inflammatory responses. Collectively, these findings highlight biocompatible NCM's potential as a novel cardioprotective agent and offer a promising therapeutic strategy for managing DIC.

Synergistic cancer treatment using porphyrin-based metal-organic Frameworks for photodynamic and photothermal therapy

Recent advancements in multifunctional nanomaterials for cancer therapy have highlighted porphyrin-based metal-organic frameworks (MOFs) as promising candidates due to their unique properties and versatile applications. This overview focuses on the use of porphyrin-based MOFs for combined photodynamic therapy (PDT) and photothermal therapy (PTT) in cancer treatment. Porphyrin-based MOFs offer high porosity, tuneable structures, and excellent stability, making them ideal for drug delivery and therapeutic applications. The incorporation of porphyrin molecules into the MOF framework enhances light absorption and energy transfer, leading to improved photodynamic and photothermal effects. Additionally, the porosity of MOFs allows for the encapsulation of therapeutic agents, further enhancing efficacy. In PDT, porphyrin-based MOFs generate reactive oxygen species (ROS) upon light activation, destroying cancer cells. The photothermal properties enable the conversion of light energy into heat, resulting in localised hyperthermia and tumour ablation. The combination of PDT and PTT in a single platform offers synergistic effects, leading to better therapeutic outcomes, reduced side effects, and improved selectivity. This dual-modal treatment strategy provides precise spatiotemporal control over the treatment process, paving the way for next-generation therapeutics with enhanced efficacy and reduced side effects. Further research and optimisation are needed for clinical applications.

Cyborg microbe biohybrids with metal-organic coating layers: Strategies, functionalisation and potential applications

The integration of living microbes, specifically bacteria and fungi, with metal-organic nanocoatings has led to the recent development of cyborg microbe biohybrids, which show excellent adaptability and functionality for a wide range of potential applications in biotechnology and medicine. This review discusses the strategies, functionalisation, and applications of these biohybrids, which are categorised into two types of coatings: metal-organic frameworks (MOFs) and metal-phenolic networks (MPNs). Key advances in their synthetic approaches via in-situ and pre-synthesised coatings are crucially addressed, and yet the methodology details and specific advantages are highlighted. Despite the notable advancements, there are various limitations and challenges, such as determination of the long-term viability and stability of the biohybrids, insufficient work on their theranostic applications and essentially scaling-up difficulties for industrial and clinical translation. The latest advancements in the biohybrids and related technology have established a critical foundation for enhancing innovative studies through the strong interdisciplinary teamwork.

Metal-Organic Frameworks (MOFs): Multifunctional Platforms for Environmental Sustainability

Metal-Organic Frameworks (MOFs) have emerged as versatile materials bridging inorganic and organic chemistry to address critical environmental challenges. Composed of metal nodes and organic linkers, these crystalline structures offer unique properties such as high surface area, tunable pore sizes, and structural diversity. Recent advancements in MOFs synthesis, particularly innovative approaches like mechanochemical, microwave-assisted, and ultrasonic synthesis, have significantly enhanced sustainability by utilizing non-toxic solvents, renewable feedstocks, and energy-efficient processes, offering promising solutions to reduce environmental impact. This review highlights these novel methods and their contributions to improving MOFs functionality for applications in environmental remediation, gas capture, and energy storage. We examine the potential of MOFs in catalysis for pollutant degradation, water purification, and hazardous waste removal, as well as their role in next-generation energy storage technologies, such as supercapacitors, batteries, and hydrogen production. Furthermore, we address challenges including scalability, stability, and long-term performance, underscoring the need for continued innovation in synthesis techniques to enable large-scale MOFs applications. Overall, MOFs hold transformative potential as multifunctional materials, and advancements in synthesis and sustainability are critical for their successful integration into practical environmental and energy solutions.

Ruthenium-Picolylamine-Incorporated Mixed-Linker MOFs: Highly Active Heterogeneous Catalysts for Olefin and Aldehyde Hydrogenation

The selective hydrogenation of aldehydes and olefins plays a crucial role in the synthesis of various industrial products. Immobilizing noble metal catalysts on solid supports has been pursued to overcome the challenges associated with catalyst separation and recovery. In this study, we explore the use of metal-organic frameworks (MOFs) as supports for the immobilization of molecular ruthenium catalysts in the hydrogenation of olefins and aldehydes. We designed a mixed-linker MOF by incorporating the picolylamine moiety, which is a ligand known for its excellent catalytic activity. The ruthenium catalysts were prepared via a simple metal-ligand coordination process without the need for additional treatments. The resulting catalysts exhibit high catalytic activity and a uniform distribution of ruthenium sites on the MOF crystals. The choice of ruthenium precursor has a significant influence on the catalytic performance, with even lower metal content resulting in higher activity. The catalysts achieve high conversion rates and selectivities in the hydrogenation of various olefins. However, in the hydrogenation of aldehydes, due to the harsher conditions required, the formation of small nanoparticles is observed after the reaction. Overall, our findings highlight the potential of picolylamine-modified MOFs as effective supports for the development of highly active heterogeneous catalysts for selective hydrogenation reactions.

Enzyme-Photocoupled Catalytic Systems Based on Zirconium-Metal-Organic Frameworks

Green, low-carbon, and efficient chemical conversions are crucial for the sustainable development of modern society. Enzyme-photocoupled catalytic systems (EPCS), which mimic natural photosynthesis, utilize solar energy to drive biochemical reactions, providing emergent opportunities to address the limitations of traditional photocatalytic systems. However, the integration and compatibility of photocatalysis and biocatalysis present challenges in designing highly efficient and stable EPCS. Zirconium-based metal-organic frameworks (Zr-MOFs) with outstanding chemical and thermal stability, large surface area, and tunable pore size are ideal candidates for supporting enzymes and enhancing photocatalytic processes. This review aims to integrate Zr-MOFs with EPCS to further promote the development of EPCS. First, an overview of the basic components and design principles of EPCS is provided, highlighting the importance of the unique properties of Zr-MOFs. After that, three different strategies for combining enzymes with Zr-MOFs are summarized and their respective advantages are evaluated. Finally, the development opportunities and some problems to be solved in this field are proposed.

Ionic porous materials: from synthetic strategies to applications in gas separation and catalysis

Ionic porous materials possess a unique combination of tunable pore sizes and task-specific interactions between guest molecules and the charged frameworks, which endow them with versatility across diverse domains in chemistry and materials science. Significant advancements in their applications for gas separation and catalysis have been achieved in recent years due to the incorporation of ionic functionalities and ultra-microporous structures that enable molecular-scale recognition of guest molecules. This review summarizes recent advancements in the synthetic strategies of ionic porous materials, establishing design guidelines for the incorporation of ionic moieties into the backbone to fine-tune pore sizes and chemistry. It highlights the synergistic interplay of task-specific interactions with custom-designed pore structures in key applications, including adsorption separation, membrane separation, and gas conversion. Additionally, it examines structure-property relationships, offering deeper insights into enhancing performance. The report also addresses the current challenges in the practical application of these materials. Finally, the review provides future perspectives on ionic porous materials from both scientific and industrial viewpoints. Overall, this review aims to provide insights into pore structure and chemistry, supporting the precise placement of ionic functionalities.

Functional crystalline porous framework materials based on supramolecular macrocycles

Crystalline porous framework materials like metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs) possess periodic extended structures, high porosity, tunability and designability, making them good candidates for sensing, catalysis, gas adsorption, separation, etc. Despite their many advantages, there are still problems affecting their applicability. For example, most of them lack specific recognition sites for guest uptake. Supramolecular macrocycles are typical hosts for guest uptake in solution. Macrocycle-based crystalline porous framework materials, in which macrocycles are incorporated into framework materials, are growing into an emerging area as they combine reticular chemistry and supramolecular chemistry. Organic building blocks which incorporate macrocycles endow the framework materials with guest recognition sites in the solid state through supramolecular interactions. Distinct from solution-state molecular recognition, the complexation in the solid state is ordered and structurally achievable. This allows for determination of the mechanism of molecular recognition through noncovalent interactions while that of the traditional recognition in solution is ambiguous. Furthermore, crystalline porous framework materials in the solid state are well-defined and recyclable, and can realize what is impossible in solution. In this review, we summarize the progress of the incorporation of macrocycles into functional crystalline porous frameworks (i.e., MOFs and COFs) for their solid state applications such as molecular recognition, chiral separation and catalysis. We focus on the design and synthesis of organic building blocks with macrocycles, and then illustrate the applications of framework materials with macrocycles. Finally, we propose the future directions of macrocycle-based framework materials as reliable carriers for specific molecular recognition, as well as guiding the crystalline porous frameworks with their chemistry, applications and commercialization.

Latest developments in the synthesis of metal-organic frameworks and their hybrids for hydrogen storage

Metal-organic frameworks (MOFs) are promising materials for hydrogen (H2) storage due to their versatile structures, high surface areas and substantial pore volumes. This paper provides a comprehensive review of MOF synthesis and characterization, as well as their practical applications for H2 storage. We explore various MOF synthesis techniques, highlighting their impact on the nanopore structure and functionality. Special emphasis is placed on strategies for enhancing H2 storage capacities by increasing specific surface areas, optimizing pore size distributions, and facilitating H2 release by improving thermal conductivity. Key advances in MOF-based hybrids, such as MOFs combined with carbonaceous materials, metals or other inorganic materials, are discussed. This review also addresses the effectiveness of linker functionalization and the introduction of unsaturated metal centers to optimize H2 storage under ambient conditions. We conclude that the development of competitive MOF-based hybrids, particularly those that incorporate carbons, offers significant potential for improving H2 storage and recovery, enhancing thermal stability and increasing thermal conductivity. These advancements are in line with the US Department of Energy (DOE) specifications and pave the way for future research into the optimization of MOFs for practical H2 storage applications.

One-Pot Synthesis of Hydrophobic Porphyrin Zirconium-Based MOFs for the Photoreduction of CO2 to Formate

Using zirconium tetrachloride as a metal source and tetra(4-carboxyphenyl)porphyrin as a ligand and by in situ introducing octadecylphosphonic acid (OPA), three hydrophobic porphyrin zirconium metal-organic frameworks (MOFs) with different structural topologies were constructed, where these MOFs are labeled as OPA@PCN-222, OPA@PCN-223, and OPA@PCN-224. Compared with the original Zr-MOFs without the modification of OPA, the modified porphyrin Zr-MOFs show excellent hydrophobic properties and can maintain excellent stability in a long-term humidity environment. Meanwhile, OPA@PCN-222, OPA@PCN-223, and OPA@PCN-224 exhibit wide absorption of visible light and steadfast and expeditious photocurrent response by leveraging the properties of porphyrin ligands. When illuminated by visible light, the hydrophobic Zr-MOFs demonstrate an efficient reduction of CO2 to HCOO-, achieving average reaction rates of 330, 260, and 258 μmol·h-1·g-1 for OPA@PCN-222, OPA@PCN-223, and OPA@PCN-224. These rates are 1.13-1.41 times higher than that of the original porphyrin Zr-MOFs. The mechanism study shows that both the porphyrin ligands and the Zr-O clusters serve as catalytically active sites, enabling the conversion of CO2 to HCOO-. This research shows that the introduction of hydrophobic alkyl chains can effectively enhance the stability of MOFs under a humid environment while maintaining their catalytic activity, which provides a reference for improving the comprehensive performance of MOF catalysts.

A Hydrolytically Stable Metal-Organic Framework for Simultaneous Desulfurization and Dehydration of Wet Flue Gas

Metal-organic frameworks (MOFs) have great prospects as adsorbents for industrial gas purification, but often suffer from issues of water stability and competitive water adsorption. Herein, we present a hydrolytically stable MOF that could selectively capture and recover trace SO2 from flue gas, and exhibits remarkable recyclability in the breakthrough experiments under wet flue-gas conditions, due to its excellent resistance to the corrosion of SO2 and the water-derived capillary forces. More strikingly, its SO2 capture efficiency is barely influenced by the increasing humidity, even if the pore filling with water is reached. Mechanistic studies demonstrate that the delicate pore structure with diverse pore dimensions and chemistry leads to different adsorption kinetics and thermodynamics as well as segregated adsorption domains of SO2 and H2O. Significantly, this non-competitive adsorption mechanism enables simultaneous desulfurization and dehydration by a single adsorbent, opening an avenue toward cost-effective and simplified processing flowcharts for flue gas purification.

Manipulating Hydrogen-Bonding Donor/Acceptor in Ultra-Robust Isoreticular Zr(IV) Metal-Organic Frameworks for Efficient Regulation of Water Sorption Inflection Point and Steepness

The development of porous materials exhibiting steep and stepwise adsorption of water vapor at desired humidity is crucial for implementing diverse applications such as humidity control, heat allocation, and atmospheric water harvesting. The precise molecular-level elucidation of structural characteristics and chemical components that dictate the water sorption behaviors in confined nanospaces, metal-organic frameworks (MOFs) in particular, is fundamentally important, but this has yet to be largely explored. In this work, by leveraging the isoreticular principle, we crafted two pairs of isostructural Zr-MOFs with linker backbones of benzene and pyrazine acting as hydrogen-bonding donor and acceptor, respectively. The outstanding water sorption cyclic durability of the four Zr-MOFs permits persuasive investigation of the correlation of the water sorption inflection point and steepness (the two central figures-of-merit for water sorption) with the linker functionality. The two pyrazine-carrying Zr-MOFs both show steep water uptake at lower relative pressure and slightly decreased steepness, which are quantitatively described by the Dubinin-Astakhov relation. We deciphered the privileged water clusters through single-crystal X-ray diffraction studies in which the pyrazine moiety formed stronger hydrogen-bonding interactions with guest water molecules and favored the formation of water pentamers instead of hexamers that are observed in the benzene analog. The hydrogen-bonding donor/acceptor manipulation approach presented in this work may facilitate future research endeavors focusing on molecular attribute engineering in predeterminedly ultrawater-resistant MOF platforms for efficient regulation of water sorption behaviors toward customized applications.

Non-van-der-Waals Oriented Two-Dimensional UiO-66 Films by Rapid Aqueous Synthesis at Room Temperature

The synthesis of MOFs in a two-dimensional (2D) film morphology is attractive for several applications including molecular and ionic separation. However, 2D MOFs have only been reported from structures that crystallize in lamellar morphology, where layers are held together by van der Waals (vdW) interaction. By comparison, UiO-66, one of the most studied MOFs because of its exceptional chemical stability, has only been reported in three-dimensional (3D) morphology. 2D UiO-66 is challenging to obtain given the robust isotropic bonds in its cubic crystal structure. Herein, we report the first synthesis of non-vdW 2D UiO-66-NH2 by developing crystal growth conditions that promote in-plane growth over out-of-plane growth. Continuous, oriented UiO-66-NH2 film with thickness tunable in the range of 0.5 to 2 unit cells could be obtained by sustainable, scalable chemistry, which yielded attractive ion-ion selectivity. The preparation of non-vdW 2D MOF is highly attractive to advance the field of MOF films for diverse applications.

Metal-organic framework-based SERS probes with enrichment capability for trace detection: applications in biomarkers and pollutants

Surface-enhanced Raman scattering (SERS) has emerged as a powerful tool for trace substances detection due to its exceptional sensitivity, high anti-interference capability, and ease of operation, enabling detection at the single-molecule level. This makes SERS particularly promising for applications such as environmental monitoring, biomedical diagnostics, and food safety. Despite these advantages, SERS faces limitations due to the difficulty of enriching trace substances and the small Raman scattering cross sections of certain molecules. Metal-organic frameworks (MOFs), characterized by their high surface areas and porosity, tunable structures, and diverse functionalities, offer a promising solution to these challenges. By integrating MOFs with SERS technology, we explore how MOF-based SERS probes can enhance the sensitivity, selectivity, and efficiency of trace substance detection through mechanisms such as analyte enrichment, selective molecular capture, and electromagnetic field manipulation. In this paper, a comprehensive review of the structure and synthesis of MOF-SERS composites is presented, with an emphasis on their application in the detection of trace substances. The paper also discusses key challenges in the design and optimization of MOF-based SERS probes, particularly in terms of stability, reproducibility, and integration with existing detection platforms, aiming to broaden their practical applications and improve their detection efficiency.

Tactical metal-organic frameworks (MOFs) adsorbent advantages in removal applications

Water pollution caused by the increasing concentration of toxic chemicals, such as heavy metal ions, pesticides, pharmaceutical waste, and plastic contaminants, has become a global issue. The rising levels of these pollutants pose significant health risks to humans and various species. Recently, adsorption has emerged as a promising method for removing these contaminants. This review focuses on metal-organic frameworks (MOFs) as adsorbents, highlighting their large surface areas and adjustable porosity, which optimize the adsorption process. The review analyzes the active sites within MOFs, their roles in adsorption mechanisms, and the underlying chemistry involved. It also discusses the structural chemistry of MOFs and its impact on pollutant removal efficiency. Furthermore, the review addresses stability, scalability, and economic feasibility challenges. Finally, it suggests future research directions for next-generation MOF materials to enhance their effectiveness in sustainable environmental remediation, ultimately improving our ability to combat contamination issues and protect healthy ecosystems.

Thermally Triggered In Situ Template-Escape Strategy for Controlled Construction of Hollow MOFs

Hollow spherical structures can endow metal-organic framework (MOF) materials with new capabilities. However, devising an uncomplicated synthesis method for hollow MOF spheres remains a formidable challenge. Here, the green hydrothermal method is employed to drive the polymer template, inducing a thermal transition (viscous flow state) that facilitates escape and enables the construction of a series of hollow MOF spheres. The hollow MIL-101(Cr) spherical capsules (Void@MIL-101) with high stability and well-defined morphology are synthesized as the first example. After encapsulating Pd nanoparticles, it exhibits an accelerated mass transfer effect and superior catalytic selectivity in synthesizing secondary aromatic amines. Furthermore, the versatility of this in situ template-escape strategy is demonstrated through the successful construction of hollow CPM-243(Cr) and SiO2 spheres. This innovative approach opens new avenues for the development of various hollow materials with enhanced properties.

Controllable Polymerization of Inorganic Ionic Oligomers for Precise Nanostructural Construction in Materials

The rational design of nanostructures is critical for achieving high-performance materials. The close-packing behavior of inorganic ions and their less controllable nucleation process impede the precise nanostructural construction of inorganic ionic compounds. The discovery of inorganic ionic oligomers (stable molecular-scale inorganic ionic compounds) and their polymerization reaction enables the controllable arrangement of inorganic ions for diverse nanostructures. This perspective aims to introduce inorganic ionic oligomers and their currently identified advantages in the precise design of inorganic and organic-inorganic hybrid nanostructures, directing the development of advanced materials with applications across the mechanical, energy, environmental, and biomedical fields. The challenges and opportunities for the controllable polymerization of inorganic ionic oligomers are presented at the end of this perspective. We suggest that inorganic ionic oligomers and their polymerization reaction offer a promising strategy for the preparation of inorganic and organic-inorganic hybrid materials.

Boosting One- and Two-Photon Excited Fluorescence of Interpenetrated Tetraphenylethene-Based Metal-Organic Frameworks (TPE-MOFs) by Linker Installation

Immobilizing organic chromophores within the rigid framework of metal-organic frameworks (MOFs) augments fluorescence by effectively curtailing molecular motions. Yet, the substantial interspaces and free volumes inherent to MOFs can undermine photoluminescence efficiency, as they partially constrain intramolecular dynamics. In this study, we achieved optimization of both one- and two-photon excited fluorescence by incorporating linkers into an interpenetrated tetraphenylethene-based MOF (TPE-MOF). This linker installation strategy enables fine-tuning of both crystal packing density and ligand conformations. Strikingly, the desolvated MOFs exhibit remarkable two-photon absorption (TPA) cross-sections, reaching an impressive 8801 GM. Consequently, these materials demonstrate exceptional performance in one- and two-photon excited cellular imaging of HepG2 cells. Our work introduces an innovative approach to enhancing two-photon excited fluorescence (TPEF) and broadens the scope of research into one- and two-photon excited fluorescence (1/2 PEF).

Single Crystalline, Non-Stoichiometric Hydrogen-Bonded Organic Frameworks Showing Versatile Fluorescence Depending on Composition Ratios and Distributions

Hydrogen-bonded organic frameworks (HOFs) composed of multicomponent molecules in a non-stoichiometric composition have drawn great interest due to their tunable properties. However, the photobehavior of the single crystals of such mixed HOFs has not been explored. Here, we report on the synthesis, characterization and photobehavior of single crystalline non-stoichiometric HOFs (NS-HOFs). NS-HOFs (BTNT-1) with various composition ratios were successfully obtained as single crystals from two analogue tetratopic carboxylic acids, possessing naphthalene and benzothiadiazole cores (NTTA and BTTA, respectively). The heterogeneous distribution of the components was thoroughly confirmed by time-resolved fluorescence microscopy and local crystallographic analysis using focused synchrotron X-ray radiation. The versatile fluorescence of BTNT-1 behavior depends on the composition ratio and distribution of the component in the single crystals. We observed not only fluorescence bands with various colors such as purple, blue, green and white, depending on the composition ratios, but also different emission bands from a single crystal. We provide details on their emission lifetimes following the composition, emission color and targeted region on the crystal. This work is the first example of single crystal studies applied to organic porous co-crystals and demonstrates unique and versatile optical properties of carboxylic acid-based NS-HOFs. The results provide a concept of creating functional mixed porous materials capable of different and tunable optical properties.

Multifunctional Lanthanide Metal-Organic Frameworks Act as Fluorescent Probes for the Detection of Cr2O72-, Fe3+, and TNP, White Light-Emitting Diodes, and Luminescence Thermometers

Two basically isostructural lanthanide-based metal-organic frameworks (Ln-MOFs), {[Eu(dptz)(H2O)2]Cl·3H2O}n (JLNU-10-Eu, JLNU = Jilin Normal University) and {[Tb(dptz)(NO3)(H2O)]·7H2O}n (JLNU-10-Tb), have been successfully synthesized by employing 3-(3,5-dicarboxylphenyl)-5-(pyrid-2-yl)-1H-1,2,4-triazole (H2dptz) as a flexible carboxylic acid ligand through solvothermal reactions. Single-crystal structural studies on Ln-MOFs manifested that the compounds have a two-dimensional (2D) layered structure. Furthermore, fluorescence sensing experiments indicated that JLNU-10-Eu and JLNU-10-Tb had significant fluorescence quenching effects on Cr2O72-, Fe3+, and TNP. It should be noted that the KSV value of JLNU-10-Eu in sensing Fe3+ could reach 7.36 × 103, and the limit of detection (LOD) was 0.57. The luminescence quenching mechanism is discussed in detail through some relevant experiments. Additionally, a series of Ln-MOFs, JLNU-10-EuxTb1-x (x = 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.1), have been obtained by simply regulating the molar ratio of Eu3+ and Tb3+. Particularly, JLNU-10-Eu0.8Tb0.2 can achieve white light emission at an excitation wavelength of 300 nm. The CIE coordinates are (0.316, 0.332), which are very approximate to ideal white light. JLNU-10-Eu0.2Tb0.8 as a luminescence thermometer exhibits good linearity over the temperature range of 303-373 K with a high sensitivity of 4.1% K-1 at 373 K. The construction of multifunctional Ln-MOFs displays prospective applications in fluorescent probes, white light-emitting diodes, and luminescence thermometers.

Novel amino-functionalized MOF-based sensor for zinc ion detection in water and blood serum samples

Aquatic systems with low zinc levels can experience a significant decrease in carbon dioxide uptake and limited growth of phytoplankton species. In this study, we describe the use of a new fluorescent sensor based on NH2-MIL-53(Al), and modified with glutaraldehyde and sulfadoxine, for selectively detecting zinc ions in water and blood serum samples. Characterization of the synthesized material was performed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), confirming successful functionalization and preservation of the MOF structure. The sensor's performance for Zn2+ detection was evaluated by spectrofluorometry, demonstrating a significant fluorescence enhancement upon Zn2+ binding due to the interaction between Zn2+ ions and the sulfonamide groups. With a detection limit as low as 3.14 × 10-2 ppm, the sensor demonstrates high selectivity for Zn2+ over other common metal ions. The sensor's response is rapid, stable, and reproducible, making it suitable for practical applications. Real sample analysis was conducted in tap water and blood serum samples, with the results compared to those obtained using ICP-OES and a colorimetric test with 5-bromo-PAPS. The comparison confirmed the high accuracy and reliability of the fluorescent sensor in detecting Zn2+ ions in complex matrices. NH2-MIL-53(Al) modified with glutaraldehyde and sulfadoxine shows potential as a selective fluorescent sensor for Zn2+ detection, making it a valuable tool for monitoring the environment and biology.

Optimizing Propylene/Propane Sieving Separation through Gate-Pressure Control within a Flexible Organic Framework

The separation of propylene (C3H6) and propane (C3H8) is of great significance in the chemical industry, which poses a challenge due to their almost identical kinetic diameters and similar physical properties. In this work, we synthesized an ultramicroporous flexible hydrogen-bonded organic framework (named HOF-FJU-106) by using molecule 2,3,6,7-tetra (4-cyanophenyl) tetrathiafulvalene (TTF-4CN). The formation of the dimer causes the TTF-4CN molecular to bend and weaken π-stacked interactions, coupled with the flexibility of C≡N ⋯ ${\cdots }$ H-C hydrogen bonds, which leads to reversible conversion between open and closed frameworks through the mutual slip of adjacent layers/columns under activation and stimulation of gas molecules. Through gas adsorption isotherms and adsorption enthalpy, HOF-FJU-106a exhibited adaptive adsorption and stronger binding affinity for C3H6, and presented a recorded gas uptake ratio of C3H6/C3H8 (23.77) among presentative HOF materials at room temperature to date. Importantly, the flexible HOF-FJU-106a shows an interesting phenomenon about the reversible gate pressure control under variable temperature, which realized the gas adsorption and separation performance enhancement for the binary C3H6/C3H8 mixtures. This strategy through designing HOFs with thermoregulatory gating effect is a powerful way to maximize the performance of materials.

Rational design and synthesis of atomically precise nanocluster-based nanocomposites: a step towards environmental catalysis

Atomically precise metal nanoclusters (NCs) and metal-organic frameworks (MOFs) possess distinct properties that can present challenges in certain applications. However, integrating these materials to create new composite functional materials has gained significant interest due to their unique characteristics through a range of applications, particularly in catalysis. Considering MOFs as hosts and NCs as guests, several synergistic effects have been observed in composites, particularly in environmental catalytic reactions. However, the precise role of encapsulated NCs within the MOF pore structure is still in its infancy. Besides, stabilizing NCs, whether through intact ligands or without ligands via the MOF host, presents challenges that are currently being investigated. This feature article reviews recent advancements in the synthesis of NC@MOF composites, focusing on cutting-edge strategies for selecting MOFs and the roles of NC ligands, as well as characterization and catalytic applications.

Morphological Evolution of Metal-Organic Frameworks into Hedrite, Sheaf and Spherulite Superstructures with Localized Different Coloration

The branched metal-organic frameworks (MOFs) are the first superstructures of this kind, and the growth mechanism may explain crystal shapes of other materials. The mechanism of the formation of fascinating structures having a hedrite, sheaf or spherulite appearance are detailed. The branching can be controlled, resulting in crystals that either exhibit multiple generations of branching or a single generation. These structures might result from an increasing number of defects on fast-grown rods. As the basal facets become less reactive, material is added to the prism facets, leading to secondary nucleation and triangular branches. These triangular structures are connected to the rod surface, growing longer than the central rod. Electron diffraction analyses show that the sheafs are polycrystalline structures with their fantails consisting of single-crystalline nanorods deviating gradually from each other in their orientation. The crystallographic structure consists of channels with opposite handedness. The accessibility of the nanochannels and the porosity of the superstructures are demonstrated by chromophore diffusion into the channels. The confinement and alignment of the chromophores inside the channels resulted in polarized-light dependent coloration of the crystals; the polycrystallinity generated areas having different optical properties.

Rational design of redox active metal organic frameworks for mediated electron transfer of enzymes

The efficient immobilization of redox mediators remains a major challenge in the design of mediated enzyme electrode platforms. In addition to stability, the ability of the redox-active material to mediate electron transfer from the active-site buried enzymes, such as flavin adenine dinucleotide-dependent glucose dehydrogenase (FADGDH) and lactate oxidase (LOx), is also crucial. Conventional immobilization techniques can be synthetically challenging, and immobilized mediators often exhibit limited durability, particularly in continuous operation. Here, we design a novel redox-active cobalt-based metal-organic framework (raMOF) obtained via the partial ligand substitution of 2-methylimidazole (MeIm) with a 1,2-naphthoquinone-4-sulfonate (NQSO) redox probe, as a promising platform for high-performance enzyme electrodes. This nanostructured raMOF, combined with multi-walled carbon nanotubes (CNTs), provided a high current density of up to 2.06 mA cm-2 during enzymatic reactions and maintained remarkable operational stability, retaining 100% of its current over 54 hours. This stability far exceeded that of adsorbed NQSO on CNTs, which experienced a complete loss of the initial current, highlighting the significant advantage of the raMOF-based platform for high-performance enzyme electrodes.

Supramolecular Chemistry in Metal-Organic Framework Materials

Far from being simply rigid, benign architectures, metal-organic frameworks (MOFs) exhibit diverse interactions with their interior environment. From developing crystal sponges to studying reactions in framework materials, the role of both supramolecular chemistry and framework structure is evident. We explore the role of supramolecular chemistry in determining framework…guest interactions and attempts to understand the dynamic behavior in MOFs, including attempts to control pore behavior through the incorporation of mechanically-interlocked molecules. Appreciating and understanding the role of supramolecular interactions and dynamic behavior in metal-organic frameworks emerge as important directions for the field.

2D Vertically Conductive Metal─Organic Framework Electrolytes: Will They Outperform 3D MOFs for Solid State Batteries?

Lithium-ion batteries are currently the mainstream for almost all portables, and quickly expand in electrical vehicles and grid storage applications. However, they are challenged by the poor safety regarding organic liquid electrolytes and relatively low energy density. Solid-state batteries, characterized by using solid-state electrolytes (SSEs), are recognized as the next-generation energy technology, owing to their intrinsically high safety and potentially superior energy density. However, developing SSEs is impeded by several key factors, including low ionic conductivity, interfacial issues, and high-cost in industrial scales. Recently, a novel category of SSEs, known as frameworked electrolytes (FEs), has emerged as a formidable contender for the transition to all-solid-state batteries. FEs exhibit a unique macroscopically solid-state nature and microscopically sub-nanochannels offering high ionic conductivity. In this perspective, the unique lithium-ion transport mechanisms within FEs are explored and 2D vertically conductive metal-organic framework (MOF) is proposed as an even more promising FE candidate. The abundant active sites in the 1D sub-nanochannels of 2D vertically conductive MOFs facilitate efficient ion transport, favorable interfacial compatibility, and scalable industrial applications. This perspective aims to boost the emergence of novel SSEs, promoting the realization of long-expected all-solid-state batteries and inspiring future energy storage solutions.

Trace Adsorptive Removal of PFAS from Water by Optimizing the UiO-66 MOF Interface

The confluence of pervasiveness, bioaccumulation, and toxicity in freshwater contaminants presents an environmental threat second to none. Exemplifying this trifecta, per- and polyfluoroalkyl substances (PFAS) present an alarming hazard among the emerging contaminants. State-of-the-art PFAS adsorbents used in drinking water treatment, namely, activated carbons and ion-exchange resins, are handicapped by low adsorption capacity, competitive adsorption, and/or slow kinetics. To overcome these shortcomings, metal-organic frameworks (MOFs) with tailored pore size, surface, and pore chemistry are promising alternatives. Thanks to the compositional modularity of MOFs and polymer-MOF composites, herein we report on a series of water-stable zirconium carboxylate MOFs and their low-cost polymer-grafted composites as C8-PFAS adsorbents with benchmark kinetics and "parts per billion" removal efficiencies. Bespoke insights into the structure-function relationships of PFAS adsorbents are obtained by leveraging interfacial design principles on solid sorbents, creating a synergy between the extrinsic particle surfaces and intrinsic molecular building blocks.

Adsorption Removal of NO2 Under Low-Temperature and Low-Concentration Conditions: A Review of Adsorbents and Adsorption Mechanisms

The efficient mitigation of harmful nitrogen oxides (NOx) under ambient conditions remains a challenging task. Selective adsorption offers a viable solution for the capture of low-concentration NOx from the polluted stream at low temperatures. This review summarizes recent progress in the development of NO2 adsorbents, delves into the understanding of adsorption mechanisms, and discusses the criteria for evaluating their performance. First, the present NO2 adsorbents are categorized according to their distinct characteristics. This review then provides insights into the mechanisms of adsorption, highlighting the interaction between active sites and NO2, drawing from both experimental and theoretical research. The performance of these adsorbents is also assessed, focusing on their capacity, reusability, stability and selectivity. Finally, perspectives are proposed to address the significant challenges and explore potential advancements for NO2 adsorbents, aiming to enhance their suitability for diverse practical application scenarios.

Polymorphism and Structural Variety in Sn(II) Carboxylate Coordination Polymers Revealed from Structure Solution of Microcrystals

The crystal structures of four coordination polymers constructed from Sn(II) and polydentate carboxylate ligands are reported. All are prepared under hydrothermal conditions in KOH or LiOH solutions (either water or methanol-water) at 130-180 °C and crystallize as small crystals, microns or less in size. Single-crystal structure solution and refinement are performed using synchrotron X-ray diffraction for two materials and using 3D electron diffraction (3DED) for the others. Sn2(1,3,5-BTC)(OH), where 1,3,5-BTC is benzene-1,3,5-tricarboxylate, is a new polymorph of this composition and has a three-dimensionally connected structure with potential for porosity. Sn(H-1,3,5-BTC) retains a partially protonated ligand and has a 1D chain structure bound by hydrogen bonding via ─COOH groups. Sn(H-1,2,4-BTC) contains an isomeric ligand, benzene-1,2,4-tricarboxylate, and contains inorganic chains in a layered structure held by hydrogen bonding. Sn2(DOBDC), where DOBDC is 2,5-dioxido-benzene-1,4-dicarboxylate, is a new polymorph for this composition and has a three-dimensionally connected structure where both carboxylate and oxido groups bind to the tin centers to create a dense network with dimers of tin. In all materials, the Sn centers are found in highly asymmetric coordination, as expected for Sn(II). For all materials phase purity of the bulk is confirmed using powder X-ray diffraction, thermogravimetric analysis, and infrared spectroscopy.

Encage the Carcinogens: A Metal-"Organic Cage" Framework for Efficient Polycyclic Aromatic Hydrocarbon Removal From Water

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and persistent organic pollutants in water. Their removal is highly challenging for existing generic and nonspecific adsorbents, creating an urgent need for tailored solutions. Herein, a metal-"organic cage" framework, MOF-CC-1, designed for the effective scavenging of PAHs from water is is introduced. This framework is constructed using a propeller-shaped cofacial organic cage (CC-1), equipped with three triazole pillars that coordinate with Ag(I) ions. The cationic MOF-CC-1 adopts a chiral (10,3)-a srs net structure, spontaneously resolving into homochiral crystals. Additionally, bulk homochirality is achieved through chirality induction using chiral counteranions. MOF-CC-1 uniquely encapsulates diverse PAH molecules within the cavities of CC-1, as confirmed by single-crystal X-ray diffraction, marking it as the first metal-"organic cage" framework with structural evidence of guest inclusion inside the organic cage linker. Further, MOF-CC-1 exhibits soft porosity, remaining nonporous to N₂ gas when compressed but expanding to encapsulate PAHs in solution. Moreover, MOF-CC-1 exhibits exceptional efficacy in scavenging ppb levels of PAHs from water. This work represents a significant advancement in utilizing organic cages as ligands toward MOF construction, paving the way for tailored adsorbents for PAH removal, and addressing a critical need for selective and efficient materials in environmental remediation.

Regulating electron transfer between valence-variable cuprum and cerium sites within bimetallic metal-organic framework towards enhanced catalytic hydrogenation performance

Modulating the electron distribution between active sites in metal-organic frameworks (MOFs) offers a promising strategy for optimizing their catalytic performance. In this study, we employed a novel heterovalent substitution strategy to synthesize bimetallic organic frameworks (CuxCey-BTC) that feature dual active sites with copper (Cu) and cerium (Ce), Our objective was to achieve efficient hydrogenation of dicyclopentadiene (DCPD) by regulating the electron transfer between the valence-variable Cu and Ce species. The designed CuxCey-BTC were characterized using various spectroscopic and microscopic techniques, along with density functional theory (DFT) calculations, confirming the successful incorporation of bimetallic nodes within the framework structure and the electron transfer between them. The transfer of electrons from the less electronegative Ce to the Cu sites promotes the chemisorption of hydrogen gas (H2) on the electron-rich Cu sites, thereby optimizing the activation of the CC bond in DCPD. The Cu4Ce-BTC catalyst demonstrated exceptional performance, achieving complete conversion of DCPD and significantly surpassing monometallic MOFs. Moreover, we proposed a plausible pathway for the hydrogenation of DCPD. This work highlights the synergistic effects between bimetallic centers and offers a novel strategy to improve the MOFs' catalytic activity by modulating electron distribution between dual active sites.