Mesoporous Metal-Organic Frameworks: Synthetic Strategies and Emerging Applications

Fluorescent Porous Materials Based on Aggregation-induced Emission for Biomedical Applications

Fluorescent porous materials based on aggregation-induced emission (AIE) are growing into a sparkling frontier in biomedical applications. Exploring those materials represents a win-win integration and has recently progressed at a rapid pace, mainly benefiting from intrinsic advantages including tunable pore size and structure, strong guest molecule encapsulation ability, superior biocompatibility, and photophysical outcomes. With the great significance and rapid progress in this area, this review provides an integrated picture on AIE luminogen-based porous materials. It encompasses inorganic, organic, and inorganic-organic porous materials, exploring fundamental concepts and the relationship between AIE performance and material design and highlighting significant breakthroughs and the latest trends in biomedical applications. In addition, some critical challenges and future perspectives in the development of AIE luminogen-based porous materials are also discussed.

Ultrastable hierarchically porous nucleotide-based MOFs and their use for enzyme immobilization and catalysis

Immobilization of free enzymes facilitates their recovery and reuse, while also enhances their enzymatic characteristics. Hierarchically porous metal-organic frameworks (HP-MOFs) are promising candidates for enzyme immobilization. However, fabrication of HP-MOFs with more kinds of components as ligands is still a challenge. Herein, ultrastable crystalline MOFs with micro-, meso- and macroporous structure were constructed using guanosine 5'-monophosphate (GMP) as organic ligand through templated emulsification method. HP-MOFs crystals with the near rhomb-like, rod-like and slab-like morphology were interestingly obtained from Zn2+, Cu2+ and Cd2+ respectively. The HP-MOFs immobilized enzymes exhibited an enhanced enzymatic activity and stability. In addition, the immobilized CALB (Candida antarctica lipase B) showed great glycerolysis and esterification performances for glycerides preparation, with diacylglycerols (DAG) content over 60 wt% and triacylglycerols (TAG) content over 90 wt% obtained respectively from glycerolysis and esterification. Moreover, it retained 82.32 % of its initial glycerolysis activity after six cycles of reuse in glycerolysis. The present study will provide clues and show new horizons to explore new organic ligands for HP-MOFs fabrication, as well as to expand the applications of HP-MOFs and their supported enzymes.

Metal-organic frameworks in oral drug delivery

Metal-organic frameworks (MOFs) offer innovative solutions to the limitations of traditional oral drug delivery systems through their unique combination of metal ions and organic ligands. This review systematically examines the structural properties and principles of MOFs, setting the stage for their application in drug delivery. It discusses various classes of MOFs, including those based on zirconium, iron, zinc, copper, titanium, aluminum, potassium, and magnesium, assessing their drug-loading capacities, biocompatibility, and controlled release mechanisms. The effectiveness of MOFs is illustrated through case studies that highlight their capabilities in enhancing drug solubility, providing protection against the harsh gastrointestinal environment, and enabling precise drug release. The review addresses potential challenges, particularly the toxicity concerns associated with MOFs, and calls for further research into their biocompatibility and interactions with biological systems. It concludes by emphasizing the potential of MOFs in revolutionizing oral drug delivery, highlighting the critical need for comprehensive research to harness their full potential in clinical applications.

Synthesis and characterisation of antimicrobial metal-organic frameworks as multi-drug carriers

Antibiotic resistance is a significant global concern, necessitating the development of either new antibiotics or advanced delivery methods. With this in mind, we report on the synthesis and characterisation of a new family of Metal-Organic Frameworks (MOFs), OnG6 MOFs, designed to act as multi-drug carriers for bacterial infection treatment. OnG6 is based on the pro-drug 4,4'-azodisalicylic acid (AZDH4), which in vivo produces two equivalents of para-aminosalicylic acid (ASA), a crucial drug for M. tuberculosis treatment. X-ray and computational studies revealed that OnG6 MOFs are mesoporous MOFs with etb topology and an [M2(AZD)] formula (M = Zn, OnG6-Zn; Mg, OnG6-Mg; Cu, OnG6-Cu; and Co, OnG6-Co), featuring 1-dimensional channel type pores of 25 Å diameter. OnG6 MOFs are the first reported MOFs bearing the ligand AZDH4, joining the family of mesoporous MOFs arranged in a honeycomb pattern. They absorb isoniazid (INH) and ciprofloxacin (CIPRO) with the former being a specific antibiotic for M. tuberculosis, and the latter being a broader-spectrum antibiotic. The stability of the MOFs and their capacity for antibiotic uptake depend on the nature of the metal ion, with OnG6-Mg demonstrating the highest drug absorption. The antimicrobial activity of these species was assessed against S. aureus and E. coli, revealing that the carriers containing CIPRO displayed optimal efficacy.

Defect-engineered chiral metal-organic frameworks

Chirality has an important impact on chemical and biological research, as most active substances are chiral. In recent decades, metal-organic frameworks (MOFs), which are assembled from metal ions or clusters and organic linkers via metal-ligand bonding, have attracted considerable scientific interest due to their high crystallinity, exceptional porosity and tunable pore sizes, high modularity, and diverse functionalities. Since the discovery of the first functional chiral metal-organic frameworks (CMOFs), CMOFs have been involved in a variety of disciplines such as chemistry, physics, optics, medicine, and pharmacology. The introduction of defect engineering theory into CMOFs allows the construction of a class of defective CMOFs with high hydrothermal stability and multi-stage pore structure. The introduction of defects not only increases the active sites but also enlarges the pore sizes of the materials, which improves chiral recognition, separation, and catalytic reactions, and has been widely investigated in various fields. This review describes the design and synthesis of various defective CMOFs, their characterization, and applications. Finally, the development of the materials is summarized, and an outlook is given. This review should provide researchers with an insight into the design and study of complex defective CMOFs.

The influence of HKUST-1 and MOF-76 hand grinding/mechanical activation on stability, particle size, textural properties and carbon dioxide sorption

In this study, we explore the mechanical treatment of two metal-organic frameworks (MOFs), HKUST-1 and MOF-76, applying various milling methods to assess their impact on stability, porosity, and CO2 adsorption capacity. The effects of different mechanical grinding techniques, such as high-energy ball milling and hand grinding, on these MOFs were compared. The impact of milling time, milling speed and ball size during high-energy ball milling was assessed via the Design of Experiments methodology, namely using a 33 Taguchi orthogonal array. The results highlight a marked improvement in CO2 adsorption capacity for HKUST-1 through hand milling, increasing from an initial 25.70 wt.% (5.84 mmol g-1) to 41.37 wt.% (9.40 mmol g-1), marking a significant 38% increase. In contrast, high-energy ball milling seems to worsen this property, diminishing the CO2 adsorption abilities of the materials. Notably, MOF-76 shows resistance to hand grinding, closely resembling the original sample's performance. Hand grinding also proved to be well reproducible. These findings clarify the complex effects of mechanical milling on MOF materials, emphasising the necessity of choosing the proper processing techniques to enhance their stability, texture, and performance in CO2 capture and storage applications.

Hollow UiO-66-NH2 Encapsulated Pd Catalysts for Highly Selective Hydrogenation of Furfural to Furfuryl Alcohol

The selective hydrogenation of furfural (FFA) to furfuryl alcohol (FA) is regarded as attractive transformation to achieve the sustainable synthesis of value-added chemicals from biomass resources. However, the conventional supported catalysts are significantly restricted by their narrow pore size, ununiform dispersion and easy leaching or aggregation of catalytic sites. Herein, we designed hollow UiO-66-NH2 as the support to encapsulate Pd nanoparticles (Pd@H-UiO-66-NH2) to achieve the highly active and selective conversion of FFA to FA. Benefiting from the void-confinement effect and substrate enrichment of hollow structure, as well as the surface wrinkles, the as-prepared catalyst Pd@H-UiO-66-NH2 exhibited 96.8 % conversion of FFA with satisfactory selectivity reaching up to 92.4 % at 80 °C, 0.5 MPa H2 in isopropanol solvent within 6 h. More importantly, as-prepared Pd@H-UiO-66-NH2 catalyst exhibited excellent long-term stability, as well as good universality toward a series of hydrogenation of unsaturated hydrocarbons.

Long-Term Antioxidant Metal-Organic Frameworks

Free radicals produced during metabolism induce effects, such as cell damage and cancer, because of their high reactivity. Although antioxidants in food products can eliminate free radicals, they are expelled within a relatively short period of time after serving their function. In this study, we investigated the possibility of using metal-organic frameworks (MOFs) with antioxidants as their ligands. Metal-organic frameworks are crystalline polymers with repetitively coordinated ligands and metal centers. We assume that once antioxidant-based MOFs are ingested, ligands are released on a long-term basis during the process of chemical and physical disintegration. To evaluate their eligibility, we established criteria for biocompatibility, particle size, and long-term antioxidant effects. For biocompatibility, we treated cells with various concentrations of MOFs and their precursors followed by a water-soluble tetrazolium 8 (WST-8) assay. The particle size distribution was analyzed using TEM and ImageJ software, and the antioxidant release was quantified using UV-vis spectroscopy. We concluded that Fe-based FeTHQ with the antioxidant tetrahydroxy-1,4-benzoquinone (THQ) as its ligand is the most effective long-term antioxidant with its effect lasting up to 7 days. Furthermore, microwave synthesis of FeTHQ was conducted to produce more suitable particles for in vivo antioxidant applications.

A biomimetic camouflaged metal organic framework for enhanced siRNA delivery in the tumor environment

Gene silencing through RNA interference (RNAi), particularly using small double-stranded RNA (siRNA), has been identified as a potent strategy for targeted cancer treatment. Yet, its application faces challenges such as nuclease degradation, inefficient cellular uptake, endosomal entrapment, off-target effects, and immune responses, which have hindered its effective delivery. In the past few years, these challenges have been addressed significantly by using camouflaged metal-organic framework (MOF) nanocarriers. These nanocarriers protect siRNA from degradation, enhance cellular uptake, and reduce unintended side effects by effectively targeting desired cells while evading immune detection. By combining the properties of biomimetic membranes and MOFs, these nanocarriers offer superior benefits such as extended circulation times, enhanced stability, and reduced immune responses. Moreover, through ligand-receptor interactions, biomimetic membrane-coated MOFs achieve homologous targeting, minimizing off-target adverse effects. The MOFs, acting as the core, efficiently encapsulate and protect siRNA molecules, while the biomimetic membrane-coated surface provides homologous targeting, further increasing the precision of siRNA delivery to cancer cells. In particular, the biomimetic membranes help to shield the MOFs from the immune system, avoiding unwanted immune responses and improving their biocompatibility. The combination of siRNA with innovative nanocarriers, such as camouflaged-MOFs, presents a significant advancement in cancer therapy. The ability to deliver siRNA with precision and effectiveness using these camouflaged nanocarriers holds great promise for achieving more personalized and efficient cancer treatments in the future. This review article discusses the significant progress made in the development of siRNA therapeutics for cancer, focusing on their effective delivery through novel nanocarriers, with a particular emphasis on the role of metal-organic frameworks (MOFs) as camouflaged nanocarriers.

From nano- to macroarchitectures: designing and constructing MOF-derived porous materials for persulfate-based advanced oxidation processes

Persulfate-based advanced oxidation processes (PS-AOPs) have gained significant attention as an effective approach for the elimination of emerging organic contaminants (EOCs) in water treatment. Metal-organic frameworks (MOFs) and their derivatives are regarded as promising catalysts for activating peroxydisulfate (PDS) and peroxymonosulfate (PMS) due to their tunable and diverse structure and composition. By the rational nanoarchitectured design of MOF-derived nanomaterials, the excellent performance and customized functions can be achieved. However, the intrinsic fine powder form and agglomeration ability of MOF-derived nanomaterials have limited their practical engineering application. Recently, a great deal of effort has been put into shaping MOFs into macroscopic objects without sacrificing the performance. This review presents recent advances in the design and synthetic strategies of MOF-derived nano- and macroarchitectures for PS-AOPs to degrade EOCs. Firstly, the strategies of preparing MOF-derived diverse nanoarchitectures including hierarchically porous, hollow, yolk-shell, and multi-shell structures are comprehensively summarized. Subsequently, the approaches of manufacturing MOF-based macroarchitectures are introduced in detail. Moreover, the PS-AOP application and mechanisms of MOF-derived nano- and macromaterials as catalysts to eliminate EOCs are discussed. Finally, the prospects and challenges of MOF-derived materials in PS-AOPs are discussed. This work will hopefully guide the design and development of MOF-derived porous materials in SR-AOPs.

Optimization of 3D Printing Parameters for Alumina Ceramic Based on the Orthogonal Test

In this paper, an alumina ink with good rheological properties was successfully prepared using pseudoboehmite as the main component, nitric acid as the colloidal solvent, and sesbania powder as the lubricant. The impact of nine different ink formulations, namely, Ink1 to Ink9, on the printability and rheological features of the ink was investigated. Consequently, it was found that Ink3 with 5 wt % nitric acid and 5 wt % sesbania powder exhibited the most favorable formability. This ink was utilized to fabricate alumina samples with direct ink writing (DIW) three-dimensional (3D) printing technology. The printed alumina samples were characterized using an automatic Brunauer-Emmett-Teller, X-ray diffractometer, Fourier transform infrared spectroscopy, and scanning electron microscope. To obtain the optimal printing parameters, a three-factor and three-level orthogonal test was designed to research the influences of different 3D printing parameters (filling ratio, nozzle diameter, and layer thickness) on the specific surface area, pore characteristics (size and volume), and radial crushing strength of the alumina specimens. The primary and secondary orders of the effects on the radial crushing strength and pore structure were determined through analysis of the experimental data. The experimental results showed that the alumina sample with a filling ratio of 80%, nozzle diameter of 0.6 mm, and layer thickness of 0.3 mm was found to have better strength of 48.07 ± 9.53 N/mm and specific surface area of 185.7315 m2/g. This study provides a theoretical base for the preparation of alumina carriers by DIW 3D printing.

Construction of Indium(III)-Organic Framework Based on a Flexible Cyclotriphosphazene-Derived Hexacarboxylate as a Reusable Green Catalyst for the Synthesis of Bioactive Aza-Heterocycles

The constant demand for eco-friendly methods of synthesizing complex organic compounds inspired researchers to design and develop modern, highly efficient heterogeneous catalytic systems. Herein, In-HCPCP metal-organic framework (SRMIST-1), a heterogeneous Lewis acid catalyst containing less toxic indium and eco-friendly robust cyclotriphosphazene and exhibiting notable chemical and thermal stability, durable catalytic activity, and exceptional reusability was produced through the reaction between indium(III) nitrate hydrate and hexakis(4-carboxylatophenoxy)-cyclotriphosphazene. In the SRMIST-1 structure, secondary building units {InO7} are assembled by a connection of η2- and η1-carboxylic oxo atoms from different HCPCP ligands, forming a three-dimensional network. The occurrence of regularly distributed In(III) sites in SRMIST-1 confers superior reactivity on the catalyst toward the synthesis of 2,3-dihydroquinazolin-4(1H)-ones and 3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxides by the cyclization reaction of 2-aminobenzamides and 2-aminobenzenesulphonamides with aldehydes under optimized reaction conditions, respectively. The notable features of this method include broad functional group compatibility, low catalyst loading (1-5 mol %), mild reaction conditions, easy workup procedures, good to excellent reaction yields, ethanol as a green solvent, reusability of the catalyst (five cycles), and economic attractiveness, which is mainly due to sustainability of SRMIST-1 as a reusable green catalyst. Our findings demonstrate that the highly reactive and reusable green catalyst finds widespread applications in medicinal chemistry.

In Situ Exfoliation Growth Strategy Realizing Controlled Synthesis of 3D to 2D MOF Materials as High-Performance Electrochemical Biosensors

Two-dimensional (2D) metal-organic framework (MOF) nanosheets with large surface area, ultrathin thickness, and highly accessible active sites have attracted great research attention. Developing efficient approaches to realize the controllable synthesis of well-defined 2D MOFs with a specific composition and morphology is critical. However, it is still a significant challenge to construct thin and uniform 2D MOF nanosheets and resolve the reagglomeration as well as poor stability of target 2D MOF products. Here, an "in situ exfoliation growth" strategy is proposed, where a one-step synthetic process can realize the successful fabrication of PBA/MIL-53(NiFe)/NF nanosheets on the surface of nickel foam (NF) via in situ conversion and exfoliation growth strategies. The PBA/MIL-53(NiFe)/NF nanosheets combine the individual advantages of MOFs, Prussian blue analogues (PBAs), and 2D materials. As expected, the resulting PBA/MIL-53(NiFe)/NF as a glucose electrode exhibits an extremely high sensitivity of 25.74 mA mM-1 cm-2 in a very wide concentration range of 180 nM to 4.8 μM. The present exciting work provides a simple and effective strategy for the construction of high-performance nonenzymatic glucose electrochemical biosensors.

Recent Advances in Hierarchical Porous Engineering of MOFs and Their Derived Materials for Catalytic and Battery: Methods and Application

Hierarchical porous materials have attracted the attention of researchers due to their enormous specific surface area, maximized active site utilization efficiency, and unique structure and properties. In this context, metal-organic frameworks (MOFs) offer a unique mix of properties that make them particularly appealing as tunable porous substrates containing highly active sites. This review focuses on recent advances in the types and synthetic strategies of hierarchical porous MOFs and their derived materials. Furthermore, it highlights the relationship between the mass diffusion and transport of hierarchical porous structures and the pore size with examples and simulations, while identifying their potential and limitations. On this basis, how the synthesis conditions affect the structure and electrochemical properties of MOFs based hierarchical porous materials with different structures is discussed, highlighting the prospects and challenges for the synthetization, as well as further scientific research and practical applications. Finally, some insights into current research and future design ideas for advanced MOFs based hierarchical porous materials are presented.

Exploring the potential of iron-based metal-organic frameworks as peroxidase nanozymes for glucose detection with various secondary building units

Finding materials in biosensing that balance enzyme-like reactivity, stability, and affordability is essential for the future. Because of their unique peroxidase properties, including variable pore size, surface area, and Lewis acid active sites, iron-based metal-organic frameworks (MOFs) have evolved as viable possibilities. In this study, we constructed a Fe-MOF and tested its peroxidase-like activity and responsiveness toward H2O2 colorimetric techniques. Using encapsulation, we incorporated glucose oxidase into the ZIF-90 PVP MOF and conducted a sequential reaction with the Fe-MOF to detect glucose. The results showed better peroxidase catalytic activity of the MIL-88B(Fe) (1,4-NDC) MOF and similar secondary building unit (SBU) Fe-MOFs were studied in other peroxidase nanozyme studies. When combined with an enzyme-encapsulating ZIF-90 PVP MOF, they could be sequentially employed for glucose detection purposes. This study highlights the potential of nanozymes as an alternative to natural enzymes, with promising applications in biosensing and beyond.

A Metal-Organic Framework-Incorporated Hydrogel for Delivery of Immunomodulatory Neobavaisoflavone to Promote Cartilage Regeneration in Osteoarthritis

The treatment of osteoarthritis (OA)-related cartilage defects is a great clinical challenge due to the complex pathogenesis of OA and poor self-repair ability of cartilage tissue. Combining local and long-term anti-inflammatory therapies to promote cartilage repair is an effective method to treat OA. In this study, a zinc-organic framework-incorporated extracellular matrix (ECM)-mimicking hydrogel platform was constructed for the inflammatory microenvironment-responsive delivery of neobavaisoflavone (NBIF) to promote cartilage regeneration in OA. The NBIF was encapsulated in situ in zeolitic imidazolate frameworks (ZIF-8 MOFs). The NBIF@ZIF-8 MOFs were decorated with polydopamine and incorporated into a methacrylate gelatin/hyaluronic acid hybrid network to form the NBIF@ZIF-8/PHG hydrogel. The hydrogel featured excellent cell/tissue affinity, providing a favorable microenvironment for recruiting cells and cytokines to the defect sites. The hydrogel enabled the on-demand NBIF released in response to a weakly acidic microenvironment at the injured joint site to resolve inflammatory responses during the early stages of OA. Consequently, the cooperativity of the loaded NBIF and hydrogel synergistically modulated the immune response and assisted in cartilage defect repair. In summary, the NBIF@ZIF-8/PHG hydrogel delivery platform represents an effective treatment strategy for OA-related cartilage defects and may attract attentions for applications in other inflammatory diseases.

Synthesis of a Co/Ni-MOF-74@PDI Z-scheme photocatalyst as a highly efficient photo-assisted Fenton-like catalyst for the removal of chlortetracycline hydrochloride

In this paper, ultra-thin nanofiber PDI was obtained by self-assembly dispersion of commercial PDINH. A novel Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material was constructed by a simple solvothermal method. XRD, SEM, TEM, FT-IR and other characterization techniques proved the successful preparation of the Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material. By degrading chlortetracycline hydrochloride, it was found that the photocatalytic activity of Co/Ni-MOF-74@PDI was much higher than that of pure Co/Ni-MOF-74 and PDI. Subsequently, Co/Ni-MOF-74@PDI was used to activate H2O2 to further improve the degradation efficiency of chlortetracycline hydrochloride. It was found that the photocatalytic performance was greatly improved after the addition of 19.6 mM H2O2 to the system, and the degradation rate of chlortetracycline hydrochloride was 87% within 90 min. The electron transfer pathway and H2O2 activation mechanism of the Co/Ni-MOF-74@PDI composite photocatalyst were proved by free radical quenching experiments, electron paramagnetic resonance analysis and X-ray electron spectroscopy. Finally, the easy exfoliation point and degradation pathway of chlortetracycline hydrochloride were studied using density functional theory, UPLC-MS and toxicity evaluation software. It was found that the main active substances were h+, ˙O2, 1O2 and ˙OH, and the toxicity of chlortetracycline hydrochloride and its intermediates was evaluated.

Template-Free Synthesis and Multifunctional Application of Foam HKUST-1

Hierarchically porous metal-organic frameworks (HP-MOFs) have attracted a lot of attention in recent years because their hierarchical pores have critical importance in strengthening their performance, including guest diffusion kinetics, catalytic activity, and selectivity, especially with reference to large molecules. However, the preparation method for simple, controllable, and stable HP-MOFs at a micro-/meso-/macroscopic scale is still lacking. Herein, we showed several forms of HKUST-1 (HKUST = Hong Kong University of Science and Technology) by simply changing the copper source and solvent type, including original micron HKUST-1 (O-HKUST-1), half-foam HKUST-1 (HF-HKUST-1), and fully foam HKUST-1 (F-HKUST-1). Compared to O-HKUST-1, HF-HKUST-1 and F-HKUST-1 possessed an apparent hierarchically porous structure due to the high fusion of HKUST-1 nanocrystals. Especially in F-HKUST-1, all of the HKUST-1 nanocrystals were tightly integrated into each other, which formed a holistic hollow foam structure. Hence, F-HKUST-1 exhibited the highest adsorption capacity toward large molecules, including proteases, phosphotungstic acid, and organic dyes. Meanwhile, F-HKUST-1 presented the highest photocatalytic degradation capability for rhodamine B. Furthermore, F-HKUST-1, loaded with phosphotungstic acid (F-HKUST-1@PTA), which was used as a catalyst, indicated a catalytic capacity comparable to that of a homogeneous catalyst (pure phosphotungstic acid).

Ultrafast Photocatalytic Detoxification of Mustard Gas Simulants by a Mesoporous Metal-Organic Framework with Dangling Porphyrin Molecules

Developing effective catalysts to degrade chemical warfare agents is of great significance. Herein, a mesoporous MIL-101(Cr) composite material dangled with porphyrin molecules (denote as TCPP@MIL-101(Cr), TCPP = tetra(4-carboxyphenyl)porphyrin) is reported, which can be used as a heterogeneous photocatalyst for detoxification of mustard gas simulants 2-chloroethyl ethyl sulfide (CEES) to 2-chloroethyl ethyl sulfoxide (CEESO) with a half-life of 1 min. The catalytic performance of TCPP@MIL-101(Cr) is comparable to that of homogeneous molecular porphyrin. Mechanistic studies reveal that both 1 O2 and O2 •- are efficiently generated and play vital roles in the oxidation reaction. Gold nanoparticles (AuNPs) are attached to the TCPP@MIL-101(Cr) to further enhance the catalytic activity with a benchmark half-life of 45 s, which is the fastest record so far. A medical mask loaded TCPP@MIL-101(Cr) is fabricated for practical applications, which can selectively photoxidize CEES to CEESO under sunlight and air atmosphere, exhibiting the best degradation performance among the reported fabric-like composite materials.

A cage-on-MOF strategy to coordinatively functionalize mesoporous MOFs for manipulating selectivity in adsorption and catalysis

Functionalizing porous materials with capping agents generates hybrid materials with enhanced properties, while the challenge is how to improve the selectivity and maintain the porosity of the parent framework. Herein, we developed a "Cage-on-MOF" strategy to tune the recognition and catalytic properties of MOFs without impairing their porosity. Two types of porous coordination cages (PCCs) of opposite charges containing secondary binding groups were developed to coordinatively functionalize two distinct porous MOFs, namely MOF@PCC nanocomposites. We demonstrated that the surface-capped PCCs can act as "modulators" to effectively tune the surface charge, stability, and adsorption behavior of different host MOF particles. More importantly, the MOF@PCCs can serve as selective heterogeneous catalysts for condensation reactions to achieve reversed product selectivity and excellent recyclability. This work sets the foundation for using molecular cages as porous surface-capping agents to functionalize and manipulate another porous material, without affecting the intrinsic properties of the parent framework.

Microstructure, ion adsorption and magnetic behavior of mesoporous γ-Fe2O3 ferrite nanoparticles

Magnetic nanoparticles with capacity for surface functionalisation have potential applications in water purification and biomedicine. Here, a simple co-precipitation technique was used to synthesize mesoporous ferrite nanoparticles in the presence of cetyltrimethylammonium bromide (CTAB) micellular surfactant. The as-synthesized ferrite nanoparticles were calcined at 250 °C for 5, 10, 15, and 24 h to remove the surfactant and create a mesoporous structure. The prepared samples were characterised using a wide range of analytical techniques. Microscopical images showed that all uncalcined particles have cauliflower shape without porosity. However, after calcination, surface and deep pores were created on the synthesized nanoparticles. In addition, transmission electron microscope (TEM) images of calcined nanoparticles revealed a wormhole-like structure, which is typical for the mesoporous architectures. Based on X-ray diffraction (XRD), the uncalcined and calcined samples exhibit pure Fe3O4 (magnetite) and γ-Fe2O3 (maghemite) ferrite phases, respectively. The γ-Fe2O3 nanoparticles demonstrated a high Brunauer-Emmett-Teller (BET) surface area with pore diameters smaller than 10 nm and a type IV isotherm similar to the mesopores. Hysteresis loops measured by vibrating sample magnetometry (VSM) showed the superparamagnetic nature for mesoporous γ-Fe2O3 nanoparticles. The first-order reversal curve (FORC) diagram revealed the formation of a mesoporous structure in calcined materials which reduces coercive distribution (Hc) and magnetostatic interaction (Hu) once compared to non-calcined samples. Mesoporous γ-Fe2O3 nanoparticles were successfully employed as an adsorbent for the removal of heavy metal ions of Pb(ii) from an aqueous solution. The highest lead ion adsorption was observed in mesoporous γ-Fe2O3 nanoparticles prepared with 3% CTAB.

Lewis Acid Catalyzed Amide Bond Formation in Covalent Graphene-MOF Hybrids

Covalent hybrids of graphene and metal-organic frameworks (MOFs) hold immense potential in various technologies, particularly catalysis and energy applications, due to the advantageous combination of conductivity and porosity. The formation of an amide bond between carboxylate-functionalized graphene acid (GA) and amine-functionalized UiO-66-NH2 MOF (Zr6O4(OH)4(NH2-bdc)6, with NH2-bdc2- = 2-amino-1,4-benzenedicarboxylate and UiO = Universitetet i Oslo) is a highly efficient strategy for creating such covalent hybrids. Previous experimental studies have demonstrated exceptional properties of these conductive networks, including significant surface area and functionalized hierarchical pores, showing promise as a chemiresistive CO2 sensor and electrode materials for asymmetric supercapacitors. However, the molecular-level origin of the covalent linkages between pristine MOF and GA layers remains unclear. In this study, density functional theory (DFT) calculations were conducted to elucidate the mechanism of amide bond formation between GA and UiO-66-NH2. The theoretical calculations emphasize the crucial role of zirconium within UiO-66, which acts as a catalyst in the reaction cycle. Both commonly observed hexa-coordinated and less common hepta-coordinated zirconium complexes are considered as intermediates. By gaining detailed insights into the binding interactions between graphene derivatives and MOFs, strategies for tailored syntheses of such nanocomposite materials can be developed.

Mesoporous Mixed-Metal-Organic Framework Incorporating a [Ru(Phen)3]2+ Photosensitizer for Highly Efficient Aerobic Photocatalytic Oxidative Coupling of Amines

[Ru(Phen)₃]²⁺ (phen = phenanthroline) as a very classical photosensitizer possesses strong absorption in the visible range and facilitates photoinduced electron transfer, which plays a vital role in regulating photochemical reactions. However, it remains a significant challenge to utilize more adequately and exploit more efficiently the ruthenium-based materials due to the uniqueness, scarcity, and nonrenewal of the noble metal. Here, we integrate the intrinsic advantages of the ruthenium-based photosensitizer and mesoporous metal-organic frameworks (meso-MOFs) into a [Ru(Phen)₃]²⁺ photosensitizer-embedded heterometallic Ni(II)/Ru(II) meso-MOF (LTG-NiRu) via the metalloligand approach. LTG-NiRu, with an extremely robust framework and a large one-dimensional (1D) channel, not only makes ruthenium photosensitizer units anchored in the inner wall of meso-MOF tubes to circumvent the problem of product/catalyst separation and recycling of catalysts in heterogeneous systems but also exhibits exceptional activities for the aerobic photocatalytic oxidative coupling of amine derivatives as a general photocatalyst. The conversion of the light-induced oxidative coupling reaction for various benzylamines is ∼100% in 1 h, and more than 20 chemical products generated by photocatalytic oxidative cycloaddition of N-substituted maleimides and N,N-dimethylaniline can be synthesized easily in the presence of LTG-NiRu upon visible light irradiation. Moreover, recycling experiments demonstrate that LTG-NiRu is an excellent heterogeneous photocatalyst with high stability and excellent reusability. LTG-NiRu represents a great potential photosensitizer-based meso-MOF platform with an efficient aerobic photocatalytic oxidation function that is convenient for gram-scale synthesis.

Dual-Drug Delivery by Anisotropic and Uniform Hybrid Nanostructures: A Comparative Study of the Function and Substrate-Drug Interaction Properties

By utilizing nanoparticles to upload and interact with several pharmaceuticals in varying methods, the primary obstacles associated with loading two or more medications or cargos with different characteristics may be addressed. Therefore, it is feasible to evaluate the benefits provided by co-delivery systems utilizing nanoparticles by investigating the properties and functions of the commonly used structures, such as multi- or simultaneous-stage controlled release, synergic effect, enhanced targetability, and internalization. However, due to the unique surface or core features of each hybrid design, the eventual drug-carrier interactions, release, and penetration processes may vary. Our review article focused on the drug's loading, binding interactions, release, physiochemical, and surface functionalization features, as well as the varying internalization and cytotoxicity of each structure that may aid in the selection of an appropriate design. This was achieved by comparing the actions of uniform-surfaced hybrid particles (such as core-shell particles) to those of anisotropic, asymmetrical hybrid particles (such as Janus, multicompartment, or patchy particles). Information is provided on the use of homogeneous or heterogeneous particles with specified characteristics for the simultaneous delivery of various cargos, possibly enhancing the efficacy of treatment techniques for illnesses such as cancer.

Beyond Microporosity in Porous Organic Molecular Materials (POMMs)

Porous organic molecular materials (POMMs) are a novel class of porous materials that cover a wide range of organic-based molecular building blocks connected through weak supramolecular interactions, such as hydrogen bonds, π-π stacking, van der Waals and electrostatic interactions. Despite of their diverse chemical and structural nature, common features to POMMs include solution processability, crystallinity and microporosity. Herein, we focus, for the first time, on the advance of the field of POMMs beyond the archetypical microporosity. In particular, we highlight relevant examples of meso- and macroporous POMMs, as well as hierchachical ones (micro-/meso-, micro-/macro- and meso-/macroporous). We also remark some of their unique properties, and how they can be key in many applications.

Utilization of Functionalized Metal–Organic Framework Nanoparticle as Targeted Drug Delivery System for Cancer Therapy

Cancer is a multifaceted disease that results from the complex interaction between genetic and environmental factors. Cancer is a mortal disease with the biggest clinical, societal, and economic burden. Research on better methods of the detection, diagnosis, and treatment of cancer is crucial. Recent advancements in material science have led to the development of metal–organic frameworks, also known as MOFs. MOFs have recently been established as promising and adaptable delivery platforms and target vehicles for cancer therapy. These MOFs have been constructed in a fashion that offers them the capability of drug release that is stimuli-responsive. This feature has the potential to be exploited for cancer therapy that is externally led. This review presents an in-depth summary of the research that has been conducted to date in the field of MOF-based nanoplatforms for cancer therapeutics.

Ionic-Liquid-Assisted One-Step Construction of Mesoporous Metal-Organic Frameworks

The synthesis of ionic-mesoporous-metal-organic frameworks (ionic-meso-MOFs) has received considerable interest in the fields of macromolecular adsorption, acid-base catalysis, ionic conductivity, etc.; yet, their synthesis still presents significant difficulties. In this study, functionalized mesoporous MIL-101-ILs (Cr) was facilely constructed via an in situ self-assembly method by using aromatic-anion-functionalized ionic liquids (ILs) as competitive ligands. It has been demonstrated that the inclusion of an aromatic moiety into an IL improves the coordination ability and is advantageous for the anchoring of ILs on Cr³⁺ via amino-metal coordination. Thus, ionic-meso-MOFs with a specific surface area of 441.9-624.9 cm²/g and an average pore diameter of 5.5 to 8.4 nm were successfully synthesized. Because of the presence of open Lewis acidic metal sites on the MOFs and basic active sites on the ILs, the resulting ionic-meso-MOFs demonstrated both an acid-base cooperative effect and a mesoporous structure, indicating a high potential for acid-base catalysis. This in situ synthesis procedure for ionic mesoporous MOFs offers a simple method for developing and fabricating multifunctional mesoporous materials.

Rapid synthesis of bismuth-organic frameworks as selective antimicrobial materials against microbial biofilms

Antibiotic resistance is a global public health threat, and urgent actions should be undertaken for developing alternative antimicrobial strategies and approaches. Notably, bismuth drugs exhibit potent antimicrobial effects on various pathogens and promising efficacy in tackling SARS-CoV-2 and related infections. As such, bismuth-based materials could precisely combat pathogenic bacteria and effectively treat the resultant infections and inflammatory diseases through a controlled release of Bi ions for targeted drug delivery. Currently, it is a great challenge to rapidly and massively manufacture bismuth-based particles, and yet there are no reports on effectively constructing such porous antimicrobial-loaded particles. Herein, we have developed two rapid approaches (i.e., ultrasound-assisted and agitation-free methods) to synthesizing bismuth-based materials with ellipsoid- (Ellipsoids) and rod-like (Rods) morphologies respectively, and fully characterized physicochemical properties. Rods with a porous structure were confirmed as bismuth metal-organic frameworks (Bi-MOF) and aligned with the crystalline structure of CAU-17. Importantly, the formation of Rods was a 'two-step' crystallization process of growing almond-flake-like units followed by stacking into the rod-like structure. The size of Bi-MOF was precisely controlled from micro-to nano-scales by varying concentrations of metal ions and their ratio to the ligand. Moreover, both Ellipsoids and Rods showed excellent biocompatibility with human gingival fibroblasts and potent antimicrobial effects on the Gram-negative oral pathogens including Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum. Both Ellipsoids and Rods at 50 ​μg/mL could disrupt the bacterial membranes, and particularly eliminate P. gingivalis biofilms. This study demonstrates highly efficient and facile approaches to synthesizing bismuth-based particles. Our work could enrich the administration modalities of metallic drugs for promising antibiotic-free healthcare.

Dye-Encapsulated Metal-Organic Frameworks for the Multi-Parameter Detection of Temperature

Temperature is an important physical parameter and plays a significant role in scientific research, the detection of which cannot be too crucial to study. In order to reduce the interference of the external environment on the detection of temperature and improve the accuracy of the detection results, a multi-parameter detection method using several optical signals was proposed. Here, a novel porous metal-organic framework (MOF), Zn-CYMPN, was synthesized and structurally characterized. Then, fluorescent organic dyes, either DPEE or DPEM, were encapsulated into the pores of Zn-CYMPN independently. The successful synthesis of the composites Zn-CYMPN⊃DPEE or Zn-CYMPN⊃DPEM could easily introduce other fluorescent centers into the original material and made it more convenient to realize multi-parameter temperature detection. More specifically, when the temperature changed, the maximum fluorescent emission wavelength (W) and the maximum optical intensity (I) of the Zn-CYMPN⊃DPEE/DPEM both showed good linear responses with temperature over a wide range, indicating that the composites were highly sensitive thermometers with multi-parameter temperature readouts. In addition, the quantum efficiency and thermal stability of the organic dyes, which bother every researcher, were improved as well.

Molecular dynamics simulation of adsorption and separation of xylene isomers by Cu-HKUST-1

Metal-organic frameworks (MOFs) are widely used in the adsorption separation of various gases. A fundamental understanding of the effective separation of xylene isomers helps improve aromatic products' separation efficiency and reduce industrial separation costs. Grand Canonical Monte Carlo (GCMC) simulations combined with Molecular Science is widely used to predict gas adsorption and diffusion in single crystals with metal-organic frameworks. We performed a GCMC + MD combined approach to study xylene isomers' adsorption and separation in Cu-HKUST-1 to predict the permeability and selectivity of the ternary gas mixture in the MOF with the adsorption and diffusion usage data. Most current studies take into account the computational cost and difficulty. Most recent research models are limited to the adsorption of a single or specific molecule, such as hydrogen, methane, carbon dioxide, etc. For this reason, we report an attempt to study the adsorption separation of aromatic gases (p-xylene/o-xylene/m-xylene) based on Cu-HKUST-1 single-crystal materials based on some previous research methods with an appropriate increase in computational cost. To predict the adsorption selectivity and permeability of the ternary mixture of xylene isomers on the MOF surface, the model simulation calculates key parameters of gas adsorption, including gas adsorption volume (N), the heat of adsorption (Q st), Henry coefficient (K), and diffusion coefficient (D).

Hierarchically Porous MOFs Synthesized by Soft-Template Strategies

The past few decades have been witnessing the rapid research boom of metal-organic frameworks (MOFs), which are assembled from metal nodes and multitopic organic linkers. In virtue of their modular assembly mode, they can be tailored according to desired functions to satisfy numerous potential applications. However, most initially reported MOFs were restricted to the microporous regime, limiting their practical applications with bulk molecules involved. Therefore, the research attention was immediately directed toward enlarging the intrinsic pore size of frameworks by extending the secondary building units or organic ligands. Unfortunately, the synthesis of more extended ligands is frequently tedious, and the most resultant MOFs are not sufficiently stable, restricting their popularization. The soft-template strategy is recognized as a promising avenue to produce hierarchically porous MOFs (HPMOFs), although early attempts generally failed due to the incompatibility between the surfactant self-assembly and guided crystallization process of MOF precursors in the organic phase. Therefore, developing a rational soft-template strategy to achieve the precise control of morphology and porosity of HPMOFs is of great significance.In this Account, we present our recent progress on the development and applications of HPMOFs prepared by soft-template strategies. We highlight the key issues upon using the soft-template strategy to synthesize HPMOFs. To enhance the interaction between the template and MOF precursor, a long-chain monocarboxylic acid strategy is introduced to synthesize HPMOFs with irregular mesopores in the organic phase. Then, to improve the order of mesopores, an aqueous-phase synthesis method using amphoteric surfactants as templates is developed to prepare ordered HPMOFs. To further enlarge the pore size and make the synthesis conditions of MOFs compatible with the self-assembly of surfactants, a salting-in species-induced self-assembly strategy is proposed and coupled with the structure-directing properties of copolymer templates to synthesize a series of HPMOFs with large mesopores and even macropores. This salting-in ion-mediated self-assembly (SIMS) strategy paves the way to modify the pore size, pore structure, morphology, and chemical composition of HPMOFs. The separated but intimately interconnected hierarchical pores in the resultant HPMOFs can not only realize rapid mass transport but also isolate different-size guest molecules so that they are competent for a broad range of applications including protein digestion, cascade catalysis, enzyme-assisted substrate sensing, and DNA cleavage. Finally, the limitations, challenges, and future developments of this rapidly evolving field are described. This Account with a highlight to the soft-template strategies not only provides interesting insights to understand the assembly process between templates and MOFs but also inspires an optimization of the properties of HPMOFs from diverse aspects for desired applications.

Preparation, Structural Characterization of Anti-Cancer Drugs-Mediated Self-Assembly from the Pluronic Copolymers through Synchrotron SAXS Investigation

Chemotherapy drugs are mainly administered via intravenous injection or oral administration in a very a high dosage. If there is a targeted drug vehicle which can be deployed on the tumor, the medical treatment is specific and precise. Binary mixing of biocompatible Pluronic^® F127 and Pluronic^® L121 was used in this study for a drug carrier of pluronic biomedical hydrogels (PBHs). Based on the same PBH ingredients, the addition of fluorouracil (5-FU) was separated in three ways when it was incorporated with pluronics: F127-L121-(5-FU), F127-(5-FU), and L121-(5-FU). Small angle X-ray scattering experiments were performed to uncover the self-assembled structures of the PBHs. Meanwhile, the expected micelle and lamellar structural changes affected by the distribution of 5-FU were discussed with respect to the corresponding drug release monitoring. PBH-all with the mixing method of F127-L121-(5-FU) has the fastest drug release rate owing to the undulated amphiphilic boundary. In contrast, PBH-2 with the mixing method of L121-(5-FU) has a prolonged drug release rate at 67% for one month of the continuous drug release experiment because the flat lamellar amphiphilic boundary of PBH-2 drags the migration of 5-FU from the hydrophobic core. Therefore, the PBHs developed in the study possess great potential for targeted delivery and successfully served as a microenvironment model to elucidate the diffusion pathway of 5-FU.

Mixed-Ligand Strategy for the Creation of Hierarchical Porous ZIF-8 for Enhanced Adsorption of Copper Ions

The adsorption of heavy metals using metal-organic framework-based adsorption technology has been pointed out as a promising technique for the removal of these toxic elements from water. However, their adsorption capacity needs to be enhanced. Thus, the current work reports the effect of using a mixed-ligand strategy on the MOF framework and its effect on the removal of copper ions from water by adding terephthalic acid (BDC) linker to the ZIF-8precursors (2-methylimidazole (mI) and Zn²⁺) under solvothermal synthesis, leading to the formation of a hierarchical microporous mesoporous MOF, named Zn-mI-BDC, which was characterized by SEM, EDX, XRD, TGA, BET, and FTIR. As a result, all of these techniques revealed that the addition of a controlled amount of BDC did not alter the crystallinity of ZIF-8, resulting in the creation of a pore size of 4.2 nm. The new hierarchical porous MOF was tested for the adsorption of copper and exhibited an enhanced adsorption capacity compared to pristine ZIF-8 and many other standard adsorbents. The adsorption isotherm matched well with the Langmuir isotherm model, suggesting that the adsorption process chemisorption had a dominant role in the adsorption of Cu²⁺ species. Therefore, the current work is considered as an important step toward the use of a mixed-ligand strategy in enhancing the adsorption capacity of heavy metals using MOF materials.

Metal organic frameworks for electrochemical sensor applications: A review

Metal-organic frameworks (MOFs) are broadly known as porous coordination polymers, synthesized by metal-based nodes and organic linkers. MOFs are used in various fields like catalysis, energy storage, sensors, drug delivery etc., due to their versatile properties (tailorable pore size, high surface area, and exposed active sites). This review presents a detailed discussion of MOFs as an electrochemical sensor and their enhancement in the selectivity and sensitivity of the sensor. These sensors are used for the detection of heavy metal ions like Cd²⁺, Pb²⁺, Hg²⁺, and Cu²⁺ from groundwater. Various types of organic pollutants are also detected from the water bodies using MOFs. Furthermore, electrochemical sensing of antibiotics, phenolic compounds, and pesticides has been explored. In addition to this, there is also a detailed discussion of metal nano-particles and metal-oxide based composites which can sense various compounds like glucose, amino acids, uric acid etc. The review will be helpful for young researchers, and an inspiration to future research as challenges and future opportunities of MOF-based electrochemical sensors are also reported.

Creating Tunable Mesoporosity by Temperature-Driven Localized Crystallite Agglomeration

A new synthetic approach for tunable mesoporous metal-organic frameworks (MeMs) is developed. In this approach, mesopores are created in the process of heat conversion of highly mosaic metal-organic framework (MOF) crystals with non-interpenetrated low-density nanocrystallites into MOF crystals with two-fold interpenetrated high-density nanocrystallites. The two-fold interpenetration reduces the volume of the nanocrystallites in the mosaic crystal, and the accompanying localized agglomeration of the nanocrystallites results in the formation of mesopores among the localized crystallite agglomerates. The pore size can be easily modulated from 7 to 90 nm by controlling the heat treatment conditions, that is, the aging temperature and aging time. Various proteins can be encapsulated in the MeM, and immobilized enzymes show catalyst activity comparable to that of the free native enzymes. Immobilized β-galactosidase is recyclable and the enzyme activity of the immobilized catalase is maintained after exposure to high temperatures and various organic solvents.

Luminescent porous metal–organic gels for efficient adsorption and sensitive detection of chlortetracycline hydrochloride assisted by smartphones and test paper-based analytical device

Developing dual functional materials for chlortetracycline hydrochloride (CTC) adsorption and detection is of great importance for wastewater treatment and pollution monitoring. Herein, three novel (Fe-Tb) JLUE-MOGs are synthesized through the...

Advances and Prospects in Metal-Organic Frameworks as Key Nexus for Chemocatalytic Hydrogen Production

Hydrogen is a clean and sustainable energy carrier, which is considered a promising alternative for fossil fuels to solve the global energy crisis and respond to climate change. Social concerns on its safe storage promote continuous exploration of alternatives to traditional storage methods. In this case, chemical hydrogen storage materials initiate plentiful research with special attention to the design of heterogeneous catalysts that can enhance efficient and highly selective hydrogen production. Metal-organic frameworks (MOFs), a kind of unique crystalline porous materials featuring highly ordered porosities and tailorable structures, can provide various active sites (i.e., metal nodes, functional linkers, and defects) for heterogeneous catalysis. Furthermore, the easy construction of active sites in highly ordered MOFs, which can work as plate for the delicate active site engineering, make them ideal candidates for a variety of heterogeneous catalysts including chemocatalytic hydrogen production. This review concentrates on the application of MOFs as heterogeneous catalysts or catalyst supports in chemocatalytic hydrogen production. Recent progresses of MOFs as catalysts for chemocatalytic hydrogen production are comprehensively summarized. The research methods, mechanism analyses, and prospects of MOFs in this field are discussed. The challenges in future industrial applications of MOFs as catalysts for hydrogen production are proposed.

Metal-organic frameworks (MOFs) as host materials for the enhanced delivery of biomacromolecular therapeutics

Biomacromolecular drugs have become an important class of therapeutic agents for the treatment of human diseases. Considering their high propensity for being degraded in the human body, the choice of an appropriate delivery system is key to ensure the therapeutic efficacy of biomacromolecular drugs in vivo. As an emerging class of supramolecular "host" materials, metal-organic frameworks (MOFs) exhibit advantages in terms of the tunability of pore size, encapsulation efficiency, controllable drug release, simplicity in surface functionalization and good biocompatibility. As a result, MOF-based host-guest systems have been extensively developed as a new class of flexible and powerful platform for the delivery of therapeutic biomacromolecules. In this review, we summarize current research progress in the synthesis of MOFs as delivery materials for a variety of biomacromolecules. Firstly, we briefly introduce the advances made in the use of biomacromolecular drugs for disease therapy and the types of commonly used clinical delivery systems. We then describe the advantages of using MOFs as delivery materials. Secondly, the strategies for the construction of MOF-encapsulated biomacromolecules (Biomacromolecules@MOFs) and the release mechanisms of the therapeutics are categorized. Thirdly, the application of MOFs to deliver different types of biomacromolecules (e.g., antigens/antibodies, enzymes, therapeutic proteins, DNA/RNA, polypeptides, and polysaccharides) for the treatment of various human diseases based on immunotherapy, gene therapy, starvation therapy and oxidation therapy is summarized. Finally, the remaining challenges and available opportunities for MOFs as drug delivery systems are outlined, which we anticipate will encourage additional research efforts directed towards developing Biomacromolecules@MOFs systems for biomedical applications.

A mesoporous ionic solid with 272 AuI 6AgI 3CuII 3 complex cations in a super huge crystal lattice

Here, we report a unique mesoporous ionic solid (I) generated from a cationic Au^I₆Ag^I₃Cu^II₃ dodecanuclear complex with d-penicillamine depending on the homochirality and crystallization conditions. I crystallizes in the cubic space group of F4₁32 with an extremely large cell volume of 2 171 340 ų, containing 272 Au^I₆Ag^I₃Cu^II₃ complex cations in the unit cell. In I, the complex cations are connected to each other through CH⋯π interactions in a zeotype framework, the topology of which is the same as that of the metal–organic framework in MIL-101, with similar but much larger two types of polyhedral pores with internal diameters of 38.2 Å and 49.7 Å, which are occupied by counter-anions and water molecules. Due to the cationic nature of the framework, I undergoes quick, specific exchanges of counter-anions while retaining its single crystallinity. This study realized the creation of a non-covalent mesoporous framework from a single complex salt, providing a conceptual advance in solid chemistry and material science.

A non-MOF ionic solid having two types of polyhedral mesopores in a very large crystal lattice is generated from a cationic Au^I₆Ag^I₃Cu^II₃ complex with d-penicillamine, showing specific exchanges of counter-anions retaining its single crystallinity.

Two methods for constructing ZIF-8 nanomaterials with good bio compatibility and robust antibacterial applied to biomedical

Metal-organic framework materials not only possess porous structures, but also have excellent antibacterial properties. It is of great practical significance to prepare new antibacterial materials with excellent antibacterial effect by metal-organic framework materials. In our study, Zeolitic Imidazolate Framework-8 (ZIF-8) nanomaterials with antibacterial properties were prepared via the solvent method and diethanolamine template method. The materials were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cold field-emission scanning electron microscope (SEM), transmission electron microscopy (TEM), N₂ adsorption-desorption experiment, antibacterial experiment, and biocompatibility experiment. Results showed that ZIF-8 prepared by solvent method has a more typical hexagonal structure, larger specific surface area, and smaller pore size, and the values are 1812.07 m²g^-1 and 2.2412 nm, respectively. At the same time, the materials prepared by the two methods have excellent antibacterial properties, and exhibit good biocompatibility at low concentrations, the antibacterial activity against Escherichia coli and Staphylococcus aureus are higher than 95%, and the cell viabilities of the selected five material concentrations of 12.5 µg mL^-1, 25 µg mL^-1, 50 µg mL^-1, 100 µg mL^-1 and 200 µg mL^-1 are more than 70%. Therefore, this study provides a feasible method for preparing Nano-scale antibacterial functional particles, and it is of great significance to broaden the application field of ZIF-8 materials and prepare ZIF-8 drug-delivery functional materials.

Effective enhancement of capacitive performance by the facile exfoliation of bulk metal-organic frameworks into 2D-functionalized nanosheets

Recently, much attention has been paid to two-dimensional MOF nanosheets (MONs) due to their widespread application in many specific areas. In this work, a simple and efficient congenerous-exfoliation strategy was developed to prepare vast and uniform few-layered Ni²⁺@Ce-MOF (Ce-MOF: {[Ce(HPIA)(PIA)(H₂O)₂]·H₂O}_n) nanosheets with a thickness of ca. 10 nm. In the exfoliation process, the synergistic action of Ni²⁺ and methanol solvents under ultrasonication plays a major role in restraining the interactions between the layers. Importantly, supercapacitor applications indicate that the exfoliated Ni²⁺@Ce-MOF nanosheet shows a remarkable improvement in the specific capacitance (921.05%) in comparison with that of the bulk Ce-MOF sample before modification.

Design of metal-organic framework composites in anti-cancer therapies

Metal-organic frameworks are a class of new and promising anti-cancer materials. MOFs with adjustable pore size, large specific surface area, diverse structure, and excellent chemical and physical properties make them a class of effective protection carriers for anti-cancer substances. This review is centered on the core point of "anti-cancer" and discusses MOFs' research progress in anti-cancer therapies. Firstly, we provided readers with the different types of MOFs, their preparation strategies and the resulting structures. Then, different MOF composites and their biological applications were systematically presented. The specificity of biomolecules endows MOFs with broader anti-cancer applications, while MOFs can protect the drugs and biomolecules to make the best of a challenging situation. Finally, we elucidated a comprehensive overview of the biological applications of MOFs, including research hotspots as drug delivery and biomolecule carriers. Besides, we looked forward to the future developments of MOFs in the field of anti-cancer therapies. As a class of novel materials, the anti-cancer applications of MOFs are extended through the combination of different materials and different methods to improve their efficacy.

Metal-Organic Framework-Based Hierarchically Porous Materials: Synthesis and Applications

Metal-organic frameworks (MOFs) have been widely recognized as one of the most fascinating classes of materials from science and engineering perspectives, benefiting from their high porosity and well-defined and tailored structures and components at the atomic level. Although their intrinsic micropores endow size-selective capability and high surface area, etc., the narrow pores limit their applications toward diffusion-control and large-size species involved processes. In recent years, the construction of hierarchically porous MOFs (HP-MOFs), MOF-based hierarchically porous composites, and MOF-based hierarchically porous derivatives has captured widespread interest to extend the applications of conventional MOF-based materials. In this Review, the recent advances in the design, synthesis, and functional applications of MOF-based hierarchically porous materials are summarized. Their structural characters toward various applications, including catalysis, gas storage and separation, air filtration, sewage treatment, sensing and energy storage, have been demonstrated with typical reports. The comparison of HP-MOFs with traditional porous materials (e.g., zeolite, porous silica, carbons, metal oxides, and polymers), subsisting challenges, as well as future directions in this research field, are also indicated.