A bifunctional anionic Zn(II)-organic framework for adsorption and fluorescence sensing of Pb2 + in rice

Nanodots of non-functionalized zinc-based metal–organic frameworks with dual-state emission: Sensitive point-of-care detection of ferric ions in food, environmental and biological samples

Owing to their high surface areas and structural tunability, metal-organic frameworks (MOFs) offer an ideal platform for stabilizing nanocatalysts within their well-defined pores. In this work, we report the synthesis of a zinc-based MOF, FICN-13, with a tris(pyrazolate) ligand tris[4-(1H-pyrazol-4-yl)phenyl]amine (H3TPPA). With a dual-solvent approach, copper oxide nanoparticles were deposited within the one-dimensional channels and on the external surface of FICN-13, forming an integrated MOF-CuOx heterojunction. Incorporation of CuOx nanoparticles led to a product selectivity shift from CO to CH4 in photocatalytic CO2 reduction, achieving a methane production of 56.12 μmol·g-1 and a selectivity of 62% and representing a 195% enhancement over pristine FICN-13. In situ infrared spectroscopy further revealed a stepwise hydrogenation pathway via *CO2 → *CO → *CHO → *CH3O → CH4.

Precisely targeting the site of bacterial infection while reducing harm to healthy tissues has turned into the primary aim of bacterial infection treatment. Based on this background, an acidity-triggered aggregation nanomaterial Cu2+/ZIF-8@PDA-GCS (CZPG) based on bimetallic doped metal-organic frameworks was designed. The zinc-based metal-organic framework doped with Cu2+, namely Cu2+/ZIF-8 (CZ), was first synthesized, followed by modification with polydopamine (PDA) and glycol chitosan (GCS) to endow the CZ with photothermal properties and pH-sensitive charge characteristics, respectively. Under normal physiological conditions, the potential value of CZPG is approximately neutral, and it shows poor affinity to normal tissue cells, but the surface potential of CZPG flips to positive potential at the site of acidic bacterial infection. This allows CZPG to aggregate and adhere on the surface of negatively charged bacteria to ensure the spatial accuracy of CDT/PTT and thus enhance the antibacterial effect.

Bacterial infection in chronic skin defect poses a global healthcare challenge, fueled by antibiotic overuse and bacterial resistance. Zinc-based metal-organic frameworks (Zn-MOFs) with pro-oxidative nanozyme-like activity and broad-spectrum antibacterial activity, complemented by their inherent biocompatibility, have emerged as a promising alternative to antibiotics. However, the translational applications of Zn-MOFs are limited by suboptimal enzyme-mimicking catalytic activity, inadequate biodistribution and target site accumulation. To overcome these limitations, this study establishes a strategy of oxygen vacancy (Ov)-based defect engineering combined with microneedle-mediated transdermal delivery. An Ov-rich Zn²⁺/H₂BDC (Ov-ZBC) MOF is first synthesized by two-step reactions, and then immobilized into the tips of gelatin methacryloyl (GelMA) microneedles to obtain the double-layer GelMA/Ov-ZBC (GOZ) microneedles. Ov-ZBC MOFs demonstrate abundant Ov defects, which consequently led to a superior reactive oxygen species (ROS) production ability. Under visible light irradiation, GOZ microneedles inhibit bacterial survival and proliferation by producing ROS and releasing Zn²⁺. Additionally, they accelerate the healing of <em>S. aureus</em>-infected wounds through multimodal mechanisms, such as anti-inflammatory, M2 macrophage polarization, and promoting cell proliferation. In conclusion, this study not only develops an antibiotic-free theranostic platform, but also provides a proof-of-concept for modifying Zn-MOFs, thereby paving the way for their advanced biomedical applications.

Efficient separation of C2H2/CO2/CH4 by a highly hydrophobic zinc-based metal-organic framework Zn(BPZ) based on pyrazole ring ligands

Herein, we have synthesized the commonly known protonated 5,10,15,20-tetrakis(4-pyridyl)porphyrin (compound 1) and a mixed-linker zinc-based metal-organic framework (compound 2) and evaluated their antibacterial photodynamic therapy. The crystal structure of 1 exhibits hydrogen-bonded scaffolds and engages in π-stacking interactions, whereas compound 2 is coordinated through zinc metal nodes to porphyrin and terephthalate ions, forming an interpenetrated 3D framework with a mog topology. In 2, we observed a high theoretical surface area of 2915 m2 g-1 calculated using a N2 apparatus. Molecular orbital calculations confirm that the highest occupied and lowest unoccupied molecular orbitals are mainly localized on the porphyrin core, with the terephthalate linker acting as an electronic spacer. Finally, 2 exhibits an enhanced reactive oxygen species production and superior antibacterial activity compared to 1 under irradiation with red light. These performances clearly resulted in inhibition zones of 28±1 mm (MRSA) and 21±1 mm (Escherichia coli) and strong binding properties to the proteins. These findings demonstrate that 2 functions as a robust, light-activated antibacterial platform and provide a rational route for next-generation antibacterial agents.

By incorporating electroactive triphenylamine units into a hexacarboxylate linker, two zinc-based metal-organic frameworks with 3,24-connected rht net were constructed, demonstrating unique anion-dependent intermolecular charge/electron and energy transfer. The crystals of Zn-MOF-1 incorporating nitrate anions within the framework are red and do not show fluorescence at all, while Zn-MOF-2 containing fluoroborate anions within the framework is colorless and exhibits significant fluorescence. Cyclic voltammetry further revealed that the two anions present in the frameworks exerted different influence on the electron transfer processes between the triphenylamine units within the framework. Furthermore, fluorescence quenching experiments with electron-deficient nitrobenzene on Zn-MOF-2 were conducted, indicating favorable electron transfer between the electron-rich linkers and electron-deficient guests. A highly luminescent energy transfer composite (DMASM@Zn-MOF-2) was achieved, which exhibited excellent dual-emission performance and adjustable dual-emission intensity accompanied by a variable emission color observed with the naked eye. In all, the two rare rht-type Zn-MOFs incorporating different anions within respective frameworks were constructed for the first time and can serve as a unique platform to uncover previously rarely explored charge/electron and energy transfer interactions related to the nature of anions, thereby enabling the rational design and construction of multifunctional MOF materials.

Efficient xenon/krypton separation remains challenging due to their similar physicochemical properties. Herein, we demonstrate that ligand isomerism can be leveraged as an effective structural handle for constructing new metal-organic frameworks from readily available, low-cost amino acids. Using leucine and isoleucine-two constitutional regioisomers among proteinogenic amino acids that possess the largest nonpolar alkyl side chains-we construct a pair of zinc-based metal-organic frameworks, Zn-LEU and Zn-ILE, which share identical connectivity yet differ subtly in side-chain branching. Zn-ILE retains a more robust framework under a range of conditions, whereas Zn-LEU undergoes a pronounced phase transformation under relatively mild conditions. This structural integrity, combined with a precisely tailored nonpolar pore environment (∼4.4 Å), enables Zn-ILE to exhibit a ∼40% increase in Xe uptake and superior Xe/Kr selectivity over its isomer. Dynamic breakthrough experiments further validate the Xe/Kr separation performance under representative operating conditions, including humid streams and ultradilute xenon concentrations (400ppm). We further formalize a cost-normalized figure of merit that quantifies dynamic xenon capture per unit synthetic input, under which Zn-ILE exhibits cost-normalized Xe productivity of 2.21 × 10-3mmol USD- 1, ranking among the most cost-efficient MOF-based xenon sorbents reported to date.

The efficient separation of fluorocarbon mixtures, such as perfluoropropene (C3F6) and perfluoropropane (C3F8), is critical for producing high-purity electronic gases, but remains a formidable challenge due to their similarity in physicochemical characteristics. Herein, we report the size-sieving separation of C3F6 and C3F8 by a robust zinc-based metal-organic framework, NCU-542, which features a "dual-channel bottleneck-cavity" pore architecture. We show that its specific pore geometry and optimal pore dimensions are beneficial to overcome the intrinsic trade-off between size-sieving precision and diffusion efficiency. The framework contains narrow sieving necks (∼5.2 Å) that fully exclude bulky C3F8, interconnected by larger cavities that serve as diffusion highways for C3F6. Consequently, NCU-542 exhibits a high C3F6/C3F8 uptake ratio of 65.6 and a high C3F6 capacity of 52.5 cm3 g-1 at 298 K and 1bar, while achieving ultrafast adsorption kinetics. In situ IR spectroscopy and DFT calculations elucidate that the specific recognition of C3F6 is driven by multiple cooperative C-H···F interactions at the imidazolate-zinc junctions. Furthermore, the shaped pellets of NCU-542 retain excellent structural integrity and separation performance, validating its industrial potential for C3F6 and C3F8 separation.

Mitigating hazardous environmental hazards, such as organic dyes present in water, remains a pressing challenge. In this study, a highly efficient zinc-based Metal-Organic Framework (MOF) is successfully employed for the adsorptive removal of Congo Red (CR) from aqueous solution. Experimental design was validated using Machine Learning (ML), and key parameters are optimized to model and predict adsorption performance. A facile synthetic approach is adopted for the synthesis of zinc benzenetricarboxylate (ZnBTC) MOF via a hydroxy double salt (HDS) intermediate under ambient conditions. The resultant ZnBTC MOF consists of zinc nodes interconnected by carboxylate linkers, forming a three-dimensional porous framework with well-defined channels and an appreciable surface area. This structural architecture was confirmed through scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption-desorption analysis, and X-ray photoelectron spectroscopy. The material demonstrates remarkable removal efficiency of over 94% across various CR concentrations in a contact time of 60 min. A detailed investigation carried out to evaluate the influence of various key parameters, such as initial concentration of dye, temperature, solution pH, adsorbent dosage, and the influence of coexisting ions, on the dye uptake performance of ZnBTC demonstrates the robustness of this material as a dye adsorbent. To further elucidate and predict the adsorption performance, the experimental data set generated from the investigation is then integrated into ML. Four basic approaches, namely, Extreme Gradient Boosting (XGBoost), Random Forest (RF), Artificial Neural Network (ANN), and Linear Regression (LR), are compared. The XGBoost model delivers the strongest performance with a test R2 value of 0.968 and establishes the catalyst dosage and contact time as the governing variables. This establishes the superiority of tree-based ensemble machine learning algorithms to predict MOF-based adsorption performance, further confirming that such approaches are particularly well-suited for small, structured data sets. Thermodynamic, isotherm, and kinetic analyses confirm the spontaneous and predominantly chemisorptive nature of CR uptake, with additional contributions from hydrogen bonding, mass-transfer effects, and π-π interaction effects. Owing to its facile preparation, biocompatibility, and sustained efficiency across varied operational conditions, ZnBTC emerges as a promising and efficient adsorbent for CR removal in wastewater treatment systems. Moreover, the combined experimental and AI-driven approach yields a reliable decision-support tool for adsorption studies, underscoring the significance of this work in bridging materials science with AI for a reliable decision-support framework for wastewater remediation studies.

Influence and mechanism of inorganic ions on Cr(VI) adsorption from wastewater by zinc-based metal-organic framework

Rod-shaped zinc-based metal–organic frameworks with dual-state emission for dual-state detection of ferric ions: Sensitive point-of-care testing in food samples

ABSTRACT A major global health concern that is fueling the urgent need for new antimicrobial medicines is the growing resistance of microorganisms to traditional antibiotics, which becomes less effective due to the quick emergence of multidrug‐resistant bacterial and fungal strains, highlighting the significance of creating novel approaches to treat microbial illnesses. To overcome this issue, a class of porous materials, known as metal–organic frameworks (MOFs), has evolved as they demonstrated significant promise in biomedical applications, as they are good candidates for creating potent antibacterial agents because of their large surface area, adjustable porosity, and chemical adaptability. The well‐known antibacterial qualities of zinc ions have drawn attention to zinc‐based MOFs (Zn‐MOFs) in particular. In this work, aliphatic dicarboxylic acid–based flexible Zn‐MOFs have been synthesized and investigated for their biological potency as an antibacterial material. The synthesized compounds were characterized by using Fourier‐transform infrared (FT‐IR) spectroscopy, powder X‐ray diffraction (PXRD), field emission scanning electron microscopy (FE‐SEM), thermogravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) surface area analysis.

The urgent need to mitigate carbon dioxide (CO2) emissions from fossil-fuel-based electricity generation has driven research into advanced materials for post-combustion carbon capture. This paper presents a modified solvothermal technique to synthesize zinc (Zn) and magnesium (Mg) based MOF-74 suitable for CO2 capture from coal-fired power plants. The materials were synthesized through a solvothermal method using N,N-dimethylformamide (DMF) as the primary solvent, and subsequently characterized using Brunauer–Emmett–Teller (BET) surface area analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and thermogravimetric analysis (TGA). Both MOFs contained oxygen-containing functional groups and were thermally stable up to 430 °C and 600 °C respectively, making them ideal for carbon capture. The low-pressure N2-BET surface areas were 55 m2/g and 24.73 m2/g. In conclusion, the Zn material had a mesoporous structure, making it more favorable for carbon capture. It was found that prolonged synthesis time weakened the MOF structure. Future work should experimentally evaluate CO2 capture from coal-derived flue gas using Zn/Mg-MOF-74 materials, investigating adsorption behavior and kinetics through isotherm and kinetic models, while also assessing the effect of varying Zn: Mg ratios under optimized synthesis conditions.

Rapid and recyclable removal of Congo Red dye using mesoporous Zinc-based metal organic framework.

Design and Application of Zinc-Based Metal-Organic Framework for 152+154Eu(III) Adsorption: Experimental and DFT Insights

MOFs-based dual-emission stable fluorescent/colorimetric probe for efficient identification and screening of trace Hg2+, In3+, Zr4.

High-performance asymmetric supercapacitor enabled by three-dimensional zinc-based metal-organic framework

A zinc-based metal-organic framework (MOF) engineered from tetrakis(4-carboxyphenyl) porphyrin (TCPP) as an organic linker and functionalized with gallic acid (GA) as an active therapeutic agent demonstrates remarkable potential for cancer treatment. The resulting Zn-TCPP@GA hybrid framework exhibits a high specific surface area, extensive π-π conjugation, and superior catalytic performance, collectively facilitating efficient reactive oxygen species (ROS) generation-an essential mechanism underlying chemodynamic therapy (CDT). Incorporation of GA significantly enhances the redox activity and biocompatibility of the framework. GA actively participates in modulating the tumor environment by depleting intracellular glutathione (GSH), thereby impairing the antioxidant defense machinery of cancer cells and amplifying ROS-mediated oxidative stress. Comprehensive physicochemical characterization confirmed that Zn-TCPP@GA exhibits an intrinsic peroxidase-mimetic and ROS generation mechanism via catalyzing the decomposition of hydrogen peroxide (H2O2) into highly reactive hydroxyl radicals (˙OH). This catalytic conversion markedly augments intracellular ROS accumulation, resulting in pronounced oxidative damage and selective cytotoxicity toward malignant cells while sparing normal tissues. In vitro cytotoxicity evaluation revealed that Zn-TCPP@GA at a concentration of 75.04 µg mL-1 induced approximately a 50% reduction in MCF-7 breast cancer cell viability, with negligible impact on normal cell lines. Collectively, these findings substantiate Zn-TCPP@GA as a potent CDT nanotherapeutic platform, capable of tumor-selective ROS amplification through peroxidase-like catalysis and chemodynamic biochemical modulation mediated by gallic acid.