ABSTRACT Hollow ZIF‐67 (HO‐ZIF‐67) was fabricated by tannic‐acid etching of ZIF‐67 grown in situ on polyamide (PA) membranes to obtain HO‐ZIF‐67@PA for Th(IV) adsorption. Microscopic and structural characterization confirmed the hollow architecture and immobilization of HO‐ZIF‐67 on the membrane surfaces and pore walls. Compared with its solid ZIF‐67@PA analogue, HO‐ZIF‐67@PA exhibited a higher specific surface area (739.1 vs. 536.4 m 2 g −1 ) and Langmuir maximum adsorption capacity (1019.38 vs. 703.59 mg·g −1 , normalized to the mass of loaded ZIF‐67) at pH 4.0 and 298 K, reaching equilibrium within 90 min. The enhancement was attributed to improved active‐site accessibility and shortened intraparticle diffusion pathways afforded by the hollow structure, together with surface phenolic hydroxyl and amino groups. X‐ray photoelectron spectroscopy indicated that Th(IV) adsorption involved coordination with these functional groups. The composite retained 90.29% of its initial adsorption capacity after five adsorption–desorption cycles. In pH‐adjusted simulated wastewater, its first‐cycle adsorption capacity was 71.03% of that obtained in a single‐solute Th(IV) solution, while preferential adsorption of Th(IV) over Ca(II) and Mg(II) was maintained. These results identify tannic‐acid‐induced hollowing as the key improvement over ZIF‐67@PA and demonstrate the potential of HO‐ZIF‐67@PA for Th(IV) removal from complex aqueous matrices.
ABSTRACT Dye wastewater treatment is frequently hampered by low adsorption capacity and inefficient simultaneous removal of cationic and anionic dyes. Herein, a hierarchical ZIF‑67@CoAl‑LDH@MIL‑100(Al) (ZLM) composite featuring an LDH‑bridged MOF‑on‑MOF architecture was fabricated via metal–ligand in situ derivation and amino functionalization. This interfacial assembly integrates the high specific surface area of MOFs, the tunable layered structure of LDHs, and abundant amino active sites, affording favorable interfacial microenvironments and abundant adsorption sites for both cationic and anionic dyes. The as‑synthesized ZLM exhibits superior adsorption performance, with removal efficiencies of 92.53% for Rhodamine B (RhB) and 97.67% for Congo Red (CR), and maximum adsorption capacities of 182.98 and 404.22 mg/g, respectively. Adsorption isotherm fitting indicates that both RhB and CR undergo Langmuir‑dominated monolayer physical adsorption on ZLM driven by non‑covalent interactions. The pseudo‑second‑order kinetic model gives the best fit for both adsorptions: CR adsorption is endothermic and can be promoted by increasing temperature, while RhB adsorption is jointly controlled by liquid‑film mass transfer and intraparticle diffusion. ZLM shows satisfactory recyclability over multiple regeneration cycles. This LDH‑bridged interfacial assembly provides a versatile strategy for designing high‑performance adsorbents with tailored interfacial properties for the simultaneous removal of cationic and anionic dyes from wastewater.
ABSTRACT Multidrug‐resistant Staphylococcus aureus remains a pressing global challenge, driving the search for novel antibacterial scaffolds. From the leaves of Phyllanthus mannianus , we isolated phyllanisoflavanone A ( 1 ), a previously undescribed pyrano‐isoflavanone, alongside seven known phenolics. The structure of 1 was elucidated by 1D and 2D NMR spectral analysis and high‐resolution mass spectrometry. Phyllanisoflavanone A showed moderate activity against S. aureus (MIC = 64 µg/mL). Molecular docking against tyrosyl‐tRNA synthetase (TyrRS) revealed a docking score (estimated binding affinity) of –8.7 kcal/mol, surpassing the reference inhibitor SB‐239629 (–8.5 kcal/mol), with key interactions at GLY38, GLN174, and ASP195. Comparative molecular dynamics simulations (500 ns for 1; 202.1 ns for SB‐239629) and MM‐GBSA calculations supported high conformational stability for 1 (mean ligand RMSD = 0.66 Å vs. 1.34 Å for SB‐239629) and a favorable relative binding free energy (Δ G _bind = –36.0 ± 2.9 kcal/mol, comparable to –37.0 ± 9.8 kcal/mol for SB‐239629). Antioxidant assays further demonstrated notable radical scavenging activity (DPPH SC 50 = 40.5 µg/mL). In silico ADME profiling predicted favorable physicochemical drug‐likeness. These findings highlight phyllanisoflavanone A as a promising lead scaffold for semi‐synthetic optimization toward narrow‐spectrum antibacterial agents.
ABSTRACT Metal‐organic frameworks (MOFs) are advanced structures which have already been explored for their high efficiency as electrocatalysts for sustainable energy conversion reactions, due to growing energy demands. This study tackles the major limitations of pristine MOFs in terms of poor conductivity and stability with a rational design strategy. A novel bimetallic NiCu–MOF was synthesized via solvothermal method using a multifunctional organic linker anthranilic acid, and then a conductive composite (NiCu–MOF/GO) was obtained by combining NiCu–MOF and graphene oxide (GO). Comprehensive characterization indicates the successful formation of the crystalline MOF and the uniform dispersion of the MOF on the GO sheets. The composite architecture is shown to be transformative through electrochemical testing. The NiCu‐MOF/GO composite shows a much lower overpotential of 252 mV at 10 mA cm − 2 for the OER with a Tafel slope of 61 mV/dec, significantly better than the pristine MOF (422 mV, 169 mV/dec). It also shows the best hydrogen evolution reaction (HER) activity (154 mV) and good kinetics. The composite has a large electrochemically active surface area and very high stability over 30 h. This work underscores the synergy between tailored ligand chemistry, bimetallic nodes, and conductive carbon engineering for creating high‐performance electrocatalysts.
ABSTRACT An environmentally benign, highly efficient, and sustainable one‐pot multicomponent strategy has been developed for the synthesis of diversely functionalized imidazo[1,2‐a]pyrimidine derivatives using an aqueous onion extract as a green catalyst. The reaction proceeds via a sequential Knoevenagel condensation, Michael addition, and cyclization cascade involving various aromatic aldehydes 1 , active methylene compounds 2a–c , and 2‐aminobenzimidazole 3 under mild reaction conditions. This convenient, rapid approach furnished varied fused heterocyclic systems in good to excellent yields (up to 96%), while offering operational simplicity, effortless workup, and column‐chromatography‐free isolation. All synthesized compounds were fully characterized by spectroscopic methods, and the structure of derivative 4aq was unambiguously confirmed by single‐crystal x‐ray diffraction analysis. The synthesized imidazo[1,2‐a]pyrimidine derivatives were evaluated for their in vitro antioxidant activity using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assay against ascorbic acid as the standard. Several derivatives have exhibited notable activity, with IC 50 values ranging from 1.09 to 1.23 × 10 −4 M and compound 4ah in particular proved more effective than ascorbic acid. Furthermore, the eco‐friendly credentials and sustainability of this synthetic protocol were quantitatively validated using standard green metrics calculations.
