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Abstract The escalating presence of per‐ and polyfluoroalkyl substances (PFAS) in drinking water poses urgent public health concerns, necessitating effective removal. This study presents a groundbreaking approach, using viologen to synthesize covalent organic framework nanospheres: MELEM‐COF and MEL‐COF. Characterized by highly crystalline features, these nanospheres exhibit exceptional affinity for diverse anionic PFAS compounds, achieving simultaneous removal of multiple contaminants within 30 min. Investigating six anionic PFAS compounds, MEL‐ and MELEM‐COFs achieved 90.0–99.0% removal efficiency. The integrated analysis unveils the synergistic contributions of COF morphology and functional properties to PFAS adsorption. Notably, MELEM‐COF, with cationic surfaces, exploits electrostatic and dipole interactions, with a 2500 mg g⁻¹adsorption capacity—surpassing all reported COFs to date. MELEM‐COF exhibits rapid exchange kinetics, reaching equilibrium within 30 min. These findings deepen the understanding of COF materials and promise avenues for refining COF‐based adsorption strategies. 

Abstract Woven covalent organic frameworks (COF) possess entangled 3D frameworks. The metallated version of these structures contains  spatially isolated Cu(I) centers and promising optoelectronic properties because of metal‐to‐ligand charge transfer (MLCT). However, despite their potential, woven COFs have not yet been investigated as photocatalysts. In this study, a new woven COF, Cu‐PhenBDA‐COF, functionalized with diacetylene bonds is developed. Cu‐PhenBDA‐COF is fully characterized, and the optoelectronic and photocatalytic properties are compared to previously reported Cu‐COF‐505. The diacetylene bonds of the linker positively impact the optoelectronic properties of Cu‐PhenBDA‐COF and result in a narrower bandgap and better charge separation efficiency. When the Cu(I) center is removed from both woven COFs, the absorption edge is blueshifted, resulting in a wider bandgap, and there is a considerable decrease in the charge separation efficiency, underscoring the pivotal role of MLCT. This trend is reflected in the photocatalytic activity of the woven COFs toward the degradation of sulfamethoxazole in water, where the highest reaction rate constant (k_app) is recorded for the metallated diacetylene functionalized woven COF, Cu‐PhenBDA‐COF. 

Abstract The synthesis of a fluorescent covalent organic framework (COF) using perylene and pyrene building blocks (PEPy‐COF), via a one‐pot condensation reaction is reported. PEPy‐COF is crystallized into 2D nanosheets with a cubic and prismatic crystalline morphology and demonstrates structural stability at temperatures up to 500 °C. The structural morphology is confirmed using X‐ray diffraction and atomic‐level simulations. These 2D porous polymer sheets form a tetragonal framework that is found to have a high specific surface area of 772 m²g⁻¹. Based on the definition of porous materials, the network is mesoporous with an observed pore size of 3.03 nm, which is in good agreement with the material's calculated pore size. The experimentally obtained HOMO‐LUMO band gap is 2.62 eV, confirming the semiconducting nature of PEPy‐COF. PEPy‐COF emits a shiny blue luminescence under UV and visible light. This luminescence intensity is temperature‐dependent in solvents with different polarities and dielectric constants demonstrating that the PEPy‐COF has potential use in a wide range of temperature‐sensing devices. The fluorescence intensity ratio is similar for different temperatures under ultra‐sound conditions and varying solvents.