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Here, an exhaustive exploration of the reaction mechanism toward the chlorination process carried out by SalL, a chlorinase enzyme that catalyzes the conversion of SAM into 5′-chloro-5′-deoxyadenosine through an S_N2 reaction, is presented. To this end, molecular dynamics simulations and quantum mechanical/molecular mechanics calculations are performed, and 14 density functionals are benchmarked. Among the tested functionals, TPSSh(BJ) provides the closest energy barrier to experimental value. Three configurations of interaction between chloride and the halogen pocket are found, where the best model exhibits a barrier height of 20.1 kcal mol⁻¹, close to the 19.9 kcal mol⁻¹ experimentally obtained. This model is characterized by the chloride interacting with the backbone-amide of Gly131 and Tyr130. The reaction pathway is calculated through the intrinsic reaction coordinate approach, and it is characterized using reaction force analysis and the activation-strain model with energy decomposition analysis to obtain chemical insights into the inner working of this enzyme. According to the main findings, the overstabilization of the halogen binding on the active site increases the barrier height, explaining the lack of activity against fluoride, while the interaction energy between nucleophile−electrophile is responsible of reducing the barrier height, with the orbital interaction energy as the main stabilizing factor during the chlorination process.

Due to their comparable molecular dimensions and volatility, distinguishing C₂H₂ from CO₂ during purification remains a significant challenge in industrial applications. Achieving effective isolation of C₂H₂ from binary mixtures of C₂H₂/CO₂ is therefore a critical objective in petrochemical processes. Herein, an adsorption mechanism enabling selective C₂H₂/CO₂ separation has been elucidated in the phosphonate metal–organic framework (MOF) Ni-STA-12. The high C₂H₂ uptake and remarkable CO₂ selectivity of Ni-STA-12 arise from the synergistic effect of diverse adsorption sites distributed throughout its structure, including various oxygen atoms and open metal sites. The adsorbed C₂H₂ interacts strongly with the exposed adsorption sites in the framework and its binding capacity is much larger than that of CO₂. Dynamic breakthrough experiments demonstrated the practical potential for the separation of C₂H₂ in mixtures, and excellent separation potential (Δq) demonstrating high C₂H₂ recovery from C₂H₂/CO₂ mixtures. Theoretical calculations show the synergistic interaction of various oxygen atoms of the MOF with the open metal site Ni and the dominant role of uncoordinated oxygen atoms in the adsorption of C₂H₂.

Covalent organic framework (COF)-based memristors are promising for novel storage and neuromorphic computing applications. The ordered porous structure, tunable chemical composition, and exceptional stability of COFs offer an ideal material foundation for the development of high-performance memristors. This review summarizes a classification method for COFs based on their distinctive bonding patterns, with particular emphasis on the key developmental milestones and functional applications of imine, amide, boronic ester, and vinylene-based architectures. Lastly, a thorough discussion of the future challenges and prospects associated with COF-based memristors is provided.

The front cover picture shows a distinct size-dependent affinity of gold (Au)-based materials for dioxygen (O₂). Although Au is chemically inert against O₂, unique reactivities emerged at the nanometer to the atomic scales. Atomically precise Au nanoclusters and molecular Au complexes with supporting ligands exhibit affinity for O₂, and detailed mechanisms for O₂-activation by these Au-based nanomaterials can be revealed on the basis of both experimental and theoretical analyses. More details can be found in the Concept by Wataru Suzuki and Toshiharu Teranishi (DOI: 10.1002/cplu.202500244).

Catalytic pyrolysis of waste flat-panel display (FPD) plastics and pure polystyrene (PS), which is the main polymer component in FPD waste, is conducted at 500 °C in a micropyrolysis reactor to enhance benzene, toluene, ethylbenzene, and xylene (BTEX) production and eliminate styrene and heteroatom compounds in pyrolysis products. A comparative study with PS reveals similar product distributions, indicating that FPD waste additives do not significantly impede the catalytic reactions. Zeolitic catalysts (HZSM-5, Hβ, and HY) effectively reduce nitrogen- and oxygen-containing compounds and also styrene with increase in BTEX and polycyclic aromatic hydrocarbons (PAHs) yields. Even at a feed:catalyst ratio of 1:1, distinct product distributions are observed compared to the noncatalytic run. In the presence of Hβ, benzene is the main compound, exhibiting a 22% increase. With HY, ethylbenzene is the dominant product, showing a 36% increase. Notably, HY, which possesses the highest concentration of Brønsted acid sites with minimum of Lewis acid sites together with the largest pore size among the studied zeolites, preferentially enhances the formation of ethylbenzene within the BTEX.

High-performance electrodes based on carbonaceous nanomaterials are pivotal for several electrochemical applications that require interfaces with enhanced kinetics. In this study, we report an innovative approach to develop composite membranes for producing laser-engineered graphene electrodes (LEGEs) for electrochemical sensing. Composite membranes were prepared by blending aminated polyethersulfone (H₂N-PES) with carbon black (CB) at different weight ratios (0.1, 0.2, and 0.3 wt%). The resulting composite membranes served as scaffolds for preparing LEGEs. Both the composite membranes and the derived LEGEs were thoroughly characterized using spectroscopic, thermal, electrochemical, and scanning electron miscroscopy techniques. The results showed that the incorporation of CB into the polymer substantially enhanced the electrochemical performance compared to the pristine H₂N-PES membrane, particularly for the membrane containing 0.3 wt% loading of CB; it can be used for ascorbic acid determination in the concentration range of 10–300 µM with a detection limit of 2.45 µM, with high selectivity over uric acid and dopamine. LEGEs were successfully applied for the selective electrochemical sensing of ascorbic acid in spiked solutions and in commercial orange juice samples.

An aqueous Al-ion hybrid capacitor (AIHC) employing a high-entropy Prussian blue analog (HE-PBA) as a positive electrode material is reported. Combined characterization using energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis confirms the chemical composition of HE-PBA as Na₂Mn_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2[Fe(CN)₆]_0.96.0.5H₂O. The HE-PBA crystalizes in monoclinic phase (space group P2₁/n) with a bandgap of 0.8 eV. XPS data reveals that only Ni and Fe exhibit both bivalent and trivalent states, while other transition metals remain in the bivalent state. Electrochemical analysis indicates a diffusion-controlled mechanism (b ≈ 0.6) associated with HE-PBA with a diffusion coefficient of 9.2 × 10⁻¹⁴cm² s⁻¹. An AIHC device is assembled using HE-PBA positive and polypyrrole negative electrodes in a SiO₂-Al₂(SO₄)₃ hydrogel electrolyte, where the electrodes operate via Faradaic and pseudo Faradaic processes, respectively. The device exhibits an energy density of 20 Wh kg⁻¹ (@ 78 W kg⁻¹), a power density of 378 W kg⁻¹ (@ 8 Wh kg⁻¹), and outstanding cycling stability (90% capacity retention after 500 cycles at 300 mA g⁻¹). It also shows an ultrafast response time of 0.66 s, highlighting excellent power capability. Compared to the only five reported aqueous AIHCs, this study demonstrates promising electrochemical performance despite the challenges of trivalent Al³⁺ insertion/deinsertion in aqueous media.

The nonlinear optical properties of aza-borondipyrromethene (aza-BODIPY) derivatives modified with 4-methoxyphenyl, 2,4-dimethoxyphenyl, and 4-N,N-diphenylaminophenyl groups at the 1 and 7 positions of the core structure are evaluated. The effects of substituents and solvent polarity (tetrahydrofuran (THF) and chloroform (CHCl₃₎) on the linear absorption and fluorescence properties are systematically investigated. The target aza-BODIPYs exhibit higher absorption in CHCl₃ compared to THF. While solvent polarity exerted a minimal effect on the absorption and fluorescence intensity, the fluorescence in BOD2 and BOD3 is markedly quenched as a result of the electron-donating methoxy groups and the pronounced intramolecular charge transfer (ICT) characteristics of the diphenylamine unit. Moreover, all compounds shows strong near-infrared two-photon absorption (TPA) behavior. The TPA cross-sections of BOD1 and BOD3 are measured as 61 and 269 GM at 1000 nm, respectively, and BOD3 showed the highest value due to the enhanced ICT efficiency. Density functional theory calculations are also performed to study the thermodynamic and photophysical properties in different media. The findings indicated an enhancement in molecular stability and a reduction in HOMO–LUMO gaps, particularly in THF. Among the compounds, BOD3 stood out with its low energy gap and high polarizability, and its theoretical NLO parameters are in strong agreement with the experimental TPA findings.

Direct fluorination, based on a gas/solid reaction with elemental fluorine F₂, is a surface treatment that is able to modify the superficial properties of polymers, like surface energy or tribological behavior. Nevertheless, side reactions occur with oxygen either present in the reactive molecular fluorine gas (F₂) or during a post-reaction when the sample is exposed to air atmosphere. A systematic study of the fluorination of polypropylene at different temperatures identifies the formation of acyl fluoride COF groups, coexisting with the fluorinated groups. COF groups evolve into carboxylic acid (COOH) groups during the first few hours after fluorination. Despite the presence of fluorine, the polar component of the surface energy increased. By introducing an esterification post-treatment of the COF groups with an alcohol in the gas phase after the fluorination step, it is possible to stabilize the surface chemistry and thus prevent its hydrolysis. Surfaces post-treated by this singular approach are less hydrophilic than their counterparts only treated by direct fluorination.

Alzheimer's disease is an age-related neurodegenerative disorder and the main cause of dementia in the elderly. The accumulation of metal ions, including iron-heme, their interaction with amyloid-β (Aβ) peptides and their ability to catalyze reactive oxygen species formation significantly contribute to the pathogenesis of the disorder. These factors are highly dependent on the surrounding environment, whether intracellular, extracellular, or membrane-associated. In this study, the interaction between heme and Aβ within a membrane-mimicking system using sodium dodecyl sulfate is investigated. UV–vis and circular dichroism data indicate that the heme/Aβ complex can be sequestered within the micelle, leaving part of Aβ largely exposed at the surface. The presence of the micellar environment significantly affects both the stability and aggregation state of the hemin group, as well as its accessibility to peptide coordination and to external molecules, such as phenols and catechols. Indeed, peroxidase-like activity studies show that the overall reactivity of the hemin–Aβ complex is markedly reduced under these conditions. Overall, these results suggest that a membrane-like environment may offer partial neuroprotection against heme-induced toxicity by limiting the formation of the heme–Aβ complex and the oxidative damage to nearby biomolecules, including neurotransmitters.