A series of symmetric and asymmetric diarylpentanoids based on N-isopropyl-4-piperidone were rationally designed and synthesized through a Claisen-Schmidt condensation reaction. This was done to investigate their potential as anticancer and anti-inflammatory agents. The synthesized compounds were evaluated for cytotoxic activity against the MCF-7 breast cancer cell line, as well as for nitric oxide inhibitory activity in LPS-stimulated RAW264.7 macrophages. Structure-activity relationship analysis revealed that the presence of electron-donating substituents and asymmetric aryl substitutions significantly enhanced biological activity. Among the synthesized derivatives, compound KB2d exhibited the strongest anticancer activity, with an IC50 value of 1.54 µM, while compound KB2c demonstrated promising anti-inflammatory activity, with an IC50 value of 2.51 µM. To understand the molecular basis of these activities, molecular docking simulations and 200 ns molecular dynamics were conducted on aromatase and PDE4D protein targets. The leading compound, KB2d, showed stable binding behavior, low ligand RMSD oscillations, and favorable binding free energy (ΔG_bind ≈ -33 kcal mol-1) as calculated using the MM-PBSA method. These findings suggest that asymmetric N-isopropyl-4-piperidone diarylpentanoids represent promising structural frameworks for the further development of anticancer and anti-inflammatory agents.

Serine hydroxymethyltransferase (SHMT) is a pyridoxal-5'-phosphate (PLP) dependent enzyme that catalyzes a chemical transformation essential for the one-carbon (1C) metabolism. SHMT reversibly converts l-Ser into Gly and transfers a 1C unit to tetrahydrofolate (THF) to give 5,10-methylene-THF (5,10-MTHF). 5,10-MTHF, a 1C-unit donor, plays a crucial role in the downstream biomolecular syntheses required for the cell homeostasis and proliferation. SHMT is a prominent target for the drug discovery to battle bacterial and parasitic infections, and to treat various types of cancer. SHMT-catalyzed chemistry is governed by the general acid-base catalysis. Knowledge of the catalytic mechanism can aid drug design but can only be achieved when the atomic details of each reaction step are mapped, including accurate determination of hydrogen atom positions. Here we utilized the inactive E53Q mutant of Thermus thermophilus (Tth) SHMT to directly determine protonation states with room-temperature neutron crystallography and to capture a reactive intermediate containing the PLP-l-Ser external aldimine and THF in the enzyme active site. We observed protonation of the Schiff base nitrogen (NSB) in the PLP internal aldimine but no change in the protonation states of other ionizable PLP groups and active site residues compared to wild-type TthSHMT. X-ray structural analysis of the ternary intermediate complex E53Q-Ser-THF that eluded previous structural characterization shows the strategic positioning of the E53Q side chain in close proximity to the external aldimine and THF and reinforces the proposed role for E53 as the driver of proton transfer events along the reaction pathway.

[This corrects the article DOI: 10.1039/D4RA04760E.].

This work reports a new dual-strategy approach for the preparation of nanostructured Ag-doped CuS (Cu1-x Ag x S, x = 0.03) photocatalysts designed by the synergy of morphology control and band gap engineering for enhanced environmental cleanup. The hexagonal covellite phase, the successful lattice substitution of Ag ions, and the change from strongly agglomerated 65 nm particles to well-dispersed 55 nm nanoparticles were confirmed by systematic characterization using XRD, FTIR, SEM, and EDX analyses. In addition, I-V analysis demonstrated a remarkable increase in conductivity. Together with UV-vis DRS, PL, electrochemical impedance spectroscopy (EIS), and transient photocurrent response analyses, the results demonstrated that Ag doping decreased the bandwidth from 1.69 eV to 1.57 eV, strongly inhibited charge recombination, and improved interfacial charge transfer. Thus, 3% Ag-doped CuS with the best performance shows excellent photocatalytic activity, with almost 98.2% MB degraded in 80 min (k = 0.029 min-1), which is 3.6 times higher than the activity of pristine CuS. In addition, an anti-bacterial assay revealed a 2.12-fold increase in the zone of inhibition against Escherichia coli (23.3 mm). Mechanistic information based on radical scavenging experiments and electron paramagnetic resonance (EPR) spectra indicated that ˙OH and ˙O2 - were the major reactive species for dye mineralization and bacterial inactivation. Cyclic degradation experiments and after-cycling XRD analysis demonstrated that the material could be reused several times without any structural degradation.

An efficient and sustainable one-pot protocol is developed for the synthesis of a broad range of isatin- and acenaphthoquinone-based spiroxanthene and spirochromenecarboxylate derivatives in aqueous ethanol. This approach involves the condensation of isatin- and acenaphthoquinone-based 1, 2 diketones with cyclic and acyclic active-methylene compounds, catalyzed by 5-6 mol% of the Brønsted acidic ionic liquid [CMMIM][BF4]. The versatility of the protocol is demonstrated by the successful synthesis of 20 isatin- and acenaphthoquinone-derived spiroxanthene and spirochromenecarboxylate derivatives. This sustainable methodology offers a short reaction time and good to excellent yield (up to 97%), with easy product isolation, avoiding column chromatographic purification and providing valuable green chemistry metrics for symmetric 8a (E-factor: 0.15 and RME: 86.92%) and unsymmetrical 9a (E-factor: 0.08 and RME: 92.5%) derivatives. This study highlights the potential activity of Brønsted acidic ionic liquids [CMMIM][BF4] as green and reusable catalysts for the atom-economical, environmentally benign construction of bioactive spiro-heterocycles.

Thermal annealing provides a facile method for tuning the optoelectronic response of semiconductor thin films. In this work, ∼700 nm-thick Bi2S3 thin films prepared by thermal evaporation were subjected to annealing in the range of 100-200 °C, and their structural, optical and photodetection properties were studied. Annealing brings about changes in the crystallinity, surface morphology, and wettability, resulting in a decrease in the bandgap from 1.022 to 0.766 eV with increasing temperature. Crystallinity improves at moderate annealing temperatures (100-150 °C) but worsens at higher temperatures (200 °C) because the lattice becomes more disordered. The refractive index and nonlinear optical parameters, such as nonlinear refractive index and nonlinear absorption coefficient, are found to increase with an increase in the annealing temperature. Photodetector response studies reveal an increase in the responsivity from 0.129 to 0.822 A W-1 and an increase in the specific detectivity from 5.17 × 109 to 1.34 × 1010 Jones with increasing annealing temperature. The results of density functional theory (DFT) calculations are also presented, which support the experimental results. It is conclusively shown that annealed Bi2S3 thin films can be employed as sensitive visible-light photodetectors.

To elucidate the mechanism underlying micro-arc oxidation (MAO) coatings in bone regeneration, biomimetic coatings with different surface roughness were fabricated on titanium alloy substrates via MAO, and their effects on osteogenic differentiation and mechanotransductive signaling were investigated. The prepared hydroxyapatite (HA)-containing MAO coating exhibited a porous micro-nano structure, with porosity and micro-roughness ranging from 28.1% to 38.6% and 9.3 to 15.8 µm, respectively. Cell experiments demonstrated that the coating with a porosity of 35.6% and a roughness of 15.8 µm significantly promoted cell adhesion, proliferation, and osteogenic differentiation (with a 76.0% increase in alkaline phosphatase activity relative to the NC group), while upregulating the expression of downstream target genes YAP1, Runx2 and OCN. Micro-CT results revealed that the 500 V coating group exhibited a 30.9% increase in bone volume fraction and an 81.3% elevation in trabecular thickness relative to the NC group, with the bone-implant contact ratio showing a corresponding 44.6% enhancement. Histological analysis further confirmed that the elevated porosity and surface roughness facilitated the tight encapsulation of the porous coating structure by newly formed bone tissue. Bond strength testing revealed that the 500 V coating group achieved an interfacial bond strength of 33.2 N after 42 days in vivo, representing a 55.87% increase compared with the NC group. This study elucidated the influence of surface roughness on osseointegration, providing a theoretical basis for optimising the surface microstructure of implant materials.

Desalination plays a crucial role in addressing freshwater scarcity resulting from the rising population, industrial expansion, and the impacts of climate change. It employs various technologies tailored to varying levels of salinity. While energy efficiency is a primary focus in desalination, its intuitive interpretation is challenging due to process variations. This viewpoint offers a thermodynamics-based understanding of energy consumption by examining it in terms of irreversible dissipation and minimal separation energy. This study examines the relationship between exergy variations across different desalination technologies, which provides insight into the minimum separation energy and serves as a basis for classifying desalination processes. Simultaneously, particular emphasis is placed on capacitive deionization (CDI) as an emerging desalination technology that requires only incremental advancements to overcome current limitations associated with high feed-water salinity and the restricted desalination capacity of conventional carbon-based electrodes. The integration of advanced battery materials, including sodium-ion and chloride-ion battery systems, with CDI represents a promising strategy to enhance deionization efficiency, thereby enabling the development of higher-performance desalination technologies.

This study reports the development of a sustainable alkali-activated glass-hydroxyapatite composite (AAC-P@HAp) synthesized entirely from waste-derived precursors, including post-consumer glass bottles, eggshells, and plantain bunch stalk ash (as an alkali source), for fluoride removal from aqueous systems. The composite was produced through controlled alkali activation of micronized waste glass followed by hydrothermal-assisted integration of eggshell-derived hydroxyapatite within the aluminosilicate matrix. FTIR, XRF, SEM-EDX, and XRD confirmed successful composite formation of a hybrid silicate-phosphate material and revealed fluoride-induced changes in Ca-P domains after adsorption, indicating strong adsorbent-adsorbate interactions and chemical immobilization. Batch adsorption experiments demonstrated rapid fluoride uptake, with kinetic behavior adequately described by the pseudo-first-order model, while equilibrium data were better represented by the Freundlich isotherm, consistent with heterogeneous surface binding dominated by chemisorption. Thermodynamic analysis indicated that fluoride adsorption was spontaneous and endothermic. Within the Box-Behnken experimental domain, AAC-P@HAp achieved stable fluoride removal efficiencies in a narrow range (83-87%), with pH exerting the dominant influence on performance. Regeneration tests showed good initial reusability followed by a progressive decline attributed to irreversible chemisorption and depletion/phase transformation. In all, the results demonstrate the feasibility of converting multiple waste streams into a robust composite adsorbent and highlights AAC-P@HAp as a circular-economy-oriented material for secure fluoride immobilization rather than extensive multi-cycle reuse.

To enable the sustainable and harmless treatment of decommissioned explosive tear gas grenades (DTGG), a holistic resource-oriented strategy was developed, which prioritizes the effective recovery of ortho-chlorobenzylidene malononitrile (CS) and its transformation into value-added chemical products. Through a systematically developed separation process, CS and RDX were recovered with exceptional efficiency and high purity. The average recovered rate of CS and RDX reached 90.92% and 94.42% respectively, with a purity of more than 98%. The recovered CS was then successfully transformed into 2-(2-chlorophenyl)-benzimidazole (2-CPBZ) via an optimized one-pot synthesis achieving an impressive 86.2% yield with 98% purity. Comprehensive characterization and complementary analytical techniques confirmed the structural integrity of both the recovered CS and the synthesized 2-CPBZ. Mechanistic investigations through density functional theory calculations revealed a sophisticated reaction pathway involving sequential nucleophilic addition, acid-base neutralization, nucleophilic substitution, proton transfer, elimination, intramolecular cyclization, and oxidative aromatization. By demonstrating a complete value chain from decommissioned munitions to pharmaceutical intermediates, the research provides both fundamental insights and practical methodologies for green chemical transformation of hazardous materials, opening new avenues for environmentally responsible disposal and resource utilization in defense and security sectors.