Layered double hydroxides (LDHs) are layered materials of increasing interest for environmental applications due to their tunable chemical composition, structure, and adjustable physicochemical properties. This review presents a critical synthesis of recent advances in LDH-based materials, highlighting the close links between synthesis methods, structural characteristics, and key properties controlling their environmental performance. The main synthesis strategies are discussed in relation to their influence on crystallinity, morphology, specific surface area, metal cation distribution, and the nature of structural defects. Particular attention is paid to the effect of cationic composition, interlayer anions, and structural modifications (doping, exfoliation, composite formation) on adsorption, ion exchange, redox activity, and heterogeneous photocatalysis mechanisms. Environmental applications of LDHs are systematically examined, including the adsorption of inorganic and organic pollutants, the photodegradation of emerging contaminants under UV and visible irradiation, and water treatment. LDH-derived materials, particularly mixed metal oxides and LDH/semiconductor composites, are also discussed due to their improved photocatalytic performance and increased stability. Finally, current challenges and future prospects are addressed, with a particular focus on the recyclability, durability, and scaling up of LDH-based materials for advanced environmental applications.
Since their original development, aptamers (or nucleic acid oligomers of defined sequence that are capable of high-affinity and high-specificity binding to a target) have been heralded as possible and promising new therapeutic modalities. Increasingly versatile and customizable aptamer selection (SELEX) processes, alongside incorporation of novel synthetic nucleic acid (XNA) chemistries, have played a key role in the development of therapeutically relevant molecules. Nonetheless, despite the significant progress in the last 40 years, clinical applications of aptamers remain a nascent field. This review summarises some of the key developments in the field in the last 40 years, highlighting the progress made in aptamer selection, XNA chemistries and computational analyses. We discuss the intricacies and limitations of the current gold standard in aptamer SELEX and underscore the added complexities of XNA incorporation. Reflecting on the distinction between the antibody and aptamer fields, we advocate how a more mature understanding of this class of molecules could be driving the next generation of applications.
The development of environmentally benign and stable alternatives to lead-based perovskites remains a key challenge for next-generation photovoltaic materials. In this work, a comprehensive first-principles investigation of lead-free alkali indium halide defect-perovskites A3InX6 (A = Rb, Cs; X = Cl, Br, I) is performed to elucidate the influence of cation and anion substitution on their structural, electronic, optical, and mechanical properties. Density functional theory calculations using GGA-PBE and PBEsol functionals confirm that all compositions crystallize in a stable cubic phase with negative formation energies and favorable Goldschmidt tolerance factors, where substitution of the larger Cs+ cation enhances lattice stability compared to Rb+. Systematic halide substitution from Cl- to Br- to I- induces lattice expansion and a pronounced reduction in the direct band gap at the Γ-point, enabling effective band gap tunability. Electronic structure analysis reveals that the valence-band maximum is dominated by halogen p states, while the conduction band is primarily governed by In-derived states, underscoring the decisive role of anion chemistry in controlling electronic transitions. Optical calculations demonstrate enhanced dielectric response and significantly improved visible-light absorption for iodide-rich compositions, whereas chloride-based compounds retain wide band gaps and stronger structural rigidity. Mechanical and elastic analyses indicate that both cation and anion substitution modulate lattice stiffness, ductility, and hardness, with Cs- and I-based compounds exhibiting increased mechanical softness and improved machinability.
A rapid, highly efficient and practically viable solid-solid melt reaction (SSMR) protocol has been developed for the synthesis of multi-colour-emissive quinoxaline-based small organic fluorophores (QBSOFs, 3) from readily available o-phenylenediamines (1) and α-bromoketones (2) or arylglyoxals/glyoxylic acids (4) under solvent- and catalyst-free conditions. This environmentally benign methodology features operational simplicity, avoidance of cost-intensive and scale-restrictive techniques such as microwave or ultrasonic irradiation, broad substrate compatibility with excellent functional-group tolerance, and a straightforward work-up affording products in high purity. Notably, the reactions proceed rapidly to deliver excellent to near-quantitative yields (95-99%). The successful gram-scale synthesis of 2-(4-chlorophenyl)quinoxaline (3a) further underscores the economic feasibility and industrial applicability of this approach for large-scale production of 2-arylquinoxalines. The solid-state photophysical properties of the synthesized quinoxaline fluorophores were systematically investigated. The compounds exhibit tunable solid-state emission spanning from purplish blue to the yellow light region, primarily governed by the nature of substituents at the 2-position of the quinoxaline core. Remarkably, compounds 4-(quinoxalin-2-yl)benzonitrile (3g) and 4-(6,7-dimethylquinoxalin-2-yl)benzonitrile (3u) display cold-white and warm-white light emission, respectively. Furthermore, the HOMO and LUMO energy levels are comparable to those of reported hole-transporting materials (HTMs), highlighting the dual luminescent and hole-transporting characteristics of these fluorophores. Consequently, these multi-colour-emissive QBSOFs, with intrinsic hole-transporting characteristics could be suitable for application in organic optoelectronic devices.
In this study, we report on the synthesis of gold microtube-based substrates and their organic modification with 11-mercaptoundecanoic acid (MUA11) for the use in surface-enhanced Raman spectroscopy (SERS). The main objective of the work was to investigate the influence of organic modification on the optical properties of the substrates and the degree of Raman signal enhancement. The synthesis of gold microtubes was carried out using a chemical template-assisted growth method, resulting in the formation of uniform and continuous gold layers on the porous template surface. The obtained structures were characterized by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Localized surface plasmon resonance (LSPR) behavior was analyzed through the optical response of the gold microtubes. The presence and efficiency of the organic modification were verified by X-ray photoelectron spectroscopy (XPS). Optical characterization revealed that the substrates with uniformly distributed gold microtubes exhibited a plasmonic resonance around 440-470 nm. To evaluate the analytical performance of the developed substrates, SERS analyses were performed using three model organic dyes: methylene blue, methyl violet, methyl red, in a concentration range from 10-2 to 10-6 M.
Developing earth-abundant, durable, and scalable oxygen evolution electrocatalysts is critical for alkaline water electrolysis. Herein, a monolithic, binder-free Se-activated FeNi layered double hydroxide (Se-FeNi-LDH) electrode grown directly on an ultrathin FeNi alloy substrate is introduced. This integrated architecture eliminates polymeric binders and interfacial resistance, enabling efficient electron/mass transport under industrial conditions. The optimized FeNi-LDH1-Se05 electrode delivers outstanding OER activity with overpotentials of only 240 and 290 mV at 10 and 100 mA cm-2, respectively, a low Tafel slope of 37 mV dec-1, and stable operation for 120 h at 100 mA cm-2. In a practical electrolyzer (Se-FeNi-LDH‖Pt), a cell voltage of 1.56 V at 10 mA cm-2 is achieved. Selenium incorporation modulates the electronic structure of Fe/Ni centers, enhances active surface area and charge-transfer kinetics, and maintains high faradaic efficiency (∼97.5%). This work establishes selenium activation in a binder-free monolithic LDH platform as a scalable, mechanically robust strategy for high-performance alkaline OER.
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.
A total of 48 compounds, including 6 undescribed triterpenoid saponins, notoginsenosides V1-V6 (1-6), were isolated and identified from the radix of Panax notoginseng. Their structures were elucidated by combining various spectroscopic techniques, such as NMR and MS analyses. Among them, (2S)-1-O-(9Z,12Z-octadecadienoyl)-3-O-β-galactopyranosylglycerol (43) exhibited the strongest anti-inflammatory activity against cyclooxygenase-2. The compounds 7, 14, 15, 16, 28, 29, 30, 39, 43, and 45 promoted the proliferation of human oral mucosa fibroblasts (hOMFs). Additionally, the compounds 1, 8, 9, 14, 35, 43, and 45 promoted the proliferation of human dermal papilla cells (hDPCs). These results revealed the potential daily functional benefits of P. notoginseng, including ameliorating oral ulcer conditions and preventing hair loss.
Drinking water treatment plants (DWTPs) face challenges in upgrading their technologies to mitigate health risks and achieve environmental sustainability. Population expansion, limited water sources, and climate change all contribute to these difficulties. The primary reasons for rising water contamination are population growth, urbanization, and industrialization, as well as increased agricultural activities. Micropollutants (e.g., pesticides, pharmaceuticals, industrial chemicals, etc.) are especially problematic because conventional treatment processes do not efficiently remove them. Advanced oxidation processes (AOPs), are required to improve drinking water quality in DWTPs since they are particularly successful at eliminating water pollutants. The purpose of this review is to provide an up-to-date and complete understanding of AOPs' use in drinking water treatment. It also attempts to close this gap by investigating the various forms of AOPs and their efficacy against various water contaminants such as natural organic matter, chlorination disinfection byproducts, and contaminants of emerging concern. Furthermore, this review will evaluate the practical implementation of AOPs, including their suitability for scaling up.
A novel series of palladium(ii) coordination complexes of the formula [Pd(CH3C(NAr)CHC(O)CH3)2] (4a-j) were synthesized by the reaction of enaminone ligands (3a-j) with [PdCl2(NCCH3)2] in a molar ratio of 2 : 1 in the presence of t BuOK. The square planar coordination geometry around Pd(ii) of the 4c complex, with electrostatic potential calculations rationalizing the formation of C-H⋯π contacts, leading to chain structures, was confirmed by single-crystal X-ray diffraction. UV-vis spectra, supported by TD-DFT (B3LYP) calculations, indicated that the long-wavelength absorptions arose from intra-ligand charge transfer transitions (π → π*) involving HOMO-LUMO+1 excitations, with Pd(ii) orbitals contributing to the HOMO. Thermogravimetric analysis demonstrated high thermal stability of the series. Biological evaluation revealed notable cytotoxicities of the compounds 4b, 4d, 4h, 4i, and 4j. The compound 4i shows the strongest activity (IC50 = 5.42 µM, MCF-7; 17.20 µM, and HCT-116) and high selectivity toward cancer cells. Molecular docking against oncogenic targets (PIK3CA-E545K, ERBB4-Y1242C, KRAS-G13D, PIK3CA-H1047R, and ATM-A112V) identified meta- and para-substituted analogues (4b, 4c, and 4h) as the most favorable binders, while bulky ortho substituents reduced the affinity due to steric effects. Docking against PIK3CA-E545K produced binding energies that qualitatively paralleled several of the measured MCF-7 selectivity indices, with planar aromatic interactions and hydrophobic contacts defining the structure-activity relationships.
Nitrogen-containing heterocycles (N-Hets) are among the most prevalent and versatile structural motifs in pharmaceuticals, serving as key scaffolds in over 85% of biologically active small molecules. Their structural diversity and functional versatility have made them integral components of both U.S. Food and Drug Administration (FDA) approved and investigational drug molecules, modulating biological activity across a range of molecular targets. In 2025, the FDA approved 26 small-molecule drugs featuring N-Het frameworks, spanning multiple therapeutic areas, including oncology, metabolic disorders, infectious diseases, and rare/orphan conditions. This review offers a comprehensive overview of these newly approved compounds, emphasizing their biological activity and synthetic approaches. Special attention is given to drug-target interactions, focusing on receptor binding and highlighting the important role of N-Hets in medicinal chemistry. By exploiting the intrinsic chemical properties of N-Hets and leveraging modern synthetic methodologies, these scaffolds continue to drive the discovery of therapeutically relevant molecules, highlighting their sustained significance in modern drug discovery.
High-performance visible-light-driven photocatalysts have emerged as a research hotspot in environmental pollution; however, the photocatalytic degradation mechanisms of Congo red using bismuth semiconductor composites are not fully understood. Herein, BiVO4/ZnIn2S4 was successfully synthesized via a hydrothermal method, and the photocatalytic performance of the composite was assessed by carrying out photocatalysis experiments to decompose Congo red. The phase composition, carrier separation capability, interface electron interactions, and morphological features were characterized by XRD, PL, XPS, and TEM analyses, respectively. The results showed that a Z-scheme heterostructure was successfully constructed between the BiVO4 and ZnIn2S4. Electrons in the conduction band of BiVO4 migrated to the valence band of ZnIn2S4, which effectively enhanced the separation of photogenerated charge carriers and improved the degradation capability. Compared with pure BiVO4, 7% BiVO4/ZnIn2S4 displayed superior photocatalytic capability and could completely remove Congo red (100 mg L-1) in 60 min under visible light. Radical trapping experiments combined with electron paramagnetic resonance characterization revealed that the superoxide anion (˙O2 -) and holes (h+) acted as the key reactive species driving Congo red degradation. In addition, six cycles of experiments were performed to verify that the BiVO4/ZnIn2S4 composite retains its high stability. This study provides a feasible strategy for fabricating effective photocatalysts to treat organic pollutants in wastewater.
Accurate knowledge of thermophysical properties and their molecular structural origins is essential for understanding liquid organization in associating mixtures. In this work, the density and viscosity of propyl ethanoate (PE) + C6-C10 1-alkanol mixtures were measured over the full composition range at several temperatures, and the corresponding excess molar volumes (V E) and viscosity deviations (Δη) were determined. To elucidate the structural origins of this behavior, molecular dynamics (MD) simulations and density functional theory (DFT) calculations were combined with experimental observations. Radial and spatial distribution functions reveal that alcohol-alcohol self-association dominates through directional hydrogen bonding, forming transient hydrogen-bonded clusters with dual-donor/acceptor configurations. In contrast, alcohol-ester hydrogen bonding is highly site-specific, occurring exclusively at the ester carbonyl oxygen with significantly weaker intensity. Atoms-in-molecules (AIM) analysis quantifies this interaction hierarchy: ROH-ROH binding energies strengthen from -8.24 to -11.31 kcal mol-1 with chain length due to cumulative dispersion interactions, while ROH-PE interactions remain invariant at ∼-8.30 kcal mol-1. Void space analysis further demonstrates that the disruption of alcohol hydrogen-bond networks by PE creates expanded free volume, with cavity radii distributions shifting toward larger voids as temperature increases. This structural asymmetry provides a quantitative molecular basis for the observed positive excess molar volumes and negative viscosity deviations, establishing a direct link between hydrogen-bond topology, void distributions, and macroscopic thermophysical behavior in ester-alkanol systems.
Eco-friendly halide perovskites have garnered interest as viable options for next-generation optoelectronic and solar-energy technologies due to their adjustable bandgaps, robust light absorption, and excellent charge-transport properties. This study presents the inaugural comprehensive theoretical examination of the eco-friendly double perovskite 'Cs2SnGeCl6' through two methodologies: density functional theory (DFT) for elucidating the physical properties of this compound and SCAPS-1D simulations to assess its viability as an absorber layer in perovskite solar cells (PSCs). Using the advanced calculation functions in DFT, we confirm that Cs2SnGeCl6 is stable in terms of structure, mechanical stability, and thermodynamics, making it a good choice for solar energy harvesting. This stability is enhanced by positive phonon dispersion, a direct bandgap of around 1.837 eV derived by the application of TB-mBJ, a robust computational method characterized by significant absorption over the visible spectrum, and advantageous optical conductivity. Building on these electronic and optical insights, SCAPS-1D simulations were performed using DFT-derived parameters to model sixteen n-i-p device architectures incorporating newly engineered electron and hole transport layers. The best initial configuration, FTO/SnS2/Cs2SnGeCl6/CuGaO2 yielded a power conversion efficiency (PCE) of 20.31%, and after optimization, the PCE increased to 23.29%.
Carbon dots have gained considerable research attention owing to their excellent optical properties and environmental compatibility. In this study, a one-step hydrothermal synthesis of carbon dots (CDs) is reported using guava extract as a bio-based source. These as-prepared carbon dots were characterized by spectroscopic techniques including ultraviolet-visible spectroscopy, fluorescence spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). High-resolution transmission electron microscopy (HRTEM) analysis was used to study their structure and particle size. The characterization results revealed that the CDs had strong blue luminescence, a high density of oxygen-containing surface functional groups and an amorphous carbon structure. The UV-vis spectrum exhibited typical absorption peaks referred to as π-π* and n-π* transitions, and the fluorescence spectrum indicated the presence of excitation-dependent emission and optimal luminescence in the blue region. The presence of surface groups like hydroxyl, carboxyl and ether groups, as confirmed by FTIR analysis, imparts good hydrophilicity to the luminescent carbon dots. The synthesized carbon dots demonstrated excellent fluorescence-based sensing behavior, showing significant quenching in the presence of hydrazine and enhancement in luminescence upon ethanol exposure. The observed sensing behavior is attributed to the electron transfer interactions between the surface groups of the CDs and analytes.
A novel, environmentally sustainable spectrofluorimetric method was developed for the determination of clemastine fumarate in pharmaceutical formulations and biological matrices using nitrogen and phosphorus co-doped carbon quantum dots (N,P-CQDs) as fluorescent nanoprobes. The N,P-CQDs were synthesized via rapid microwave-assisted carbonization of citric acid, urea, and phosphoric acid, yielding uniform nanoparticles (3.2 ± 0.9 nm) with high quantum yield (47.2 ± 2.3%) and strong blue emission at 445 nm. Face-centered central composite design was employed to optimize analytical parameters, achieving optimal conditions at pH 8.7, a buffer volume of 1.5 mL, an N,P-CQD concentration of 175 µg mL-1, and an incubation time of 3 minutes. Mechanistic studies confirmed static fluorescence quenching through ground-state complex formation driven by electrostatic interactions between protonated clemastine and deprotonated carboxyl groups on the nanoprobe surface. The validated method exhibited excellent linearity (0.1-4.0 µg mL-1, r 2 = 0.9997), high sensitivity (LOD = 0.03 µg mL-1), satisfactory accuracy (100.41 ± 1.12%), and high precision (RSD < 2%). Successful application in synthetic pharmaceutical tablets and spiked human plasma samples demonstrated practical applicability, with statistical equivalence to reported HPLC methods. Comprehensive green chemistry assessment using MOGAPI (76), CaFRI (78), BAGI (72.5), and RGB12 (whiteness = 84.3) confirmed outstanding environmental sustainability and balanced analytical performance. The proposed method offers a rapid, cost-effective, and environmentally friendly alternative to conventional chromatographic techniques for clemastine quality control and bioanalytical applications.
In this research, a novel method for synthesizing various heterocyclic derivatives via the Minisci radical substitution reaction has been presented. The Minisci reaction offers a very efficient and valuable approach for directly functionalizing heteroarenes with an electron-deficient group, allowing the formation of carbon-carbon bonds straightforwardly and efficiently. We have developed a metal-free, light-independent Minisci-type strategy for the direct C-H functionalization of pyrimidines, thereby facilitating the design of heteroaromatic derivatives containing hydrazone groups. The target derivatives were successfully synthesized in good yields using aromatic aldehydes as alkyl radical precursors. The reaction proceeds through a sequence of hydrogen atom abstraction (HAA) from the aldehyde, followed by decarbonylation under oxidative conditions using K2S2O8 and trifluoroacetic acid (TFA). This method provides a practical and scalable approach to accessing structurally heterocyclic compounds of various classes.
High-density lipoprotein (HDL) carries proteins and glycoproteins involved in lipid metabolism and inflammatory regulation, yet quantitative characterization of HDL-associated peptides in Alzheimer's disease (AD) cohorts remains challenging due to small biological effect sizes superimposed on substantial technical variability. We applied a Locally Estimated Scatterplot Smoothing (LOESS)-based drift correction and internal-standard-guided normalization workflow to targeted multiple reaction monitoring (MRM) glycoproteomic data generated from HDL isolates collected from 194 participants spanning the cognitive spectrum. Of the 164 transitions originally targeted, 59 features passed quality control (QC), and 21 HDL-associated peptide and glycopeptide features showed consistent signal across all 194 samples; these 21 analytes were used for analysis. Normalization improved analytical reproducibility, reducing median HDL pooled QC coefficients of variation from 69.1% to 55.2%. APOE genotype analyses identified six peptides with statistically significant differences between APOE3/E3 and APOE3/E4 carriers, five of which remained statistically significant after false-discovery rate correction, and all six of which remained significant in covariate-adjusted models, whereas disease-related differences within APOE3/E3 carriers were modest and did not remain statistically significant after covariate adjustment. These findings demonstrate that LOESS-based drift correction combined with feature-specific internal-standard selection stabilizes quantitative HDL glycoproteomic measurements and support downstream comparisons. This workflow provides a practical framework for QC-informed normalization in targeted glycoproteomics and highlights APOE-associated variation in HDL peptides within an aging clinical cohort.
Water hyacinth (Eichhornia crassipes) is an invasive aquatic plant (originally from South America) that colonizes tropical and subtropical waterbodies worldwide. In this work, we present the sustainable application of carbon dots, obtained by green chemistry from E. crassipes roots, as fluorescence-based ratiometric sensors of ethanol and acetone traces in water with a limit of detection (LOD) of ∼1% v/v and ∼0.03% v/v, respectively. The proposed carbon nanoprobe acts as a spectrally multiplexed sensing platform to simultaneously monitor multiple spectral features associated with molecular interactions, allowing for the detection of methanol-spiked ethanol under laboratory conditions with a LOD of ∼1.4% v/v. The viability of the multi-responsive sensor has also been tested in methanol-adulterated commercial alcoholic beverages. The solvation effect of the proposed CDs in different surrounding systems could lead to their potential application as a straightforward, eco-friendly, and affordable alternative for the quality control of certain solvents, thereby improving accuracy, sensitivity, and selectivity compared to traditional analytical methods as well as safeguarding public health by preventing the consumption of adulterated alcoholic beverages.
This study combines experimental and theoretical approaches to investigate the catalytic pyrolysis of polystyrene (PS) waste using CeO2 and Co/CeO2 catalysts. A laboratory-scale reactor was designed and optimized at 450 °C under a nitrogen atmosphere to maximize liquid product yield. The catalysts, synthesized via the combustion method and characterized by XRD, BET, and potentiometric titration, exhibited high surface areas (110 and 100 m2 g-1, respectively). Experimental results revealed that pure CeO2 selectively promoted PS depolymerization toward styrene monomer formation through a β-scission mechanism, achieving 87.04% styrene selectivity. In contrast, cobalt incorporation altered the reaction pathway, reducing styrene yield but increasing overall liquid fraction and calorific value, indicating a more energy-efficient process. Density functional theory (DFT) calculations supported these findings, showing that styrene dimer adsorption and β-scission on the CeO2(111) surface are energetically favorable, whereas Co modification raises the activation barrier and enhances dimer adsorption, suggesting a possible reduction in the accessibility of the catalyst's acid active sites. These combined results suggest that CeO2 is well-suited for selective monomer recovery, while Co/CeO2 offers a balanced route for both material and energy valorization of PS waste, thus advancing the development of catalytic systems for sustainable chemical recycling.