Chemical Review and Letters

Abstract This study investigates the hot corrosion resistance of NiCoCrAlY coatings deposited on Inconel 718LC superalloy in a molten Na2SO4-50%V2O5 environment at 900°C. The coatings were fabricated via electrodeposition using varying current densities (20 and 30 mA/cm2) and NiCrAlY powder concentrations (10, 20, and 30 g/l). Results revealed that coatings with 20 g/l powder concentration and a current density of 20 mA/cm² exhibited optimal performance, demonstrating superior corrosion resistance due to the formation of protective Al2O3 and Cr2O3 scales, as well as spinel phases such as NiCr2O4. In contrast, samples with lower powder concentrations (10 g/l) suffered complete degradation owing to insufficient aluminum content. The corrosion mechanism involved the decomposition of molten salts into aggressive compounds (e.g., NaVO3 and NaAlO2), which deteriorated the protective layers. Additionally, the formation of metallic sulfides (e.g., NiS and CrS) and acid-base reactions accelerated corrosion. SEM and XRD analyses confirmed that the optimized coatings possessed a uniform microstructure and stable protective phases. This research highlights that controlling deposition parameters and coating composition can significantly enhance the service life of Superalloys in high-temperature corrosive environments.

Abstract Pyrazoles are an important class of five-membered heterocyclic compounds containing two adjacent nitrogen atoms, known for their broad spectrum of pharmacological activities. These compounds have garnered significant interest in medicinal chemistry due to their diverse therapeutic applications, including anti-inflammatory, anticancer, antimicrobial, antifungal, antioxidant, antiviral, anti-tubercular, anti-AIDS, and anti-anxiety effects. The structural versatility and biological relevance of pyrazoles have led to extensive investigations from both chemical and biological perspectives. Recent developments in synthetic methodologies have further expanded the accessibility and structural diversity of pyrazole derivatives. Various synthetic strategies—such as cyclization, condensation, and metal-catalyzed reactions—have been employed to construct pyrazole scaffolds efficiently. This growing interest highlights the potential of pyrazoles as key pharmacophores in drug discovery and development

Abstract Heavy metals pose a persistent and escalating threat to ecosystems and human health due to their environmental persistence, bioaccumulative potential, and pronounced toxicity. This systematic review synthesizes current knowledge on the distribution, mechanisms of toxicity, regulatory approaches, and analytical strategies concerning four priority toxic metals: arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb). Relevant literature published between 2020 and 2025 was retrieved from Scopus, Web of Science, and PubMed, focusing on peer-reviewed studies. Included publications address contamination sources, toxicodynamics, international standards (WHO, EFSA, EU, Codex), and monitoring practices. Marked discrepancies in permissible exposure limits were identified across jurisdictions, while the neurotoxic, nephrotoxic, and carcinogenic effects of these metals are well documented. Particular concern arises from chronic low-dose exposure, combined metal exposure, and the emergence of nanoparticulate forms—areas where regulatory frameworks remain insufficient. The findings highlight the urgent need for harmonized standards, expanded biomonitoring efforts, and improved risk assessment methodologies to better safeguard environmental and public health

Abstract The growing demand for environmentally friendly smart packaging has driven the development of novel biopolymer-based materials that serve as food quality indicators. This study aims to evaluate the effect of different alkali agents in the production of cellulose nanocrystals (CNCs) derived from the bark of Calotropis gigantea, which are utilized as fillers in colorimetric biocomposite foams (BCFs) for non-destructive fish freshness monitoring. Two alkali agents, NaOH and 20% Na₂SO₃, were applied during the delignification stage prior to hydrolysis with sulfuric acid (40% H₂SO₄). The resulting CNCs were thoroughly characterized using spectroscopic, morphological, and thermal techniques. Morphological and structural analyses revealed that CNCs treated with NaOH exhibited the highest crystallinity index (89.54%) and featured shiny, needle-like crystals with a more uniform size distribution. In contrast, CNCs produced using Na₂SO₃ showed a lower crystallinity index (51.11%) with agglomerated morphology and uneven particle size distribution. The BCF formulated with CNCs-NaOH (0.25 g) exhibited a porous structure with a high specific surface area (10.64 m²/g), which supported the immobilization of anthocyanin-based pH indicators extracted from Clitoria ternatea. Application testing during the storage of Oreochromis niloticus at 5 °C over 30 days showed a significant color change in the indicator, corresponding to a pH increase from 5.2 to 6.3 and a rise in TVB-N values from 2.83 mg/100 g to 32.86 mg/100 g. The CNCs-NaOH-based BCF demonstrated excellent responsiveness to environmental pH changes associated with fish spoilage. This study represents the first investigation of C. gigantea as a source of CNCs through varied alkali treatment approaches for use in foam-based colorimetric indicators. The findings suggest that CNCs-NaOH derived from C. gigantea show strong potential as superior fillers in responsive and sensitive porous smart packaging for real-time detection of fish freshness deterioration

Abstract This work aims to create a quaternary composite of reduced graphene oxide (RGO), multi-walled carbon nanotubes (MWCNTs), urea, and choline chloride by employing discrete flame deposition technology to create MWCNTs and graphene oxide in a tour method. Reduced graphene oxide was created by reduction using ascorbic acid, and the deep eutectic solvent was then synthesized. The product was characterized using several techniques, including field emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR). In order to adsorb and eliminate the dye methyl orange (MO), the current work employed a mixture of Deeb Eutictic Solnents (DES) such as urea and choline chloride with RGO and MWCNTs. Some techniques such as: HNMR, C13 and IR tests, were used to examine the data for the eutectic solvents of urea and choline chloride. The weight of the adsorbent, the duration of contact between the dye and the composite, temperature, pH, and ionic density were among the characteristics whose effects on dye adsorption were examined. Additionally, isotherms and adsorption kinetics were investigated.

Abstract The aim of this study is to investigate QSAR modeling for a set of novel pyridine derivatives as inhibitors of p38α enzyme. After calculating a set of molecular descriptors, the selection of variables was performed using two methods: genetic algorithm (GA) and stepwise regression (SW). To build and evaluate the models, the dataset was divided into two training and test sets based on the clustering method, which included 35 compounds in the training set and 10 compounds in the test set. The results showed that the genetic algorithm-based model (GA-MLR) performed better than the stepwise regression model (SW-MLR). The final GA-MLR model was developed using six descriptors and its statistical values were obtained as R²train = 0.835, RMSEtrain = 0.385, Ftrain = 26.199, R²test = 0.645, RMSEtest = 0.601 and Ftest = 1.065. In order to confirm the accuracy of the model, in addition to validation by the test set, cross-validation techniques, domain determination, and Y-randomization test were also performed. These results indicate that the developed model can be used as an effective tool for designing new pyridine derivatives with higher inhibitory potency and predicting their activity before synthesis.

Abstract Since the early 2000s, extensive research has focused on developing effective materials and technologies for removing heavy metals from industrial wastewater due to their severe toxicity, persistence, and bioaccumulative nature. Traditional methods, such as chemical precipitation, ion exchange, membrane filtration, and adsorption using activated carbon, have been widely used; however, these approaches often have limitations, including low efficiency, high costs, and secondary pollution. In contrast, carbon nanotubes (CNTs) have emerged as highly efficient adsorbents, providing superior performance because of their large specific surface area, tunable surface chemistry, and unique hollow cylindrical structure. This review summarizes research from 2000 to the present, focusing on the comparative performance of CNTs, particularly as-grown, oxidized, and functionalized forms, in adsorbing and removing heavy metals compared to conventional materials. The underlying adsorption mechanisms, dominated by surface complexation and electrostatic interactions between metal ions and functional groups on CNTs, are discussed in detail. It highlights the dual functionality of CNTs in both adsorption and sensing applications, as well as their integration into advanced solid-phase and liquid-liquid extraction techniques for rapid and sensitive monitoring. Overall, CNTs represent a versatile and promising platform for environmental remediation, outperforming many traditional methods in efficiency, reusability, and detection sensitivity.

Abstract ABSTRACT: The oil-collecting and oil-dispersing properties of a quaternary ammonium salt (QAS) formed by octadecane (8-DA) and cis-9-octadecenoic acid (8 -cis-9-DA) with triethanolamine (TEA) {triethanolammonium salt of 8-DA and triethanolammonium salt of 8 -cis-9-DA}, as well as its use as an analytical reagent for the extractionphotometric determination of nickel in the form of a mixed-ligand complex (MLC) with 2-hydroxy-5-chlorothiophenol (L) and QAS in water were studied. The maximum absorption of MLC Ni(II)-L-QAS is observed at λ = 500-510 nm (pHop. 3.5–5.9). The molar absorption coefficients range from (2.58-2.71)×10⁴. With single extraction using chloroform, 99.1–99.3% of nickel is extracted as MLC. Beer's law is followed within the range of 1.0–90 µg/mL of nickel. The methods we proposed were applied under already established optimal conditions for the determination of nickel in various objects: in wastewater and bottom sediments of metallurgical plants, in samples of natural soils, and also in samples of food products.

Abstract HSV-1 and HSV-2 are the two main subtypes of the herpes simplex virus (HSV), which causes oral and genital herpes and is common all over the world. In addition, varicella-zoster virus (VZV)-induced herpes zoster (HZ) is a painful neurocutaneous disease. The popular antiviral medication acyclovir (ACV), a guanine nucleoside analogue, is extensively effective against Epstein-Barr virus (EBV), HSV, and VZV by preventing the production of viral DNA. Despite being quite successful, ACV can have negative consequences, such as renal impairment, especially if used for an extended period of time. As a result, therapy is required to be closely monitored. This review highlights the antiviral mechanism and synthesis techniques of ACV while giving a summary of its discovery, pharmacology, and therapeutic uses. It also discusses various modifications of ACV to improve its pharmacokinetic qualities, and effectiveness, and minimize adverse effects. Prodrugs and structural analogues that improve bioavailability and target specificity are examples of such modifications. The paper further discusses the synthesis of ACV, focusing on high-yield and economical techniques. In order to ensure the quality and therapeutic efficacy of the drug, the review concludes by reviewing the analytical methods used to analyze ACV in pharmaceutical formulations and biological matrices, including spectrophotometry, thin-layer chromatography, mass spectrometry (MS), and high-performance liquid chromatography (HPLC).

Abstract This study investigates the conversion of phenol-formaldehyde resin (PFR) and polystyrene (PS) waste into activated carbon materials with controlled porous structures. Each polymer was modified with 0–10 wt.% polyacrylonitrile (PAN), followed by carbonization at 700–800 °C in combination with chemical activation using sodium hydroxide (NaOH) at a carbon-to-NaOH ratio of 1:0.4–1:1.5. Thermogravimetric analysis revealed that PAN increases the total mass loss: for PS, from 42% to 51% at 1000 °C, and for PFR, from 36.7% to approximately 39%. X-ray diffraction analysis indicated the formation of short-range graphitic domains: in PFR-derived carbon at 800 °C, the (002) peak narrows and a weak (100) reflection appears, whereas ordering in PS-derived carbon was observed only upon PAN addition. Optimal activation with NaOH at a ratio of 1:0.8 produced an ultramicroporous structure, with specific surface areas reaching 873 m²/g for PFR-based carbon and 750 m²/g for PS-based carbon, micropore volumes of 0.9–1.0 cm³/g, and average pore radii of 3.5–3.8 Å. Electron microscopy confirmed uniform microporosity in PFR-derived matrices and a hierarchical, “cellular” morphology in PS-derived matrices. The combination of 10% PAN and NaOH activation at 800 °C yielded the most favorable textural properties, demonstrating that separate processing of PFR and PS waste with PAN modification and alkaline activation is an effective strategy for producing highly porous carbon sorbents at moderate temperatures.

Abstract Aflatoxin B1 is a well-established carcinogen, and even low concentrations pose significant health risks by increasing the likelihood of cancer development. Therefore, various sensors have been tested to identify the most effective adsorbents for its detection. In this study, pristine and Pt-embedded nitrogen-doped graphene quantum dot sensors were modeled to investigate their interactions with Aflatoxin B1 (AFB1). Two types of nitrogen doped graphene (pyrrolic and pyridinic ones) were examined to evaluate their potential as AFB1 sensors. Multiple configurations of AFB1 were considered for each sensor to calculate binding energies and changes in the HOMO-LUMO gap. Results indicate that without a Pt single atom, the average band gap change due to AFB1 adsorption on pristine pyrrolic N-doped graphene is only 3%, which is insufficient for effective sensing. The average binding energy between AFB1 and pyrrolic N-doped graphene is approximately −1.1 eV, indicating moderate interaction. In contrast, pyridinic N-doped graphene shows an average band gap change of less than 2% and a binding energy of about −0.5 eV. Introducing a Pt single atom significantly enhances performance: the average band gap changes increase by approximately 16% for pyrrolic and over 800% for pyridinic N-doped graphene. Correspondingly, their averaged binding energies with AFB1 increase to −1.5 eV and −2.7 eV, respectively. These findings suggest that Pt-embedded pyridinic N-doped graphene is a promising candidate for disposable AFB1 sensors. Additionally, various physicochemical parameters—including ionization potential, hardness, electrical conductivity, recovery time, chemical reactivity, and electrophilicity—were analyzed. The nature of interactions between AFB1 and the two Pt-embedded N-doped graphene sensors was further examined using quantum theory of atoms in molecules (QTAIM), while stabilities arising from intermolecular charge transfers were investigated via natural bond orbital (NBO) analysis. All noncovalent interactions were analyzed and visualized using noncovalent interaction (NCI) and reduced density gradient (RDG) methods.

Abstract Acridines are notable heterocyclic compounds characterized by three fused six-membered rings, contributing to a planar aromatic structure. This study focuses on synthesizing the ligand 6,6'-((1E,1'E)-acridine-3,6-diylbis(diazene-2,1-diyl))bis(2,4-dimethoxybenzoic acid) through key steps involving diazonium salt formation. The synthesis begins with dissolving 3,6-diamino acridine in hydrochloric acid and water, cooled to stabilize the diazonium salt. Sodium nitrite is added for diazotization, followed by 2,4-dimethoxybenzoic acid in an alkaline medium to yield the ligand, which is then purified. Metal complexes were formed by dissolving the ligand in ethanol and adding metal chloride salts such as PdCl₂, H₂PtCl6.6H2O, and HAuCl4⋅4H2O under controlled conditions suitable for various applications. They confirmed by thermal analysis, 1H and 13C-NMR, UV-Vis, FT-IR, mass, elemental analysis, atomic absorption, and molar conductance. X-ray diffraction and FESEM techniques were employed to analyze the crystallographic structure and surface morphology of the compounds, revealing significant differences among them. Molecular docking studies indicated that the Au(III) complex exhibits strong binding affinity with the RhoA protein, a potential target in gastric cancer therapy. The MTT assay was utilized to evaluate the cytotoxicity of ligand and Au(III)-Complex against human adenocarcinoma of the stomach (AGS) cells and normal line cells (Hs 738.St/Int), highlighting their potential effectiveness in cancer treatment.

Abstract In this study, five novel chalcone derivatives—2,5-di((E)-benzylidene)cyclopentan-1-one (4a-1), 2,5-bis((E)-4-methylbenzylidene)cyclopentan-1-one (4a-2), 2,5-bis((E)-4-bromobenzylidene)cyclopentan-1-one (4a-3), 2,5-bis((E)-4-methoxybenzylidene)cyclopentan-1-one (4a-4), and 2,5-bis((E)-4-(dimethylamino)benzylidene)cyclopentan-1-one (4a-5)—were successfully synthesized via a base-catalyzed condensation reaction between cyclopentanone and para-substituted benzaldehyde derivatives. The resulting compounds were isolated, purified, and structurally characterized using Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR) spectroscopy (1H and 13C). To complement experimental findings, Density Functional Theory (DFT) calculations at the B3LYP/cc-pVDZ level were performed to optimize molecular geometries, predict vibrational spectra, and simulate theoretical 1H and 13C NMR chemical shifts. The strong agreement between theoretical and experimental data validated the proposed structures. Furthermore, key quantum chemical descriptors—including dipole moment (μ_D), hardness (η), softness (σ), electronegativity (χ), electrophilicity index (ω), nucleophilicity, and chemical potential (μ)—were computed to evaluate the compounds' potential as corrosion inhibitors. Monte Carlo simulations were conducted to investigate the adsorption behavior of the chalcone derivatives (4a-1 to 4a-5) on Fe(110) and Cu(111) surfaces under vacuum conditions. All compounds demonstrated spontaneous and energetically favorable adsorption, with 4a-5 exhibiting the highest binding affinity, indicating its superior corrosion inhibition efficiency. Additionally, in silico pharmacokinetic and toxicity assessments—including oral toxicity prediction, drug-likeness screening, and BOILED-Egg modeling—were employed to evaluate bioavailability and therapeutic prospects. Molecular docking studies targeting the 11β-HSD1 enzyme revealed significant binding affinities, particularly for compounds 4a-1 and 4a-2, suggesting potential pharmacological activity. Collectively, these results underscore the dual functionality of the synthesized chalcone derivatives as both effective corrosion inhibitors and promising pharmacological candidates.

Abstract A novel porous Vanadium pentoxide\Zinc Oxide\Palladium ternary nanocomposite (V2O5\ZnO\Pd) was synthesized by photoreduction method. Many techniques were used to characterize the prepared nanocomposite. XRD chart shows The composite contains two crystal phases of pure zinc oxide and vanadium pentoxide , first one related to orthorhombic structured of V2O5 and the other is identified to hexagonal structure of ZnO, indicating.Transmission electron microscopy (TEM) and field emission scanning electron microscopy were used to examine the morphology. The results suggest that V2O5/ZnO/Pd nanocomposite has the ability to remove organic contaminants from wastewater and soil pollution treatments. Finally, the nanocomposite 96% efficiency of the photo degradation of dye after 100 min under visible light. The ground-state structures were optimized using density functional theory (DFT), with equilibrium geometries and frontier molecular orbital surfaces, including the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), determined accordingly. The stability of the ground-state structures was corroborated by a frequency analysis carried out at the same computational level, which verified the lack of imaginary frequencies. The excitation energies of the singlet states were computed based on the optimized ground-state geometries using time-dependent density functional theory (TD-DFT),utilizing the identical functional and foundational set. Along with their configuration interaction descriptions and oscillator strengths, this method yielded the permitted vertical electronic excitation energy, which correlate to absorption energies in the UV/Vis spectral range.

Abstract This research endeavor successfully synthesized 1,6-naphthyridine, an innovative category of fused heterocyclic compounds, with remarkable efficiency through the implementation of a multicomponent reaction. The reaction comprised benzaldehyde or its derivatives, two moles of malononitrile, and either 1-naphthylamine in an aqueous medium at ambient temperature, utilizing SiO2/Fe3O4@ MWCNTs as a recyclable catalyst. This investigation further explores the antioxidant characteristics of 1,6-naphthyridine in conjunction with the additional research conducted within this study. The synthesis protocol for 1,6-naphthyridine exhibited numerous advantageous attributes, encompassing expedited reaction times, elevated yields of the final product, and the ease of separating both the catalyst and product from the reaction mixture.

Abstract This study investigates the influence of electronic and structural factors on the synthesis and stability of nitrones derived from various aromatic aldehydes. Experimentally, four nitrones were synthesized with varying yields, with nitrones III and IV derived from 5-nitro-2-thiophenecarboxaldehyde and cinnamaldehyde exhibited the highest yields of 75% and 78%, respectively. Their structures and purity were confirmed through IR and 1H-NMR spectroscopy, validating the successful synthesis. To complement the experimental work, Density Functional Theory (DFT) calculations were performed to provide detailed insights into the electronic properties and thermodynamic stability of the nitrones. These calculations included parameters such as enthalpy (ΔH), entropy (ΔS), Gibbs free energy (ΔG), the HOMO-LUMO energy gap, electrophilicity, and electron acceptance (A). Notably, nitrone III demonstrated the greatest thermodynamic stability with the lowest Gibbs free energy and a larger HOMO-LUMO energy gap, suggesting lower chemical reactivity. This computational finding is consistent with the high yield observed experimentally, indicating a strong correlation between stability and reaction efficiency. Additionally, the analysis highlighted the significant roles of electronic effects. These included the inductive and mesomeric influences of substituents on the aldehyde moieties, which modulate nitrone formation and stability. Integration of experimental and theoretical approaches enabled a deeper understanding of the structure–reactivity relationship in nitrone chemistry, offering predictive insights that could to guide the design and optimization of future nitrone syntheses.

Abstract This review article aims to survey the literature on methodologies for the direct vicinal 1,2-thiosulfonylation of alkenes. This review is divided into two sections based on the type of thiosulfonylating reagents: the first covers the thiosulfonylation of alkenes using bifunctional reagents, while the second focuses on three-component reactions.

Abstract Lariat-type ligands are a specialized class of macrocyclic ligands distinguished by the presence of one or more pendant arms or tail-like extensions attached to the macrocyclic core. These pendant arms typically contain donor atoms such as nitrogen, oxygen, or sulfur, which participate in metal coordination. The unique structural features of lariat-type ligands enable them to modulate the coordination environment and binding affinity toward metal ions. This study primarily focuses on the synthesis of novel lariat-type ligands that function as [ONS] donors for diamide crown compounds. The experimental procedure involved conversion of 2,4-dimethylphenol (2,4-DMP) into a bisphenol compound. Transformation of the bisphenol into a methyl diester derivative through reaction with methyl chloroacetate. Reaction of the methyl diester with a suitable diamine, triethylenetetramine, to produce the corresponding diamide macrocycle. Modification of the diamide macrocycle to obtain the lariat structure by reaction with various monofunctional agents, such as ditosylate, 4-chlorophenol, hexanoyl chloride, and formaldehyde. Finally, The structures of all synthesized compounds were thoroughly characterized and confirmed using a combination of spectroscopic techniques, including 1HNMR, 13CNMR, MS(mass spectrometry), and FT-IR spectroscopy. The reaction efficiency of lariat 4 and lariat 5 were 55% and 96% respectively. Also, the melting point of lariat 4 and lariat 5 171-174 °C and 153-155 °C respectively.

Abstract The direct sulfonylation of terminal acetylenes and the decarboxylative sulfonylation of acetylenic acids are novel and straightforward approaches for preparing biologically and synthetically significant acetylenic sulfone derivatives. These methods offer several advantages over conventional protocols, including the utilization of inexpensive and readily accessible starting materials, improved atom and step economy, and reduced waste generation. This mini-review highlights recent advancements in these promising approaches to acetylenic sulfones, with an emphasis on the scopes, limitations and the mechanisms of the reactions.

Abstract This review highlights recent progress in the direct synthesis of α,β-epoxy ketones via oxidative coupling of alkenes and aldehydes, with a particular focus on mechanistic features of the reactions. For clarity, the review is organized into two sections: metal-catalyzed and metal-free epoxyacylations, covering literature up to the end of May 2025.