Chemistry - An Asian Journal最新文献

Glycerol, the byproduct of a multi-ton biofuel industry, is a cheap and useful feedstock for value-added chemical transformations. The conversion of glycerol to lactic acid has been realized using pincer complexes, mainly based on 4d and 5d transition metals. Herein, a well-defined, nonsymmetrical PN³P-Fe complex (Fe-1) was synthesized and characterized. Single-crystal x-ray diffraction (SC-XRD) revealed a distorted square pyramidal geometry, while spectroscopic analysis and the Evans method confirmed a high-spin Fe(II) center. The complex Fe-1 performed glycerol to lactate transformation with an excellent yield and selectivity of up to 87%. Furthermore, a series of control experiments demonstrated the molecular nature of the transformation and elucidated the role of the catalyst in the organic cascade.

The chemical modification and self-assembly capability of fullerenes offer advantageous conditions for tailoring Fe/N-doped carbon-based catalysts. However, their strong π–π stacking tendency may partially restrict metal loading and the generation of active Fe species. Therefore, how to utilize the distinctive features of fullerenes to precisely regulate and optimize Fe–N active sites along with their local coordination environment remains challenging. In this work, water-soluble C₆₀ (wsC₆₀) was synthesized via a facile interfacial oxidation process. The presence of –OH on the C₆₀ cage may strengthen its binding affinity with Fe³⁺ ion and effectively modulate the incorporation of Fe/N into the C₆₀-derived carbon electrodes. By varying the wsC₆₀/Fe³⁺ mixing ratios followed by pyrolysis under NH₃, we obtained Fe/N-doped carbons (FeN@wsC₆₀-900) with distinct Fe/N-doping states, including FeN₄, O–FeN₄/Fe cluster, and FeN₄/Fe cluster. The abundant –OH in wsC₆₀ also promoted the formation of a highly porous network, enhancing active site accessibility. The resultant FeN@wsC₆₀-900 exhibited excellent oxygen reduction reaction (ORR) activity, outperforming both conventional C₆₀-derived carbons and commercial Pt/C. Structural characterizations and density functional theory (DFT) simulations revealed that the O-coordinated Fe–N₄ with adjacent Fe cluster could optimize the coordinate geometry and adsorption energies of key ORR intermediates.

A facile and efficient approach for the halospirocyclization of N-benzylpropiolamides has been developed. Employing N-halosuccinimides (NXS) as halogenating reagents, this reaction proceeds smoothly at room temperature without the need for photochemistry, electrochemistry, or metal reagents. A diverse array of halogenated azaspiro[5.5]undecanones was obtained in moderate to excellent yields, displaying excellent functional group tolerance. The gram-scale reaction and the synthesis of brominated 2-oxaspiro[5.5]undecanone further underscore the scalability and practicality of this method.

Multicomponent reactions (MCRs) are powerful tools for the rapid construction of complex molecules, as they enable the assembly of diverse functional fragments into a single skeleton. Herein, we report an efficient and practical copper-catalyzed multicomponent radical process that couples readily available Togni's reagent II, alkenes, and alkynes to afford β-trifluoromethyl propynes with high regioselectivity. Under mild copper-catalyzed conditions, this strategy enables chemoselective and regioselective radical trifluoromethylalkynylation of alkenes while suppressing undesired copper-catalyzed or radical-mediated side reactions. The method exhibits a broad substrate scope for both alkenes and alkynes, with excellent functional group compatibility.

Zirconium phosphates are stable under thermal and acidic conditions, making them useful ion exchangers for recovering rare earth elements from bauxite residues. This study evaluates the selective uptake of Sc³⁺ by α-disodium zirconium phosphate (α-Na₂ZrP) and α-magnesium zirconium phosphate (α-MgZrP), both prepared via a minimalistic mechanochemical route that uses only the water present in the reactants for homogenization and employs stoichiometric or close-to-stoichiometric reactant ratios. Both crystalline materials show high selectivity for scandium in the presence of other rare earth ions and iron which shares similar chemical properties and occurs at much higher concentrations. α-MgZrP displays a high uptake at low Sc³⁺ concentrations compared with α-Na₂ZrP. However, its overall capacity is only 0.56 versus 1.2 mmol/g for α-Na₂ZrP, illustrating differences in their low-concentration uptake efficiency and total loading. Stripping the Sc³⁺-loaded ion exchangers with H₃PO₄ results in pure α-zirconium phosphate (α-ZrP; Zr(HPO₄)₂∙H₂O), indicating complete removal of the exchanged Sc³⁺.

Ferritin, an iron-storage protein, plays a crucial role in the management of cellular iron homeostasis and prevents iron-induced toxicity. It rapidly sequesters free Fe²⁺ and synthesizes soluble protein-caged ferric-mineral, while ensuring controlled iron-release upon cellular requirements. Given the reducing environment of the cytosol, reductive dissolution of ferritin bio-mineral is considered one of the plausible iron release pathway in vivo. NADH (∼ 0.1–0.3 mM), GSH (∼ 1–8 mM), and AscH₂ (∼ 0.1 mM) mostly contribute toward this redox milieu. The current work investigates the effectiveness of these reductants in promoting iron mobilization from ferritin in vitro. Ascorbate was found to release the highest amount of iron, even at its lower physiological concentrations. To further enhance iron-release efficiency, a series of quinones, varying in structure and redox potential, were employed as electron mediators along with ascorbate (electron-source). While certain quinones enhanced the process, others inhibited it. Our findings highlight that ascorbate/quinone-mediated iron release from ferritin is largely dictated by the molecular structure and the reduction potentials of quinones. This study may provide insights into the redox behavior of quinones, in vivo iron release pathways and also strengthen our understanding on other biological ET processes and O₂-based cellular toxicity.

Nanosponges (NSPs), a class of porous, tunable, and high-surface-area materials, have emerged as next-generation platforms for chemo- and bio-sensing applications, enabling enhanced detection sensitivity, selectivity, and real-time responsiveness. Their unique architecture, engineered through metal-based, metal-oxide, and hybrid frameworks, offers controlled porosity, flexibility in functionalization, and high analyte-binding affinity. Over the past decade, NSPs have been progressively integrated into optical, electrochemical, and enzymatic sensor systems, targeting environmental toxins, toxic gases, metal ions, and biological markers. This review systematically discusses the structural fundamentals of NSPs, including polymeric backbones, crosslinking chemistry, and active sites responsible for molecular recognition. A critical analysis of NSP functionalization strategies, fabrication factors, and performance limitations is presented to guide material optimization. Applications are explored across chemosensing (heavy metal ion detection, toxic gas analysis) and biosensing (glucose, enzyme activity, and pathogen identification), highlighting the integration of NSPs into field-deployable diagnostic platforms. Furthermore, the review outlines the key challenges in NSP-based sensor technology, such as stability, reusability, and multiplexed detection, and provides a future outlook on their role in intelligent, miniaturized, and sustainable sensing devices for environmental and healthcare diagnostics.

Azo dyes such as Tartrazine (Tz) and Sunset Yellow (SY) are extensively used in food and consumer products, but their overuse poses significant health and environmental risks. Developing simple and reliable detection methods for dyes is, therefore, crucial. In the present study, Samarium-doped zinc oxide (Sm-ZnO) nanorods anchored on graphitic carbon nitride (gCN) sheets were synthesized via a hydrothermal route and further applied as a fluorometric sensor for Tz and SY. The gCN/Sm-ZnO hybrid showed strong blue fluorescence, which underwent pronounced quenching upon interaction with the dyes through a combination of the inner filter effect (IFE) and static quenching mechanisms. The probe showed excellent photostability and long-term thermal stability, retaining its fluorescence intensity even after prolonged irradiation and storage under varied temperature conditions. The sensor exhibited remarkable sensitivity, achieving detection limits of 0.164 µM for Tz and 0.305 µM for SY. To exemplify its practical utility, the probe was successfully applied to real-world matrices such as turmeric powder, soft drinks, cosmetics (face wash), and jellies, yielding high recovery rates of 93.33%–105.42% with good reusability. The synergistic combination of Sm-ZnO nanorods and gCN sheets enhanced charge transfer and amplified the fluorescence quenching response, offering a cost-effective and robust approach for monitoring synthetic colorants in complex samples.