Chemistry - An Asian Journal最新文献

The development of efficient and durable non-precious electrocatalysts for the oxygen evolution reaction (OER) is crucial for sustainable hydrogen production. In this study, we developed a Fe-doped NiCo₂S₄/carboxymethyl cellulose (CMC) aerogel composite by a combined solvothermal and sol-gel approach. Fe doping induces lattice distortion and electron redistribution, increasing the contents of highly active Ni³⁺ and Co²⁺ species. Concurrently, the three-dimensional porous network of the CMC aerogel host greatly enhances the exposure of active sites and structural integrity. As a result, the optimal 5% Fe-NiCo₂S₄/CMC aerogel composite catalyst requires an ultralow overpotential of 262 mV to achieve a current density of 10 mA cm⁻² in 1.0 M KOH, exhibits a small Tafel slope of 88 mV dec⁻¹, and, most notably, demonstrates outstanding long-term stability for over 312 h. This work provides a dual-optimization strategy—through both electronic modulation and structural engineering—for advancing electrocatalyst design for energy conversion applications.

The deep-UV nonlinear material, Ba₃ZnB₅PO₁₄, has been explored for synthesizing new colored compounds, Tb³⁺/Tm³⁺-based white light emission and Eu³⁺-based turn-off luminescence sensing. Isostructural analogues were obtained by partial substitution of Ba²⁺ with Sr²⁺/Pb²⁺ ions and V⁵⁺ with P⁵⁺ ions. Transition metal–substituted compounds display bright colors under daylight. The origin of color was understood based on ligand field transitions. The oxidation states of the transition metal ions were confirmed using x-ray photoelectron spectroscopy (XPS) analysis. The near–IR reflectivity studies indicate that the synthesized compounds exhibit good near–IR reflectivity behavior. Rare-earth substitution (Eu³⁺, Tb³⁺, Tm³⁺) yield red, green, and blue emissions, respectively. White-light emission was successfully achieved by optimizing the green (Tb³⁺) and blue (Tm³⁺) components. Based on the lifetime measurements, a possible schematic of the energy transfer pathway has also been proposed. Eu³⁺-substituted Ba₃ZnB₅PO₁₄ host was found to be sensitive and selective for the fluorometric detection of Pb²⁺, Fe³⁺, Cl⁻, and NO₂⁻ ions in aqueous medium with low detection limits. The dielectric studies indicate reasonable dielectric constant values with low dielectric loss. Magnetic studies indicate antiferromagnetic behavior. The different properties demonstrated in the present study suggests that mineral structures offer fertile ground to investigate newer compounds and properties.

This article reviews the latest developments in electrochemiluminescence microscopy (ECLM) technology, which combines electrochemical input and optical output, and features low background noise, high controllability, as well as high spatial resolution. Through various adjustment strategies such as temperature regulation, ultrasonic enhancement, electro field regulation, and optical regulation, researchers have achieved precise control of ECL signals, thus improving the measurement sensitivity of ECLM. These technologies provide new strategies and tools for biological imaging, clinical testing, and nanomaterial analysis. For example, efficient ECL emission and direct modulation of ECL intensity at low potentials were achieved through a metal-insulator-semiconductor structure or an external magnetic field. In addition, the application of aggregation-induced luminescence effect demonstrates the potential of ECLM in improving the specificity of sensors and solving aggregation quenching problems. Despite the challenges, continuous innovation of ECLM technology is expected to bring wider applications in the biomedical field.

Establishing a benign and straightforward protocol for synthesizing biorelevant and synthetically valuable quinoxaline is very important. Herein, we report a simple and efficient protocol for the sustainable synthesis of diverse quinoxaline derivatives catalyzed by cobalt salt. The reaction proceeds through the dehydrogenative coupling of alkyl and aryl ethane 1,2-diols with aryl diamines in the presence of a catalytic CoBr₂/K₂CO₃. The usage of the greener solvent 2-MeTHF and the release of H₂ and H₂O as the sole byproducts make the process advantageous. The protocol led to the synthesis of diverse quinoxalines bearing synthetically useful functionalities, such as fluoro, chloro, bromo, cyano, trifluoromethyl, and ether. The reaction is presumed to proceed via the dehydrogenative-condensation pathway involving a cobalt-hydride intermediate.

A series of nitrogen-rich heterocyclic compounds were designed and synthesized as novel fluorescent ligands for the specific detection of rare earth elements. Monoimidazolylpyrazine and bisimidazolylpyrazine species (1 and 2) were synthesized via a green electrochemical approach. This method utilized platinum electrodes under constant-current conditions, achieving optimized yields while minimizing environmental impact. Subsequent tetrazole ring functionalization yielded derivatives 3 and 4, which exhibited enhanced metal coordination capabilities. Structural analyses revealed a two-dimensional planar architecture for 1 and a three-dimensional framework for 2. Compound 3 demonstrated exceptional performance as a “turn-on” fluorescent probe for La³⁺ ions, showing remarkable selectivity and significant fluorescence enhancement over other metal ions. Combined experimental and theoretical studies confirmed a unique 10:1 binding stoichiometry (3:La³⁺) revealed by isothermal titration calorimetry (ITC). The probe 3 shows a low detection limit of 2.32 µM. The efficiency stems from minimized energy dissipation and optimal ligand-to-metal energy transfer (LMET), underscoring its potential for practical sensing applications in environmental monitoring and rare-earth separation.

The amide bond of ceramide can adopt either a cis or trans conformation, but the biological relevance of this geometry remains unclear. We used 1,4- and 1,5-disubstituted 1,2,3-triazoles as conformationally restricted bioisosteres to investigate the functional consequences of amide bond geometry. Antiproliferative assays, sphingomyelin synthase 1 metabolite profiling, and molecular docking analyses all indicate that the trans conformation better reflects the biologically active state. These findings provide direct evidence that amide bond conformation plays a critical role in ceramide function.