Chemistry - An Asian Journal最新文献

Bioresorbable electrically-active neuromodulation devices (BEANDs) integrate degradable materials with the neuromodulation function of electrical stimulation, allowing the implants to gradually resorb after completing their therapeutic tasks and thereby eliminating the need for secondary removal surgery. This technological paradigm creates new opportunities for the treatment of neurological disorders. This review summarizes the material foundations of BEANDs, including the degradation pathways and biological effects of metals, natural polymers, and synthetic polymers; functional material systems comprising conductors, semiconductors, and dielectrics; and the core device modules required for operation, such as energy harvesting, storage, transmission, and regulation. We highlight the balance between material performance and bioresorbability and emphasize that multimodal energy management plays a critical role in achieving precise and personalized neuromodulation. Finally, we outline future directions in interdisciplinary integration and clinical translation, which are expected to advance BEANDs from proof-of-concept demonstrations toward practical clinical applications.

Helicenes represent a unique class of chiral molecular scaffolds with significant potential in multifunctional materials. Herein, we report the efficient synthesis and characterization of a novel [7]helicene derivative, [7]-OTf, bearing reactive triflate groups. X-ray crystallography confirms the helical structure and enantiomer stacking of [7]-OTf, while a high racemization barrier of 46.5 kcal·mol⁻¹ enables the chiral separation by high-performance liquid chromatography. [7]-OTf exhibits green emission (λ_em = 487 nm) with a quantum yield of 20% and mirror-image chiroptical responses. Importantly, post-synthetic modification was successful via Sonogashira coupling. This work establishes [7]-OTf as a versatile and modifiable platform for advanced chiral materials.

Propene is one of the major platform petrochemicals, traditionally produced on an industrial scale via steam cracking of propane. As an alternative route, the oxidative dehydrogenation of propane (ODHP) offers a more energy-efficient pathway to obtain propene. In the current context of CO₂ mitigation, carbon dioxide can serve as a soft oxidant in the ODH of propane, reducing coke formation and enabling CO₂ utilization. Indium-based catalysts have shown promise in this regard, as indium can effectively activate CO₂ and promote reactions such as ODH. A series of indium oxide (In₂O₃) supported on TUD-1 mesoporous silica were prepared using a sol–gel method. The as-prepared catalysts were thoroughly characterized by several characterization techniques like XRD, SAXS, Raman, UV–vis spectroscopy, and TEM analysis. XRD result revealed the crystalline In₂O₃ with exposed (222) planes whereas Brunauer–Emmett–Teller (BET) analysis suggested incorporation of In₂O₃ inside the pores of the TUD-1. The addition of indium decreased the pore diameter of TUD-1 material. Under optimized reaction condition (500°C; C₃H₈: CO₂: N₂ = 1: 4: 5; GHSV = 6000 mL g⁻¹ h⁻¹) 10In-TUD-1 catalyst achieved 16% propane conversion with 70% propene selectivity.

Lithium-sulfur batteries have garnered significant attention from the scientific community due to their intrinsic advantages, including low cost, abundant resources, and high specific energy. However, the shuttle effect of soluble polysulfides and the sluggish redox kinetics of sulfur species have greatly hindered their commercialization and practical application. Herein, we propose a straightforward strategy to construct NiCo₂O₄-NC heterostructure nanocages, which serve as multifunctional separator modifiers to improve the electrochemical performance of lithium-sulfur batteries. Specifically, nitrogen doping enhances the polarity of the carbon matrix, enabling both physical confinement and chemical anchoring of polysulfide species. Meanwhile, the embedded NiCo₂O₄ provides abundant catalytic sites that accelerate the redox kinetics of lithium polysulfides. Consequently, the battery assembled with the optimal NiCo₂O₄-NC-1 modified separator demonstrates an excellent initial capacity of 1017.8 mAh g⁻¹ at 0.5 C and a remarkable cycling stability with only 0.04% capacity decay per cycle at 2 C. Moreover, NiCo₂O₄-NC-1 exhibits stable electrochemical behavior under high sulfur loading, highlighting its multifunctional structural advantages. This work provides a viable strategy for designing advanced separators in high-performance lithium–sulfur batteries.

Driven by accelerating global warming and the imperative of carbon neutrality, the search for efficient electrochemical energy-conversion technologies has intensified. Recent advances in electrocatalysis have introduced strategies to overcome kinetic, selectivity, and stability constraints in the carbon dioxide reduction reaction, oxygen reduction reaction, and water splitting. These developments range from atomic-scale structural modulation to microenvironment engineering, yielding substantial gains in product selectivity, reduced overpotential, and enhanced operational durability. This review consolidates representative breakthroughs across these three reaction domains and emphasizing design principles that couple performance optimization with mechanistic insight through operando X-ray absorption spectroscopy (XAS) and Raman spectroscopy. XAS resolves chemical states and local coordination environments, while Raman tracks surface-bound intermediates; together, they enable a comprehensive elucidation of catalytic mechanisms. The review also outlines key directions for advancing efficient, robust, and scalable electrochemical energy-conversion systems.

This work reports on the discovery of new materials in the Sc_2-x-yFe_xAl_yW₃O₁₂ family. Members with compositions containing high concentrations of Fe are found to crystallize to a structure in the monoclinic P2₁/a symmetry, while compositions with low values of Fe and Al crystallize in the orthorhombic Pnca structure at room temperature. The orthorhombic samples in the compositional range x = 0.5, y ≤ 0.5 are found to transition to the monoclinic P2₁/a structure at 210–230 K. Specifically, Sc_1.25Fe_0.5Al_0.25W₃O₁₂ is found to exhibit a volumetric coefficient of thermal expansion (CTE) of −0.48(7) × 10⁻⁶ K⁻¹ over the range 300–1000 K, a near-zero thermal expansion material—this CTE value is lower than precision invar variants and it is persistent over seven times the temperature range. Increasing the Al concentration to y = 0.75 increases the CTE to 4.69(8) × 10⁻⁶ K⁻¹ over the range 300–1000 K and decreasing it to y = 0 decreases the CTE to −4.22(6) × 10–6 K⁻¹ over the range 300–1000 K. This work probes the phase-space with an intention to correlate doping regimes to the physical property of volume change.

Reaction of 1-nitroso-2-naphthol (Hnn) with [{Ru(p-cymene)Cl₂}₂] afforded [Ru(p-cymene)(nn)Cl], (1), in good yield. Attempted chloride abstraction from 1 via its interaction with Ag⁺ in acetonitrile medium led to chloride removal, associated with displacement of the p-cymene by acetonitrile, yielding [Ru(nn)(CH₃CN)₄]PF₆, (2). The favorable thermodynamics behind conversion of 1 to 2 was found out by DFT calculation. The potential of 2 as a precursor for synthesis of new complexes retaining the Ru(nn) moiety was examined by its reaction with 2,2ʹ-bipyridine (bpy), which afforded [Ru(nn)(bpy)₂]PF₆, (3). Preliminary characterization of 1–3 was done by different spectral techniques. Crystal structures of all the complexes were determined, which revealed their stereochemistry and binding modes of the different ligands in them. Electronic absorption spectra of the complexes displayed intense absorptions in the visible and ultraviolet regions, the origin of which was probed with TDDFT method. Electrochemical redox properties of 1–3 were also investigated by cyclic voltammetry. Potential of 1 as a catalyst-precursor was explored toward two types of reactions, transfer-hydrogenation of aldehydes to alcohols and hydration of nitriles to amides, and it showed notable efficiency in catalyzing both the reactions. Probable mechanisms for the observed catalytic reactions were proposed.

A facile, high-yielding synthetic protocol has been developed to access azepino-fused porphyrins via iodine(III)-mediated oxidative intramolecular cyclization of β-imidazole or benzimidazole substituted porphyrins. The absorption of the synthesized compounds showed the characteristic features of meso-β-fused porphyrins, with intense Soret bands centered between 440 and 460 nm and two weak bands ranging from 550 to 750 nm (Q-bands) Among the synthesized compounds, the free-base imidazo-azepino-fused porphyrin was found to be an efficient ¹O₂ producer with a higher singlet oxygen quantum yield (Φ_Δ ∼0.78 in DMF) as compared to H₂TPP (Φ_Δ = 0.64 in DMF). It was observed that the protonated form of 4aH₂ exhibits a significant red shift of ∼24 nm in Soret and ∼150 nm in Q-bands. Fitting of the titration data of 4aH₂ with TFA yielded an apparent pK_a of ∼3.58, demonstrating that imidazole fusion enhances the basicity of the porphyrin system.