Chemistry - An Asian Journal最新文献

The cover picture illustrates the synthesis of a new copillar[5]arene-based pyrene Schiff base which shows aggregation-induced emission (AIE) feature. Hydrophobic effect is the driving force in the formation of aggregates. The aggregation behavior is described by several spectroscopic studies. Importantly, the aggregated state in aqueous THF recognizes picric acid selectively by turning of the activated fluorescence. More information can be found in article number e202401586 by Subhasis Ghosh and Kumaresh Ghosh.

The electrochemical CO₂ reduction reaction (CO₂RR) holds significant promise as a sustainable approach to address global energy challenges and reduce carbon emissions. However, achieving long-term stability in terms of catalytic performance remains a critical hurdle for large-scale commercial deployment. This mini-review provides a comprehensive exploration of the key factors influencing CO₂RR stability, encompassing catalyst design, electrode architecture, electrolyzer optimization, and operational conditions. We examine how catalyst degradation occurs through mechanisms such as valence changes, elemental dissolution, structural reconfiguration, and active site poisoning and propose targeted strategies for improvement, including doping, alloying, and substrate engineering. Additionally, advancements in electrode design, such as structural modifications and membrane enhancements, are highlighted for their role in improving stability. Operational parameters such as temperature, pressure, and electrolyte composition also play crucial roles in extending the lifespan of the reaction. By addressing these diverse factors, this review aims to offer a deeper understanding of the determinants of long-term stability in the CO₂RR, laying the groundwork for the development of robust, scalable technologies for efficient carbon dioxide conversion.

CO₂ emissions and accumulation in the ecosystem have exacerbated climate change and increased the global temperature. This study focused on the activation of hydrothermally synthesized Cu metal-organic framework (MOF-199) with potassium citrate (C₆H₅K₃O₇) to produce MOF-derived carbon incorporated with nano-dispersed metallic Cu and oxidative Cu species to facilitate electrochemical CO₂ reduction. Among all MOF samples, the resulting MOF-derived carbon, activated by C₆H₅K₃O₇, demonstrated the highest electrocatalytic current and lowest charge transfer resistance, achieving a Faradaic efficiency exceeding 50% for the production of acetic acid (CH₃COOH) at an applied potential of - 1.1 V (vs RHE). The addition of C₆H₅K₃O₇ during preparation endowed the MOF-derived C with a mesoporous structure, thereby enhancing CO₂ adsorption and activation. A proposed reaction pathway suggested that the generation of nano-dispersed metallic Cu is critical for forming Cu─C bonds for producing CH₃COOH. This study indicates that Cu-containing MOF-derived carbon with beneficial properties for electrocatalytic applications owing to its nanoispersed Cu features could be readily synthesized.

Chemically powered colloidal motors exhibit significant potential for applications in oral cleaning and antimicrobial treatment. The integration of MnO₂-based colloidal motors with common mouth-rinsing H₂O₂ solutions for sterilization and disinfection via reactive oxygen species (ROS) represents an ideal approach. In this study, we fabricate uniform dumbbell-shaped (DS-MnO₂-motor), spherical (S-MnO₂-motor), and silver half-coated spherical Janus Ag-MnO₂ colloidal motors (JS-MnO₂-motor) using hydrothermal, co-precipitation, and sputtering methods, respectively. These motors are propelled by O₂ bubble ejection generated from the catalytic decomposition of low-concentration H₂O₂ by peroxidase-like MnO₂ components. Notably, the JS-MnO₂-motors achieve a maximum speed of 146.4 µm s^-1 in gargle containing 1.5% H₂O₂. In vitro and in vivo antimicrobial trials demonstrated that the JS-MnO₂-motor gargle exhibits superior sterilization rates of 98.1% and 97.4% against both planktonic and biofilm-forming P. gingivalis and F. nucleatum. Consequently, it significantly enhances the therapeutic efficacy in treating periodontitis in Wistar rats, as evidenced by a marked reduction in inflammatory cells. The mechanical force exerted by these colloidal motors, along with cation adhesion to bacterial membranes and the antimicrobial effects of ROS, collectively contribute to this enhanced performance. Our findings introduce a novel strategy for the treatment of chronic inflammatory diseases.

A convenient route for the mechanochemical synthesis of fluorinated aromatic compounds, that is, fluoro, trifluoromethyl, and trifluoromethoxy arenes, has been developed via pyrylium tetrafluoroborate (Pyry-BF₄)-mediated desulfonamidative cross-coupling of primary sulfonamides under the synergy of a piezoelectric material BaTiO₃, and Ru-catalysis. This is the first-ever report on the selective transformation of sulfonamide (SO₂NH₂) functionality to CF₃/OCF₃/F group in a single step under mechanochemical ball-milling conditions. Considering the importance of primary sulfonamides as the valuable pharmacophores, the present desulfonamidative cross-coupling approach could have potential to get synthetic utility in pharmaceutical industries for the late-stage functionalization of sulfonamide drugs and related active pharmaceutical ingredients (APIs).

Hydrogels have emerged as flexible biomaterials with enormous potential in biomedical applications due to their outstanding biocompatibility and ability to hold a high water concentration. Hydrogels have low toxicity and are biodegradable. This review begins with a look at the various riveting characteristics and classifications of hydrogel nanocomposites reinforced with various metallic and ceramic components. A distinct focus is offered on thoroughly deliberating surface modification techniques with special attention on fabrication, patterning, and their applications in biomedical fields. The review describes the value of novel cross-linking techniques including physical, chemical, and physical-chemical dual cross-linking in adapting hydrogel characteristics to specific applications. This review also explains the major bioapplication of functionalized hydrogels. It emphasizes the importance of nanocomposite hydrogels and multifunctional self-assembled monolayers in solving contemporary biological difficulties such as infection control, medication delivery, and tissue regeneration. It explains the need for interdisciplinary collaboration and ongoing research efforts to realize the full potential of hydrogels and nanomaterials in biomedical applications. Overall, this review gives useful insights into current advances and future possibilities for hydrogels grafted with metals and ceramic additives in biomedical applications, highlighting the need for multidisciplinary cooperation and ongoing research in nano(bio)technology.

MXene is a cationic 2D material made of transition metal carbides known for its diverse structure and multifunctionality. It faces challenges like stacking, oxidation, and weak mechanical properties that limit its use. By integrating MXene with self-supporting porous materials, it can be stabilized and converted from fragile 2D sheets to strong 3D structures. Wood, due to its natural structure and stability, is ideal for depositing MXene, which adheres to wood via adsorption, hydrogen bonding, or reactions with wood fibers. New MXene-wood composites with improved functions have been created and show great potential for interdisciplinary research. This review covers preparation methods, applications, potential development, and challenges of MXene-wood composites, aiming to provide a research framework and progressive direction for their future development.

Molecular cages are distinguished supramolecular structures with stable cavities, enabling applications in molecular recognition, catalysis, and drug delivery. While the synthesis of purely organic cages is less common and often hindered by entropy-related challenges in irreversible reactions. In this study, we present a novel single-precursor strategy featuring dual aldehyde and hydrazine units to facilitate ring closure via hydrazone chemistry. This approach yielded a double-layered aromatic arylhydrazone macrocycle with 88% yield. Furthermore, this macrocycle with electron-rich properties showed strong binding to the electron-donor fullerene guest C₆₀ and C₇₀.

Mechanochromic polymers have potential in visualization of microscopic damages in materials, and the integration of non-invasive switching into mechanochromic polymers can enable rich on-demand functionality of polymer materials. In this work, we report the development of a mechanoresponsive fluorescent polymer with photogated properties, comprising poly(methyl acrylate) (PMA) and the photoswitchable mechanophore S₂A₂, which features two anthracene groups linked by a disilane spacer. The mechanochromic polymer PMA-S₂A₂ exhibits ratiometric fluorescence response upon mechanical deformation, which arises from the monomer and excimer emission ratio of anthracene controlled by the polymer strain. The mechanochromic property of the polymer can be switched off by irradiation with 365 nm UV light which induces [4 + 4] cycloaddition of the anthracene groups between and within the polymer chains. Importantly, the anthracene dimers can be reversibly dissociated in situ within the polymer film by irradiation with 254 nm UV, restoring the mechanochromic function. Furthermore, intermolecular photodimerization of anthracene increases the molecular weight and forms an entanglement network, significantly enhancing the material toughness. This reversible photocontrolled switch design offers a novel strategy for developing mechanochromic materials with modulated responses and mechanical properties.

Cancer remains a critical global issue, marked by its high mortality rates. Despite achieving remarkable progress in cancer treatments, conventional chemotherapeutic drugs face numerous limitations. To this end, nanomaterial-based targeted drug delivery systems have emerged as a hope of promise. In this study, we report the design and development of transferrin (Tf) tethered naphthalene-diimide-based fluorescent organic nanoparticles (NDI-OH-Tf) for targeted delivery of paclitaxel to cancer cells with over expressed transferrin receptors (TfR). Spherical NDI-OH FONPs were fabricated through J-type of aggregation of NDI-OH amphiphiles in a 1:99 (v/v) DMSO-H₂O mixture. These NDI-OH FONPs exhibited aggregation induced emission (AIE) at an emission wavelength of λ_em = 594 nm. The hydroxyl groups on the surface of the NDI-OH FONPs were conjugated with carboxyl groups of transferrin, forming NDI-OH-Tf FONPs. These NDI-OH-Tf FONPs were successfully used for targeted bioimaging and drug delivery to TfR+ cancer cells through ligand receptor interaction between transferrin and TfR. Notably, paclitaxel loaded NDI-OH-Tf exhibited ∼2.9-fold higher efficacy toward TfR+ cancer cells compared to normal cells and ∼3.3-fold higher cytotoxicity than free PTX due to transferrin mediated targeted accumulation of PTX in cancer cells.