Chemistry - An Asian Journal最新文献

The heme/Cu sulfite reductase bears a distal Cu metal coordinated to two cysteines. This enzyme catalyzes the reduction of sulfite to H₂S. Very little is known about the electronic structure and reactivity of this enzyme. Synthetic modelling can allow access to the properties of the active site. However, installing thiolates on porphyrin rings is not adequately represented in the literature. In this paper, we describe a synthetic methodology to install multiple thiolates on porphyrin rings which can be used to bind a second metal. In addition, to the complexity of keeping several thiols adjacent to each other, this work also reports unprecedented demetallation of iron porphyrin in the presence of multiple thiol functional groups in the vicinity.

Jayaramulu Kolleboyina and co-workers engineered a nickel single-atom catalyst (UiO-66/Ni) with Ni atoms covalently anchored to defect-engineered Zr-oxide clusters in the UiO-66 framework, synthesized via a simple solution impregnation method. This catalyst shows uniform Ni atom distribution, exceptional stability, and high catalytic performance in C–S coupling reactions of aryl thiols and aryl halides, achieving high activity and selectivity across various substituents at room temperature, maintaining stability. More details can be found in article number e202401578.

The increased production of biodiesel has resulted in a corresponding rise in glycerol (GLY) production. The glycerol oxidation reaction is characterized by mild reaction conditions and relatively simple products, making it a widely utilized method for glycerol conversion and one of the most promising industrial approaches. In this study, we prepared black titanium dioxide-supported platinum catalysts with different morphology. Different catalysts were synthesized by altering the morphology of the support and the reduction temperature of the support, which exhibited distinct activities and performance in the catalytic oxidation of glycerol to glyceric acid under alkali-free conditions. The evaluation of the catalysts revealed that when flaky black titanium dioxide (F-B-TiO₂) is employed as a support, the catalyst Pt/F-B-TiO₂ (600 °C), reduced at 600 °C, demonstrates the best catalytic performance. Characterization results indicate that the Ti³⁺ content in the flaky (F-B-TiO₂) support is higher compared to other morphologies. Additionally, at a calcination temperature of 600 °C, the Pt° content is maximized among the synthesized catalysts. Based on the experimental and characterization results, the catalytic performance is collaboratively influenced by the presence of Ti³⁺ and Pt⁰.

Lanthanide metal-organic frameworks (Ln-MOFs) exhibit distinctive emission spectra and prolonged luminescent lifetimes, thereby offering a unique platform for the advancement of solid-state photoluminescence (PL) materials. However, the mismatch between the energy levels of metal ions and organic ligands leads to a weak PL emission. Herein, this study presents a pressure-treated strategy aimed at achieving efficient green PL in Tb₂(BDC)₃(H₂O)₄ MOF. Compared to the initial intensity, the PL intensity is enhanced eightfold below 3.1 GPa. Intriguingly, the PL intensity of pressure-treated sample is amplified by 2.5-fold compared to the initial state, and the green emission monochromaticity is maintained. Experiments and calculations reveal that the enhanced hydrogen bonds are retained to the ambient conditions after pressure treatment. They lock the conjugated configuration formed between the planes of carboxyl group and benzene ring, facilitating the intersystem crossing. The reduced distances between metal ions and organic ligands drive the ligand-to-metal energy transfer process. This finding provided significant insights into structure-property relationship of Tb₂(BDC)₃(H₂O)₄, offering a new platform for boosting emission enhancement in Ln-MOFs.

The cover highlights a novel electro-oxidative approach towards the synthesis of N-hydroxymethylated indoles and related derivatives with the use of N-(hydroxymethyl)-N-methylacetamide generated in situ from N,N-dimethylacetamide (DMA) and water (H₂O) as a formaldehyde surrogate. The design of the artwork featuring the integration of the synthetic transformation process with the celebration of the accomplishment of this work, is inspired by the Thailand Countdown 2025 Festival in Bangkok. Celebrated on New Year's Eve, this iconic event displays dazzling fireworks illuminating the sky and shimmering lights reflecting off Bangkok's magnificent Thai architecture. The imagery symbolizes a celebration of Thailand's advancement in electrochemical synthesis. More details can be found in article number e202401489 by Chutima Kuhakarn and co-workers.

Tetrathiafulvalene (TTF) and polycyclic aromatic hydrocarbons (PAHs) represent two distinct classes of redox-active chromophores. By merging these two classes in so-called extended tetrathiafulvalenes, new physico-chemical characteristics emerge. Here in this study, we summarize the properties of such PAH-extended TTFs for which the PAH core incorporates five-membered carbo-cyclic rings together with six-, seven-, and/or eight-membered rings. A key structural motif of these molecules is the planar 2-(1H-inden-1-ylidene)-1,3-dithiole unit. Fusing two such units directly together or via various one- or two-dimensional PAH scaffolds has during the past decade provided a large selection of planar, twisted, or curved extended TTFs. Strong associations of radical cations are in some cases obtained, corresponding to redox-controlled self-assembly in solution, and these associations have allowed for the ready generation of semi-conducting salts by electrocrystallization. Some molecules exhibit remarkable multiredox behavior and can reversibly reach high cationic states, and, in some cases, also anionic states. Several structural examples also reveal how closed-shell versus open-shell characters of the dication states can be controlled by the nature of the PAH core, particularly by the number of Clar sextets within the core.

Separation and enrichment are critical steps in analytical detection, necessitating advanced materials with high selectivity and adsorption capacity for target compounds. In order to improve separation efficiency and selectivity, computational simulation could elucidate interaction mechanisms and analyze potential adsorption/desorption processes, providing a theoretical foundation for the optimization and design of separation materials. Recently, computational simulation has become an indispensable and crucial mean in separation science for analytical chemistry. Using various simulation software, researchers could investigate the structures, properties, and performance of separation materials at multiple levels and scales. In this review, we summarize the applications of computational simulations in the field of separation science, focusing on the separation of polar molecules, geometric isomers, enantiomer compounds, and post-translationally modified peptides. These calculation methods include quantum chemistry, molecular docking, molecular dynamics simulations, high-throughput screening, and machine learning. Finally, we discuss the current challenges and potential breakthroughs in computational simulation, aiming to offer valuable insights for researchers dedicated to computational simulation, material development, and separation applications.

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.