Chemistry - An Asian Journal最新文献

Surface ligands significantly influence the optical properties and stability of metal nanoclusters. In this study, we synthesized [Pt₁Ag₃₁(S-Adm)₁₆(DPPM)₃(DPPMO)Cl₃](SbF₆)₄ (Pt₁Ag₃₁-DPPMO). Compared to [Pt₁Ag₃₁(S-Adm)₁₆(DPPM)₃Cl₃](SbF₆)₄ (Pt₁Ag₃₁), the introduction of secondary phosphine oxide ligand, DPPMO, results in Pt₁Ag₃₁-DPPMO exhibiting enhanced photoluminescent properties in both solution and solid states, as well as improved stability and electron-withdrawing ability. This work presents a novel strategy to regulate the properties of metal nanoclusters, especially enhancing photoluminescence performance and stability, through the incorporation of secondary phosphine oxide ligand.

Herein, a three-step general strategy featuring a thermal intramolecular Diels-Alder (IMDA) reaction to prepare the tricyclic 9-methyl-7-aryl-tetrahydro-6H-benzo[c]chromen-6-one core of morusalisin A is reported. This developed chemistry is applicable to the synthesis of a variety of tricycles, including 9-silyloxy and 9-phenyl-7-aryl-tetrahydro-6H-benzo[c]chromen-6-ones. In addition, a one-pot dehydration/IMDA procedure was demonstrated. The positioning of substituents on the aryldiene moiety played a significant role in governing the endo/exo selectivity, while the overall yield and reaction rate were affected by the electronic properties of both cinnamates and aryldienes. Functional group manipulations of the resulting cycloadducts were performed to furnish synthetically useful derivatives.

Photoelectrochemical (PEC) water-splitting is an energy-efficient and eco-friendly technique to produce green hydrogen (H₂). Here, WO₃ is synthesized for saline water-splitting reaction. Initially, the activity of WO₃ is enhanced through morphology tuning. Nanoparticles (NPs), thick nanosheets (TSs), and nanoflakes (NFs) of WO₃ are synthesized, and their PEC activity is determined. The NFs show a photocurrent density of 1.53 mA/cm² at 1.2 V vs. Ag/AgCl, whereas TSs and NPs can generate 1.17 mA/cm² and 1.07 mA/cm² at 1.2 V vs. Ag/AgCl, respectively. The low charge transportation rate inhibits the PEC performance of these NFs in water-splitting reactions. To mitigate this problem, the type-II heterojunction is constructed with optimized deposition of ZnWO₄ on WO_3, which favors the migration of charge-carriers in opposite directions, facilitating the charge-carrier separation and eventually enhancing the PEC activity. The optimized heterojunction shows a photocurrent density 1.5 times greater than bare WO₃ and 2.4 times enhanced carrier density, 2.16×10²¹ cm^-3. The heterostructure's rapid OCP decay and higher charge injection efficiency indicate an improved charge transport capability, the primary driving force for enhanced PEC activity. The stability of WO₃/ZnWO₄ is studied for one hour.

Fluoride ions (F^-) are well-known for their beneficial effects on oral health and their involvement in acting osteoporosis. But it is crucial to understand that consuming too much fluoride can of several adverse health effects. Dental fluorosis, urolithiasis, and even cancer can result from excessive fluoride exposure. This is why monitoring fluoride levels is so important. A 2,4-dinitrophenyl hydrazine derivative of a BODIPY-based aldehyde system (BDNP) is a sensitive, ratiometric, and selective naked-eye sensor that we have developed for the quick detection of fluoride ions in biological and environment samples showed a significant color change from pink-to-grey and a significant redshift in absorbance maxima when interacting with fluoride ions. The notable color shift demonstrates the effectiveness of both BDNP and Poly-BDNP in detecting fluoride ions. Interestingly, here we also showed that the ring-opening polymerization (ROP) technique-synthesized biodegradable and biocompatible ε-Caprolactone homopolymer of BDNP (Poly-BDNP) is a great system that can detect fluoride ions colorimetrically with a higher limit of detection (LOD) value than the monomer and rapid detection ability. Using the UV-visible spectroscopy study and the ¹H NMR spectroscopic titration technique, the interaction between BDNP and fluoride ions was examined. It was determined that the deprotonation of N-H protons triggers the intermolecular charge transfer (ICT) reaction, which results in the system's dramatic color change. The precision of both BDNP and Poly-BDNP in detecting F^- ions with LOD values of 7.73 µM and 87.9 nM, respectively, is determined by the ratiometric absorbance change of the sensor during the sensing process.

An external-photocatalyst-free visible light-induced regioselective C-3 sulfenylation of imidazo[1,2-a]pyridines using Bunte salts has been accomplished via C(sp2)-H functionalization. This protocol allows the coupling of a wide range of imidazoheterocycles with alkyl-, benzyl-, and aryl Bunte salts under ambient air as the sole oxidant. The radical scavenging, UV-visible spectroscopic studies, and Stern‒Volmer experiments revealed that the reaction occurs through energy transfer followed by a radical SET pathway. In this work, the dual role of imidazopyridines as photoexciting species and as energy transfer vehicle is proposed. Activation of the triplet oxygen as a result of energy transfer, which acts on somophlic Bunte salts to generate thiyl radical, eventually resulting in the C(sp2)-H functionalization.

The crux for the advancement of high-performance sodium-ion batteries resides in the development of low-cost, high-performance hard carbon anode materials. In this study, waste plastics are utilized as precursors to prepare plastic-derived hard carbon materials through a simple high-temperature one-step carbonization method, which is particularly suitable for new energy storage devices such as sodium-ion batteries and supercapacitors. Through in-depth exploration, we discover that the initial coulombic efficiency of hard carbon is intimately associated with its structure, within which the PU material exhibits the attributes of high capacity, initial coulombic efficiency, and excellent cycle performance, meriting further optimization of hard carbon precursor materials. In this study, a novel idea of preparing a high-performance hard carbon anode by a low-carbon and environmentally friendly method is proposed, and the key factors influencing the electrochemical performance of hard carbon materials are revealed, providing a valuable experimental basis for the further development of sodium anodes.

Supramolecular polymers (SPs) based on the stacking of hydrogen-bonded rosettes are attracting increasing attention due to their potential applications as soft materials. However, a detailed description of the interactions that give rise to these one-dimensional architectures is still scarce in the literature. In this work, we use molecular dynamics to analyze in aqueous solution the stability of two SPs based on amino triazines (AT) and amino pyrimidines (AP) modified with a hydrophilic chain of succinic acid (-saH). Our results reveal that the AT-based polymers are stable in both their neutral and anionic (succinate -sa-) forms. In contrast, the anionic AP-based polymer is completely dissociated in the presence of sodium cations. While chloride anions can stabilize AT polymers and even induce helical coordination, sodium cations destabilize the AP polymer by penetrating its structure and coordinating with the N atoms, thereby disrupting the hydrogen bonds of the rosettes. On the contrary, the AT-sa- monomers are able to hold back sodium cations due to their extra endocyclic N atom. The side chains are also essential for the formation of these SPs. In summary, we show how non-covalent interactions can be strategically used to control the stability of these systems.

Vinyl sulfides and their sulfones act as very important building blocks in organic synthesis. Further they are prevalent in bioactive natural and unnatural products and exhibit diverse bioactivities. Here in we report a Z-enoate assisted Meyer-Schuster rearrangement approach for the rapid generation of 1,4-ketoester based vinyl sulfides. The thiols were employed as nucleophiles during this versatile transformation the propargylic alcohols. The process exhibited broader scope for thiols (aryl and alkyl), and propargylic alcohols. Further these vinyl sulfides were efficiently converted into the corresponding vinyl sulfones by employing a Mo-based oxidizing agent. Sodium borohydride reduction of the 1,4-ketoester based vinyl sulfides directly gave the butyrolactones having the vinyl sulfide unit. The phenols, alcohols and amines were found to be inefficient as nucleophiles to give the corresponding vinyl ethers.

The construction of organic-inorganic semiconductor heterojunctions is an important way to improve the photocatalytic performance of semiconductors and inhibit the recombination of photogenerated charge carriers. In this paper, a novel Sb₂S₃-3,4,9,10-perylene tetracarboxylic acid (Sb₂S₃-PTCA) heterojunction was prepared by hydrothermal method. Compared with Sb₂S₃ and PTCA, Sb₂S₃-PTCA composite catalyst had better photocatalytic reduction ability for Cr(VI) in aqueous solution under visible light conditions. The optimized Sb₂S₃-1.0 wt.% PTCA heterostructures exhibited significantly enhanced photocatalytic activity compared to pure Sb₂S₃ and PTAC, achieving a complete Cr(VI) reduction rate of 100 % in just 50 min. This will lead to cleaner effluent water being discharged into the environment, thereby reducing pollution and protecting aquatic ecosystems. The enhanced photocatalytic efficacy exhibited by the Sb₂S₃-PTCA heterostructure stems from the creation of a type II heterojunction, which facilitates a more proficient dissociation and transportation of the electron-hole pairs, thus contributing to its superior performance.

In recent years, there has been a noteworthy expansion in the field of main-group compounds, attributed to their intrinsic capacity for the activation of small molecules. In this regard, the alkaline earth metal complexes have garnered important attention. Herein, we showed the utilization of a Mg complex Mg-1 as a catalyst in cyanosilylation reactions involving several aromatic and aliphatic aldehydes, conducted under mild reaction conditions. Although complex Mg-1 demonstrated its effectiveness in this transformation, complexes Mg-2 and Mg-3 yielded lower amounts of cyanosilylated products, highlighting the influence of the ligand spacer in catalytic activity. To further assess this effect, a mononuclear magnesium complex, Mg-4, was synthesized and the catalytic performance of Mg-4 in the cyanosilylation of aldehydes was found to be lower than that of Mg-1. This study establishes that magnesium complexes can independently catalyze the cyanosilylation of aldehydes, with those featuring an oxygen-bridged spacer exhibiting enhanced catalytic efficiency. Furthermore, employing complex Mg-1, we explored the cyanosilylation and hydroboration reactions involving N-heteroarene carboxaldehyde, an area with limited substrate scopes. Experimental and theoretical studies were performed to establish the mechanism which shows that the cyanosilylation reaction initiates with the initial coordination of trimethylsilyl cyanide (TMSCN) with the catalyst, followed by the subsequent attack of aldehydes. Whereas, in the hydroboration reaction, HBpin first reacts with the Mg complex Mg-1 to form Mg-H, which subsequently reacts with the aldehyde to form a hydroborylated product via a four-membered transition state.