Chemistry - An Asian Journal最新文献

Luminescent coordination polymer gels (CPG) have received significant advancements in the field of supramolecular chemistry due to their stimuli-responsiveness and tunable processability, which allows them to be practical in the field of sensing, anticounterfeiting, and multimodal security systems. Herein, a triad of tunable Eu and Tb-based luminescent self-assembled CPGs has been synthesized using tetrapodal carboxylic-based imide-mediated linker N,N'-bis(5-isophthalic acid)-pyromellitic diimide (BIPD). Tuning Eu(III) and Tb(III) in a stoichiometry with the blue emissive ligand created a chameleon-like optical response under UV-light, ultimately resulting in the synthesis of white-light emitting materials. The obtained CPGs demonstrate considerable potential for anticounterfeiting applications, functioning effectively as security luminous inks that can be applied to various surfaces, along with their remarkable reversible sol-gel phase transitions. The synthesized Tb_BIPD xerogel exhibits notable selectivity and sensitivity for the detection of the oxoanion MnO₄ ^-, operating through a turn-off sensing mechanism and attaining a limit of detection (LOD) of 0.83 ppm.

We performed a computational study on the photocatalytic hydrogen evolution mechanism using a Zn-based metalloporphyrin (ZnP), water, and a cheap sacrificial donor. Based on previous experiments, the active species is a Zn chlorin (ZnC), formed by photohydrogenation of ZnP. Our calculations favor an electron-proton-electron-hydride (EPEH) photocatalytic cycle that consists of one-electron photoreduction of ZnC followed by protonation of a bridge carbon and a second photoreduction, leading to a key ZnCH_P4 ^- intermediate. One-electron photoreduction increases the aromaticity of the porphyrin rings, which explains the favorable photoreduction steps. The final step is a hydride transfer from ZnCH^- to a proton donor like an ammonium cation or water, resulting in hydrogen generation. Although this process is thermodynamically allowed, it has a high kinetic barrier and leads to loss of aromaticity, which limits catalytic efficiency. Hydrogen generation competes with ZnCH^- protonation and photohydrogenation. The poor activity of ZnCH_P4 ^- as a hydride donor may be related to the loss of aromaticity associated with the hydride donation. The results have implications for electrocatalytic hydrogen production using porphyrins, which share a similar common intermediate. Therefore, our work will be useful to improve the molecular design of porphyrin-based photo- and electrocatalysts for hydrogen generation.

Herein, we liquefied fused-nitrogen compounds as a viable alternative to traditional high-sensitivity plasticizers by employing ionic liquid engineering. We synthesized three novel fused-nitrogen compounds N⁶-(1,3,4-oxadiazol-2-yl)-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazin (DTOZ), N⁶-(5-diamine-1,2,4-oxadiazole-3-yl)-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazin (DTFA) and N⁶-(4,5-dicyanoimidazol-2-yl)-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazin (DTIZCN) based on triazolo-tetrazine backbone having high energy and low sensitivity (impact sensitivity > 40 J) by incorporating amino nitrogen heterocycles. The decomposition temperature (T_d) and enthalpy of formation (ΔH_f) of DTIZCN were 327.9°C and 1118.7 kJ mol^-1, respectively, while the density of DTOZ (1.814 g cm^-3) was comparable to cyclotrimethylenetrinitramine (RDX). Nine fused-nitrogen-based energetic ionic liquids (EILs), with ΔH_f between 204.9 and 531.1 kJ mol^-1, were synthesized via neutralization of three aliphatic quaternary ammonium cations. The DDA-DTOZ showed a low glass transition temperature (T_g = -46.1°C). Fused-nitrogen compounds demonstrated improved performance compared to conventional energetic materials, with a maximum specific impulse performance of 267.69 s being reached for DODA-DTFA with 14% plasticizer. Fused-nitrogen-based EILs showed application potential in high-energy propellants.

In this study, we synthesized a layered double hydroxide (LDH) with bimetallic centers of copper and iron (CuFe-LDH) and employed it as a multifunctional flame retardant and smoke suppressant to enhance the flame retardancy and smoke suppression properties of polyvinyl chloride (PVC). The results indicate that during the combustion of the CuFe-LDH/PVC composite, a dense carbon layer with tortuous pathways forms in the condensed phase through Lewis acid-catalyzed and reduction-coupling mechanisms. Coupled with the dilution effects of H₂O and CO₂ during combustion, the CuFe-LDH/PVC composite exhibits remarkable flame retardant and smoke suppressant properties, achieving a limiting oxygen index value of 34.8% and achieving a UL-94 V-0 rating. Compared to pristine PVC, the peak heat release rate of the CuFe-LDH/PVC composite was reduced by 20.55%, and the maximum average rate of heat emission decreased by 27.9%. Furthermore, the maximum smoke density and maximum average rate of smoke emission were reduced by 36.5% and 67.8%, respectively. This research proposes a novel method for designing and synthesizing additives that enhance the flame retardancy and smoke suppression performance of PVC from a catalytic perspective while avoiding the formation of multi-phase interfaces, thereby alleviating the adverse effects of traditional co-addition methods on polymers.

Urinary tract infections (UTIs) remain one of the most prevalent bacterial infections worldwide, and their complications are increasingly exacerbated by antibiotic resistance. The predominant pathogen, Escherichia coli (E. coli), contributes to both uncomplicated and complicated infections through adhesion and biofilm formation, posing major therapeutic challenges. This review critically examines current and emerging antibiotic drug candidates for UTI therapy, integrating insights from microbiology, clinical studies, and medicinal chemistry. Existing antibiotics for UTI treatment include trimethoprim/sulfamethoxazole, nitrofurantoin, fosfomycin, ciprofloxacin, levofloxacin, cephalexin, ceftriaxone, amoxicillin/clavulanate, doxycycline, and piperacillin/tazobactam. Additionally, Orlynvah and Pivya, two recently approved antibiotics, are discussed for their potential use in UTI therapy. The review also discusses structure-activity relationship (SAR)-guided development of trimethoprim derivatives and heterocyclic analogues targeting dihydrofolate reductase (DHFR), with docking and mechanistic studies proposed for future evaluation. Nonantibiotic strategies, such as mannosides, curli inhibitors, and FimH antagonists, are also being explored as promising anti-adhesion and biofilm-targeting therapies. This review emphasizes the urgent need for novel, resistance-resilient antibacterial agents and highlights recent chemical and biological innovations that could transform future UTI prevention and therapy.

Supramolecular gels have been developed with flexible network to stabilize species such as flavin mononucleotide hydride with extraordinary short lifetime. In this work, we targeted to stabilize our synthesized radical CP• (chromenopyridine) in the supramolecular gel network. The rigidity aspects of EPR active multicomponent supramolecular gels were addressed. The gels were obtained from the combination of air stable carbon centered radical DCP• (dicyanomethylchromenopyridine) and diverse range of aromatic di-/tri-amine in DMSO and water mixture. During the gel formation, DCP• was converted into another EPR active molecule CP•. Interestingly, poor solubility of CP• restricted its direct use in the gel formation with the same set of amines from the similar DMSO and water mixtures. The rheological properties and morphologies of the gels were completely dependent upon the amine nature and solvent ratio. EPR activities of the rigid supramolecular gels remained stable even after H₂O₂ treatment. In the case of a selective soft gel with benzene-1,3,5-triamine (3), the EPR intensity selectively enhanced after the H₂O₂ treatment, due to the formation of DCPC• formed by reaction of DCPH and in situ formed hydroxyl radical. This radical formation was further validated by the detection of CP-OH adducts from other gel, as confirmed by mass spectrometry.

Metallodrugs with organotin(IV) compounds emerging as a potential alternative to platinum-based drugs have revolutionized the field of both diagnosis and therapy, offering enhanced anticancer efficacy and bio-imaging capabilities for targeting intracellular organelles. In this regard, we embarked on an effort to explore the theranostic potential of a new class of azo hydrazone-based organotin(IV) complexes [Sn^IVL^1-4(Ph)₂] (1-4). The speciation studies suggested the complexes possess exceptional hydrolytic stability. Moreover, the hydrophobic nature of complexes, as determined through partition coefficient measurements, allows their efficient cellular penetration. The cytotoxic potential of 1-4 was evaluated against A549, HT-29, and NIH-3T3 cell lines, revealing that 3 was the most toxic among the series, with an IC₅₀ of 7.8 ± 0.2 µM against A549. Further in-depth mechanistic studies revealed that they preferentially accumulate in the lysosome, damage lysosomal membrane potential, and upregulate intracellular reactive oxygen species (ROS), leading to apoptotic-mediated cancer cell death.

Simple arsine-boranes were explored as precursors to the semiconductor ceramic cubic boron arsenide (BAs). In preparing Ph₂AsHBH₃, spontaneous hydrogen loss was observed to give cyclo-arsine boranes, (Ph₂AsBH₂)_n, and other products. At low temperature, Ph₂AsHBH₃ could be isolated and observed to engage in spontaneous hydrogen to form (Ph₂AsBH₂)_n rings. These rings exhibit dynamic behavior through varying ratios of n = 3 or 4, but n = 5 could be observed and promoted under nonequilibrium conditions. Interestingly, the arsine substrate appears catalyze the decomposition of THF-borane, and simple boranes are catalysts for the dehydrocoupling of Ph₂AsH. However, the most chemically odd observation was the relative lability of As-C bonds under mild conditions. While (Ph₂AsBH₂)_n and Ph₃AsBH₃ are competent substrates for the formation of BAs products under pyrolysis conditions, particularly in air, ceramic yields suffer from from factors including volatility of the substrate under pyrolysis conditions and competitive arsenic oxidation occurred unpredictably. Arsenic chemistry aside, this overall strategy is valid for the production of bulk BAs substrates, though further substrate development is needed.

Porous carbons (YZPCs) with self-doped heteroatoms (oxygen and nitrogen) were successfully prepared from mixed Chinese herbal medicinal residues via a simple KOH activation process under a nitrogen atmosphere. The resulting carbon exhibits a high specific surface area of 3359 m²·g^-1 and a hierarchical pore structure, which together provide abundant active sites for charge storage and facilitate rapid ion transport. Moreover, the substantial pseudocapacitance derived from the self-doped heteroatoms (N: 1.89 at%; O: 16.11 at%) further enhances the overall specific capacitance. The corresponding electrode delivers a specific capacitance of 344 F·g^-1 at 1 A·g^-1, 270 F·g^-1 at 10 A·g^-1, along with excellent cycling stability (96% capacitance retention after 10,000 cycles at 10 A·g^-1). Overall, this study demonstrates the potential of the proposed method as an effective and low-cost approach to fabricate high-performance supercapacitors.

Carbon dots (CDs) have been well due to intrinsic and desirable qualities, such as tunable optical/physicochemical characteristics (like photoluminescence and absorptivity), high photostability, and biocompatibility. These are considered as a reliable alternative to traditional fluorophores for applications in disease diagnosis, early treatment, and healthcare sector. Furthermore, a key advantage of CDs is their ability to undergo surface modification, which allows them to be functionalized with various ligands. Among the ligands, peptides are particularly effective for modifying the CDs surface due to their inherent compatibility and similar characteristics. Peptides are also highly recommended for the surface modification because they are water-soluble and possess excellent biocompatibility. Numerous reports of successfully created CD-peptide nanoconjugates have demonstrated the broad range of applications. This review, elaborates the fundamental properties, characteristics, preparation and synthesis principles of CDs-peptide conjugates. We offer a comprehensive overview of CD-peptide nanoconjugates, detailing their main features and exploring their broad applications in areas like tissue/cell imaging, drug delivery, and sensing. Ultimately, this review serves to give readers a clear understanding of the utility of these developed CD-peptide nanoconjugates in nanoscience.