Chemistry - An Asian Journal最新文献

This work reports one Ru(bpy)₃²⁺-N,N-dibutylethanolamine (DBAE) coreactant-sodium dodecyl sulfate (SDS) enhancer system on an automated electrochemiluminescence immunoassay (ECLIA) analyzer for the ECL immunoassay of carbohydrate antigen 19-9 (CA19-9). The ECL intensity of the MB@SA•biotin-GSK-Ru1 bio-conjugates in DBAE solution on the automated ECLIA analyzer, which employs a platinum working electrode under the “Heterogeneous” model, demonstrates a 333% enhancement in comparison with that of the conventional tri-n-propylamine coreactant. Subsequently, the developed novel DBAE coreactant-based automated ECL method was estimated by the determination of CA19-9, while the MB@SA•biotin-Ab1 was taken as the capture probe and the Ru(bpy)₃²⁺ derivative-labeled CA19-9 antibody (Ab2-Ru1) was employed as signal probe. In the presence of the SDS enhancer, the relative ECL intensity of the formed “sandwich” MB@SA•biotin-Ab1/CA19-9/Ab2-Ru1 biocomplexes exhibits a 4.3-fold enhancement on the automated ECLIA analyzer. Notably, under the optimized conditions, the increased ECL intensity was directly in proportion to the concentration of CA19-9 in the range from 0.5 to 8.0 U/mL with a limit of detection of 0.25 U/mL. This approach has the potential to be extended to magnetic bead-based automated ECL methods for the sensitive detection of clinical protein biomarkers.

Although bimetallic heterogeneous catalysts are widely used in several industries, understanding the active components at the atomic and molecular levels and their intricate structure is quite challenging. Through the analysis of various bimetallic systems, their differing structural properties, along with catalytic efficiencies, an understanding of the structure–reactivity relationships for heterogeneous bimetallic catalysts can be developed which can be utilized to enhance catalyst technology. This review will focus on the geometric and electronic structures of the three representative types of bimetallic catalysts (bimetallic binuclear sites, bimetallic nanoclusters, and nanoparticles) while providing details of their synthesis routes and characterization methods that have been achieved over the last decade. The roles of catalysis for supported bimetallic binuclear sites, bimetallic nanoclusters, and nanoparticles in a number of significant reactions will be presented. Finally, the gaps in research with an emphasis on supported bimetallic catalysts will be discussed along with broader expectations on the next advances in heterogeneous catalysis from a fundamental and applicative point of view. Bimetallic nanoparticles (NPs) are changing catalysis by combining two metals to create effects that are better than those of systems with only one metal.

The present work documents organophotocatalytic transformation of N-phosphorylated arylhydrazones into indazoles. The strategy relies on the visible light-mediated generation of N-centered radical intermediate. The reaction employs organic dye as a photocatalyst and air as a terminal oxidant. The mild conditions, operational simplicity and fairly general scope are the notable attributes of the methodology.

The ongoing quest for developing new chromophores or fluorophores capable of detecting heavy metal ions and explosive nitroaromatic compounds remains a critical challenge. Higher rylene dyes, particularly terrylene and its structural derivatives are renowned for their exceptional photophysical properties, characterized by remarkably high molar extinction coefficient and fluorescence emission. Inspired by the distinct photophysical characteristics of terrylene, herein, for the first time, we synthesized a novel pyridine-substituted terrylene small molecule (TERPy), which emerged as a highly selective probe for colorimetric and fluorometric sensing of mercuric ion (Hg²⁺) and nitroaromatic explosives like 2,4,6-trinitrophenol (TNP). TERPy exhibited an impressive limit of detection (LOD) at 140 nM with an exceptionally high binding constant (logK = 11.4), indicating remarkable sensitivity and strong molecular interaction with Hg²⁺. Morphological evolution upon addition of Hg²⁺ indicated a successful complex formation between TERPy and Hg²⁺. Moreover, a reversible unbinding of Hg²⁺ from the complex by EDTA in both solution and solid-state enables their future optoelectronic device applications. Additionally, TERPy displayed remarkable selectivity for TNP, achieving a detection limit of 360 nM and demonstrated strong molecular affinity with a high binding constant (logK) of 0.92, reflecting excellent analytical performance.

We report the synthesis and catalytic evaluation of new Ru(II)-protic-NHC complexes featuring β-NH groups with either γ-NH (Ru8) or γ-NMe (Ru9) substituents. These compounds, along with previously reported Ru(II)-protic-NHC and their classical NHC analogues (Ru1–Ru7), provide a platform for systematically probing the influence of β- and γ-substituents on formic acid dehydrogenation (FADH). All complexes exhibited notable catalytic activity under both base-assisted, solvent-free conditions and in the ionic liquid 1-butyl-3-methylimidazolium acetate (BMIMOAc) without an external base. Among them, Ru1 excelled in the ionic liquid medium, achieving a remarkable turnover number (TON) of 65,000 and turnover frequency (TOF) of 4300 h⁻¹ over 15 consecutive formic acid addition cycles. Mechanistic investigations, supported by NMR and control experiments, reveal that under base-assisted conditions, catalysis proceeds via a protic-NHC pathway, whereas in ionic-liquid mediated FADH, anionic-NHC intermediates dominate. Furthermore, the evolved H₂/CO₂ mixture was successfully applied for the hydrogenation of alkenes, and CO₂ capture experiments confirmed the selective utilization of the generated gases. The presence of a β-NH moiety enhances the catalytic activity relative to its N-methylated analogue, suggesting a favorable role in facilitating the reaction pathway, whereas the γ-NH functionality exerts a detrimental effect compared to its corresponding γ-N-alkyl and γ-N-aryl substituted derivatives.

Thermally activated delayed fluorescence (TADF) materials hold the key to next-generation optoelectronics by converting both singlet and triplet excitons into light via rapid reverse intersystem crossing (RISC). However, designing chromophores that simultaneously feature a small singlet-triplet gap (ΔE_ST), strong charge-transfer (CT) character, and high photoluminescence efficiency remains elusive, as conventional donor–acceptor scaffolds suffer from nonradiative losses. Here, we harness through-space charge transfer (TSCT) architectures, which spatially separate donor and acceptor units to suppress vibrational quenching and boost RISC, to overcome this trade-off. We pair an N-(4-methylphenyl)-1,8-naphthalimide acceptor with a suite of heteroatom-modified 9,9-dimethyl-9,10-dihydroacridine donors (D–A), including a dual-donor (D–A–D) analogue, and systematically tune electronic coupling and molecular rigidity. To evaluate the photophysical implications of these structural modifications, we performed quantum-chemical analyses of ground and excited-state parameters (S₁, T₁, ΔE_ST, ΔE_HL), along with natural transition orbital and energy decomposition studies to probe the nature of electronic transitions. Spin-orbit coupling constants and ISC/RISC rate estimates were calculated to assess the excited-state mechanism, while electron-hole correlation metrics quantified the extent of charge separation. Together, these descriptors offer a comprehensive understanding of how donor identity, spatial arrangement, and conjugation control TADF behavior.

Herein, we report the first total synthesis of the conjugation-ready tetrasaccharide repeating units of Pseudomonas aeruginosa (Lányi) O11. The all-6-deoxy-sugars containing tetrasaccharides were synthesized using an efficient convergent methodology employing a (2 + 2) glycosylation strategy. A key to this approach is utilizing a common disaccharide donor, which streamlines the assembly of both the tetrasaccharides by minimizing protecting group manipulations and enhancing overall efficiency. The disaccharide donor was synthesized through a highly chemoselective activation of a meticulously designed reactive thioglycoside donor, allowing for precise control over stereochemistry and regioselectivity during the glycosylation.

One of the most important sources of chemical hydrogen, Ammonia-Borane (AB), contributes greatly to the advancement of the Hydrogen Economy. The real challenge lies in addressing its sluggish kinetics and thermodynamics in terms of its dehydrogenation or the formation of molecular H₂ employing catalysis. Although it has been a decade-long enigma, the quest for an appropriate catalyst that can enable the utilization of AB in a more pragmatic way, such as its mass commercialization in society, is still ongoing. In this regard, there have been many contributions in terms of molecular catalysis towards AB dehydrogenation, encompassing both metal and metal-free compounds as efficient catalysts. Herein, we have focused on some of the transition metal-based complexes as homogeneous catalysts for AB dehydrogenation that have been known for paving the way for synthesizing, modeling, and investigating better complexes of this kind, showing improved functionality and efficacy towards the release of molecular H₂ from AB.

We report a reversible dehydrogenation–hydrogenation of cyclohexanol–cyclohexanone pair over Ru supported on Hierarchical Zeolite (Ru/HZ4A) under neat conditions. The catalyst Ru/HZ4A demonstrated high activity for both dehydrogenation of cyclohexanol to cyclohexanone (at 160°C) and hydrogenation of cyclohexanone back to cyclohexanol (60°C) with appreciably high selectivity and conversion. Moreover, the catalyst Ru/HZ4A displayed high durability under bulk and recyclability experiments, achieving hydrogen productivity as high as 156 L_H2/g_Ru (STY 89 mmol_H2/g_Ru/h). The developed protocol was also applied to 5-membered and 8-membered cycloalkanol–cycloalkanone pairs with excellent selectivity for a one-pot reversible dehydrogenation–hydrogenation cycle. These findings underscore the potential of the developed catalytic system for a reversible hydrogen storage system.