Bulletin of the Korean Chemical Society最新文献

Pluronic® F127 (Poloxamer 407) is a thermoresponsive triblock copolymer widely used for drug delivery and templating for porous materials, owing to its temperature-dependent micellization and gelation in aqueous systems. While its self-assembly behavior in water-rich or low-ethanol cosolvents (≤30%) is well established, the molecular behavior of F127 in near-anhydrous ethanol (90%–100%) remains largely unexplored. Here, we report a reversed self-assembly mechanism governed by the solubility and crystallinity of the hydrophilic poly(ethylene oxide) (PEO) blocks, rather than the hydrophobic PPO segments that drive micellization in water. F127 remains molecularly dissolved up to ~95% ethanol but undergoes precipitation above this threshold due to collapse of the dehydrated PEO chains. Upon heating, the precipitates reversibly dissolve through melting of PEO crystalline domains, a process confirmed by turbidity and dynamic light scattering analyses. Additionally, tannic acid (TA)—known to strongly hydrogen bond with PEO—modulates the precipitation and re-dissolution kinetics. These findings highlight a fundamentally distinct assembly mechanism of F127 in ethanol-rich environments, where solvent polarity and segmental solvation dominate. This study not only provides critical insight into the thermoresponsive behavior of amphiphilic polymers in poor solvents but also expands the potential utility of F127 in ethanol-dominant drug formulations and soft-material systems, particularly where aqueous conditions are undesirable.

We have prepared racemates of two new chiral keto[3,3]paracyclophanes and one keto[3,3]metacyclophane by irradiation of the corresponding phenacyl benzoates tethered with a phenol moiety via conformational preorganization enabled by intramolecular charge transfer complex. Their structural properties have been analyzed by X-ray crystallography. The photochemistry of the new cyclophanes has also been examined, in which the beta CO bond cleavage is the major reaction pathway.

The cover image illustrates the electrochemical cell in water-in-salt electrolytes (WISE), highlighting recent advances on redox electrolyte reactions under WISEs. By altering solvation structures, WISEs extend the electrochemical stability window and reshape the behavior of hydrogen/oxygen evolution, metal electrodeposition, halides, ferro/ferricyanide, and organic redox species (TEMPO, quinone, pyrazine). The review emphasizes how solvation-structure engineering governs stability, reversibility, and degradation. Details are in the article by Jaeyoung Lee, Jinho Chang.

Proteases play essential roles in both physiological and pathological processes, driving the need for sensitive and specific detection methods. Among these, electrochemical detection strategies based on proteolytic cleavage have emerged as powerful tools thanks to their high sensitivity, rapid response, and suitability for point-of-care applications. In this review, we classify electrochemical protease detection strategies into heterogeneous and homogeneous formats, and further organize them by signal-transduction modes such as signal-on, signal-off, and impedance-based assays. Heterogeneous formats utilize proteolytic cleavage at electrode surfaces, using protein, hydrogel, or peptide layers, which are particularly effective for endopeptidases. Homogeneous formats, by contrast, rely on proteolytic cleavage in solution and are suitable for detecting both endopeptidases and exopeptidases. We also examine substrate-design principles tailored to each protease class, and compare the strengths and limitations of each detection format. Despite significant progress, electrochemical detection of low-abundance protease biomarkers with high specificity remains a challenge. Future efforts should focus on improving sensitivity and selectivity via advanced electrode architectures, redox-cycling amplification, and rational substrate design. The continued development and integration of these technologies promise impactful applications in point-of-care diagnostics, environmental monitoring, and biomedical research.

Understanding plasmon-mediated electrocatalytic activity enhancement in single gold nanorods (AuNRs) is still limited. Herein, we present the formation of copper (Cu) layers on individual AuNRs immobilized on an ITO substrate as a function of potential and their effect on the localized surface plasmon resonance (LSPR) property of individual AuNRs by in situ monitoring of LSPR spectral changes in AuNRs via dark-field scattering microscopy and spectroscopy. The Cu adlayer formation on AuNR within the under potential deposition range increases the free electron density of Cu@AuNR, which affects the LSPR spectrum, leading to increased peak intensity and a blueshift. The overpotential deposition resulted in the formation of bulky Cu deposits and an increase in the size of individual AuNRs, leading to an additional Cu LSPR peak at higher energy levels, in addition to the peak for Au. The high electron density donated by Cu to Au facilitated the generation of energetic hot electrons at the tip of Cu@AuNR particles, thereby enhancing electrocatalytic activity, as confirmed through the electrocatalytic reduction of 4-nitrophenol to 4-aminophenol in the single-particle system.

Two-step sequential deposition has gained attention as a scalable and reproducible method for fabricating high-efficiency perovskite solar cells (PSCs). Unlike one-step methods, this approach allows better control over crystallization kinetics and layer-by-layer conversion. However, critical issues such as incomplete conversion of PbI₂ into the perovskites, formation of buried interface defects, poor film uniformity, and residual lattice strain still limit device performance and long-term stability. To address these challenges, recent research has focused on additive engineering as a versatile and effective solution for two-step fabricated PSC and has enabled a rapid increase in device performance. This review discusses key additive strategies causing several positive effects to enhance both efficiencies and stabilities of PSCs: (1) inducing porous and disordered PbI₂ structures to promote the diffusion of organic halide salts and enable complete conversion into the perovskites, (2) controlling facet orientation to improve charge transport and moisture stability, (3) buried interface passivation to eliminate voids and defects of the hidden surface, and (4) strain engineering to relieve strain stress during the formation of the perovskite layer. Taken together, this additive engineering has enabled PSCs fabricated via two-step deposition to reach power conversion efficiencies exceeding 26%, while also enhancing environmental stability. This review provides a clear look at how specific additive chemistry can control crystal growth, improve interface quality, and control lattice strain, giving straightforward guidelines for designing the next generation of two-step fabricated PSCs.

Driven by the compelling environmental and economic advantages of chemical upcycling of waste plastics, there is a growing push to develop highly efficient catalytic systems. These systems promise access to a wide spectrum of valuable chemical feedstocks, moving beyond the simple monomers obtained via traditional plastic recycling. This review specifically examines transition-metal-catalyzed hydrogenation, dehydrogenation, and transfer hydrogenation of depolymerized monomers derived from polyesters, polycarbonates, polyamides, and polyethylene. A key insight is the profound influence of ligands: multidentate coordination by phosphines, amines, pyridines, and carbenes provides distinct electronic and steric effects, which are instrumental in achieving the desired product formation.

Metal–organic frameworks (MOFs) have emerged as promising platforms for colorimetric sensing due to their tunable structures, high porosity, and ability to support diverse optical responses. Among various sensing technologies, colorimetric sensing stands out for its simplicity, cost-effectiveness, and visual interpretability, making it especially suitable for point-of-need applications. This review highlights recent advances in MOF-based colorimetric sensors, with a particular focus on the mechanisms by which analyte-induced signals are transduced into visible color changes. We classify these sensing systems into three mechanistic categories: (i) direct chromogenic responses arising from interactions between analytes and intrinsic or modified MOF components; (ii) structural or refractive index changes in the MOF framework itself; and (iii) MOF-mediated external chromogenic reactions, in which the MOF acts as a catalyst or host. Representative examples for each category are discussed, along with data acquisition methods and strategies for signal analysis. By emphasizing the mechanistic underpinnings of color generation, this review aims to provide a framework for the rational design of MOF-based sensors. Key challenges and future opportunities are also discussed, including enhancing selectivity, environmental robustness, and single-sensor multiplexing capabilities.

Hypochlorite ion (ClO⁻) plays a critical role in sterilization processes within biological and environmental aqueous systems, but its excessive levels can lead to harmful oxidative reactions associated with various human diseases. In this study, we present Naph-HOCl, a novel water-soluble naphthalimide–thiomorpholine derivative, as a turn-on fluorescent probe for the selective and sensitive detection of ClO⁻. Upon exposure to ClO⁻, the probe exhibits a rapid fluorescence enhancement at 563 nm, demonstrating excellent selectivity over other reactive oxygen species, biothiols, and common ions. The probe demonstrates a low detection limit of 287 nM and a high signal-to-noise ratio (s/n) of 42, indicating strong potential for analytical monitoring of ClO⁻. The exploration of its applicability in real sample analysis will be carried out in future studies.

This study demonstrates the exceptional peroxidase-mimicking activity of a novel Cu-based metal–organic framework (MOF) catalyst and its effectiveness for the colorimetric detection of phenol and hydrogen peroxide (H₂O₂) in water samples. The Cu-MOF catalyst leverages the synergistic Cu²⁺/Cu⁺ interface to achieve a remarkable peroxidase activity, wherein the Cu ions significantly promote the adsorption of 3,3′,5,5′-tetramethyl benzidine (TMB), activate H₂O₂, and facilitate the generation of free hydroxyl radicals (^•OH). Kinetic analysis revealed that the Cu-MOF exhibited a superior catalytic performance compared to traditional catalysts such as horseradish peroxidase. The Michaelis–Menten constants (K_m) for H₂O₂ and TMB were determined to be 0.032 and 0.225 mM, respectively, while the maximum reaction rates (V_max) were 3.10 × 10⁻⁷ M·s⁻¹ for H₂O₂ and 1.16 × 10⁻⁷ M·s⁻¹ for phenol. Additionally, detection limits of 0.13 and 0.07 μM were determined for H₂O₂ and phenol, respectively. These findings underscore the significant potential of Cu-MOFs in peroxidase-like catalysis, particularly for the sensitive detection of phenol and H₂O₂, and suggest the broad applicability of such materials in various catalytic and analytical domains.