Bulletin of the Korean Chemical Society最新文献

The cover illustration shows the solvent-dependent amphiphilic assembly of Pluronic® F127 in ethanol and water. In ethanol, F127 forms reversed micelle-like structures with a PEO core and PPO corona, whereas in water, conventional micelles are formed with a PPO core and PEO corona. This structural difference of F127 assemblies leads to polyphenol-induced aggregation of F127 assemblies specifically in ethanol, highlighting the solvent-driven tunability of polymer-polyphenol interactions. Details are in the article by Woongrak Choi, Eunu Kim, Helen H. Ju, Haeshin Lee.

We report transparent and soluble poly(amide-imide)s with high glass transition temperature (T_g) synthesized from alicyclic diacid monomer containing trifluoromethyl groups. The good solubility of the polymers in polar aprotic solvents allows solvent casting of transparent polymer films having good transparency. We found that the alicyclic units, together with trifluoromethyl groups, between imide and amide bonds in the polymer main chains were critical for improving the optical properties of aromatic polymers. The transparent films exhibit good thermal properties, even with alicyclic units, due to hydrogen bonding along the main chain.

Alzheimer's disease (AD) is a complex neurodegenerative disorder marked by progressive cognitive decline and neuronal loss. A key pathological hallmark of AD is the accumulation and aberrant aggregation of amyloid-β (Aβ) peptides, which contributes to synaptic dysfunction and neurotoxicity. While the aggregation behavior of Aβ has been extensively studied, it can be altered by various factors, particularly metal ions, such as Fe(II/III), Cu(I/II), and Zn(II). These metal ions directly interact with specific amino acid residues in Aβ, influencing its oligomerization, fibrillization, and capacity to generate reactive oxygen species, thereby exacerbating oxidative stress and accelerating disease progression. Understanding the coordination chemistry between metal ions and Aβ is critical for deciphering their pathological impact in AD. This review provides a comprehensive overview of metal-bound Aβ (metal–Aβ) coordination at the molecular level, with a focus on insights gained from advanced spectroscopic methods. Nuclear magnetic resonance, electron paramagnetic resonance, and x-ray absorption spectroscopies collectively illuminate metal-binding sites, coordination geometries, and dynamic structural behavior of metal–Aβ complexes. These complementary approaches enable detailed structural characterization and mechanistic understanding of metal-induced Aβ aggregation and toxicity. By integrating spectroscopic findings on Fe(II/III), Cu(I/II), and Zn(II) coordination to Aβ, we highlight their distinct roles in AD pathogenesis as well as the broader significance of metal–peptide interactions underlying the mechanisms of neurodegenerative diseases.

The transition metal dichalcogenides (TMDs) are an important class of two-dimensional materials due to their tunable band gap, high carrier mobility, and adjustable carrier concentration. Owing to these advantages, TMD can be utilized in a wide range of applications. In this work, we discuss the role of TMDs and their modifications on semiconductor materials for photocatalytic activity studies. Several modification strategies of MoS₂ have been explored to enhance its photocatalytic activity. These include: (i) deposition of few-layered MoS₂ on CdS to increase surface-active site density (FMC), (ii) activating basal plane sites in addition to edge sites via Cu doping (Cu-FMC), and (iii) coupling with conductive reduced graphene oxide to facilitate charge transport while retaining catalytic edge sites (RGO-FMC). Comparative photocatalytic studies under solar light irradiation with lactic acid as a hole scavenger reveal that Cu doping enhances the intrinsic activity of MoS₂, while reduced graphene oxide suppresses electron–hole recombination, and their combined structural modifications significantly boost hydrogen evolution performance, providing valuable insights into the rational design of transition metal sulfide-based heterostructures for solar fuel production.

Polyketide synthases (PKSs) are large, highly orchestrated enzymatic assemblies that produce a wide array of biologically active compounds with antibiotic, anticancer, and immunosuppressive properties. In particular, modular PKSs (mPKSs) are composed of multiple catalytic domains arranged in an assembly-line fashion, typically encoded within gene clusters dedicated to polyketide biosynthesis. Recent advances in cryo-electron microscopy have enabled high-resolution structural characterization of diverse mPKSs, providing crucial insights into their molecular mechanisms and supporting structure-guided engineering efforts. In this review, we introduce the individual domain structures and the overall domain architectures of mPKSs as revealed by recent structural studies. Despite the high conservation of individual domains, comparative analyses uncover unexpected variability in the overall architecture of PKS megasynthases, offering explanations for the limitations of earlier engineering attempts and suggesting strategies for more effective metabolic reprogramming.

The cover image illustrates a security checkpoint symbolizing metal-organic framework(MOF)-based colorimetric sensors. Various MOF sensors with carefully engineered properties selectively response to their targeted analytes, by means of color changes. The colorimetric responses of the sensors enable facile and intuitive detection of selected chemical species. Details on the role of MOFs in the sensing mechanisms are available in the review article by Solmin Lee, Hyejin Yoo, and Jin Yeong Kim.

Photocatalysis provides a promising and sustainable pathway for converting solar energy into chemical fuels, particularly via the hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CO₂RR). The integration of metal cocatalysts with semiconductor photocatalysts offers an effective strategy to enhance three fundamental steps of photocatalysis: light absorption, charge separation, and surface reactions. In this review, we present a comprehensive overview of cocatalyst deposition techniques and engineering strategies, with emphasis on five key parameters—chemical composition, size, morphology, loading density, and spatial distribution. We discuss their individual effects and synergistic roles in governing photocatalytic performance for HER and CO₂RR. In addition, we highlight recent progress in the use of in situ characterization techniques, which provide critical insights into dynamic structural and chemical changes of cocatalyst–semiconductor systems under operating conditions. Finally, we outline the remaining challenges—such as long-term stability, scalable synthesis, and mechanistic understanding—and suggest that future advances will be accelerated by integrating in situ techniques with computational approaches and machine learning. This review aims to guide the rational design of next-generation cocatalyst–semiconductor photocatalysts for efficient solar-to-chemical energy conversion.

Gallium-based liquid metals (LMs) are emerging as versatile functional materials for next-generation stretchable, wearable, and bio-integrated electronics. Their combined attributes of metallic conductivity, mechanical softness, and room temperature fluidity allow for applications beyond the limitations of conventional rigid conductors. However, despite their promise, intrinsic challenges such as high surface tension, uncontrolled wetting, and poor substrate adhesion remain major obstacles to their practical utilization. Recent advances in LM micro-patterning strategies—including surface energy modulation, chemical treatment, metal adhesion layering, and electrochemical control—have substantially improved printing resolution and device integration. Simultaneously, the development of LM particle composites with tunable rheological and thermal properties has enabled the scalable fabrication of soft electromagnetic interference shielding films and Joule heating devices. LM functionality has been further extended by bio-inspired applications that integrate patterning strategies with neuromorphic electronics, as demonstrated by artificial synaptic interfaces and electrochemically actuated soft robotics. Bridging the intrinsic fluidity of LMs with electronic functionality establishes a pathway toward reconfigurable, adaptive, and human-compatible systems. Despite the remaining challenges, future research directions highlight the potential of gallium-based LMs as a central platform for intelligent, closed-loop soft electronics.

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.