Bulletin of the Korean Chemical Society最新文献

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.

Metal–organic frameworks (MOFs) offer a versatile platform for integrating photoactive chromophores to enable selective photocatalysis under mild conditions. Here, we report the fabrication of I-BOPHY-functionalized UiO-67 (I-BOPHY@UiO-67) by embedding a newly designed triplet photosensitizer ligand, I-BOPHYPhCOOH, into UiO-67 with tunable ligand defect levels. Comprehensive optical spectroscopy revealed not only strong visible-light absorption but also a highly efficient energy transfer pathway from the MOF's linkers to the anchored (bis(difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine) (BOPHY) photosensitizers. The composites demonstrated exceptional photocatalytic activity in the selective photooxidation of thioanisole to sulfoxide, achieving near-quantitative conversion with no sulfone formation, in stark contrast to pristine UiO-67 which showed negligible activity. These results establish the critical role of the I-BOPHY ligand in driving triplet-sensitized photocatalysis via an antenna effect and highlight MOF-based architectures as promising platforms for green oxidative transformations.

Metal–organic macrocycles (MOCs) designed by the self-assembly process contribute to an interesting field of research representing various important applications in different branches of chemistry and material sciences. The roles of metal sources as well as the participating ligands are significant as they impart the overall properties to the final self-assembled products. The use of fluorescent materials, as building blocks/ligands, in the synthesis of MOCs is very advantageous for biomedical, light harvesting, photocatalysis, and several other important applications. This review brings together some of the recent important biological developments achieved with fluorescent MOCs. More precisely, we focused on the biological applications of MOCs designed by the self-assembly process from BODIPY (boron dipyrromethene) and Porphyrin-functionalized chromophores.

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.

In biological systems, steric hindrance plays a critical role in supramolecular assembly by controlling intermolecular packing, interaction geometry, and the resulting structural specificity. Accordingly, introducing small substituents on ligands provides an artificial model to finely regulate the helicity and assembly pathway of supramolecular polymers. In this study, we report the self-assembly behavior of a terpyridine-based Pt(II) complex, R-Pt-Ph-C3, bearing a propylphenylacetylene ligand. Remarkably, R-Pt-Ph-C3 forms right- or left-handed helical supramolecular architectures in mixed DMSO/H₂O media, with the handedness being solvent-composition dependent. The self-assembled structures exhibit intense photoluminescence at 570–620 nm, arising from metal-to-ligand charge transfer (MLCT) and/or metal–metal-to-ligand charge transfer (MMLCT) transitions. Circular dichroism (CD) analysis revealed opposite Cotton effects in DMSO/H₂O (6:4, v/v) versus (4:6, v/v), indicating solvent-controlled inversion of supramolecular helicity. Spectroscopic (UV–vis, CD, FT-IR, ¹H NMR) analyses demonstrated that assembly is driven by π–π stacking, intermolecular hydrogen bonding, and Pt···Pt interactions. Variable-temperature UV–vis studies and curve fitting using the equilibrium (EQ) model revealed that the assemblies follow either an isodesmic or cooperative nucleation–elongation growth mechanism, depending on solvent composition. The DMSO/H₂O (6:4, v/v) system exhibited lower thermodynamic stability (ΔGₑ = −23.3 kJ·mol⁻¹) consistent with isodesmic growth, whereas the (4:6, v/v) system showed higher stability (ΔGₑ = −27.0 kJ·mol⁻¹) and strong cooperativity (σ = 4.7 × 10⁻⁴). These findings highlight the ability to control supramolecular helicity, morphology, and growth mechanism of Pt(II)-based assemblies through subtle changes in solvent environment.

Nine new Zintl phase thermoelectric (TE) materials in the Ca_3−xSr_xAl_1−YZn_YSb₃ (0 ≤ x ≤ 1.55(4); 0 ≤ Y ≤ 0.06(1)) system were successfully synthesized by arc-melting and the Pb-flux methods. All the title compounds adopted the orthorhombic Ca₃AlAs₃-type phase (space group Pnma, Pearson code oP28), where three distinct cationic sites and one tetrahedral anionic site exhibited the mixed occupancies of Ca/Sr and Al/Zn. Interestingly, the Sr-substituent preferred to fill the largest M2 site, then the M3 site, reaching the M1 site only at higher overall loading, which was consistent with the ionic size-factor criterion. A series of DFT calculations by the TB-LMTOASA method on the three model structures: Ca₃AlSb₃, Ca_1.5Sr_1.5AlSb₃, and Ca_1.5Sr_1.5Al_0.75Zn_0.25Sb₃, indicated (1) the Sr substitution widened the small bandgap, (2) the Zn substitution pushed E_F through the valence-band region yielding p-type character while maintaining a narrow direct gap at Γ, and (3) the valence-band flattening between Γ and Z, and T and Y increased effective mass. Optical reflectance study using the Kubelka–Munk function gave the bandgap of 0.28 and 0.30 eV for Ca₃AlSb₃ and Ca_2.00(3)Sr_1.00AlSb₃, respectively, which corroborated the calculated results. TE property measurements showed an increase of electrical conductivity σ with temperature and the positive Seebeck coefficients S between 303 and 850 K. Atomic disordering through the Sr and Zn substitutions strongly suppressed total thermal conductivity κ_tot down to 0.46 W/mK at 873 K for Ca_2.48(2)Sr_0.52AlSb₃. The maximum ZT value was obtained for the Zn-doped Ca₃Al_0.96(1)Zn_0.04Sb₃, and this enhanced result should be attributed to the synergy of enhanced σ, moderated S, and reduced κ_tot.

We developed a novel synthetic route to belumosudil featuring an oxidative cyclization of anthranilamide with meta-substituted benzaldehyde as the key step for constructing the quinazolinone scaffold. Alkylation of 3-hydroxybenzaldehyde with 2-chloroacetamide furnished a benzaldehyde derivative bearing the desired meta-substituent. Subsequent metal-free aerobic oxidative cyclization of anthranilamide and the aldehyde in DMSO afforded the desired quinazolinone. Treatment with POCl₃ converted the quinazolinone intermediate into the corresponding quinazolinyl chloride, which was then coupled with 5-aminoindazole to complete the synthesis of belumosudil.

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.

The porous Ag⁺ ionic conductor was acheived by incoporating silver iodide (AgI) nanoparticles (NPs) in two dimensional Ti-dobdc MOF. AgI, known for its polymorphs, exhbits superionic conductivity (>1 S cm⁻¹) in the α-phase above 147°C and undergoes phase transition into poorly conducting β/γ-phase below 147°C. Here, we demonstrate the tuning of AgI phase transition temperature through the encapsulation of various molar ratios AgI NPs into Ti-dobdc MOF. The confinement effect of the MOF stabilizes AgI NPs while its intrinsic porosity and pore surface functionalization by free oxygen atoms facilitate ion diffusion. Among the composites, AgI_2.00@Ti-dobdc indicated thermal hysteresis of Δ142.8°C which is 8°C wider than pristine AgI NPs (Δ135.8°C), and AgI_0.75@Ti-dobdc exhibited the highest ionic conductivity at 180°C of 2.15 × 10⁻⁴ S cm⁻¹—over 6 orders of magnitude higher than pristine Ti-dobdc. These results demonstrate that phase transition temperature tuning by confinement effect within porous frameworks can simultaneously expand the thermal operating window and provide a strategy for designing the porous Ag⁺ ionic conductor.