Bulletin of the Korean Chemical Society最新文献

This study introduces a novel hybrid catalyst synthesized by electrostatically assembling porous layered double hydroxides (P-LDH) and bovine-serum-albumin (BSA)-stabilized Au nanoclusters (BSA(Au)). Although protein-capped Au nanoclusters demonstrate excellent catalytic potential, considerable BSA aggregation hinders the practical application of BSA(Au). P-LDH's positively charged, porous structure prevents such aggregation, enhancing stability and catalytic efficiency in NaBH₄-mediated p-nitrophenol hydrogenation. Structural analysis confirms uniform BSA(Au) decoration onto P-LDH without disrupting LDH's framework. The catalyst maintains activity over multiple reaction cycles, demonstrating potential for green and sustainable chemistry.

Metal–organic frameworks (MOFs) have gained significant attention for their antimicrobial properties due to their structural versatility and functional tunability. In this study, two Zn-MOFs, namely, 1-bpe and 2-AZPY, were synthesized using bpe and AZPY ligands, respectively, via solvothermal reactions. These MOFs were systematically evaluated for their antifungal activities against C. cladosporioides, A. niger, and C. albicans. Structural characterization confirmed both MOFs as two-fold interpenetrated frameworks with thermal stability up to 300 °C. Antifungal tests demonstrated that 2-AZPY exhibited superior antifungal efficacy compared to 1-bpe. At a concentration of 2 mg/mL, 2-AZPY achieved 95% inactivation of A. niger and 61% inactivation of C. cladosporioides, while 1-bpe showed relatively weaker antifungal performance. The enhanced antifungal activity of 2-AZPY is attributed to the release of AZPY ligands, which promote thiol oxidation in fungal proteins, leading to cellular inactivation. Further improvement was achieved by incorporating 2-AZPY into a polyvinyl alcohol (PVA) nanofiber matrix, forming 2-AZPY@PVA. This composite significantly enhanced antifungal performance, achieving nearly complete inactivation of all tested fungal species. These findings underscore the potential of AZPY-functionalized MOFs for targeted antifungal applications, particularly when integrated into nanofiber materials for enhanced bioavailability and stability. The results highlight the promising role of MOFs in developing effective antifungal agents for environmental and medical applications.

The catalytic synthesis of chiral azaarenes has become a focal point of research due to their signifi`1cant applications across various fields, including medicinal chemistry and materials science. α-Azaaryl carbonyl compounds, featuring both an electron-withdrawing C=N moiety within an azaarene core and a carbonyl functional group, have proven to be versatile precursors in the synthesis of stereochemically intricate azaaryl molecules. In particular, the generation of chiral α-azaaryl enolate intermediates, catalyzed by chiral Lewis acids, has enabled the precise construction of α-stereogenic chiral azaarenes. This review explores recent advances in the stereodivergent transformations of α-azaaryl carbonyl derivatives with an array of carbon electrophiles, emphasizing the efficiency of catalytic systems involving chiral copper Lewis acids combined with Ir, Pd, Ni, amine, or Ru catalysts. These strategies offer precise control over the stereochemical outcome, facilitating access to all stereoisomers of multi-stereogenic chiral azaarenes. Additionally, we discuss a sequence-dependent approach that allows for controlled stereodivergence in reactions with α-azaaryl carbonyl derivatives. Through a detailed exploration of recent advancements, mechanistic insights, and practical applications, this review underscores the potential of stereodivergent catalytic reactions to unlock new avenues in the synthesis of azaaryl compounds. By presenting diverse strategies and expanding opportunities for controlling stereochemistry, it fosters further development in the design of structurally and stereochemically complex azaarene-based frameworks.

Dynamic protein–protein interactions are essential for diverse cellular processes but often evade structural characterization due to their transient, heterogeneous, and disordered nature. This review focuses on how nuclear magnetic resonance (NMR) spectroscopy can provide detailed, residue-level insights into these complex interactions. By categorizing dynamic interactions into three distinct yet interconnected classes—(1) interactions with multiple binding interfaces, (2) interactions retaining disorder, and (3) interactions that stabilize or induce disorder—we provide a framework for interpreting diverse interaction modes. Through representative case studies, we highlight the value of NMR in decoding dynamic interactions, where disorder and flexibility persist even in high-affinity complexes.

Recent advances in photocatalytic organic transformations have enabled new bond formations that are otherwise challenging under thermal reaction conditions. Among these, significant progress has been achieved especially in amination reactions by harnessing the reactivity of nitrogen-centered radicals or organic nitrene species, generated from various prefunctionalized amino group precursors, through photoinduced single-electron transfer (SET) or triplet–triplet energy transfer (TTEnT). Although plausible mechanisms leading to the reactive nitrogen-centered intermediate have been proposed, a detailed depiction of the electron flow during the photoinduced process would be highly intriguing. In this study, we employed computational intrinsic bond orbital (IBO) analysis to illustrate the electron relocations during the activation of several types of aminating precursors into nitrogen-centered radicals or organic nitrenes. Our quantum chemical investigations provide critical mechanistic insights into the nitrogen-centered reactive intermediate formation, offering foundations for designing photocatalytic amination strategies.

Mosses are known for their rich diversity in bioactive compounds and their essential role in maintaining ecosystems. While genetic and metabolomics studies have been conducted on some model species, research on comprehensive metabolomics of common mosses in East Asia remains limited. In this study, we conducted an untargeted analysis of three East Asian moss species, Niphotrichum japonicum, Calohypnum plumiforme, and Polytrichum formosum, by ultrasonic-assisted extraction and liquid chromatography coupled with high-resolution mass spectrometry. This approach facilitated the detailed profiling and compound classification through reference databases. Tandem mass spectrometry with positive mode tentatively identified 188, 183, and 186 metabolites, respectively, with lipids and terpenoids as the predominant class. Among these, 25 potential biomarkers were identified to differentiate between species. Multivariate analysis, including principal component analysis, revealed distinct metabolic profiles for each species, representing taxonomical differences, confirming data reproducibility, and clear species differentiation. Enrichment analysis further highlighted the upregulation of unsaturated fatty acid biosynthesis across all moss species. This is the first report utilizing an untargeted metabolomics approach with chemometrics to differentiate moss species cultivated in the same location, offering a new foundation for studying the metabolic responses of East Asian mosses.

The cover illustration depicts the schematic structure and applciation of femtosecond mid-infrared spectroscopy. This technique provides powerful insights into intra- and intermolecular interactions within molecular systems covering from Li ion batteries to protein aggregation. For a detailed discussion on state-of-the-art femtosecond mid-infrared spectroscopy, refer to the article by Joongwon Shim et al.

BL2D-SMC is a bending magnet beamline dedicated to chemical crystallography at the 3 GeV PLS-II in Korea. The beamline features tunable energy in the range from 8.3 to 21.8 keV to support single wavelength experiments. At the standard supporting energy of 17.7142 keV (0.70000 Å), the monochromatic X-ray beam is focused to a full width at a half-maximum of 100 μm (horizontal) × 85 μm (vertical) at the sample position, with a measured photon flux of 6.2 × 10¹¹ photons/s. The experimental hutch is equipped with a Rayonix MX225HS detector and a PH6 (Crystal Logics Inc.) goniometer, which can be configured for both single-axis and multi-axis setups. This beamline is particularly suitable for studying weakly diffracting crystalline materials such as micrometer-sized crystals, highly porous metal–organic frameworks, and disordered coordination polymers. To date, support for various experiments has been extended, encompassing structural studies involving variable temperature crystallography, investigations into photo-excitation phenomena, and research on gas sorption in porous materials. This article offers detailed descriptions of the current beamline design, technical information for users, and highlights recent scientific findings.

As climate change accelerates due to the continued use of fossil fuels, hydrogen production technologies that offer both high efficiency and environmental sustainability are urgently needed for the global energy transition. However, conventional water electrolysis is limited by the oxygen evolution reaction (OER), which suffers from sluggish kinetics and high overpotentials, significantly reducing overall energy efficiency. To address this challenge, the hydrazine oxidation reaction (HzOR) has emerged as a promising alternative, featuring more favorable reaction kinetics and lower overpotentials. Despite its advantages, the practical implementation of HzOR remains limited due to its reliance on noble metal-based catalysts, which are costly and scarce. In this study, we propose a dual-atom catalyst (DAC) design strategy for efficient HzOR, using combinations of noble and non-noble metals (NiCo, CoPt, and NiIr). Density functional theory (DFT) calculations were performed to evaluate their structural stability, electronic structures, and catalytic performance. The results reveal that heterometallic DACs can enhance HzOR activity by optimizing intermediate adsorption and lowering activation energy. Among the studied systems, NiCo Type-I demonstrates the most favorable balance of catalytic efficiency and electronic conductivity. This work highlights the potential of DACs as cost-effective and efficient HzOR catalysts and provides design insights for next-generation hydrogen production technologies aligned with global decarbonization goals.

Protein–protein interactions (PPIs) occur in most cellular processes, and characterizing PPIs is essential for understanding biological function and regulation. One of the most important parameters is the dissociation constant (K_d), which reflects the strength of PPIs. A range of in vitro methods, including isothermal titration calorimetry, fluorescence resonance energy transfer (FRET), surface plasmon resonance, and single-molecule fluorescence assays, have been developed to determine K_d values under controlled conditions. However, the living cell environment differs markedly from dilute buffer systems due to macromolecular crowding, compartmentalization, and regulatory complexity, often leading to discrepancies between in vitro and in-cell K_d values. In mammalian cells, advances in fluorescence-based techniques, including fluorescence lifetime imaging microscopy-FRET and fluorescence cross-correlation spectroscopy, have enabled quantitative measurements of PPI affinity in living systems. In contrast, accurately measuring K_d in bacterial cells has remained a challenge. Recently, in-cell NMR and quantitative FRET approaches have been developed for measuring K_d in bacterial cells. This review highlights the principles, capabilities, and limitations of representative in-cell K_d measurement techniques and provides guidance for selecting appropriate approaches to quantitatively characterize PPIs in physiologically relevant contexts.