Bulletin of the Korean Chemical Society最新文献

Hydrogen abstraction is essential for CH bond activation by Compound I in cytochrome P450 and is influenced by various factors, including spin states, bond dissociation energies of the CH and FeOH bonds, axial ligands, and quantum mechanical tunneling. The role of axial ligands has been extensively studied, but it is still not fully understood. To explore their role, we used density functional theory calculations to determine whether a linear free energy relationship is established for the hydrogen transfer reaction, according to changes in axial ligands. The B3LYP* functional exhibits a strong linear correlation, but the slopes are inconsistent with the characteristics of the transition state. Natural bond orbital analysis reveals no direct orbital interaction between axial ligands and the reaction center of hydrogen transfer. The electron-donating orbitals of the axial ligands weaken the FeO bond, lowering the energy barrier, but they do not directly participate in the intrinsic hydrogen transfer. During the reaction, the FeO bond length increases significantly before the hydrogen transfer itself, generating an asynchronous shift in the bond orders, and most of the activation energy is used for the increase in the FeO bond rather than the hydrogen transfer itself. This study may explain why there is no apparent correlation between the rate constants and the FeO bond strength.

Thermoelectric materials can generate electric power from dissipating heat without releasing any undesirable chemicals. They thus can increase global energy efficiency and reduce the use of fossil fuels that are a major resource for generating electric energy, thereby concurrently addressing energy and environmental crises seriously threatening humanity. Increasing a thermoelectric figure of merit, ZT, of materials has been a prime goal in thermoelectrics because an efficiency of thermoelectric power generation has been low until very recently. The recent development of ultrahigh thermoelectric performance in polycrystalline SnSe-based materials is one of the most prominent breakthroughs in the history of thermoelectrics. They show an exceptionally high ZT of ~3.1 at 783 K and average ZT of ~2.0 from 400 to 783 K, which are the highest for any bulk thermoelectric systems. Here we review the recent advances in SnSe thermoelectrics, greatly changing the paradigm of studies and applications of thermoelectric technology.

Core-shell materials containing carbon shells surrounding Co particles are prepared one-pot process involving thermal treatment of Co(II) acetylacetonate and show excellent electrocatalytic oxygen reduction reaction performance and cyclic durability. The core-shell materials could have the potential as practical electrocatalysts with high stability. More details are available in the article by Yunseok Shin, Sungjin Park

Atomically thick two-dimensional transition metal dichalcogenides (TMDs) have been extensively studied as optoelectronic materials because of their distinctive electronic structures and outstanding photonic and catalytic properties. In particular, when the size of TMDs are decreased to the quantum scale, they possess wider bandgaps and higher surface-to-volume ratios with more active edge sites per unit mass. Hence, they are promising for use in sensor, battery, and electrocatalytic applications. In this study, we briefly review the various popular synthesis methods of TMD quantum dots (QDs) from top-down and bottom-up approaches. Then, we summarize the optical, electronic, and catalytic properties of TMD QDs. Furthermore, recent progress on electrochemistry, energy storage, and solar cell applications of TMD QDs is summarized in detail. Finally, we summarize current research bottlenecks of TMD QDs and discuss potential avenues for future research.

Plasmonic nanorings are promising building blocks for a variety of applications, including optical and biological sensing, and energy because the open inner spaces of the nanorings exhibit a high surface-to-area ratio and possess unique optical properties that are different from solid nanostructures. However, the simple architecture of mono-rim based structures leads to low electromagnetic near-field confinement, which requires a more complex structure to facilitate effective interaction with light. Herein, we report on recent progress of synthetic strategies for fabricating plasmonic nanorings using both top-down and bottom-up approaches. First, we introduce the conventional methods for achieving classical ring architectures. Then, we discuss rationally designed synthesis methods for creating advanced and structurally unique nanostructures to increase near-field enhancement. This process involves multi-step chemical toolkits that enable control over the shape and the introduction of repeated units in a single entity. Then, we explore the potential applications of complex nanoring architectures.

This study introduces a novel and versatile method for synthesizing honeycomb-structured silicon carbide (SiC). The innovative approach utilizes a sucrose solution as the carbon source and nonporous silica spheres, which serve both as silicon precursors and templates, allowing for precise control over pore sizes. Notably, the process is characterized by its cost-effectiveness, eco-friendliness, and the utilization of milder conditions attributed to magnesiothermic reduction. The tunable pore sizes achieved through adjustments in the size of silica particles offer a versatile platform for customizing SiC materials to meet specific application requirements. Beyond its customizable nature, the method reduces the environmental footprint of SiC synthesis by utilizing eco-friendly materials. Its combined attributes of accessibility, sustainability, and performance optimization underscore its potential for driving advancements in SiC-based applications across various industrial and scientific domains.

Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) have been important monitoring targets in the atmosphere due to their deleterious biological effects. Pine needles have been used to monitor atmospheric pollutants. An analytical method was developed to measure 21 PAHs, 14 alkyl PAHs, 7 PCBs, and 23 OCPs in pine needles using ultrasonically assisted extraction and gas chromatography-tandem mass spectrometry (GC–MS/MS). The ranges of the lower limits of detection of PAHs, PCBs, and OCPs were 0.01–0.05, 0.02–0.06, and 0.01–0.07 μg/kg, respectively. The feasibility of the proposed method was validated by analyzing dust standard reference materials of the samples, which gave satisfactory results with a precision of 0.83%–7.80% (PAHs), 0.93%–4.78% (PCBs), and 0.73%–4.71% (OCPs), and an accuracy of 89.2%–102% (PAHs), 94.6%–109% (PCBs), and 99.4%–102% (OCPs). The PAHs, PCBs, and OCPS were determined from real pine needle samples using the developed method.

Conducting polymers (CPs) possess the intrinsic attractive properties of conventional polymers, coupled with unique electronic characteristics reminiscent of metals or semiconductors. Nanostructured CPs have recently gained significant interest for their distinct advantages over bulk counterparts. They demonstrate potential applications in energy storage devices, sensors, and catalysts, attributed to their large surface areas and shortened charge transport paths. A crucial structural aspect in this context includes introducing porous morphologies into CPs, and enhancing their functionality through interconnected channels. In this review, various synthetic methods of nanostructured CPs are introduced, emphasizing two-dimensional (2D) configurations. The primary objective is to achieve high-performance devices with highly organized stacking of conjugated backbones. Particular attention is placed on integrating 2D structures and porous morphologies into CPs through ice-assisted methods and interfacial synthesis. The review also highlights successful applications of porous 2D CPs in practical devices and explores insights into future developments in the porous CPs field.

Transition metal dichalcogenides (TMDs) are promising 2D materials which are attracting significant interest because of their distinctive physicochemical properties. The possibility of being exfoliated and dispersed in liquid solutions offers a viable pathway to scalable production. This personal account focuses on recent advancements in 2D TMD inks produced by liquid-phase exfoliation (LPE) methods and intercalation-based electrochemical exfoliation. In particular, different LPE production strategies, like ultrasonication LPE, high-shear mixing exfoliation, and microfluidization, are introduced alongside a broad range of liquid media employed to provide functionalized TMD inks. The main advantage of TMD inks is its scalability, for practical applications in printed optoelectronics, energy storage, and conversion. Furthermore, the chemical functionalization of TMD inks can solve the poor electrical conductivity attributed to edge defects inherent in TMD inks. Finally, the ultimate orientations for future applications of chemically functionalized TMD devices are forecasted, with a specific focus on wearable and flexible printed electronics.