Bulletin of the Korean Chemical Society最新文献

Rapid advancements in energy storage technology, driven by a growing demand for energy storage devices, underscore the crucial need to comprehend ionic conduction behavior. Consequently, intensive research on high-performance ionic conductors becomes imperative. Covalent organic frameworks (COFs) have emerged as invaluable materials in the realm of solid-state or quasi-solid-state ion-conduction, leveraging their unique properties such as significant porosity, tunability, and robust physicochemical durability. These distinctive attributes position COFs as promising candidates for the development of electrodes, electrolytes, and separator materials characterized by high capacities, rapid ion transport, and electrochemical stability. This review provides insights into COFs as ionic conductors, discusses recent advancements in COF-based energy storage devices, and explores the influence of structural functionalization, pore size engineering, and dimensional regulation on ionic conduction. Moreover, the review aims to deepen understanding and pave the way for future advancements in the utilization of COFs within energy storage technologies.

Amines bearing diverse aryl substituents for potential utilities as energy and new materials have been synthesized from aziridine-2-carboxaldehyde and diverse aryl-containing substrates. At first two aryl groups were to yield (aziridine-2-yl)-1,1-diaryl-methane which was converted to 5-diarylmethyl oxazolidin-2-one as a synthetic intermediate. They were further reacted with another aryl group in the presence of methanesulfonic acid to yield 2,3,3-triarylpropylamine with the possible carbenium ion intermediate. In addition, this reaction with a second additional phenolic aryl group gave rise to the diversely substituted 3-(4-methoxyphenyl)-(2,3-dihydrobenzofuran-2-yl)methanamine derived from the intramolecular aziridine ring-opening reaction by hydroxy group at phenol.

Bipyridine-based gelator 1 having two D-alanine units was prepared, and its gelation ability was evaluated in the presence of Co(NO₃)₂ and AgNO₃ in water. Gelator 1 could gelate H₂O in the presence of Co(NO₃)₂ or AgNO₃ (1.0 equiv.) in water. Gelator 1 formed a 2:1 (1:Co²⁺) octahedral complex with Co²⁺, whereas it formed a 2:1 (1:Ag⁺) tetrahedral complex with Ag⁺. The metallosupramolecular hydrogel with Co²⁺ assembled into a left-handed helical fiber, whereas that with Ag⁺ assembled into a nanorod structure. ¹H NMR and FTIR analyses revealed that π–π stacking and intermolecular hydrogen bonds acted as the driving force for the formation of the supramolecular nanoarchitectures. Furthermore, to characterize the viscoelastic properties of hydrogels, rheology experiments were conducted at 25°C, including time, strain, and frequency sweeps.

In this study, selenium nanoparticles (SeNPs) were synthesized and stabilized by reducing sodium selenite using ascorbic acid in an aqueous solution of sodium carboxymethylcellulose (Na-CMC) with a degree of substitution of 0.97 and a degree of polymerization of 810. IR-Fourier spectroscopy revealed that coordination bonds between functional groups in Na-CMC and SeNPs resulted in the development of polymer-metal complexes. UV–Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods were used to determine the SeNP sizes in the structure of the nanocomposite film. Investigation of the stabilization and nonstabilization of SeNPs over several cycles has shown that the effect of the polymer matrix of Na-CMC on the stabilization of nanoparticles was achieved for 672 h, which was confirmed by the unchanged size distribution and resistance to change of the SeNPs synthesized in Na-CMC solutions.

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.