Bulletin of the Korean Chemical Society最新文献

The cover image depicts the synthesis of cyclic carbonates from carbon dioxide and epoxides using a ferrocene-based catalyst in which two dimethylamino groups were introduced in the same Cp ring. The new catalyst does not need halide-based additives or tethered salts attached to ligands when used for this coupling reaction. More details are available in the article by Jienu Lee, Wooram Lee, Yoseph Kim, Mujin Choi, Seol Ryu, Joonkyung Jang, Youngjo Kim.

1,2,4,5-Tetrazines serve as versatile two-carbon synthons, essential for synthesizing a variety of (hetero)aromatic compounds. Their specific reactivity with certain dienophiles, without interfering with biochemical processes, makes them ideal for bioorthogonal ligation. Despite their broad utility, current synthetic methods are costly and raise safety concerns, particularly during scale-up. This study introduces safer and more cost-effective synthetic strategies utilizing zinc chloride or boron trifluoride diethyl etherate as catalysts. These alternatives significantly reduce costs and enhance safety, potentially expanding the applicability of tetrazine synthesis across broader research domains.

The detection of explosive materials, particularly nitroaromatic compounds such as 2,4,6-trinitrotoluene (TNT), is critical for public safety and national security. Existing detection methods often require complex instrumentation, limiting their applicability for real-time or in-field use. Fluorescent sensors, which offer rapid and sensitive detection through fluorescence quenching, present a promising alternative. This study evaluates the performance of two pentiptycene-based polymers, P-1 and P-2, in detecting explosive vapors, with a specific focus on their behavior under high-humidity conditions. P-2, modified with triethylene glycol groups, demonstrated significantly increased hydrophilicity compared to the commonly studied P-1, as confirmed by contact angle measurements. Spectroscopic analysis revealed a blue shift in P-2's UV–Vis absorption and photoluminescence spectra, indicating electronic property changes due to structural modifications. The enhanced hydrophilicity of P-2 enabled it to maintain stable sensing performance under moist conditions, showing less than a 10% reduction in sensitivity, compared to the 20% decrease observed in P-1. This superior moisture resistance suggests that P-2 is a more robust and practical sensor for explosive detection in environments with variable humidity levels.

We used stable and nontoxic [(dimethylamino)methyl]ferrocene (Fc-N), (hydroxymethyl)ferrocene (Fc-O), 1,2-bis[(dimethylamino)methyl]ferrocene (Fc-N2), and 1-[(dimethylamino)methyl]-2-(hydroxymethyl)ferrocene (Fc-NO) as halide-free, neutral, and bifunctional one-component catalysts for the synthesis of cyclic carbonates. They do not need halide-based additives or tethered salts attached to ligands when used for this coupling reaction. Among them, Fc-N2 exhibited the best catalytic activity under the same reaction conditions. Catalytic activity decreased rapidly in the order Fc-N2 > Fc-NO > Fc-N > Fc-O, and interestingly, the more amino groups introduced into the Cp groups, the higher the activity. Various terminal and internal epoxides were easily converted into the corresponding cyclic carbonates. Calculations based on the density functional theory were also carried out to elucidate the mechanism of the coupling reaction.

Paramagnetic molecules, such as main-group radicals and transition metal complexes, play crucial roles in catalytic and enzymatic reactions in organometallic and bioinorganic chemistry. Electron paramagnetic resonance (EPR) spectroscopy emerges as a powerful tool for probing the intricate electronic and geometric structures of these molecules. The application of EPR spectroscopy spans a wide spectrum of chemical entities, from simple radicals to transition metal complexes, metalloproteins, and metal clusters, emphasizing its versatility across various fields of chemistry. This review introduces the EPR spectra of transition metal complexes, offering a comprehensive theoretical foundation along with illustrative examples from both bioinorganic and organometallic chemistry. These examples highlight the effectiveness of EPR spectroscopy in characterizing transition metal complexes, reinforcing our understanding of their structure and reactivity.

Organic photovoltaics (OPVs) attracted a lot of research attention owing to its advantages such as convenient processing technique, unsubstantial weight, low cost, flexibility and use of environmentally benign materials. In general, these are bulk heterojunction (BHJ) OPVs obtained through a solution process and the large-area OPV production is achieved via roll-to-roll process. In OPVs, the BHJ active layer consists of electron donor (D) and electron acceptor (A) materials blended together by dissolving them in a common organic solvent. The new low band gap non-fullerene based acceptors could be used as potential candidates for the fabrication of OPVs in combination with suitable donor polymers. More details are available in the article by Radhiha Ravindran, Inchan Kim, Yun-Hi Kim, Soon-Ki Kwon

Growing market demands on portable electronics, electric vehicles, and energy storage system calls for the development of high-energy density lithium (Li) batteries. Li metal is considered as a promising anode material owing to their high capacity and low electrochemical potential. However, high reactivity of Li metal with conventional flammable liquid electrolytes easily forms Li dendrites, which may cause short-circuit and even catching fire, obstructing the wide application of Li metal batteries. Although non−/less-flammable solid electrolytes have replaced the conventional liquid electrolytes, solid-state Li metal batteries (SSLMBs) suffer from lower Li⁺ conductivities, chemical/electrochemical incompatibilities toward Li metal, and inhomogeneous Li⁺ flux at the interfaces. Therefore, many researchers have devoted themselves to solve these problems. For a better understanding on the current issues and recent advances, this article provides (1) a review on various solid electrolytes with high Li⁺ conductivity and their interfacial issues in SSLMBs, and (2) recent progress in stabilization of the interface between the Li node and solid electrolytes, including an electrolyte modification (e.g., composition, additives) and introduction of an interlayer.

Photolysis of phenacyl benzoates tethered with a phenol or anisole in acetone resulted in the formation of 1,4-dicarbonyl compounds, coupling products of the phenacyl moiety with acetone. The reaction occurs via electron and/or proton transfer from a triplet exciplex, leading to the formation of a phenacyl radical, which then adds to the enol form of acetone. The reaction also occurs in intermolecular fashion with external electron donors.

Excess hypochlorite (ClO⁻) is harmful to living organisms and can cause various oxidative diseases in the human body. Owing to the toxicity of ClO⁻, the development of efficient fluorescence sensors to track ClO⁻ is necessary. In this work, we report a novel thiourea-based fluorescent turn-on sensor 1-(9-ethyl-9H-carbazol-3-yl)-3-(naphthalen-1-yl)thiourea (ECNT) for recognizing ClO⁻. ECNT can detect ClO⁻ with high selectivity, relatively low interference with other analytes, and a significantly fast response time (<1 s) through a desulfurization reaction. The detection limit of ECNT for ClO⁻ is calculated as 5.59 μM. Of note, ECNT is a chemosensor that reacts the fastest with ClO⁻ among the reported thiourea-based fluorescence turn-on sensors for detecting ClO⁻. The response mechanism of ECNT to ClO⁻ is demonstrated through ¹H NMR titration, ESI mass, and density functional theory calculations.

Halogenation is one of the most important transformations in organic synthesis. Halogenated compounds are employed in many reactions to prepare useful molecules. Many methods have been developed to introduce halogens into different compounds. Visible light-mediated reactions are the efficient, low-toxic, and mild-condition methods applied for various organic chemistry transformations. Remarkably, there has been an increasing development in the application of visible light-induced halogenation in recent years. Herein, we present a comprehensive summary of halogenation reactions including chlorination, bromination, and iodination under visible light irradiation since 2020.