Bulletin of the Korean Chemical Society最新文献

Identification of cancer from normal tissues is important for early diagnosis of cancer. Combined detection of multiple tumor markers is important for accurate diagnosis. It is urgent to develop fluorescent probes that are responsive to multiple cancer characterizations for selective cancer imaging. Herein, we designed a novel near-infrared (NIR) fluorescent probe (IRAPA) using a hemi-cyanine skeleton as fluorophore and 3-acrylamidopropanoic ester as recognizing unit that is responsive to both oxidative and reductive molecules. IRAPA has faint fluorescence emission as the intramolecular charge transfer (ICT) process is blocked. H₂O₂, glutathione (GSH) and cysteine (Cys) can individually induce the hydrolysis of ester bond and give fluorescent NIR IROH. IRAPA shows low cytotoxicity and produces strong fluorescence specifically in cancer cells/tissues. While the normal cells/tissues showed very weak fluorescence. Moreover, IRAPA shows higher differences between cancer and normal cells compared to probes that only response to biothiols or ROS.

Three co-substituted quaternary and quinary Zintl phases belonging to the Ba_1-xSr_xZn_2-yCu_ySb₂ (x = 0, 0.09; 0.24 ≤ y ≤ 0.42) system were prepared by the molten Pb metal-flux method. Co-substitution using the cationic Sr and anionic Cu for Ba and Zn was initially applied to lower the thermal conductivities and to improve the electric conductivities of these title compounds simultaneously. The homogeneities of single-phase products were verified by powder x-ray diffraction analysis, and the BaCu₂S₂-type orthorhombic crystal structures with the Ba/Sr and the Zn/Cu mixed-sites were refined by single crystal x-ray diffraction analysis. Structural selectivity for the observed BaCu₂S₂-type phase was rationalized by the radius ratio of cationic and anionic elements, where r₊/r₋ > 1. DFT calculations using the three structural models revealed that the Sr and Cu substitutions can increase the structural stability and the hole carrier concentration. A series of temperature-dependent electrical transport property measurements for BaZn_1.76Cu_0.24Sb₂ and Ba_0.91Sr_0.09Zn_1.70Cu_0.30Sb₂ successfully proved that the co-substitution using Sr and Cu enhanced electrical conductivities, but reduced the Seebeck coefficients resulting in the slight change in power factor.

Unnatural β-amino acids play pivotal roles in organic synthesis, drug development, and peptide chemistry. Highlighting their significance, the study by Jungwoo Hong, Wonchul Lee, and Hee-Seung Lee presents an optimized, scalable method for producing enantiopure five-membered cyclic trans-β-amino acid building blocks. More details are available in the article by Jungwoo Hong, Wonchul Lee, Hee-Seung Lee

Although organic photovoltaics (OPVs) have evolved over the last two decades, the discovery of new materials and optimization of numerous considerations for high-performance devices remain challenging. To reduce these laborious processes and expedite the advancement of OPVs, we constructed machine learning (ML) models that predict photovoltaic parameters. We designed a unique descriptor that divides the molecular structure into smaller units and translates them into a concise matrix. This allows the ML model to easily track structural units and understand which units are important for predicting target performance, enabling the ML model to prioritize crucial units. Therefore, without requiring additional data from measurements or calculations, the ML models can extract chemical properties from molecular structural information and accurately predict the photovoltaic parameters. The ML models that predict the photovoltaic parameters, including the open-circuit voltage, short-circuit current density, fill factor, and power conversion efficiency, all show remarkably superior prediction performance, with Pearson correlation coefficients exceeding 0.68. Consequently, in this article, we propose a highly precise and reliable predictive OPV-ML platform that can robustly screen for unnecessary experiments and accelerate OPV development.

This work analyzes the crystal structural properties and photoluminescence properties of six Eu²⁺-activated thiogallates: CaGa₂S₄:Eu²⁺, SrGa₂S₄:Eu²⁺, EuGa₂S₄, BaGa₂S₄:Eu²⁺, Sr₂Ga₂S₅:Eu²⁺, and Eu₂Ga₂S₅. Photoluminescence parameters such as the absorption energy (E_abs), emission energy (E_em), zero-phonon line energy (E₀), Stokes shift (ΔS), and red shift (D) are discussed. This work is the first report on the photoluminescence parameters of these six Eu²⁺-activated thiogallates and therefore provides important information about these materials.

The synthesis and functionalization of privileged nitrogen heterocycles has emerged as a central topic in drug discovery and material science. In this context, the tandem C–H functionalization and intramolecular annulation has received prodigious attention, as it is able to expedite the construction of heteroaromatic frameworks beyond conventional C–H functionalization. In general, significant effort has been made to develop the [3 + 2] dipolar cycloaddition of azomethine imines with π-unsaturated compounds. Moreover, the [3 + 3], [4 + 3], [3 + 2 + 2], and [5 + 3] cycloaddition reactions of azomethine imines with various dipolarophiles have been demonstrated. To date, however, the combination of catalytic C–H functionalization and intramolecular cyclization using azomethine imines as both directing groups and dipolar units has been less explored. This review focuses on recent progress toward the catalytic tandem C–H functionalization and dipolar cycloaddition of azomethines imines with a range of coupling partners.

The generalized solutions of the dimensionality reduction problem in diffusion–reaction systems have been found for the first time by rigorously decoupling probability functions. Numerically exact results are obtained by straightforwardly applying the generalized solution to three models: protein-DNA binding model (3D-1D reduction), surface-mediated diffusion (3D-2D reduction), and line-mediated diffusion cases (2D-1D reduction). The results are confirmed by Monte Carlo simulations.

In this study, we introduce two ortho-carboranyl compounds, namely ICzCB and mTPCB, which exhibit different planarity in their appended π-conjugated aromatic groups, to investigate the influence of geometric effects on the regulation of the radiative efficiency. Both the compounds are fully characterized, revealing distinct geometric differences (planarity) in their single-crystal structures. While ICzCB presents strong ICT-based emission in the solid (film) state, mTPCB displays dual emission in the high- and low-energy regions that originates from locally excited (LE)- and ICT-based processes, respectively. Quantitative analysis of the photophysical characteristics of the compounds shows that the ICT-based radiative efficiency in ICzCB is higher than that in mTPCB. Consequently, these findings demonstrate that the planarity of the π-conjugated aryl group appended on o-carborane, which is represented by planar ICzCB and distorted mTPCB, is an important key to control the ICT-based radiative decay efficiency.

To date, ionic conduction in nonaqueous electrolytes has been explained through the vehicle-type migration mechanism. Yet, new research hints at another conduction mode: ion-hopping, seen in highly concentrated solutions with multi-coordinating solvents. Our research uncovers that Li-ion hopping conduction also occurs in monodentate acetonitrile (AN) electrolytes, enabled by a highly associative Li-salt. Using techniques like pulse-field gradient NMR, Raman spectroscopy, and dielectric relaxation spectroscopy, we examined AN solutions with lithium trifluoroacetate (LiTFA) and lithium bis(fluorosulfonyl)imide (LiFSI). Results showed that Li-ion diffusion in LiTFA-AN was faster due to an anion-bridge structure formed by the associative nature of LiTFA. In contrast, the LiFSI-AN solution demonstrated slower Li-ion movement. In practical applications, like LiFePO₄ symmetric cells, 4 M LiTFA-AN outperformed 1 M LiTFA-AN in rate performance, despite its lower ionic conductivity. This challenges the belief that associative Li-salts are unsuitable for battery electrolytes and prompts reconsideration of other associative Li-salts.

For an analog-based design of novel Wee1 inhibitors, we profiled in vitro ADMET and in vivo PK properties of adavosertib. Based on the properties of adavosertib, we aimed to improve its metabolic stability by designing a novel target compound 1a with an aminosulfonyl group instead of the 2-hydroxypropan-2-yl moiety in adavosertib. Derivatives of target compound 1a were synthesized and evaluated for Wee1 enzyme inhibition and liver microsomal phase I stability. We identified compound 1a as a sub-nanomolar Wee1 inhibitor and 10 additional compounds with one-digit nanomolar Wee1 inhibitory activity, among which seven compounds including 1a exhibited improved metabolic stabilities compared with adavosertib. However, MDA-MB-231 cell growth inhibitory activities of all synthesized compounds and Wee1 substrate phosphorylation inhibitory activities of selected compounds were inferior to adavosertib overall. Moreover, the representative compound 1a exhibited low permeability, which may be the reason for the low cellular activities of compound 1a.