Journal of Chemical Sciences最新文献

A pyrene-functionalized cationic based on 6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-D-galactopyranose (MAIpGP) and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) polymer (Py-PMAIpGP-b-PDMAEMA+) was synthesized, characterized and DNA interaction was investigated by UV-Vis spectroscopy, ethidium bromide (EB) competitive fluorescence and agarose gel methods. By comparing the UV spectrum of PMAIpGP-b-PDMAEMA and Py-PMAIpGP-b-PDMAEMA+. The addition of the pyrene ring to the polymer was first understood by comparing the UV spectra of the polymer and the cationic polymer. Later, the shifts of aromatic hydrogens in the pyrene ring in the 1H-NMR spectrum supported the information obtained in the UV spectrum and proved the structure. DNA binding studies by UV titration showed that the pyrene ring is intercalated between base pairs while the main skeleton interacts electrostatically with DNA. Competitive experiments with EB confirmed that the cationic polymer intercalates between DNA base pairs via the pyrene ring. Agarose gel electrophoresis studies determined the concentration at which the cationic polymer could neutralize the negative charge of DNA.

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The PMAIpGP-b-PDMAEMA polymer was functionalized with methylpyrene to impart cationic character, aiming to enhance its DNA affinity and solubility in water. The results demonstrated that the cationic polymer binds DNA via both electrostatic and intercalative interactions, displaces EB through pyrene intercalation, and modulates plasmid DNA migration in gel electrophoresis, indicating its potential as a non-viral gene delivery candidate.

Amides and α-ketoamides are ubiquitous in drugs and fine chemicals. A recent study by Li and co-workers¹ reported a modular electrolysis-paired tandem strategy that produces both families of compounds in a single electrochemical setup by combining cathodic CO₂-to-CO conversion with palladium-catalyzed aminocarbonylation and anodic iodine-mediated ketoamidation. The system achieves “two birds with one stone” synthesis. This commentary highlights the significance of this study from an electrochemist’s perspective.

Graphical Abstract

This highlights the recent work by Qing Li and co-workers (Angew. Chem. Int. Ed. 2025, 33, e202503440) on the modular synchronous electrosynthesis of amides and α-ketoamides from a broader perspective.

This study investigated diketopyrrolopyrrole-spacer-based dye sensitizers for dye-sensitized solar cells (DSSCs) applications, specifically the effects of electron-donating and electron-withdrawing groups on donor moieties. Using the computational methods, we evaluated the photophysical properties and efficiency metrics like light harvesting efficiency, electron injection efficiency, regeneration efficiency, and overall solar energy conversion efficiency, and compared them with the existing experimental results. Further, we have predicted better and more efficient dyes with small changes, like adding electron-donating groups on the para position of the donor moieties with density functional theory. The three donor groups: carbazole (CB), diphenylamine (DA), and indole (IN)- and their derivatives with electron-donating and electron-withdrawing substituents were examined.

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Electron-donating groups on donor groups enhances the efficiency whereas electron-withdrawing groups reduces the efficiency.

The misfolding and subsequent brain accumulation of two intrinsically disordered proteins, amyloid-beta (Aβ) and tau, are considered major hallmarks of Alzheimer's disease (AD), a neurodegenerative disorder characterized by cognitive decline and memory loss. Aβ accumulates extracellularly in the brain parenchyma, while tau aggregates intracellularly within neurons. Understanding the underlying molecular mechanisms is essential for uncovering the origins of AD and has remained an active area of research for over three decades, with the aim of developing therapeutics to mitigate or prevent disease progression. Our research group has made significant contributions over the years to explore the Aβ aggregation process, with particular emphasis on unraveling the role played by the solvent in guiding the process using large-scale atomistic molecular dynamics simulations. More recently, we have expanded our focus to probe the microscopic mechanism of aggregation of the tau protein. Some of the important findings that originated from our work have been presented in this review.

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Alzheimer's disease is caused due to aggregation of two intrinsically disordered proteins (IDP), amyloid-β and tau. Simulation studies have unravelled that water plays a pivotal role in the aggregation process. A schematic image depicting water molecules confined within the core and at the surface of an IDP aggregate is shown.

The microscopic understanding of the morphology and ion/proton dynamics in hydrated Nafion systems is extremely essential for optimizing the efficiency of thermochemical/electrochemical processes like the Cu–Cl thermodynamic cycle for hydrogen generation. The present study addresses the gap in theoretical investigations on the structure and proton dynamics in aqueous Nafion systems, focusing on Cu⁺/Cu²⁺ and proton dynamics using robust MD simulations. We report a systematic investigation of the structure, transport and dynamics of protons and copper ions by varying water content, temperature and copper ion concentration. The present study captures the formation of continuous water channels within the hydrophobic Nafion matrix as observed in many experimental findings. Simulations are also conducted with 10% hydrated Nafion in contact with 11 N HCl and 1 M copper ions to represent the real composition of Cu–Cl electrolyzer. The MD analyses demonstrated that the highly acidic environment (11 N HCl) of the Cu–Cl electrolyzer would boost the swelling of Nafion membrane with reduced water–water interactions. On the other hand, the pairing of Cu–Cl ions would enhance the Nafion–hydronium ion interactions in the presence than in the absence of acid. The augmented interaction of hydronium ions with the sulfonic acid group of Nafion, would in due course, assist in faster transport of hydronium ions following Grotthuss mechanism. The hydrogen-bond life time of Nafion hydrated water was higher than that of bulk water due to the formation of separate water clusters within the Nafion membrane. The pores of Nafion allows only the transport of hydronium ions and water molecules whereas copper and chloride ions are restricted. The present findings on the structure and proton dynamics of the polymeric Nafion membranes might contribute towards the optimization of Cu–Cl electrolyzer for efficient and trouble free hydrogen production.

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The effects of water content, temperature, presence of Cu⁺/Cu²⁺ ions and acidity in Nafion membrane were investigated. The increasing water content led to the formation of water channels within the membrane. Swelling, formation of channels and enhanced hydrogen bonding were observed at higher water content.

Traditionally, thermally activated delayed fluorescence (TADF) molecular design has focused on donor–acceptor (D–A) structures. However, this study explores alternate molecular configurations that extend beyond the conventional models. Using density functional theory (DFT) and time-dependent DFT calculations, we systematically investigated the impact of various donor and acceptor arrangements, such as D_A, D_A_D, A_D_A, D_A_D_A, and D_A_A_D, on the TADF properties of emitters using 5,10-dihydrophenazine (DHPZ) as the donor and benzophenone (BP) as the acceptor. In tetrad systems, the electronic structure of TADF emitters strongly depends on the spatial arrangement of the donor and acceptor units. For instance, in the D_A_D_A configuration, the lowest three singlet and triplet states exhibit charge transfer character. In contrast, the D_A_A_D configuration reveals significant Frenkel-type character in T₃ and T₄ states. The involvement of these higher triplet states enhances the spin–orbit coupling value and improves the reverse intersystem crossing (RISC) rates. Additionally, the configuration of donor and acceptor units influences the number of potential RISC channels. Overall, the D_A_A_D configuration emerges as a promising design, demonstrating superior TADF performance through multiple efficient exciton utilization pathways (up to 10 RISC channels) and faster RISC rates (> 10⁵ to 10⁸ s^–1) compared to D_A_D_A.

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The D_A_A_D configuration emerged as a promising design, demonstrating superior TADF character through multiple efficient exciton utilization pathways (10 channels) and faster RISC (> 10⁵ to 10⁸ s⁻¹) rates compared to D_A_D_A.

Using the accurate quantum chemical calculations, the origin behind the hydrophobicity/hydrophilicity of two similar ionic liquids (ILs), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]⁺[PF₆]⁻) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]⁺[BF₄]⁻) is thoroughly investigated. The structure of all the species and their corresponding interaction energies with water are computed by employing the wB97XD functional and 6-311G++(d,p) basis set. The use of the functional and basis set has been benchmarked either considering the experimental data or predictions from the sophisticated ab initio calculations. A continuum solvation model is utilized initially to understand the hydration (solvation) behaviour of the ILs as well as the hydration of the constituent ions. The explicit solvation has also been performed to monitor the effects of each molecular water addition to IL ion pairs and their anionic counterparts. This is done by calculating the interaction energy profiles as well as their charge distributions. It is found that anions and their charges transfer to cations or surroundings play a decisive role in this qualitatively different behaviour of these two ILs towards water. In addition, classical molecular dynamics simulations have been performed to investigate the hydration structure of the ions in the bulk water. The quantum chemical calculations presented here demonstrate the importance of anion-medium interactions in determining the hydrophobicity/hydrophilicity character of these two ILs.

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This paper investigates quantum mechanical origin of hydrophobicity by considering two ionic liquids, differing only in anions, as representative systems. The non-ionic interaction was found play an important role. The Gradient isosurfaces and the corresponding RDG plots for both the represenattive ILs in water are also shown