Chemistry - An Asian Journal最新文献

A series of PANI/VO₂/Ni(OH)₂ (PVN) nanocomposites with different weight compositions was synthesized by a single-step chemical method to determine the best weight composition and, in turn, to study their supercapacitive behavior. A composite with a weight composition of PANI58.33%:VO₂25.00%:Ni(OH)₂16.67% (PVN16) provided superior performance as a symmetric supercapacitor cell among the PVN composites synthesized. The obtained performances of PVN16 are a specific capacity (Q) of 60.44 C g^‒1, a specific energy (E) of 10.07 W h kg^‒1, a specific power (P) of 0.6 kW kg^‒1, and a coulombic efficiency (ƞ) of 98.18%. In addition, this symmetric device exhibited no reduction in its Q up to 5000 cycles at 0.4 V s^‒1. The asymmetric supercapacitor cells of the PVN16 were fabricated using activated carbon in the presence of two different aqueous electrolytes, which are 1 M H₂SO₄ and a liquid by-product that was obtained after the synthesis of PANI (SLP). The asymmetric cell in the presence (ITP) of SLP provided electrochemical stability up to 1.55 V, better performance, and the E comparable with vanadium redox flow batteries (VRFB). The obtained higher energy storage the parameters of a Q of 102.8 C g^‒1, an E of 22.13 W h kg^‒1, a P of 0.775 kW kg^‒1, and a ƞ of 70.44%. The asymmetric devices exhibited 95% and 73.88% retention of their initial Q up to 5000 cycles at 0.4 V s^‒1 ITP of 1 M H₂SO₄ and SLP, respectively. The symmetric and asymmetric devices exhibited 15.75% and 22.33% retention of their initial Q up to 17 and 30 A g^‒1, respectively, ITP of H₂SO₄ exhibiting their promising rate capability. Since, the PVN16 asymmetric cells ITP of SLP provide higher energy than those of the VRFB, they could be used to fabricate real-time hybrid supercapacitor devices at desirable working voltages for real applications as energy storage and conversion devices, where both high E and P are required.

The selective hydrogenation of privileged heterocycles with earth-abundant metal catalysts remains a significant yet practically important challenge in heterogeneous catalysis. Herein, we report a simple and efficient Raney nickel-catalyzed protocol for the selective hydrogenation of quinolines and indoles, delivering isolated yields of up to 99%. The practical utility of the method was further demonstrated through successful gram-scale transformations, and its use of a green solvent, an inexpensive catalyst, and operationally simple conditions affords a robust and sustainable approach for scalable heterocycle hydrogenation.

Developing efficient orange-red emitters based on donor-acceptor (D-A) π conjugates with thermally activated delayed fluorescence (TADF) remains a significant challenge. Herein, we designed a series of donor-acceptor emitters (3,6-Az-DBP, 2,7-Az-DBP, and 2-Az-DBP) by incorporating twisted 10,11-dihydro-5H-dibenzo[b,f]azepine (Az) as a donor alongside the rigid and planar dibenzo[a,c]phenazine (DBP) acceptor core molecule at different sites viz., 3,6-, 2,7-, and 2- positions. As a result of site-specific substitution, considerable alteration in electronic properties was observed. For 3,6-Az-DBP, the energy gap between singlet and triplet states (ΔE_ST) was found to be 0.42 eV, which is much higher than that for 2-Az-DBP (0.25 eV) and 2,7-Az-DBP (0.06 eV). Owing to miniscule ΔE_ST, 2-Az-DBP and 2,7-Az-DBP showed orange and red TADF, respectively, in CBP blend. Both these compounds also showed red room temperature phosphorescence in powder samples having lifetimes in milliseconds time regime. Further, organic light emitting diode (OLED) of CBP doped 2-Az-DBP showed a high luminance of 6 × 10³ Cd/m² @ current density of 50 mA/cm²with EQE_max of about 12.3%. These studies provide a promising strategy, site selective substitution of donor on acceptor core, to improve the emission properties for red TADF emitters.

This cover art visualizes how side-chain chemistry of peptides modulates biomolecular droplets. G-quadruplex DNA interacts with a series of RX repeat peptides, revealing that specific amino acid substitutions tune LLPS (left) or LSPS (right) behavior. The vibrant gradient reflects changing intermolecular forces, while molecular assemblies highlight how hydrophobicity, aromaticity, and charge drive selective LLPS, offering insights into droplet design. More details can be found in the Research Article by Daisuke Miyoshi and co-workers (DOI: 10.1002/asia.202500805).

Thioethers, amines, and ethers represent the key compounds finding application throughout life and material sciences. In this vein, transition metal-catalyzed Csp²-S, Csp²-N, and Csp²-O cross-couplings provide an influential synthetic tool and serve as an imperative toolbox for the edifice of above privileged compounds from laboratory to industrial scale. These reactions are significantly discovered in organic and halogenated solvents, thereby posing health and environmental hazards. Lately, efforts are thus being made toward the utilization of more sustainable solvents for the above purpose. Contextually, the use of water has witnessed noteworthy attention over the past couple of decades, thereby allowing for substantial chemical waste reduction. This review summarizes the recent advances (2008-July 2025) in transition metal-catalyzed cross-coupling reactions for the synthesis of thioethers, amines, and ethers via Csp²-S, Csp²-N, and Csp²-O bond formation in aqueous media. The discussed transformations are organized according to the nucleophilic coupling partners, sulfur, nitrogen, and oxygen, reacting with aryl halides and related electrophiles.

Guanosine (G) self-assembles into metal-stabilized architectures such as G-quartets (G₄·Mⁿ⁺) with metal ions, including Na⁺, K⁺, Rb⁺ and Cu⁺, and G-dimers G₂·(Mⁿ⁺)₂ with Ag⁺. Here, we show that Cu²⁺ forms a stable G₂·(Cu²⁺)₂ dimer-based gel at elevated temperatures. This gel exhibits self-healing and time-dependent syneresis behavior. In situ reduction of Cu²⁺ to Cu⁺ by ascorbic acid converts the G₂·(Cu²⁺)₂ dimeric gel to a G₄·Cu⁺ G-quadruplex gel, enabling a redox-controlled gel-to-gel transformation. The G₂·(Cu²⁺)₂ gel is mechanically stronger but dilution-sensitive, whereas the G₄·Cu⁺ gel is weaker yet more dilution-tolerant. These results establish copper oxidation states as determinants of G-based assembly and demonstrate a redox-triggered route to adaptive, stimuli-responsive soft materials.

Cyclic peptides are peptidic macrocycles with ring-constrained backbones that have distinct physicochemical and biological properties, with the simplest being cyclic dipeptides. Four cyclic dipeptides, cyclo(Pro-Pro), cyclo(Pip-Pip), cyclo(PrS-PrS), and the unique sulfur-rich cyclo(PipS-PipS), were synthesized from unprotected amino acids by using a one-pot thionyl chloride-mediated cyclization process, producing 19%-40% without the use of protective-group strategies. FTIR, NMR, and high-resolution mass spectrometry (HRMS) were used to confirm the structures. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was used to assess antioxidant activity, and it was discovered that sulfur incorporation and six-membered ring size significantly increase radical quenching. A cloud-based platform was used to predict electronic properties, such as HOMO-LUMO gaps, dipole moments, and oxidation potential. Compounds with smaller HOMO-LUMO gaps and lower oxidation potentials had higher DPPH scavenging efficiencies, establishing a clear structure-property-activity relationship. This study identifies promising sulfur-containing cyclic dipeptides for future development as antioxidant therapeutics and presents a scalable pathway to diverse cyclic dipeptides.

The electrochemical nitrate reduction reaction (NO₃RR) has attracted considerable attention for the sustainable production of NH₃, urea, amino acids, and other value-added chemicals. Among these, NH₃ is particularly significant due to its large-scale industrial synthesis via the Haber-Bosch process. Herein, we report the design of an efficient NO₃RR catalyst prepared through a simple synthesis route. Fe₂O₃ clusters (2-5 nm) were uniformly deposited on iron phthalocyanine (FePc)-modified N-doped carbon nanotubes (Fe₂O₃/FePc/CNT), yielding a high NH₃ production rate of 58.67 mg h^-1 cm^-2 with a Faradaic efficiency (FE) of 81.89% at -1.0 V versus RHE. Comparative studies with FePc/CNT, Pc/CNT, and Fe₂O₃/CNT confirmed the synergistic effect between Fe₂O₃ clusters and FePc, with the optimized Fe₂O₃/FePc/CNT catalyst showing superior activity and selectivity. Furthermore, the optimized catalyst exhibited excellent stability for 24 h. A possible mechanism for NH₃ formation is proposed on the basis of the reaction intermediates identified by ex situ FTIR and x-ray photoelectron spectroscopy (XPS) analyses.

Chiral trivalent lanthanide complexes are of interest since their parity-allowed magnetic dipole transition generally shows large luminescence dissymmetry (g_lum) factors. However, the luminescence intensity is normally weak, which is yet another challenge. Herein, we introduce electron-withdrawing and -donating moieties (F and methyl, respectively) at the para-positions of phenyl on N,N'-bis (1-phenylethyl)-2,6-pyridinediamide. We found that this approach, for example, modifying the remote positions of ligands, enables decreasing the triplet state energy levels of ligands from 27060 cm^-1 (H) to 24154 cm^-1 (F) and 24390 cm^-1 (methyl) and enhancing the ligand-to-ion sensitization from 0.35 to 0.41 and 0.47 and photoluminescent quantum yields (PLQYs) from 17% to 23% and 25%. The g_lum-factors are ±0.1 for the three Tb(III) complexes coordinated with the synthesized ligands in their ethanol solutions, yielding circularly polarized luminescence (CPL) brightness (B) values of 0.017, 0.023, and 0.025, respectively. Single crystal structures reveal the chirality transfer from the chiral ligands to the complex and then to supramolecular chiral packing of complexes and also effective modulations on the supramolecular chiral packing. Collectively, these findings establish remote ligand engineering as a robust and versatile strategy for fine-tuning CPL brightness.