New Journal of Chemistry最新文献

The selective oxidation of toluene is critical for synthesizing oxygenated compounds from aromatic hydrocarbons, in which catalysts play an irreplaceable and decisive role. In the present work, the CeO₂–MnO_x/C₃N₄ catalyst was successfully prepared using a co-precipitation method, and its structure was systematically characterized using a combination of analytical techniques, including FT-IR, SEM, XRD, nitrogen adsorption–desorption test, XPS, TGA, H₂-TPR, and O₂-TPD. The characterization results confirmed successful doping and uniform dispersion of CeO₂ and MnO_x into the C₃N₄ support. Subsequently, the catalytic performance of the CeO₂–MnO_x/C₃N₄ catalyst was evaluated for the liquid-phase oxidation of toluene, employing molecular oxygen as the oxidant in a system free of solvents and additives. To obtain the optimal reaction efficiency, the influence of four key parameters—catalyst dosage, oxygen pressure, reaction time and temperature—on the reaction was systematically investigated. Under optimal conditions, toluene conversion reached 5.1%, while the combined selectivity for benzaldehyde (Bz-CHO) and benzyl alcohol (Bz-OH) was 67.9%. Furthermore, recyclability tests demonstrated that the catalyst retained good stability after 5 cycles. Additionally, a preliminary speculation on the mechanism of CeO₂–MnO_x/C₃N₄ was proposed. Owing to its favorable catalytic activity and low preparation cost, this catalyst offers a novel, promising strategy for the selective oxidation of aromatic compounds to high-value oxygenated derivatives.

The catalytic cleavage of C–O bonds is a fundamental transformation in organic synthesis and biomimetic chemistry, with particular relevance to enzymatic O-demethylation. Inspired by oxidative O-demethylase enzymes, we investigated Cu(II)-mediated O-demethylation as a selective and environmentally friendly approach to breaking C–O–C bonds under mild conditions. To probe the electronic effects governing this transformation, we synthesized and characterized a series of Cu(II) complexes based on three imine ligands with varying methoxy substituent patterns. Structural and reaction studies identified key factors influencing the demethylation process, enabling a strategy for controlled O-demethylation at the Cu(II) center. Notably, exposure of complex C1 to a weakly coordinating perchlorate anion, visible light, oxygen and water induced selective demethylation of ligand L1, yielding complexes C2 and C3. X-ray crystallography confirmed the demethylated products, while spectroscopic and electrochemical analyses provided mechanistic insights. Additionally, DFT calculations elucidated the regioselectivity, demonstrating why only the methoxy group closest to the metal center undergoes cleavage. This study represents the first example of Cu(II)-mediated O-demethylation, revealing the critical interplay of electronic and geometric factors. These findings offer new perspectives for catalytic demethylation strategies and may have broader implications in sustainable lignin valorization, materials science, and environmental chemistry, showing the catalytic potential of Cu(II) ions in this reaction.

A high-performance ultraviolet (UV) nonlinear optical (NLO) material should possess three essential characteristics: a short UV absorption edge, a strong second-harmonic generation (SHG) response, and favorable NLO coefficients. In this study, a novel rare-earth borate compound with the formula K₇MgY₂(B₅O₁₀)₃ was successfully synthesized using a high-temperature solution method combined with chemical co-substitution. The crystal adopts a non-centrosymmetric (NCS) structure (space group R32) and exhibits a SHG intensity 1.2 times greater than that of potassium dihydrogen phosphate (KDP) under 1064 nm laser irradiation within the particle size range of 38–55 µm. Its UV cutoff edge is determined to be 290 nm, demonstrating exceptional potential for UV optical applications. Combined experimental and theoretical analyses reveal that the synergistic interplay between polarizable [B₅O₁₀] groups and heterovalent K⁺/Mg²⁺/Y³⁺ substitution underpins its superior NLO performance.

Sodium alginate, a natural polysaccharide with renewable, biodegradable and multifunctional characteristics, represents an ideal sustainable material for diverse industrial applications. However, its potential for developing eco-friendly mosquito-repellent textiles remains largely unexplored, with only limited studies reported to date. This research gap persists despite the significant global health threat posed by mosquitoes, which are among the most dangerous disease vectors worldwide and spread diseases that cause millions of deaths every year. In view of the challenges, such as high volatility rate and complex fabrication processes, posed by the application of mosquito repellents to clothing through spraying or micro-encapsulation methods at present, developing textiles with simple preparation, high-efficiency and long-lasting mosquito repellency offers a highly promising solution to mosquito-related health issues. In this study, an eco-friendly synthesis strategy for grafting alginate derivatives with p-menthane-3,8-diol was developed through acidification and esterification reactions using environmentally friendly and biocompatible sodium alginate (SA) as a raw material. Furthermore, by exploring the optimal mosquito repellent ratio and coating thickness through the system, the synthesized p-menthane-3,8-diol-grafted alginate derivatives could be applied to wearable textiles, such as ice sleeves, exhibiting excellent mosquito-repellent performance while balancing air and moisture permeability, effectively preventing mosquitoes from approaching humans.

In this study, a photorechargeable supercapacitor was prepared with ZnMoO₄, Zn(CF₃SO₃)₂ and reduced graphene oxide hydrogel (rGH) as the photoanode, electrolyte and cathode, respectively. The microstructure, phase composition, light absorbance, specific surface area and chemical structure of products and the photoelectrochemical performance of supercapacitors were characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electrochemical workstation. The ZnMoO₄//rGH supercapacitor exhibited a high specific capacity of 156.09 F g⁻¹ under photoelectric synergistic charging (namely, a light intensity of 95 mW cm⁻² and a current density of 0.5 A g⁻¹), which increased by 35.66% relative to that of only electric charging. Meanwhile, the capacity retention and coulombic efficiency rates of the device are 137% and 100%, respectively, under photoelectric synergistic charging and discharging for 10 000 cycles. This suggests that the ZnMoO₄//rGH photorechargeable supercapacitor exhibits excellent stability and shows applications in the wearable electronic industry.

Based on electrostatic adsorption theory, this study innovatively employs an aqueous-phase synthesis method combining in situ growth and simultaneous etching to successfully prepare SO₄-ZIF-67/BiOBr Z-type heterojunction composite photocatalysts. Experimental results demonstrate that 30% SO₄-ZIF-67/BiOBr achieves an 89.72% degradation rate of TC under visible light, representing 3.95, 16, and 1.59 times improvements over pure BiOBr, SO₄-ZIF-67, and ZIF-67/BiOBr, respectively. A series of characterization analyses revealed that the performance enhancement stems from the following factors: first, this material utilizes the surface anchoring of SO₄²⁻ on ZIF-67 and the electrostatic adsorption between SO₄²⁻ and BiOBr to construct a uniform and dense interfacial structure. The vacant orbitals of sulfur atoms in SO₄²⁻, with their high electronegativity, rapidly capture photoelectrons. Increasing the hole density near the Fermi level of the material promotes electron migration toward the material and forms a stable trap state. The uniform interfacial charge effect synergizes with the Z-type heterojunction to achieve enhanced charge separation and migration. Second, SO₄²⁻ modification and the uniform morphology induced by electrostatic adsorption contribute to spectral broadening and increased specific surface area, further enhancing surface activity and adsorption capacity. This study provides a novel strategy for constructing highly efficient Z-type photocatalytic systems through surface modification of nanomaterials and electrostatic adsorption.

The combined effect of MnO₂ and ZnO provides an effective approach to enhance the electrode materials' surface area and redox characteristics for usage in efficient energy storage devices. In the present work, a 1-D α-MnO₂/ZnO binary nanocomposite was successfully synthesized and evaluated for supercapacitor applications. The α-MnO₂/ZnO electrode exhibited a remarkable capacitance of 650 F g⁻¹ with a current density of 2 A g⁻¹, which is higher than that of pure α-MnO₂ (452 F g⁻¹). Moreover, the fabricated asymmetric supercapacitor device (α-MnO₂/ZnO//AC) delivered an excellent specific capacitance of 156 F g⁻¹ at 1 A g⁻¹ and an impressive energy density of 55.6 Wh kg⁻¹ in a 1.0 M Na₂SO₄ electrolyte. Additionally, the prepared electrode maintained exceptional stability, preserving approximately 96% capacitance after 6000 cycles. These findings show that the α-MnO₂/ZnO nanocomposite effectively enhances redox activity and offers great potential for practical supercapacitor applications.

Fluorescein-based anionic chemosensors, fluorescein-L-3-phenyl-2-aminopropyl-trimethylammonium tosylate (FPTMATs) and fluorescein-L-3-phenyl-2-aminopropyl-triphenylphosphonium tosylate (FPTPPTs), were synthesized via a mechanochemical route from naturally occurring fluorescein dyes. These sensors exhibit selective optical responses toward specific anions in aqueous methanol (95 : 5 v/v). FPTMATs selectively detects the corrosive bisulfate ion (HSO₄⁻) with a strong fluorescence quenching, while FPTPPTs responds to the toxic cyanide ion (CN⁻) with a colorimetric shift from fluorescent blue to fluorescent green under fluorescent light and marked fluorescence enhancement. The limits of detection (LODs) for HSO₄⁻ using FPTMATs were determined to be 0.3823 µM (UV-vis) and 3.13 nM (fluorescence), whereas for CN⁻ with FPTPPTs the LODs were 2.26 µM (UV-vis) and 51.17 nM (fluorescence), respectively. Mechanistic studies suggest that FPTMATs interacts with HSO₄⁻ (1 : 2 binding) via strong hydrogen bonding and protonation, while FPTPPTs binds with CN⁻ (1 : 1 binding) through a nucleophilic addition and protonation followed by an intramolecular charge transfer mechanism. These results demonstrate the potential of structurally tuned fluorescein derivatives as efficient, selective, and sensitive probes for anion detection in aqueous media.

The site-selective α-C(sp³)–H oxidation of thioethers has been achieved using N-chlorosuccinimide (NCS) as the additive. A variety of thioester derivatives were obtained in good yields with excellent functional group compatibility. Notably, upon the use of thioethers containing α-ester groups, the reaction site shifts to the α-C(sp³)–H bond adjacent to the ester group. Mechanistic studies indicate that water serves as the oxygen source in thioester formation, and this α-C(sp³)–H functionalization strategy proceeds through a cascade α-C(sp³)–H chlorination and hydrolysis.

The anti-Markovnikov hydrogenation of terminal epoxides represents a straightforward strategy for the synthesis of primary alcohols. However, the reductive ring-opening of epoxides typically follows Markovnikov's rule, with secondary alcohols as the major products; thus, the development of catalytic processes that favor primary alcohols as the main products remains a significant challenge. Herein, we report the design and fabrication of a heterogeneous catalyst consisting of yttrium (Y)-doped cobalt (Co) and nickel (Ni) bimetallic species supported on alumina (Al₂O₃), which enables the selective reductive opening of epoxides using molecular hydrogen (H₂) to generate primary alcohols. Benefiting from the tailored electronic properties and acid–base characteristics of the NiCo/Al₂O₃ catalyst induced by Y doping, as well as the synergistic effect of Ni–Co bimetallic species in facilitating the heterolytic cleavage of H₂, the resulting NiCo/Y-Al₂O₃ catalyst achieves a conversion of up to 99% and a primary alcohol selectivity of 96% under mild reaction conditions. Importantly, this catalyst maintains a conversion of 82% and a selectivity of 88% even at a substrate concentration of 40 wt%. Furthermore, it also exhibits excellent stability over five consecutive catalytic cycles without significant degradation in performance.