New Journal of Chemistry最新文献

Based on the chemical structure and luminescence mechanism of luminol, the synthesis of luminol analogues has been widely studied. However, luminol and its derived reagents are still suffering from some drawbacks, such as short luminescence time and weak intensity. Herein, we designed and synthesized a novel hydroxyphenyl benzothiazole-based phthalhydrazide derivative DAH-AMPH, which has a hydroxyphenyl benzothiazole structure as a strong fluorescent site and a cyclic phthalhydrazide structure as a chemiluminescence (CL) emitting site. DAH-AMPH exhibited excellent CL properties in the DAH-AMPH/UHP/hemin CL system for hemin detection with a wide linear range of 0.1 nM to 20.0 nM and low LOD of 3 pM. It exhibited good selectivity in bloodstain imaging on different substrate materials. The DAH-AMPH/UHP/hemin CL system represents a powerful tool for trace detection of bloodstains. Moreover, as a new CL substrate for HRP, DAH-AMPH showed high sensitivity (0.8 pg mL⁻¹ of LOD) in the DAH-AMPH/UHP/SPTZ/MORP/HRP CL system indicating bright prospects for the use of DAH-AMPH in heme-containing peroxidase detection.

Correction for ‘Synthesis of chiral hexynones for use as precursors to native photosynthetic hydroporphyrins’ by Khiem Chau Nguyen et al., New J. Chem., 2024, 48, 2097–2117, https://doi.org/10.1039/D3NJ03900E.

The present study explores the properties of a chitosan-decorated graphene oxide–silver (chitosan@GO–Ag) composite hydrogel, with a focus on its improved rheological characteristics and notable biological activity. The antimicrobial performance of chitosan@GO–Ag was assessed against Streptococcus mutans, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, revealing substantial inhibition zones, underscoring its potential as an effective antimicrobial agent. To evaluate the safety profile of the composite, genotoxicity assays were conducted using zebrafish embryos, providing insights into its toxicity levels. Comprehensive rheological tests were also performed to examine the hydrogel's viscoelastic properties, such as storage and loss moduli, as well as its flow behavior under various stress conditions. These rheological assessments shed light on the mechanical stability and gelation properties of chitosan@GO–Ag, which are closely related to its antimicrobial effectiveness and cytotoxicity, especially through their impact on the structural robustness of the composite. The synthesized chitosan@GO–Ag hydrogels demonstrated significant mechanical strength, with a linear viscoelastic region (LVER) ranging approximately from 0.01 to 014%, shear thinning behavior and well fitted to the Herschel–Bulkley model. Additionally, they exhibited strong antimicrobial activity against both Gram-positive and Gram-negative bacteria, with zones of inhibition (ZOIs) measured between 31 and 40 mm. Key rheological parameters such as critical strain, yield strain and crossover points were also determined, providing a comprehensive view of the material's stability and performance. In addition to mechanical stability, swelling behavior was evaluated over 15 hours at definite time intervals to understand the hydrogel's ability to absorb and retain water. This assessment revealed the hydrogel's high swelling capacity, indicative of its potential applications in the biomedical field. Furthermore, stability studies were performed under varying conditions to determine the long-term usability of the hydrogel in physiological environments. These investigations confirmed the structural integrity and sustained performance of the hydrogel, reinforcing its suitability for biomedical and antimicrobial applications.

Electrocatalytic nitrate reduction (NO₃⁻RR) provides an environmentally friendly alternative to the traditional Haber–Bosch technology for ammonia (NH₃) production. Herein, cupric oxide (CuO) nanorods (NRs) were synthesized by a simple one-pot method and applied as NO₃⁻RR electrocatalysts. Due to the nanorod-like structure and large specific surface area, the CuO NR electrocatalyst exhibited excellent NO₃⁻RR performance. The electrocatalyst experienced in situ reconstruction and its phase partly changed from CuO to Cu/Cu₂O in the process of the NO₃⁻RR. The formed Cu/Cu₂O/CuO mixed valence state promoted its catalytic activity for the NO₃⁻RR. At −0.7 V potential, the faradaic efficiency and NH₃ yield could reach 94% and 28.76 mg h⁻¹ mg_cat⁻¹, respectively, along with excellent durability for 10 h.

Unlike synthetic dyes that produce a single hue, natural dyes offer a rich spectrum of colors. In old times, artisans controlled these colors through their expertise, making the results dependent on each dyer's skill and subjectivity. Nowadays, modern computational methods allow precise predictions of visible absorption spectra, enabling a more standardized color control. However, most studies focus on individual molecules, while natural dyes are made of complex mixtures. We address this gap by proposing improved methods for predicting the spectra of a mixture of natural dyes, focusing on the madder plant, a renowned source of complex colorants. Molecular compositions were determined using liquid chromatography, and the visible spectrum of the mixture was computed, converted to standard color coordinates, and compared with experimental data. Our approach achieved high accuracy, with deviations within accepted theoretical error margins, and successfully handled large molecules with sugar groups. Our workflow can be used for other various chemical systems, notably dye mixtures.

Herein, we describe a new methodology for selective cephalosporin functionalization at the C3 position. First, an optimization study of the reaction conditions was performed and allowed favourable parameters for the Suzuki–Miyaura coupling reaction to be defined. Then, the scope of the reaction was evaluated using various boronic acids, and the reaction demonstrated a good functional-group tolerance profile. Finally, the formation of some side-products was also investigated, and the main limitations of the reaction were defined.

We synthesized NaYF₄:Yb³⁺/Er³⁺ nanorods (NRs) through a hydrothermal process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed that these nanorods are composed of smaller NaYF₄:Yb³⁺/Er³⁺ nanocrystals. Subsequent annealing treatments caused these nanocrystals to fuse into larger structures. We incorporated the NaYF₄:Yb³⁺/Er³⁺ NRs into a mesoporous TiO₂ film to create NaYF₄:Yb³⁺/Er³⁺ NR/TiO₂ photoanodes for application in dye-sensitized solar cells (DSSCs). Our investigation focused on how variations in the structure and doping concentration of NaYF₄:Yb³⁺/Er³⁺ NRs within the TiO₂ matrix affected the photovoltaic performance of the DSSCs. Notably, the photoanode that incorporated 1.0 wt% NaYF₄:Yb³⁺/Er³⁺ NRs, annealed at 500 °C, exhibited superior photovoltaic performance, achieving a short-circuit current density (J_sc) of 10.60 mA cm⁻² and a power conversion efficiency (PCE) of 6.20%. This represents a 31.35% increase in J_sc and a remarkable 95.58% improvement in the PCE compared to the reference TiO₂-based DSSC, which had a J_sc of 8.07 mA cm⁻² and a PCE of 3.17%. The enhancements in photovoltaic performance can be attributed to the upconversion properties of NaYF₄:Yb³⁺/Er³⁺ NRs and their ability to facilitate charge separation, which ultimately improves the efficiency of the solar cells.

The selective extraction of lithium from salt lake brines has attracted widespread attention with the rapid increase in demand for lithium. Since Mg²⁺ and Li⁺ are chemically similar, this poses a huge challenge to the selective extraction of Li⁺ from salt lake brines with a high Mg/Li ratio. This paper reports a new amide extractant, N,N-dioctyl-2-methoxyacetamide, and constructs an N,N-dioctyl-2-methoxyacetamide-FeCl₃-sulfonated kerosene extraction system. The effects of operating conditions on the Li⁺ extraction performance are investigated. Under the optimal operating conditions by three-stage countercurrent extraction, the extraction rate for Li⁺ could reach 97.5%, and the separation factor of Li/Mg reaches 1225. After washing the impurity ions in the organic phase with an HCl + LiCl mixed solution, HCl is used for back extraction, achieving a 95% back extraction rate of Li⁺. During the five extraction cycles, the extraction efficiency of Li⁺ remained above 70%, indicating that the extraction system has good stability and reusability. In addition, the extraction system operates at low acidity, which can effectively avoid the formation of phase interfaces and does not produce emulsification. This work provides a new way to selectively recover lithium from high Mg/Li ratio salt lake brines.

Dyed crystals belong to the family of mixed or composite crystals, which are usually studied for solid-state laser devices. However, there have been few studies on their third-order nonlinear optical properties under nanosecond pulsed laser irradiation. In this work, potassium acid phthalate (KAP) was chosen as the matrix crystal. KAP crystals were doped with different functional dyes, such as basic fuchsin (BF), acid fuchsin (AF) and neutral red (NR), through evaporation technology. The third-order nonlinear optical properties of dyed KAP crystals were studied using the Z-scan technique. KAP crystals doped with BF, AF and NR exhibited saturable absorption at 532 nm. Compared with the property of dyes in solution, the saturated absorption performance of dye-doped KAP crystals was improved significantly. For example, the nonlinear absorption coefficient (β) and the imaginary part of the third-order NLO susceptibility (Imχ⁽³⁾) of AF increased from −13.11 cm GW⁻¹ to −247.44 cm GW⁻¹ and from −6.54 × 10⁻²⁰ to −1.23 × 10⁻¹⁸ esu after the incorporation of KAP crystals. These results indicate that dyed KAP crystals are promising third-order nonlinear optical crystal composites.

The isomerization between dimethyldihydropyrene (DHP) and cyclophanediene (CPD) generates a potential molecular switch, while topological regulation can provide an effective strategy to tune its optical response and switching efficiency. In this work, we twisted a fused pyridine structure into three topological configurations, namely, Hückel, Möbius and twisted-Hückel (t-Hückel), and integrated them at both ends of a DHP/CPD switch. By theoretical calculation, we determined the effect of topological characteristics on the molecular structure, electronic state and optical properties of these configurations. Especially for Hückel and Möbius molecules, CPD was in a closed-shell state, and DHP showed a diradical property. However, for t-Hückel molecules, CPD and DHP were both in open-shell singlet states. The topological effect was significant on absorption intensity in the 200–500 nm range for both the open- and closed-ring structures. Within the framework of Hückel, β_tot gradually decreased from Möbius to t-Hückel for closed-ring structures as the degree of twisting of the pyridine ring increased, but an opposite tendency was noted in open-ring systems. Consequently, the Hückel-type switches demonstrated high efficiency, with a β(C)/β(O) ratio of 12.6. The DHP derivative with Hückel-type molecules exhibited the best nonlinear optical response due to the highly conjugated structure with the largest first-order hyperpolarizability of the closed-ring structure (β_tot = 3.17 × 10⁴ a.u.). This work highlights the crucial role of the topological structure in regulating the performance of switch molecules and provides insights for the design of switch molecules with unique topological structures.