Journal of Fluorescence最新文献

To explore new luminescent materials, two novel luminescent salts, [HAD]⁺BSA⁻∙methanol (1) and [HAD]⁺TSA⁻∙methanol (2), incorporating the 4-amino-1,2,4-triazole functional moiety (AD = 4,4'-(4-amino-4H-1,2,4-triazole-3,5-diyl)dianiline), were successfully synthesized through reactions with benzenesulfonic acid and p-toluenesulfonic acid, respectively. Comprehensive characterization via single-crystal X-ray diffraction, FT-IR, UV-Vis, and PXRD revealed distinct photophysical properties governed by their supramolecular architectures. Solid-state emission studies demonstrated blue-shifted maxima at 443 nm for salt 1 and 449 nm for salt 2 compared to the free AD ligand (457 nm), corresponding to shifts of 14 nm and 8 nm, respectively. This emission modulation directly correlates with π∙∙∙π stacking interactions, where shorter stacking distances in salt 1 (3.878 Å) versus salt 2 (4.406 Å) enhance intermolecular electronic coupling. Hirshfeld surface analysis confirmed stronger C∙∙∙H contacts in salt 1, consistent with its more pronounced stacking interactions and shorter emission wavelength. The lifetimes can be observed to 1.41, 0.96 and 0.90 ns, while the quantum yields of compounds can be found to be 0.20, 0.26 and 0.38 for AD, 1 and 2, respectively. The study establishes definitive structure-property relationships, demonstrating that strategic manipulation of weak intermolecular forces provides an effective pathway for engineering luminescent properties in triazole-based materials through crystal engineering.

Levofloxacin (LEV) and ciprofloxacin (CIP) are widely common antibiotics. However, their misuse can lead to bacterial resistance and pose significant risks to both environment and human health. To address this issue, we synthesized and characterized two novel fluorescent composite materials: Fe₃O₄/HAP/Eu and Fe₃O₄/HAP/Tb. Fe₃O₄/HAP/Eu was designed for detection of LEV, whereas Fe₃O₄/HAP/Tb was developed for detection of CIP. The results showed that Fe₃O₄/HAP/Eu exhibited optimal excitation and emission wavelengths of 394 nm and 624 nm, respectively, with the fluorescence lifetime of 0.77 µs and the fluorescence quantum yield of 6.61%. Fe₃O₄/HAP/Tb performed optimal excitation and emission wavelengths of 370 nm and 551 nm, respectively, with the fluorescence lifetime of 1.06 µs and the fluorescence quantum yield of 8.28%. In terms of application, the linear range for detection of LEV was 1-50 µM, with detection limit of 0.67 µM. For CIP, linear range was 0.1-60 µM, and the detection limit was 0.086 µM. The two types of fluorescent composite provided reliable approach for detecting trace amounts of LEV and CIP in food. It demonstrated significant potential for practical applications in the fields of environment, food and medicine.

In this study, a dual-ratiometric optical probe utilizing europium-doped carbon dots (Eu-CDs) was developed for simultaneous fluorescent and colorimetric detection of tetracycline (TC). The Eu-CDs complex was synthesized through a hydrothermal approach. Upon coordination with Eriochrome Black T (EBT), the Eu-CDs complex exhibits a distinct magenta coloration. Introduction of TC triggers a ligand displacement reaction, resulting in color transition from magenta to blue, resulting in ratiometric colorimetric visual detection. Meanwhile, the TC-bound EBT-CDs@Eu complex emits ratiometric fluorescence change. A ratiometric fluorescence detection method was established for TC based on the absorbance-energy transfer-emission (AETE) mechanism, culminating in the successful design of a dual-ratiometric optical probe. The colorimetric assay demonstrated a detection limit (LOD) of 20.5 nM for TC. Furthermore, the practical applicability of this sensor was validated through successful TC detection in aquaculture samples, highlighting its potential for real-world monitoring applications.