Kumar Malavika S, Das Avijit Kumar
Department of Chemistry, Christ University Hosur Road Bangalore Karnataka 560029 India
RSC Adv. 2025 Sep 11;15(39):32894-32905. doi: 10.1039/d5ra05068e. eCollection 2025 Sep 5.
A fluorescent naphthalene-anthracene dyad (AMN) was developed as a dual-mode sensor for turn-on detection of ammonia (NH) and turn-off detection of picric acid (PA). AMN initially emits strong fluorescence at 427 nm due to excited-state intramolecular proton transfer (ESIPT), showing a large 62 nm Stokes shift. Upon PA addition, fluorescence is quenched and red-shifted to 463 nm. Conversely, NH induces a red shift to 435 nm. These spectral responses are attributed to ESIPT inhibition strong hydrogen bonding between the hydroxyl group of AMN and the analytes. AMN has been successfully applied in dipstick-based PA detection and as a low-cost food spoilage indicator for NH. Detection limits are 8.77 μM for PA and 5.29 μM for NH, with a Stern-Volmer constant of 5.62 × 10 M for picric acid. Additionally, AMN shows ratiometric fluorescence upon interaction with BSA and ct DNA, accompanied by notable absorption changes. These findings, supported by UV-vis, fluorescence spectroscopy, NMR, molecular docking, and DFT studies, underscore the potential of AMN as a multifunctional fluorescent sensor for environmental and biological applications.
一种荧光萘 - 蒽二元化合物（AMN）被开发为一种双模式传感器，用于开启式检测氨（NH₃）和关闭式检测苦味酸（PA）。由于激发态分子内质子转移（ESIPT），AMN最初在427 nm处发射强荧光，显示出62 nm的大斯托克斯位移。加入PA后，荧光猝灭并红移至463 nm。相反，NH₃会使其红移至435 nm。这些光谱响应归因于ESIPT抑制——AMN的羟基与分析物之间形成了强氢键。AMN已成功应用于基于试纸条的PA检测，并作为NH₃的低成本食品变质指示剂。PA的检测限为8.77 μM，NH₃的检测限为5.29 μM，苦味酸的斯特恩 - 沃尔默常数为5.62×10⁴ M⁻¹。此外，AMN与牛血清白蛋白（BSA）和小牛胸腺DNA（ct DNA）相互作用时表现出比率荧光，并伴有显著的吸收变化。这些发现得到紫外 - 可见光谱、荧光光谱、核磁共振、分子对接和密度泛函理论（DFT）研究的支持，强调了AMN作为一种用于环境和生物应用的多功能荧光传感器的潜力。
