A simple azo-dye based bis-Schiff base chemosensor, L, has been designed, synthesized and characterized by NMR and IR spectroscopy, ESI-MS and elemental analysis. The chemosensor L can successfully detect sulfide ions both visually and spectro-photometrically in perfect aqueous medium as well as in an organic–aqueous mixture through a de-protonation mechanism. The detection limit reaches 16 μM in pure aqueous medium (1.7 μM by UV-vis titration and 3.35 × 10⁻⁷ M by fluorescence titration in a 1 : 1 DMSO–H₂O mixture), which is the lowest detection limit ever reported in the family of Schiff base chemosensors for sulfide ions. Other interfering anions (F⁻, Cl⁻, Br⁻, HSO₃⁻, N₃⁻, PO₄³⁻, NO₃⁻, OAc⁻, CO₃²⁻ and CN⁻) exhibited no interference for the detection of sulfide ions. The mechanism of interaction between L and sulphide ions has further been confirmed by DFT studies. The chemosensor L has also been applied for real sample analysis and in building a molecular logic gate.

中文翻译：

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一种基于荧光比色偶氮染料的化学传感器，用于检测完美水溶液中的S ²⁻，及其在实际样品分析和建立分子逻辑门中的应用†

设计了一种简单的基于偶氮染料的双Schiff碱化学传感器L，并通过NMR和IR光谱，ESI-MS和元素分析对其进行了表征。化学传感器L可以通过去质子化机制，在理想的水性介质以及有机-水性混合物中，通过视觉和分光光度法成功地检测出硫化物离子。在纯水介质中的检出限达到16μM（在1：1 DMSO–H ₂ O混合物中，通过UV-vis滴定测得1.7μM，通过荧光滴定测得3.35×10 ^-7 M ），这是有史以来最低的检出限用于硫化物离子的席夫碱化学传感器家族。其他的干扰阴离子（F ^- ，氯^- ，溴^-，HSO ₃ ^-，N ₃ ^-，PO ₄ ^3-，NO ₃ ^-，OAC ^-，CO ₃ ^2-和CN ^- ）显示出用于检测硫化物离子的无干扰。DFT研究进一步证实了L与硫化物离子之间相互作用的机理。化学传感器L也已用于实际样品分析和构建分子逻辑门。