A new donor-π-acceptor derived from phenothiazine, namely 2-(2-((10-hexyl-10H-phenothiazin-3-yl)methylene)-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (PTZON) was synthesized and fully characterized, and its potential as a fluorescent sensor for cyanide anion was investigated. The PTZON showed a visible absorption band at 564 nm corresponds to an intramolecular charge transfer (ICT) and an emission band at 589 nm in CH3CN/H2O. The results of cyanide anion titration revealed ratiometric changes in both absorption and fluorescence spectra as a result of the nucleophilic addition of cyanide anion via Michael addition. The optical studies, FT-IR spectra, NMR, high-resolution mass, and DFT calculations confirmed the sensing mechanism. The selectivity of PTZON as a cyanide anion fluorescent sensor was proved in mixed solvent solutions, and the sensitivity was as low as 0.011 µM, which is far lower than the value allowed by the United States Environmental Protection Agency for drinking water (1.9 µM). Also, the detection limit of PTZON was assessed to be 3.39 μM by the spectrophotometric method. The binding stoichiometry between PTZON and cyanide anion was found to be 1:1 as evidenced by mass spectra. TLC silica-coated plates test strips demonstrated the fluorescent detection of cyanide anion.

中文翻译：

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一种新的基于吩噻嗪的氰化物选择性视觉和荧光传感器。

衍生自吩噻嗪的新的供体π受体，即2-（2-（（（10-己基-10H-吩噻嗪-3-基）亚甲基）-3-氧代-2,3-二氢茚-1-基）丙二腈（合成并充分表征，并研究了其作为氰化物阴离子荧光传感器的潜力。PTZON在CH3CN / H2O中的564 nm处具有可见的吸收带，对应于分子内电荷转移（ICT），在589 nm处具有发射带。氰化物阴离子滴定的结果表明，通过迈克尔加成亲核加成氰化物阴离子，可以使吸收光谱和荧光光谱发生比例变化。光学研究，FT-IR光谱，NMR，高分辨率质量和DFT计算证实了传感机制。在混合溶剂溶液中证明了PTZON作为氰化物阴离子荧光传感器的选择性，灵敏度低至0.011 µM，远低于美国环境保护局对饮用水的允许值（1.9 µM）。另外，通过分光光度法将PTZON的检出限评价为3.39μM。质谱表明，PTZON和氰化物阴离子之间的结合化学计量为1：1。TLC硅胶板检测条证明了氰化物阴离子的荧光检测。