Abstract A novel dicyanomethylene-4H-pyran-based sensor bearing 2-thiophenecarbonyl as a masking group was established for the detection of cyanide anions. Upon the addition of cyanide, sensor 1 manifested a near-infrared emission band at 717 nm, with an extremely large red-shift (~180 nm) in the absorption spectrum. It also showed an obvious color change from yellow to green. Sensor 1 was used to sensitively measure CN− with low detection limit of 1.44 μM. The stoichiometric ratio between probe and CN− were determined as 1:1, with the association constant of 7.87 × 102 M−1. The reaction mechanism was investigated by ESI-MS, 1H NMR, HPLC, and density functional theory methods. Results indicate that the nucleophilicity of the cyanide catalyzes the elimination of 2-thiophenecarbonyl, which strengthens the intramolecular charge transfer effect of the dicyanomethylene-4H-pyran fluorophore. Furthermore, sensor 1 was found to be efficient in detecting cyanide in the intracellular region of MCF-7 cells.

中文翻译：

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基于二氰基亚甲基-4H-吡喃的用于氰化物检测的近红外比色荧光双通道探针

摘要 建立了一种以2-噻吩羰基为掩蔽基团的新型二氰基亚甲基-4H-吡喃传感器，用于检测氰化物阴离子。添加氰化物后，传感器 1 在 717 nm 处显示出近红外发射带，在吸收光谱中具有极大的红移（~180 nm）。它还表现出明显的颜色变化，由黄色变为绿色。传感器 1 用于以 1.44 μM 的低检测限灵敏地测量 CN-。探针和CN-之间的化学计量比确定为1:1，结合常数为7.87 × 102 M-1。通过ESI-MS、1H NMR、HPLC和密度泛函理论方法研究了反应机理。结果表明氰化物的亲核性催化了 2-噻吩羰基的消除，这加强了二氰基亚甲基-4H-吡喃荧光团的分子内电荷转移效应。此外，发现传感器 1 可有效检测 MCF-7 细胞胞内区域的氰化物。