A simple thiocarbazone-appended coumarin derivative 1 with high selectivity as a ratiometric fluorescence sensor towards Cu²⁺ and Zn²⁺ in a semi-aqueous solution was synthesised and characterised. Upon the addition of Cu²⁺ and Zn²⁺, the emission of 1 solution undergoes a blue and red shift to 480 and 545 nm according to the intense blue and yellow colour under a 365-nm ultraviolet lamp, respectively. Binding was confirmed by ultraviolet-visible absorption analysis, fluorescence measurement, mass spectrometry, proton nuclear magnetic resonance, Fourier Transform-infrared spectroscopy and density functional theory calculation. The results show that 1 coordinated with Cu²⁺ and Zn²⁺ in different modes, resulting in different ratiometric fluorescence responses. The detection limits of the sensor 1 for Cu²⁺ and Zn²⁺ were 100.8 and 11.5 nM, respectively. The association constants (K_a) of Cu²⁺ and Zn²⁺ with 1 were determined to be 5.59 × 10⁴ and 5.08 × 10⁴ M⁻¹, respectively. Fluorescent microscopy experiments demonstrated that probe 1 has the potential to be used to monitor Zn²⁺ and Cu²⁺ in living cells.

中文翻译：

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Thiocarbazone 附加香豆素：一种用于多分析物（Zn2+ 和 Cu2+）系统的易于获得的比率荧光化学传感器

合成并表征了一种简单的含硫脲的香豆素衍生物1 ，该衍生物 1 作为对半水溶液中Cu ²⁺和 Zn ²⁺的比率荧光传感器具有高选择性。在加入 Cu ²⁺和 Zn ²⁺后， 在 365 nm 紫外灯下，根据强烈的蓝色和黄色， 1溶液的发射分别经历蓝移和红移至 480 和 545 nm。通过紫外-可见吸收分析、荧光测量、质谱、质子核磁共振、傅里叶变换-红外光谱和密度泛函理论计算证实了结合。结果表明，1与不同模式的Cu ²⁺和Zn ²⁺配位，产生不同的比率荧光响应。传感器1对 Cu ²⁺和 Zn ²⁺的检测限分别为 100.8 和 11.5 nM。Cu ²⁺和Zn ²⁺与1的缔合常数( K _a )分别确定为5.59×10 ⁴和5.08×10 ⁴  M ^-1。荧光显微镜实验表明，探针1 具有用于监测 Zn ²⁺和 Cu ^2+的潜力在活细胞中。