A new rhodamine-based derivative bearing a naphthyridine group (compound 1) was synthesized as a colorimetric and fluorescent “off-on” chemosensor for Cu2+ in aqueous solutions. The sensing behaviors of 1 toward various metal ions in neutral aqueous solutions were investigated by absorption and fluorescence spectroscopies. Compound 1 is found to exhibit a significant increase in absorbance at 561 nm and an amplified fluorescence at 590 nm toward Cu2+ in a selective, sensitive and rapid manner. The quantification of Cu2+ by 1 using an absorption spectroscopy method was satisfactory in the linear working range 0.9–10 μM, with a detection limit of 5.4 × 10−8 M for Cu2+ and good tolerance of other metal ions. Upon addition of Cu2+, the spirolactam ring (colorless and nonfluorescent) of 1 was opened to ring-opened amide (red color and fluorescent) and a 1:1 stoichiochemetry for the 1-Cu2+ complex was formed with an association constant of 1.57 × 104 M−1.
一种新的基于
罗丹明并带有
萘啶基团的衍
生物(化合物1)被合成为一种用于检测
水溶液中Cu2+的比色和荧光“开-关”
化学传感器。通过吸收和荧光光谱法研究了化合物1对中性
水溶液中各种
金属离子的感应行为。发现化合物1对Cu2+的选择性、灵敏度和快速性在561纳米处表现出明显的吸光度增加,在590纳米处表现出放大的荧光。在0.9-10微米的线性工作范围内,使用吸收光谱法用化合物1对Cu2+进行定量分析的结果令人满意,对Cu2+的检测限为5.4×10-8M,对其他
金属离子的耐受性也很好。在添加Cu2+后,化合物1的螺内酰胺环(无色且不发光)被打开为环状开环酰胺(红色且发光),并形成1:1的1-Cu2+络合物
化学计量,其结合常数为1.57×104M-1。