一种用于识别Cu2+的荧光增强型化学传感器的合成及性能研究

通过对香豆素母体结构进行修饰,采取7-位引入二乙基氨基供电子基团,3-位引入酰胺基吸电子基团,成功制备了一种结构简单的荧光化学传感器:7-二乙氨基-N'-(2,4-二硝基苯基)-2-氧代-2H-色烯-3-甲酰肼,并通过1HNMR、13CNMR和ESI-HR-MS对其结构进行表征。传感器对Cu^2+显示出明显的“off-on”型荧光增强响应,荧光强度增强了21.8倍,Stokes位移为2033 cm^-1,检测限为0.52μmol/L。由Job曲线可知,传感器和Cu^2+之间的配位比为2∶1,通过推测,传感器对Cu^2+的识别机理属于光诱导电子转移机理(PET)。pH测试结果表明,传感器适宜的pH范围为7~8.5。

Synthesis and Properties of a Fluorescent Enhanced Chemosensor for the Recognition of Cu2+

A new coumarin based fluorescent chemosensor 7-(diethylamino)-N'-(2,4-dinitrophenyl)-2-oxo-2H-chromene-3-carbohydrazide was successfully synthesized,in which diethylamino and amide were introduced as electron-donating group and electron-withdrawing group,respectively.The chemical structure of the sensor was confirmed by 1HNMR,13CNMR and ESI-HR-MS.The sensor showed obvious“off-on”type fluorescence enhancement response to Cu^2+ ion,fluorescence intensity increased by 21.8 times,the Stokes shift was 2033 cm^-1,and the detection limit was 0.52μmol/L.To illustrate the mechanism of the sensor towards binding of Cu^2+ions,a Job's plot analysis was performed,the results of Job's plot indicated that the sensor and Cu^2+ ion coordinated with each other with a binding stoichiometry of 2∶1.After speculation,predicting that the recognition mechanism of Cu^2+ by the sensor belong to photoinduced electron transfer mechanism(PET).And the pH test results showed that the most suitable pH range for the sensor was 7~8.5.