A Bis-Quinoline Appended Azobenzene Based Naked Eye Sensor for Selective Detection of Cd2+ Ion
作者:Elango Hrishikesan、Rangasamy Manjunath、Palaninathan Kannan
DOI:10.1007/s10953-016-0473-y
日期:2016.6
A new azobenzene chromophore (AZQU), appended with a bis-quinoline unit as a turn-on chemosensor for selective detection of Cd2+ ions, has been designed and synthesized. The fluorescent receptor AZQU has an excellent selectivity and sensitivity towards Cd2+ ions over other metal ions in CH3CN:H2O (80:20, v/v) solution. AZQU is red colored and non-fluorescent in the absence of Cd2+ ions, but upon addition of Cd2+ ions it turns colorless with appreciable fluorescence. This “off–on” type signaling behavior is attributed to the CHEF (chelation-enhanced fluorescence) effect of the quinoline unit and the change in color from red to yellow occurs by an ICT process with Cd2+. The association constant for AZQU + Cd2+ was calculated to be 1.68 × 105 L·mol−1 with binding in the 1:1 stoichiometric ratio.
设计并合成了一种新型偶氮苯生色团(AZQU),其上附加了一个双喹啉单元,作为Cd2+离子的选择性化学传感器。在CH3CN:H2O(80:20,v/v)溶液中,荧光受体AZQU对Cd2+离子表现出优异的选择性和灵敏度,优于其他金属离子。AZQU在无Cd2+离子时呈红色且无荧光,但加入Cd2+离子后变为无色并发光。这种“关–开”型信号行为归因于喹啉单元的强化配位荧光(CHEF)效应,以及通过与Cd2+的电荷转移过程(ICT)从红色变为黄色。AZQU与Cd2+的结合常数计算为1.68×105 L·mol−1,符合1:1的化学计量比。