Abstract：
An efficient and anions fluorescence \"on-off\" sensor of 1-(prop-2-yn-1-yl)-3-(quinolin-3-ylimino)indolin-2-one (PQI) has been developed for the selective sensing of dual anions of F- and NO3- ions in aqueous medium. Active hydrogen and Lewis acidic binding sites free, Z- isomer of isatin based π-conjugated quinoline exhibited excellent sensing activity against F- and NO3- ions in UV light. The fluorescence turns on the process accomplished via the PET \"on-off\" mechanism. The interaction between probe molecule and anions is thought to be a non-covalent interaction of the low electron density covalently bonded N-methylene moiety of propargyl isatin (-N-CH2-) of probe molecule with F- ion and the terminal acidic proton of propargyl group of isatin (-C≡C-H) with NO3- ions. The modes of anions binding with PQI and plausible mechanisms are proposed by 1H and 13C NMR titrations. The selectivity of anions sensing may be offered by the bucked structure of the Z-isomer. The calculated association constant values for PQI and F- and NO3- are ions 2.5 × 104 M-1 and 2.2 × 103 M-1, respectively, indicating strong binding interaction between the PQI and anions. The association nature of anions and probes was analyzed by a Jobs plot and the finding indicates both F- and NO3- ions are in 1:1 complexation with PQI. The limit of detection (LOD) of the probe with F- and NO3- ions is calculated and is to be 6.91 × 10-7 M and 9.93 × 10-7 M, respectively. The proposed PQI fluorophore possesses a low limit of detection (LOD) for both F- and NO3- ions which is within the WHO prescribed detection limit.
摘要：
已开发出一种有效的阴离子荧光“开-关”传感器1-（丙-2-炔-1-基）-3-（喹啉-3-亚氨基）吲哚啉-2-酮（PQI），用于选择性传感水介质中F-和NO3-离子的双阴离子。活性氢和路易斯酸结合位点自由，基于Isatin的Z-异构体的π-共轭喹啉在紫外光下对F-和NO3-离子表现出优异的传感活性。荧光开启了通过PET“开-关”机制完成的过程。探针分子与阴离子之间的相互作用被认为是探针分子的炔丙基拉丁的低电子密度共价键合的N-亚甲基部分（-N-CH2-）与F-离子和末端酸性质子的非共价相互作用。与NO3-离子。通过1H和13CNMR滴定提出了阴离子与PQI结合的模式和合理的机理。阴离子传感的选择性可以由Z-异构体的阻塞结构提供。计算出的PQI和F-和NO3-的缔合常数值分别为离子2.5×104M-1和2.2×103M-1，表明PQI和阴离子之间的强结合相互作用。通过乔布斯图分析了阴离子和探针的缔合性质，发现表明F-和NO3-离子均与PQI1：1络合。经计算，F-和NO3-离子探针的检测限（LOD）为6.91×10-7M和9.93×10-7M，分别。所提出的PQI荧光团对F-和NO3-离子都具有低检测限（LOD），该检测限在WHO规定的检测限之内。
