Design, Synthesis Of Quinoline-based Fluorescent Chemosensors And Study Of Recognition Properties

Fluorescent chemosensors not only could realize the rapid and real-time detection of guest molecules, but also have the advantages such as high selectivity, high sensitivity and expedience of operation. Considerable research interests have been focused on the development of chemosensors for the selective and efficient detection of chemically and biologically important ionic species in biological, materials science and environmental science. Based on this, we have designed and synthesized two kinds of quinoline-based fluorescent chemosensors, and studied the properties of selective recognition for ions. Meanwhile, we apply them to carry out biological cell imaging, and achieved some interesting results. All the compounds obtained were characterized by1H NMR,13C NMR and LC-MS.1. The design principle and mechanism, influence factors, research history and status on fluorescent sensors for Zn2+and CIO-have been reviewed.2. Based on intermolecular charge transfer (ICT) mechanism, the sensor DZn for the detection of Zn2+was designed and synthesized. Phenylethynyl group was linked to the6-position of the quinoline skeleton, which could increase the rigidity of conjugate plane, and improve the optical properties of the system. The Bromo butoxy group was introduced at the para position of the phenyl ring to achieve ICT process. Meanwhile, we introduced Quaternary phosphonium salt to target mitochondria. DPA was introduced at the2-position of the quinoline skeleton as the recognition group for Zn2+. After the complex of Zn2+, this system exhibits obvious fluorescence enhancement, and fluorescence generated68nm red-shift. Furthermore, we researched on sensor’s biological cell imaging, and DZn showed the specific recognition for Zn2+within the cell.3.Based on optical dual mechanism, we designed and synthesized a sensor6-MPQO, which can identify CIO-by using Oxime group.4-Methoxy phenylethynyl group was linked to the6-position of the quinoline skeleton, which could increase the rigidity of conjugate plane, and improve the optical properties of the system. Oxime was get by the reaction of aldehyde of quinoline skeleton and hydroxylamine hydrochloride, and the hydroxyl hydrogen and the nitrogen atom on the quinoline ring could formed a hydrogen bond. After the addition of CIO-ions, the structure of hydrogen bond was destroyed, which led to the change of UV-vis and fluorescence spectra, and the color of the solution also changed from yellow to colorless. We researched on sensor’s biological cell imaging, and6-MPQO showed the specific recognition for CIO" within the cell.