Synthesis And Properties Of Oxygen Mixture [3] Aromatic Hydrocarbon Fluorescence Sensor

Fluorescent chemosensors for ion recognition have attracted increasing attention because of its high sensitivity, selectivity and simple application. Real-time and real-space analysis of heavy and transition metal(HTM) ions by employing fluorescent probe molecules has received much attention over the past few years. However, fluorescent sensors for heavy metal ions with enhancement fluorescence, have remained rare up to now because these metal ions are known to quench fluorescence emission via enhanced spin-orbital coupling, energy, or electron transfer. Fluorescence quenching is not only disadvantageous for the development of chemosensor but is also undesirable for analytical purpose. Therefore, the critical question now is whether the heavy atom effect caused by HTM ions can be avoided.Calixarenes, the third generation supra molecular compounds, have many advantages such as tunable cavity, flexible conformational change, easily modify and so on. Therefore, fluorescence sensors based on calixarenes as molecular recognition platform have been widely exploited. Among of the fluorophpre, pyrene is one of the most useful for constructing fluorescent chemosensor for its longer fluorescence lifetime, higher fluorescence quantum yield and novel signal excimer-to-monomer emission.In this dissertation, a series of fluorescence enhanced chemosensors based on a homooxacalix[3]arene have been obtained by incorporating pyrene as the fluorophore. The results suggested that the chemosensors have selective recognition ability to heavy metal ion such as Cu2+、Hg2+、Pb2+、Zn2+ in the form of fluorescence enhancement. From these studies, we demonstrated that heavy atom effect caused by HTM ions can be blocked or avoi ded in some case. For example, some benefit proofs for understanding the procedure and effect of heavy atom effect and energy electron transfer between fluorescent chemosensors and heavy atoms have been fully inverstigated and confirmed. Furthermore, in this thesis, we also try to discover how to construct related chemosensors with different structure and geometry to protect the fluorescence of an ionophore from being quenched by heavy atoms. Overall, we expect that the present study will help to extend the design and the applications of fluorescent enhancement chemosensors for heavy metal ions.