Investigation On Phosphorescent Chemodosimeter Based On Planar Pt(?) Complexes

With the development of material science,the research field of functional materials is undergoing a series of changes and extensions.As one kind of functional materials,luminescent materials has attracted more and more attention currently.There is no doubt that chemosensors are a kind of useful tool for detecting the specific analytes through the change of optical spectrum,which has become a research hotspot in the fields of analytical chemistry and functional materials.Compared with traditional organic fluorescent dye chemodosimeters,phosphorescent chemodosimeters based on heavy metal complexes have unique characteristics and advantages?such as stable luminescence,large Stokes shift,longer luminescence lifetime and adjustable emission wavelength?,which play irreplaceable roles in chemical analysis,biomarkers and disease diagnosis.Among phosphorescent chemodosimeters,platinum complex-based phosphorescent chemodosimeters have gained intense attention because of its own special physical and chemical properties.However,researches on the design and application of platinum complex-based phosphorescent chemodosimeters are relatively rare.Therefore,we hope to design and develop valuable platinum complex-based phosphorescent chemodosimeters,which may not only be helpful to further understand the properties of platinum complex and recognize mechanism of phosphorescent chemodosimeter,but also be valuable for finding novel functional material system and developing new applications.The main content of the thesis:Chapter 1:The review part introduces the typical design principles,design patterns,development status and luminescent mechanism of phosphorescent chemosensors.Some important design ideas and applications of Pt???complex-based phosphorescent chemosensors are summarized and introduced.Chapter 2:We designed and synthesized a new platinum???complex-based phosphorescent chemodosimeter Pt-1,which linked deliberately by square-planar Pt???complex with red phosphorescence and Hg²⁺-selective recognition moiety.The irreversible chemical reaction of reactive recognition moiety could change dramatically the structure of Pt???complex and affect significantly the self-aggregation of Pt???complexes in the presence of Hg²⁺ions,resulting in phosphorescent and colorimetric response toward Hg²⁺in aqueous solution.The change of self-aggregation and sensing process were analyzed in detail by luminescence spectra,transmission electron microscopy and dynamic light scattering.Furthermore,the self-aggregation modulation was applied to eliminate the interference and improve the signal-to-noise ratio for the detection of Hg²⁺by using time-resolved photoluminescence.The cellular imaging showed that not only was the Pt???complex-based phosphorescent material a very good staining dye compatible with the DNA staining dye,but could monitor intracellular Hg²⁺effectively by luminescence imaging.Chapter 3:We designed and synthesized a platinum???complex-based phosphorescent chemodosimeter Pt-2,which showed very weak phosphorescent emission at low concentration in aqueous solution but presented remarkable red phosphorescent emission in the presence of perchlorate.The photophysical properties and sensing process of Pt-2 were analyzed in detail by luminescence spectra,transmission electron microscopy and dynamic light scattering.The results showed that Pt-2 could form nanoscale self-aggregation status with the help of the stronger hydrogen bonding interactions between platinum complexes and guest perchlorate anions when perchlorate was added,resulting in aggregation-induced luminescence enhancement.According to the result,we futher understood the effects of self-aggregation and Pt-Pt interaction on the luminescence of Pt???complexes.