Theoretical Study On The Floureence Recognion Performance Of Rhenium(?)Complexes On Different Ions

With the development of society,the use of fluorescent sensors to identify small organic molecules and anionic metal ions has been a hot topic in scientific research.Fluorescent probes possess a variety of advantages,such as simple operation,high sensitivity,wide selectivity and detection range,convenient use,low cost,no pretreatment required,and long-distance luminescence.Fluorescent recognition plays an important role in environmental and biological monitoring as well as medical testing.In recent years,fluorescent recognition agents based on rhenium complexes have been researched continuously in the design and synthesis.Because the rhenium complexes have good thermal stability and relatively short excited state lifetime and high quantum efficiency.It is important to study and analyze the structure characteristics and spectral properties for developing new fluorescent probesBased on the structure of experimentally synthesized rhenium complex,we designed new molecular by changing the ligand.The molecular structures,molecular orbital and spectral properties are analyzed by quantum chemical calculation methods.The solvation effect is taken into consideration.Meanwhile,we have investigated the performance of rhenium complexes to identify different ions by comparing the changes of the spectral nature.It provides the theoretical basis to synthetic the new fluorescent probes based on rhenium complexes.The main content is as follows:1.The different substituents effects of rhenium tricarbonyl diimine complex on the recognition of dihydrogen phosphate are studied.By introducing different electron withdrawing groups(-NO₂,-F,-C?C),a series of complexes are designed.The DFT/TDDFT method was used to explore the electronic structure and spectral properties of complexes,The results show that the spectrum has a blue shift with the enhancement of the electron-withdrawing ability.When the complex is combining with dihydrogen phosphate,the spectrum is red-shifted obviously compared with parent complex.The absorption and emission spectra can be obtained in the visible light region.Complex 5(-NO₂)shows better recognition ability for dihydrogen phosphate,and both the absorption and emission spectra are found the largest shift.2.The performance of rhenium complexes with different rigid ligands(O^O)to recognize small organic molecules anthracene and nitrobenzene is studied.The electronic structures and spectral properties of these complexes are researched.It show that the electronic structure,and orbital properties of HOMO and LUMO are affected by different rigid ligands.The complex 4(2,3,5,6-tetrahydroxy-[1,4]benzoquinone)has better ability to recognize small molecules of anthracene(An)and nitrobenzene(NB)in organics.