Tuning The Triplet Excited State Of Pt~Ⅱnd Au~Ⅲ Complexes With Coumarin As Ligands And Their Applications

In recent years, transition metal complexes have applied in many fields, such as:the application of solar cells, photocatalysis, phosphorescent probe, as well as the latest triplet-triplet annihilation (TTA) on up-conversion. Due to diverse excited state properties of the complexs, and their triplet excited states may have long-lived phosphorescence emission, so it is of theoretical significance and great practical value. How to effectively regulate triplet excited state to turn transition metal complexes into the long-lived, high quantum yield of phosphorescence complexes has become a hot research topic in the chemical science. In this thesis, we focused on the N^N Pt(Ⅱ), N^C^N Au(Ⅲ) series of complex. We introduced the ligands with different structures to regulate the nature of their excited states with the purpose on turning their in the photophysical properties. To fully understand grasp the luminescence mechanism of these types of excited state complexes, and to help the design and application of the phosphorescent material.We introduced modified ligands to the metal center with alkynyl, and then design and synthesize N^N Pt (II) and N^C^NAu (Ⅲ) series of complexes. Then, these complexes were fully tested for their luminesence properties, flash photolysis, and low temperature luminesence. At the same time, with the help of Gaussian theoretical calculations,we confirmed that the triplet excited state of these complexs have been adjusted effectively. Coumarin ligand with strong visible light adsorption has been introduced to Pt-2complex to tune the excitation to3MLCT*/3IL*mixed state, and the phosphorescence of triplet excited state of coumarin was observed at room temperature for the first time. The triple excited states life time of Pt-3complexes separately are20.15μs, and its phosphorescent emissions are the emission of3IL*. So we achieve the transition from the short-lived3MLCT*to the long-lived3IL*of complexs effectively. At present, the excited states of Au(Ⅲ) complexes were reported to be short-lived3MLCT*, and their phosphorescence quantum yield are low. After modification, the photophysics of these N^C^N Au(Ⅲ) complexes have been changed dramatically:the excited state lifetime of Au-2and Au-3reach to59.24ms and71.78ms respectively (Au-1excited state lifetime is only0.05μs), the phosphorescence quantum yield reach to0.31%and1.4%, possess a typical3IL*excited state characteristics. We also found that Au-3is a rare dual launch molecule. Based on longer excited lifetime of3IL*complexes, we further tested the performance of the synthetic molecules in the TTA up-conversion and as oxygen sensor, We have realized the conversion of emission light wavelength, and to determine the trace amount of of oxygen in the system, and achieved high quantity of the up-conversion efficiency and the higher determination sensitivity of different oxygen contents. Among them the up-conversion quantum yield of Pt-3reached19.7%, under the same conditions of Pt-1is only8.9%; the up-conversion quantum yield of Au-2and Au-3reached15.7%,20.9%which we measured in certain conditions. The test in Oxygen sensor proved that the longer of lifetime of complexe, the more sensitive to oxygen, the corresponding quench constant KSV is also increased. The results are of great significance and pave the way for the future application of these phosphorescence transition metal complexes.