Study On The Luminescent Switching Properties Of Pt(Ⅱ) Complex Based On 2-phenylpyridine Derivatives

The luminescent switching materials will change its luminescence(color)significantly after being stimulated by external signals.Therefore,these materials have important application prospects in many fields such as environmental detection,medical and military,biosensing,communications,and information storage.In this thesis,Eight kinds of cyclometalated Pt(Ⅱ)complexes were designed and synthesized by using 2-phenylpyridine compounds as the main ligand and 8-hydroxyquinoline compounds as the auxiliary ligand.We used ~1H-NMR,fluorescence spectroscopy,ultraviolet spectrophotometer,X-ray single crystal diffractometer,elemental analysis,mass spectrometry,infrared spectroscopy and other means to systematically study the composition,structure and photophysical properties of the complexes.We found that these complexes have stable luminescent properties in solid or solution.In the solid state,the light emission of the complex 1-3 is in the visible light region,while the light emission of the complex 6-8 is in the near infrared region.Complexes 4 and 5 have triple-responsive luminescent switching properties for steam,mechanical grinding,and thermal stimulation.Studies have shown that the mechanism of the luminescent switching properties of the complexes 4 and 5 is that after the complex is stimulated,its stacking structure is changed to cause weak intermolecular interactions(mainly π-π stacking between aromatic rings and Pt-Pt interaction),and then realize the transition of the lowest excited state energy level from MLCT/LLCT to MMLCT/LLCT.In addition,the complex 5 has a peculiar self-encrypting behavior and is successfully used in information encryption-decryption technology.We have also initially explored the effect of complex structure on the properties of light-emitting switches.The results show that when the complex molecule has good planarity and hydrogen bond forming ability,it is easy to cause the complex to be closely packed,which is not conducive to the generation of the luminescent switch properties of the complex.