Synthesises,structures And Properties Of B/N-embedded Dioxygen-bridge Polycyclic Based Phosphorescent Iridium And Platinum Complexes

B-or N-embedded?-conjugated organic units have always been the focus in the field of organic semiconductor because of their novel structures,peculiar eclectronic properties and infinite space for application research.However,at present most of the research about these units mainly focus on the their synthesis and structural analysis,while studies on how to use these new structural units regulate the luminescence properties of photofunctional molecules are very limited,especially on how to regulate the photophysical properties of phosphorescent metal complexes.On the other hand,phosphorescent metal iridium and platinum complexes are widely used in organic light-emitting diodes?OLED?and chemical sensing application due to their rich chemical structure and excellent photophysical properties.Nevertheless,with nearly 20 years of development,the research space for their molecular structure,excited state property and photofunctional application is getting narrower and narrower.Therefore,the introduction of these organic units with new structures and electronic properties has become an important strategy for the development of new phosphorescent iridium and platinum complexes with excellent performance.The involvement of B-or N-embedded?-conjugated organic units in the field of optoelectronic materials has just begun,and is almost a blank in the fleld of optical functional metal complexes.Therefore,to develop new and multifunctional phosphorescent iridium and platinum complex materials and study the roles of these new units on the structure,intermolecular interaction,excited state and photophysical property of complex,this paper aims to introduce B-or N-embedded oxygen-bridge polycyclic units into various classic phosphorescent iridium and platinum complexes.The specific contents unfold four parts as follow:1.Synthesises,structures and properties of N-embedded oxygen-bridge polycyclic unit based tris-cyclometalated heteroleptic iridium complexesWe designed and synthesized a N-embedded oxygen-bridge polycyclic unit based tris-cyclometalated heteroleptic iridium complex,and also prepare triphenylamine and 3,5-diphenoxybenzene unit based non-embedded iridium complexes as the model compounds.The effects of the N-embedded oxygen-bridge polycyclic unit on the excited state and photophysical properties of the complexes can be studied by comparing the spatial structure and electronic properties of these complexes.The results indicate that the N-embedded oxygen-bridge polycyclic unit shows certain planarity,resulted in obvious rigidity and interesting?-?-stacking between molecules.More importantly,compared with the model complexes,the introduction of the unit can greatly increase the HOMO level and only induce ³ILCT excited state properties for the complex.In addition,the introduction of this unit can make the complex show orange phosphorescence and 1982 cm^-1redshift relatived to triphenylamine unit based model complexes,and its phosphorescent lifetime increases significantly.Finally,electrochemistry and quantum calculation are performed to explain the above photophysical properties of the complexes.2.Synthesises,structures and properties of N-embedded oxygen-bridge polycyclic unit based cationic iridium complexesWe designed and synthesized a N-embedded oxygen-bridge polycyclic unit based cationic iridium complex,and also prepare triphenylamine and 3,5-diphenoxybenzene unit based non-embedded iridium complexes as the model compounds.The effects of the N-embedded oxygen-bridge polycyclic unit on the excited state and photophysical properties of the complexes can be studied by comparing the spatial structure and electronic properties of these complexes.The results show that the strong?-?interaction between two N-embedded polycyclic units of one complex molecular and two pyridine ring of auxiliary ligand in the other molecule can be formed.Compared with the auxiliary ligand of model complexes,this interaction can cause a larger structural distortion of auxiliary ligand of the complex.In addition,the N-embedded iridium complex exhibited phosphorescence quenching in solution,but shows effective phosphorescence emission in PS solid film.This phenomenon is different from those of model complexes and may be attributed to the aggregation induced phosphorescence?AIPE?behavior.Quantum calculations reveal that unusual ³LMCT excited state character can be found in both N-embedded and triphenylamine unit based iridium complexes,which is in contrast to ³MLCT excited state property in 3,5-diphenoxybenzene unit based iridium complex.3.Synthesis,structures and properties of B/N-embedded oxygen-bridge polycyclic unit based neutral hybrid iridium complexesWe designed and synthesized a series of B/N-embedded oxygen-bridge polycyclic unit based neutral hybrid iridium complexes,and also prepare 3,5-diphenoxybenzene unit based non-embedded iridium complex as the model compound.The structure and optical properties of complexes can be tuned by controlling the number of boron or nitrogen atoms embedded.The results show that B-embedded polycyclic unit exhibits better planarity than the N-embedded polycyclic unit,which leads to different?-?-stacking between molecules.In addition,phosphorescence color can be tuned from green to deep red by controlling the number of boron or nitrogen atoms embedded.Moreover,solution-processed OLED devices incorporating these complexes as emitting layers can show low-efficiency roll-off and turn-on voltage.Notably,the B-embedded complex shows good color purity with a narrow full width at half maximum(1211 cm^-1)and a color coordinate of?0.67,0.31?.4.Synthesis,structures and properties of B-N Lewis adducts based iridium complexesWe have synthesized four new B–N Lewis adducts based iridium complexes by reaction of B-embedded iridium complexes and different Lewis bases?pyridine and DMAP?.The results show that the original planar B-embedded polycyclic units have formed shallow bowl-shaped structures due to B-N coordination.More interestingly,during this process,significantly different structural and optical changes are triggered by the different structures and electronic properties of Lewis bases,as confirmed by X-ray crystallographic,¹H NMR and spectral analysis.5.Synthesis,structures and properties of B/N-embedded oxygen-bridge polycyclic unit based platinum complexesWe designed and synthesized a series of B/N-embedded oxygen-bridge polycyclic unit based neutral and cationic platinum complexes,and the results show that the different planarity between B-and N-embedded oxygen-bridge polycyclic units and the structural characteristics of different kinds of complexes,eventually lead to a very different interesting intermolecular interaction in their single crystals.Moreover,B-embedded platinum complexes show more redshift and efficient emission relative to the N-embedded platinum complexes.Theoretical calculations reveal that unusual ³LMCT excited state character can be found in all N-embedded neutral and cationic platinum complexes,which is in contrast to³MLCT excited state property in corresponding B-embedded neutral and cationic platinum complexes.In addition,the luminescence performance of neutral platinum complexes is better than that of cationic platinum complexes.