Synthesis And Properties Of Symmetric Carbazolyl Pyrimidine Platinum(Ⅱ) And Palladium(Ⅱ) Complexes

With the development of the times and the improvement of people’s living standards,the progress of display technology is extremely obvious.And among them,the organic light emitting diode（OLED）screen is developing rapidly and slowly replacing the liquid crystal display（LCD）screen.The biggest breakthrough of OLED is that the phosphorescent material is used in the light-emitting material instead of the original fluorescent material.Among all the phosphorescent materials,the metal complexes have higher phosphorescent quantum yields,shorter radiation times in the triplet state,and have higher thermal and chemical stability.By constructing tetradentate metals with rigid steric hindrance The complex and the introduction of the electron-donating group carbazole with excellent performance can not only improve the optoelectronic properties of the material,but also reduce the cost of optoelectronic materials through the low price of carbazole.Therefore,we envisage that the introduction of carbazole and carbazole-like groups into platinum complexes,palladium（Ⅱ）complexes and compounds with aggregated luminescence can improve and fabricate lower-cost organic optoelectronic materials.Based on this idea,this thesis designed tetradentate platinum（Ⅱ）complexes and palladium complexes of carbazolyl pyrimidines with rigid steric hindrance,as well as carbazolyl naphthalene anhydride compounds with AIE properties.1.Synthesis and Properties of tetradentate platinum（Ⅱ）complexes based on symmetrical carbazolylpyrimidinesIn this chapter,three symmetric tetradentate platinum（Ⅱ）complexes with rigid steric hindrance based on carbazolylpyrimidine were synthesized,and carbazole,diphenylamine and phenoxazine with similar structures were introduced into the tetradentate platinum（Ⅱ）complexes based on pyrimidine,A rigid sterically hindered tetradentate complex is constructed.In the case of excellent electron transport performance,its molecular structure has greater steric hindrance,thereby reducing the non-radiative transition,thereby reducing theπ-πstacking to improve the luminous efficiency.And we found that by changing the spacing between benzene molecules on the spatial structure,the luminescence of the material can be blue-shifted.In this chapter,we designed three platinum（II）complexes Pt-CDP,Pt-DDP,Pt-PDP maximum The emission peaks are 561 nm,530 nm,and 474 nm,respectively.2.Synthesis and Properties of tetradentate palladium（Ⅱ）complexes based on symmetrical carbazolylpyrimidinesIn this chapter,three tetradentate ligands of carbazolylpyrimidines designed in previous chapters are used as main ligands,and the center is coordinated with metal palladium to obtain three metal-assisted delayed fluorescence palladium complex materials.By testing its UV absorption and fluorescence emission spectra,we found that the palladium complex has an obvious blue shift compared to the platinum（Ⅱ）complex.The maximum fluorescence emission peaks of Pd-CDP,Pd-DDP and Pd-PDP in dichloromethane are 505 nm,476 nm and 433 nm.Therefore,the study of palladium（II）complexes is crucial for the fabrication of improved blue-light devices.3.Synthesis of carbazole-based anhydride-naphthalene compounds and their AIE propertiesIn this chapter,carbazole is used as the donor material,naphthalene anhydride compound is used as the acceptor,and an alkyl chain is used as the link in the middle.Made of spiral D-A organic compounds.The structure of such compounds has large rotation in space,and its fluorescence efficiency is very low in benign solvents.However,when the concentration of the poor solvent（H₂O）is increased,the extrusion of water molecules enhances its rigid structure,thereby enhancing its fluorescence efficiency.We analyzed the AIE properties of the compounds by fluorescence spectroscopy,and measured the compounds IDCB,OCB,OPCB,ONCB and OSCB with the best H₂O/THF concentrations of 65%,50%,85%,60%,and 85%,respectively.The luminescence properties of the aggregated state,the maximum fluorescence emission wavelengths are 483 nm,501 nm,532 nm,535 nm,554 nm,which found that the powdered ocb will have better luminescence properties.