Study On Synthesis And Photoelectricity Properties Of Fluorinated Ter(9,9-diphenylfluorene)s

Compared with traditional light-emitting devices, organic light-emitting devices matched equally with integrate circuits in the performance of low direct current drive voltage can work in lower power and provide wider visual angle, higher brightness and shorter responding time. It is a new superior technology of flat-panel displays. The tremendous materials following the discovery of efficient electroluminescence in organic conjugated thin films have been found, and fluorene-basedπ-conjugated compounds now are generally regarded as the most promising candidates for OLEDsHere we synthesized five new fluorinated ter(9,9-diphenylfluorene)s by introducing electronegative fluorin to the conjugated or branched chain of ter(9,9- diphenyl- fluorene)s. Then we confirmed their structures and researched their perfor- mance of photoelectricity for indicating the tendency to find new fluorene-based organic light-emitting materials and electron transport materials.Firstly, 4-fluoro-2,7-dibromofluorene was synthesized from 2,7-dibromofluorene by 4-nitration, reduction, diazotization and fluorination. The former and 2,7-dibromo- fluorene, 2-bromofluorene were 9-oxidation, and then we attained six 9,9-diaryl- fluorene-based compounds by Grignard reaction and Friedel-Crafts reaction. We prepared the boracic esters of the three 9,9-diphenylfluorene-based compounds made by Friedel-Crafts reaction. Finally, we attained the ter(9,9-diphenylfluorene) and five new fluorinated ter(9,9-diphenylfluorene)s by Suzuki Coupling reaction. We prepared twenty-seven compounds in all and attained sixteen new compounds which included eleven intermediates and five products. The structures of all intermediates and products were confirmed by IR, 1HNMR, 13CNMR, MS and EA. Some fluoride were confirmed by 19FNMR.It is found that those five fluorinated ter(9,9-diphenyl-fluorene)s have strongπ→π* absorption in the region of 280~400nm. Their maximum absorption which are similar to ter(9,9-diphenylfluorene) distribute over 340nm to 350nm. They emitted strong blue-green fluorescence in solution of THF in the region of 360~500nm, and their maximum emission which distribute over 394nm to 398nm are same as ter(9,9-diphenylfluorene). The organic electroluminescent device made of 4'-fluoro-9,9',9',9''-tetraphenyl-9,9''-di(penta-...