Synthesis And Characterization Of Novel Organic Functional Materials With Aza-Spirofluorene As Skeletons

Spriobifluorenes are widely used as organic materials due to their excellent thermostability, high quantum efficiency and glass transition temperature. The introduction of nitrogen-containing substitutents on spirobifluorene skeleton or hetecocycle-fused sporibifiuorenes will have strong impact on their propertes as electroluminescent materials.In this thesis, we design heterocycle-fused spirobifluorenes and nitrogent-containing substituted spirobifluorenes as target molecules. The synthese of diaza-spirobifluorenes and diaza-fluorenes,2-phenylpyridine substituted fluorine and spirobifluorene compounds, and their iridium complexes, and indolo-fused spirobifluorenes are reported, prelimary study on their properties are also investigated.Firstly, we synthesized a series of spirobifluorene and fluorene derivatives with 3,4-diazaspirobifluoren-2-yl substituent.2-Acetyl or 2,7-acetylfluorene or spiro-bifluorene, ninhydrin, hydrazine hydrate were employed to form substituted diazafluorenes or diazafluorenone-spirobifluorenes through condensation, cyclization. Then 2-bromobiphenyl lithium salt or Grignard reagent was employed to generate tertiary alcohol, and finally acid-promoted ring closure was used to form targeted 3, 4-diazaspirobifluoren-2-yl fluorenes and spirobifluorenes.Secondly a series of fluorenes and spirobifluorenes with 2-phenylpyridine substituents and their iridium complexes were studied. The key step for the syntheses of 2-phenylpyridine ligands is retro-Diels-Alder reaction between 1,2,4-triazine and dicyclo[2.2.1]heptadiene.The reaction of 2-phenylpyridine ligands with IrCl3-3H2O was performed to afford chlorine-bridged dimeric iridium complexes, followed by exchange with acetylacetone (acac) in polar solvents to form 2-phenylpyridyl substituted fluorine and spirobifluorene-iridium complexes, which might be used as precursors for electroluminescent phosphorescent materials.Finally, we design a series of indolo-spirobifluorenes by combining the priorities of spriobifluorenes and carbazoles. Starting with spirobifluorene and 2,7-ditbutyl-spirobifluorene bromide, the Suzuki cross coupling reaction with 2-nitrophenylboronic acid in the presence of palladium catalyst to afford 2-nitrophenyl substituted spirobifluorene and di-t-butylspirobifluorene, then a reductive Cadogan ring-closure was used to produce a series of indolo-spirobifluorene.