Synthesis And Characterization Of Novel Organic Electronic Materials With Spiro-fluorenes And Polyacenes As Skeletons

Organic light-emitting diodes (Organic Light-mitting Diode, OLED) and organic field-effect transistors (Oganic Field Effect Transistor, OFET) belong to the organic' electronic materials. The excellent optical properties make them one of the hottest research firleds in materials sciences. Small molecule organic electronic materials with sprio-fluorenes, and polycyclic rings as skeletons generally play an important role in the field of organic electronic materials due to their relative easy purification, simple chemical modification with wide range of options.In this paper, we present the synthesis approaches, optical spectroscopy, the HOMO/LUMO calculations, crystal structures and thermal stabilities of three types of new spriofluorenes, polyacenes organic electronic materials:(1) pyrimidine appended spriofluorenes; (2) indeno-spirofluorene and dispirobifluorenes; (3). indeno-and spirobifluoreno-polyacens.In the first part of the thesis, we used 2-acetyl-spirobifluorene forming a series of chalcones by Aldol condensation, and then cyclization of chalcones with guanidine nitrate afford a series of pyrimidine appended spriofluorenes derivatives. The optical properties characterizations showed that this kind of compounds generally have good blue light emession, and excellent thermal stability. Intramolecular and intermolecular hdrogen bonds enhances them potentials as fluorescent molecular probe.In the second part:the Diels-Alder reaction was employed to construct indenodluorens in the mode of [1,2-a] and [2,1-c], which have never been reported before. Indeno-spirobiluorenes and dispirobifluorenes were successfully prepared. The synthetic approached involved are concise and efficient with high yields. The characterizations revealed that above mentioned compounds generally have high fluorescence quantum yield (>60%), excellent thermal stabilities (m. p.>250℃) as well as good electrochemical stability. The comparation of indeno-spirobifluorenes and dispirobifluorenes indicated that the spiro-skelteons play important role to improve their thermal stability and fluorescence quantum efficiency.In the third part:1,4-diphenyl-2,3-dimethylfluoren-9-one was employed to construct polyacene and heteroacenes never reported before. Indeno-polycenes, spirobifluoreno-polyacenes, indeno-heteroacenes, spirobifluoreno-heteroacenes were synthesized through multiple steps such as protection, reduction, alkylation, bromination, consensation, alkynylation etc. The spectroscopic characterization and HOMO/LUMO studies have shown that the introduction of energy gap caused by the indene and fluorene fused onto polyacenes is lower than typical aromatic polyacenes. The changes of energy gaps from different polyacenes also provide novel approaches for the future development. The good electrochemical stability, thermal stability and oxygen persistence made the above mentioned polyacenes as potential materials for OFETs. The heteroacenes fused with diazathiadiazole ring can be considered as motif for larger heteroacenes in the future.