Synthesis And Characterization Of Aikyl-substituted Dibenzosilole-Based Small Fluorescence Molecules And Polymers

Silole (silacyclopentadiene) is of great concern in the field of optoelectronic materials due to their good electron affinity and fast electron mobility. Many small molecules and polymers based on silole have been designed and synthesized and have shown promising applications in organic light-emitting diodes, field-effect transistors, solar cells, etc. Dibenzosilole is a planar silole derivative with efficient deep blue fluorescence, and can serve as an excellent building block for the creation of functional materials for optoelectronic devices. In this thesis, a series of alkyl-substituted dibenzosilole derivatives are prepared, based on which various new fluorescent materials including small molecules and polymers are synthesized by Suzuki coupling and characterized. The optical properties of the new compounds are investigated and the structure-property relationship is discussed. The main results are outlined as follows:(a) Dibenzosilole possesses a low-lying lowest unoccupied molecular orbital arising from the σ*-π*conjugation between σ*orbital of silicon and π*orbital of the phenyl rings. It has good fluorescent property in addition to the strong electron affinity and good electron mobility. Terpyridine is excellent receptor for metal ions, due to the lone electron pair on the N atom. It is envisioned that connection dibenzosilole with tripyridine at molecularly level will generate good chemosensors for methal inos. In this work, a series of tripyridine-dibenzosilole adducts are synthesized by Suzuki coupling. The new compounds are fully characterized and the optical properties are measured. The sensing properties of the compounds are under investigation.(b) Tetraphenylethylene is a typical luminogen, exhibiting interesting aggregation-induced emission. Triphenylamine is widely studied for it has good hole-transporting capacity. Novel luminogens comprised by alkyl-substituted dibenzosilole and tetraphenylethylene or triphenylamine are synthesized via Suzuki coupling. The compounds are fully characterization and their optical properties are measured. The results show that tetraphenylethene-dibenzosilole adducts show aggregation-induced emission while those with triphenylamine have no such effect.(c) A series of fluorescent polymers comsisting of alkyl-substituted dibenzosilole and9,9-dihexylfluorece or9,9-dihexylfluorece groups are synthesized and fully characterized. Polymers with high molecular weight with narrow molecular weight distribution revealed by GPC are attained under optimum polymerization conditions. The optical properties of the polymers are measured.