Synthesis And Properties Of New N-containing Fluorescent Organic Small Molecules

Organic small molecular luminescent materials have the advantages of simple synthesis and purification, wide selection of colors, strong brightness and the easy film formation.2,4,6-Triarylpyridine, 1,8-naphthalimide, carbazole, triphenylamine and coumarin all showed great luminescence. If connecting these excellent chromophores with each other, we can obtain series of novel products with longer conjugated chain, higher fluorescence quantum efficiency and stronger hole-transporting ability. This dissertation which is composed of five sections mainly focused on the synthesis of the organic electroluminescent materials based on 2,4,6-triarylpyridine, 1,8-naphthalimide, carbazole, triphenylamine, coumarinand their optoelectronic properties were studied in detail.The first section involved the basic knowledge and development of organic small molecular luminescent materials, the creative points and the research techniques.In the second section, seven compounds were synthesized by linking the 2,4,6-triarylpyridineand 1,8-naphthalimide framework through Suzuki coupling reaction. The results of their absorption spectroscopy, fluorescence, electrochemical characteristics and thermal stability characteristics indicated that their UV absorption and fluorescence emission wavelengths in DCM were in the range of 290-360 nm and 435-438 nm respectively, representing blue fluorescence. The relationship between their structure and luminescence comply with the general law, their decomposition temperature(Td) were over 360 oC.In the third section, eight compounds werealso synthesized based on carbazole,aryl and 2,4,6-triarylpyridine framework via Suzuki coupling. The results of their absorption spectroscopy, fluorescence, electrochemical characteristics and thermal stability characteristics indicated that their UV absorption and fluorescence emission wavelengths were in the range of 299-312 nm and 390-440 nm respectively, representing blue light.In the forth section, four D-π-A compounds were synthesized based on triphenylamineand 2,4,6-triarylpyridine framework through Suzuki coupling reaction. The results of their absorption spectroscopy, fluorescence, electrochemical characteristics and thermal stability characteristics indicated that their UV absorption and fluorescence emission wavelengths in methylene dichloride were in the range of 370-375 nm and 480-482 nm respectively. Theoretical studies have shown that these compounds have good performance in hole transmission.Finally, four compounds were synthesized based on coumarin framework through Suzuki coupling and addition reaction. The results of their absorption spectroscopy, fluorescence indicated that their UV absorption and fluorescence emission wavelengths in DCM were in the range of 290-300 nm and 372-491 nm respectively. Since the two hydroxyl groups on the coumarin were failed to form a pyran ring and the tertiary carbon atom blocked the transfer of the π electron, such compounds had low fluorescence quantum efficiency.The above compounds except the last parts all showed great electro-optical properties which may apply in OLEDS.