Synthesis Of Fluorescent Molecules Containing Phenanthrene Or Dipyrromethene, And Their Application In Materials And Fluorescent Chemical Sensors

A series of phenanthrene-containing and dipyrromethene-containing compounds were synthesized from carbonyl compounds. Compounds with blue, green and red emitting have been developed. Based on the investigation of their photophysical properties, these compounds were found to be useful as pH or explosive sensors from a practical point of view.In the first part of this thesis, the application and classification of organic optoelectronic materials, as well as the mechanism and application of fluorescent chemosensor were presented.Then, a series of oligo-phenanthrenes linked by triple bonds were constructed by Sonogashira cross-coupling reaction. Their fluorescent structure-property relationship were studied. The result showed that these oligomers exhibited bright blue emitting in both solutions and in thin-film states with high quantum efficiencies. Oligomers with long chain showed the excimer emission in solutions which might be due to the intramolecular π-π stacking caused by the spiral configuration. This viewpoint was supported by the theoretical calculation.Subsequently, the synthesis and characterization of imidazo[1,2-a]pyridine derivatives were illustrated. The hexaaryl substituted imidazo[1,2-a]pyridines were directly synthesized by the condensation of benzil derivatives and1,3-diphenyl-2H-cyclopenta[1]phenanthren-2-one in a singal step. The nitrogen located in ring skeleton came from ammonium acetate. This method changed the traditional routes that starting from2-aminopyridine. The imidazo[1,2-a]pyridines exhibited excellent green emissions. Among them, the compound with dimethylamino group(DMAIP) showed a variable emission as the solution acidity changed. It also presented the emission quenching upon the addition of nitro-aromatics (such as nitrobenzene,TNT) because of the formation of the electron-transfer complex. These characters implied that DMAIP might be used as a fluorescent chemosensor in detecting solvent polarity, acdity as well as the trace explosive.Finally, Heptaaryl dipyrromethenes were synthesized from tetraaryl cyclopentadienone and ammonium acetate in a single step. The nitrogen contained in pyrro skeleton came from ammonium acetate. This method was better the previous synthetic routes that started from pyrrole derivatives. Absorptions of these heptaaryl dipyrromethenes were sensitive to acidity. The colour of their solutions changed from red to green when the solutions were acdified. The corresponging Bodipys were futher prepared by the reaction of heptaaryl dipyrromethenes with BF3.Et2O in DCM in quantitative yields. Their emission wavelength could be adjusted by the substituents. These Bodipys emitted lights with high fluorescence quantum efficiencies which suggested that these Bodipys could be used as optoelectronic materials.In this thesis, a lot of new compounds were synthesized which eventually covered the emission colour from blue,green to red with high emission efficiencies. The new synthesized compounds greatly enriched the field of fluorescent molecules in organic optoelectronic materials and fluorescent chemosensors.