Ullmann coupling for low-cost synthesis of anthracene-based polyfluorenes: A photophysical approach

A set of anthracene containing polyfluorenes (PFs) having 9,10-diphenylanthracene with alkyl substituents and aniline containing fluorenes were prepared. Commonly, light-emitting polymers were synthesized using expensive palladium-like catalysts. In the present work, palladium was replaced by copper as a cost-effective PF synthesis catalyst, which is also suitable for large-scale polymer synthesis. Synthesized PFs emit light in the blue region with a bandgap of 2.87–2.90 eV. Thermally stable PFs had a decomposition temperature of more than 305°C and a glass transition temperature of 125–138°C. PFs were soluble in organic solvents and had a molecular weight of around 21,700–25,500. The electrochemical study of these PFs showed low level of highest occupied molecular orbital (HOMO) energy of −5.16 to −5.26 eV, which was significantly higher than that of PF (5.7 eV). These findings suggested that the resulting PFs could be used as a component of the light-emitting diode.

A series of organosoluble polyamides with 4-(dimethylamino)triphenylamine

A series of novel aromatic polyamides containing 4-(dimethylamino)triphenylamine were prepared via the polycondensation reactions of the newly synthesized dicarboxylic acid, 4,4′-dicarboxy-4″-(dimethylamino)triphenylamine, and various diamines. Introduction of 4-(dimethylamino)triphenylamine units along the polymer chain enhanced the solubility of the polymers. The 10% weight loss temperatures of these polymers ranged from 432°C to 471°C with the char yields more than 63% at 800°C under nitrogen atmosphere. The polymers displayed low oxidation potentials because of the incorporation of dimethylamino at the para position of triphenylamine. Cyclic voltammograms of the polyamide films showed their onset potential around 0.38–0.47 V with color changing from nearly colorless to light blue.