Polyquinolines containing both spirobifluorene and cardofluorene units: Synthesis and characterization

We have synthesized aromatic polyquinolines containing both spirobifluorene and cardofluorene moieties in the main chain by applying acid-catalyzed Friedlander quinoline synthesis. The incorporation of these rigid nonplanar structures into the polymer backbone, which restricts segmental mobility, significantly increases both the glass-transition temperature and thermal stability, while providing enhanced solubility as a result of a decrease in the degree of molecular packing and crystallinity. We have also examined the optical and electrochemical properties of these polyquinolines. The low-lying lowest unoccupied molecular orbital energy level and quasireversible electrochemical reduction of these polyquinolines suggest their potential for use as electron-injecting/transporting materials in polymer light-emitting diodes. (C) 2004 Wiley Periodicals, Inc.