Functionalization of conjugated copolymers with phosphorescent iridium complexes and carbazole/1,3,4-oxadiazole dendrons via click chemistry

New types of polyfluorene derivatives containing Ir complexes and carbazole/1,3,4-oxadiazole dendrons on the side chain have been synthesized through “click chemistry” efficiently. By introducing propargyl group into the binaphthyl unit on the polyfluorene backbone, different Ir complex- and functional dendron-containing azides could be quantitatively clicked into the main chain through the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition. The efficiency of the click reaction was confirmed by using 1H NMR and FT-IR spectra. The resulting copolymers exhibited desirable properties, such as excellent solubility, good thermal stability, high molecular weights and narrow molecular weight distribution. The photophysical properties of the copolymers in solutions and solid films were investigated, and the results indicated that the energy transfer from the main chain to the green or red Ir complex was incomplete, and more efficient energy transfer in solid films was observed as compared with that in solution.