Synthesis and properties of new electroluminescent polymers possessing both hole and electron-transporting units in the main chain

New EL polymers possessing both hole and electron-transporting units in the main chain are synthesized. The polymer prepared by palladium catalyzed Heck reaction of 10 and 15 show a large weight average molecular weight (Mw) (25,000) and small polydispersity index (PDI) (1.2). The oligomers synthesized by Wittig condensation have Mw of 4000 and PDI of 1.8. All the polymer and oligomers synthesized exhibit remarkable thermal stability with high decomposition temperature and high Tg as determined by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) under nitrogen atmosphere. The EL emission maximum peaks of the materials prepared are in the range of 535–560 nm corresponding to green–yellowish-green. Among the three electron-transporting moieties, the 1,3,4-oxadiazole unit shows the best electron injection and transporting property.