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 (M-w) (25,000) and small polydispersity index (PDI) (1.2). The oligomers synthesized by Wittig condensation have M-w of 4000 and PDI of 1.8. All the polymer and oligomers synthesized exhibit remarkable thermal stability with high decomposition temperature and high T-g 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. (C) 2002 Elsevier Science Ltd. All rights reserved.