New π-conjugated polymers containing oxazole in the main chain: Optical and electrochemical properties

Oxazole-containing π-conjugated polymers, an alternating copolymer of 9,9-dioctylfluorene-2,7-diyl and 2,5-bis(p-phenylene)oxazole (P(Flu-DPOxz)) and an alternating copolymer of 2,5-dialkoxy-p-phenylene and 2,5-bis(p-phenylene(oxazole)) (P(ROPh-DPOxz)), have been synthesized by Pd-catalyzed organometallic polycondensation. They were soluble in organic solvents, and had number average molecular weights of 18 600 and 24 700, respectively, in GPC analysis. P(Flu-DPOxz) and P(ROPh-DPOxz) showed UV-vis absorption peaks at about 380 nm in CHCl3. Powder XRD patterns and UV-vis data of the polymers indicated that the polymer solid was amorphous. The polymers were photoluminescent both in chloroform and in solid. In chloroform, the emission peak appeared at about 420 nm with a high quantum yield of about 70%. The polymers were electrochemically active, and electrochemical data revealed that the oxazole unit behaved as a moderate electron-accepting unit.