Synthesis of poly(3-hexylthiophene) by using the VO(acac)(2)-FeCl3-O-2 catalytic system

Poly(3-hexylthiophene) (P3HT) was prepared by the oxidation coupling polyme rization of 3-hexylthiophene (3HT) with molecular oxygen as an oxidant in t he presence of vanadyl acetylacetonate (IV) (VO(acac)(2)) and ferric chlori de(FeCl3). The polymerization at a molar ratio of VO(acac)(2) / FeCl3 / 3HT =1 / 2 / 5 in 1,2-dichloroethane at 0 degrees C for 164 h under oxygen gav e P3HT in 61% yield. The resulting polymer gave a number average molecular weight (Mn) of 2. 1 x 10(4) (Mw I Mn = 3.0; Mw: weight average molecular we ight) and a head-to-tail content of 65%. The VO(acac)(2) - FeCl3 complex is supposed to work as a catalyst.