Incorporation of Different End Groups in Conjugated Polymers Using Functional Nickel Initiators

摘要

Well-defined conjugated polymers remain intensively studied polymers, since they reveal promising applications in the field of molecular electronics.1 These polymers significantly owe their potential to the fact that their polymerization can proceed via a chain-growth mechanism, as demonstrated by McCullough et al.2,3 and Yokozawa et al.4,5 They showed that the polymerization of monobromo-monobromomagnesio-3-alkylthiophenes to head-to-tail poly(3-alkylthiophene)s (HT-P3ATs) proceeds via a controlled chain-growth mechanism in the presence of Ni(dppp)Cl2 (dppp=1,3-bis(diphenylphosphino)propane). This also allows the synthesis of HT-P3ATs end-capped with selected functional groups,6-8 which may act (after some transformations) as an initiator for the polymerization of a second block, for instance poly(styrene) or poly(methyl acrylate).9 Second, the living nature of the polymerization allows the preparation of conjugated block copolymers by successive additions of the respective monomers.