Synthesis of conjugated diblock copolymers: two mechanistically distinct, sequential living polymerizations using a single catalyst

Block copolymers comprised of poly(3-hexylthiophene) and three different poly(isocyanide)s were synthesized in a single pot via the sequential addition of 2-bromo-3-hexyl-5-chloromagnesiothiophene followed by 2-(2-methoxyethoxy)ethyl 4-isocyanobenzoate, tert-butyl 4-isocyanobenzoate, or 1-isocyanohexadecane to a solution of 1,3-bis(diphenylphosphino)propane dichloronickel. Similarly, block copolymers of poly(1-dodecylpyrrole) along with poly(2,5-bis(hexyloxy)phenylene) and a poly(arylisocyanide) were also prepared using an analogous methodology. The respective mechanistically distinct polymerizations proceeded in a controlled fashion, were mediated by a common catalyst, and afforded well-defined block copolymers with tunable molecular weights and compositions. Selected block copolymers exhibited higher-order structures in solution and microphase separation characteristics in the solid state.