Cationic and free radical polymerization of N-vinyl-2,3-diphenylpyrrole

Cationic polymerization of N-vinyl-2,3-diphenylpyrrole (FeCl3·6H2O, complex LiBF4–dimethoxyethane, WCl6, BF3·OEt2, Me3SiCl, 2 wt%, benzene, 20–80 °C, 24–48 h) affords oligomers with alternating pyrrole and ethylydene units in up to 61% yields (molecular weight 800–3100). Free radical polymerization of this monomer (AIBN, 0.5–5 wt%, benzene, 80 °C, 1–50 h) leads to oligomers having polyethylene backbone with pendant 2,3-diphenylpyrrole moieties (in up to 92% yield, molecular weight 2100–2500). The oligomers show semiconducting (σ = 2.6 × 10−7–4.2 × 10−6 S/cm after doping with I2) and paramagnetic (N = 1.2 × 1018–4.8 × 1019 spin/g) properties and fluoresce in the region 383–388 nm (solution in dioxane).