ELECTROCHEMICAL PREPARATION OF POLY(3-PROPANOYLPYRROLE) AND POLY(3-PHENYLPYRROLE)

Two pyrrole derivatives, 3-propanoylpyrrole (PRNPY) and 3-phenylpyrrole (PHPY) have been prepared. Electrochemical polymerization of these compounds yields a film on the anodic surface. Conductivities of poly-PRNPY (PPRNPY) and poly-PHPY (PPHPY) are 0.3 and 1 S/cm, respectively. The oxidation potential of PPRNPY is remarkably higher than that of polypyrrole, because of the lowering of the valence band energy by the electron-withdrawing acyl group. However, the bandgap is smaller. The addition of the phenyl group to pyrrole rings does not reduce the interband transition energy, indicating that the steric effect is dominant in PPHPY. These results show that the oxidation potential and the absorption edge of polypyrrole can be adjusted over a wide range by the addition of various substituents to the polymer backbone. © 1990.