Synthesis and Characterization of Chiral Conducting Polymers Based on Polypyrrole

A range of optically active pyrrole monomers have been synthesized in which a chiral sub- stituent is covalently bonded either to the pyrrole N or C3 ring position, namely (–)-(1R)-4-methyl-N-(1-phenylethyl)pyrrole-3-carboxamide, (+)-(1S)-4-methyl-N-(1-phenylethyl)pyrrole-3-carboxamide, (–)-(1R)-4-methyl-N-(1-naphthylethyl)pyrrole-3-carboxamide, (+)-(1S)-4-methyl-N-(1-naphthylethyl)pyrrole-3-carboxamide, (+)-(2S)-2-(1H-pyrrol-1-yl)propionic acid, (+)-(1S)-N-(1-phenyl-ethyl)pyrrole, and (–)-(1R)-N-(1-phenylethyl)pyrrole. Their chiroptical properties have been established by circular dichroism spectroscopy. Electropolymerization of the three N-substituted pyrrole monomers provided films of chiral conducting polymers, whose electrical and spectroscopic properties are described. Although oxidation of the C3 substituted pyrrole monomers was also facile, electrodeposition was poor and films of the associated polymers could not be obtained.