Macroscopic modulation of the #pi#-electron density of pendant groups grafted on conductive polymers

摘要

The influence of the redox switching reaction of aconductive polymer upon the #pi# electron density of graftedpendant groups has been studied. PoIy(N-phenylpyrrole) andpoly(N-benzylpyrrole) have been compared by means of IRspectroscopy and molecular modelling. In the case of poly(N-phenylpyrrole) the evolution of the infrared vibrational bandsexpresses a reversible modulation of the #pi# electron density ofthe benzene nucleus when the polymer is switched from itsreduced to its oxidized form. There is no such effect when thearomatic moieties are separated from the polymer backbone by aCH_2 group. Moreover, molecular modelling suggests thatoxidation of poly(N-phenylpyrrole) makes it possible to break theconjugation between the benzene nuclei and the polypyrrole backbone.