Conductive and Magnetic Properties of 3,4-Dimethoxy- and 3,4-Ethylenedioxy-Capped Polypyrrole and Polythiophene

Electrochemically prepared poly(3,4-dimethoxypyrrole), poly(3,4-dimethoxythiophene), poly(3,4-ethylenedioxypyrrole), and poly(3,4-ethylenedioxythiophene) have been characterized by cyclic voltammetry (CV) and ultraviolet−visible (UV−vis) and Fourier transform infrared (FTIR) spectroscopy and were subsequently investigated by in situ conductivity, in situ electron spin resonance spectroscopy (ESR), and electrochemical quartz crystal microbalance (EQCM) analysis. Blocking the 3 and 4 positions of the heteroaromatic ring allows the display of a complete potential window of conductivity for the polypyrroles during the oxidative doping process, whereas a potential window of conductivity wider than usual, but still open, is displayed for the polythiophenes. The combination of redox-type conduction and solvation in poly(3,4-dimethoxypyrrole) gives this material unusual solvatoconductive properties.