Syntheses and electropolymerization behavior of ethylenedioxythiophene-substituted silanes

Silicon-bridged thiophene oligomers have been prepared via the reactions of lithiated (3,4-ethylenedioxy)thiophene (EDOT) (1) or 2,2'-bis-(3,4-ethylenedioxy)thiophene (biEDOT) (2) with dichlorodimethylsilane to afford bis-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-5-yl)-dimethylsilane (3) and dimethyl-bis-(2,3,2',3'-tetrahydro-[5,5']bi[thieno[3,4-b] [1,4]dioxinyl]-7-yl)silane (4). Products 3 and 4 were characterized and show good stability in organic solvent and in air. The electropolymerization of these monomers affords stable and highly conducting polymers. The conductivity was found to be 25 and 60 S/cm for Poly3 and Poly4, respectively. Characterization data for the polymers suggested that the resulting materials have a backbone identical to p(EDOT), which formed through cleavage of the silicon-carbon (Si-C) bonds during electropolymerization.