HIGH-MOLECULAR-WEIGHT POLY(FERROCENEDIYL SILANES) - SYNTHESIS AND ELECTROCHEMISTRY OF [-(C5H4)FE(C5H4)SIR2-]N, R = ME, ET, N-BU, N-HEX

High molecular weight poly(dialkylsilane-ferrocenediyls) of general fo rmula [-(C5H4)Fe(C5H4)SiR2-]n, R = methyl, ethyl, butyl, and hexyl) we re synthesized by thermal polymerization of the corresponding [1]-(dia lkylsilyl)ferrocenophane. The polymers are stable up to 450-500-degree s-C and with the smaller alkyl groups, e.g., methyl and butyl, the pol ymers are predominantly crystalline in the solid state. The voltammogr ams of these polymers in Et4NBF4/dichloromethane show two reversible r edox peaks for the stepwise oxidation of the polymer where half of the ferrocene centers on the polymer chain (possibly alternating) are oxi dized in the first reaction and the remaining in the second reaction. Both oxidation states of the polymers are stable to the electrochemica l conditions. The redox potentials of both reactions are affected by t he size of the alkyl group. Although, these polymers are soluble in di chloromethane, they deposit on the electrode surface and influence the shape of the voltammograms by affecting the diffusion of the electrol yte ions to the electrode. The polymers were chemically oxidized with anhydrous FeCl3. Two equivalents of FeCl3/(ferrocene) are required to fully oxidize the polymers.