Reactive groups on polymer coated electrodes, 12 New conducting carrier materials: polyalkylthiophene functionalized with amino group and its protected forms

The synthesis and electropolymerization of 3-alkylthio-phenes functionalize d with a terminal amino group and its protected forms are reported. As expe cted, due to the strong electronic interference of the amino group, the ele ctropolymerization of the unprotected monomer is fully inhibited. After pro tection of the amino group the polymerizability of the corresponding monome rs is considerably improved; however, the successful polymerization process clearly depends on the nature of the used protective group. Only such mono mers in which the nucleophilic character of the amino group is strongly sup pressed by a suitable protective group undergo electropolymerization to for m the corresponding electroactive polymers. The obtained polymers are elect rochemically stable and, besides the typical properties such as redox behav ior and electrochromism, they exhibit a distinct solvatochromic behavior. E lectrical conductivity measurements on their oxidized forms by means of the two-probe method give values in the range of 10(-3) to 10(-2) S . cm(-1). The feasibility of using the resulting polymers as conducting carrier mater ials was demonstrated by the removal of the protecting groups and the subse quent attachment of a redox active ferrocene compound. Electrochemical and spectroscopic experiments confirmed that after the polymer analogous reacti on the used redox active ferrocene model compound is covalently immobilized onto the polymer surface and the electroactivity Of the bonded redox group s as well as the carrier materials is retained.