Voltammetric investigation of new polythiophene derivatives possessing electrochemically cleavable arylsulfonamide groups as precursors for solid phase electrosynthesis

New thiophene derivatives substituted by electrochemically cleavable sulfon amide groups have been synthesised and their electrochemical behaviour has been investigated in acetonitrile. The anodic oxidation of phenyl (I)- and naphthyl (II)sulfonamide-substituted thiophenes yielded corresponding polym er films exhibiting p- and n-doping processes. The cathodic cleavage of the S-N bond grafted to the polymer backbone was performed by applying a poten tial lower than - 2.5 V (versus Ag \ 10(-1) M Ag+) to the polymer. The effi ciency of this solid-state electrochemical reaction was found to be strongl y lowered when the him thickness was increased. It was demonstrated that th e decrease of this parameter was less important when a copolymer electrofor med from II or a phenylsulfonamide-substituted terthiophene (III) was invol ved. The recycling properties of this type of material were illustrated by the grafting of an aminoferrocene moiety after the cathodic cleavage step t o poly(II-co-3-methylthiophene). (C) 1999 Elsevier Science S.A. All rights reserved.