PALLADIUM-CATALYZED SYNTHESIS OF MONODISPERSE, CONTROLLED-LENGTH, ANDFUNCTIONALIZED OLIGOANILINES

The palladium-catalyzed amination of aryl halides, in conjunction with an orthogonal protective group scheme, forms the basis of two routes to oligoaniline precursors. One method consists of a bidirectional cha in growth from a symmetric core piece, whereas the other involves a di vergent-convergent synthesis of nonsymmetric fragments, followed by co upling to a symmetric core fragment. The oligoaniline precursors are s oluble in a variety of common organic solvents and are easily converte d to the deprotected oligoanilines. The method allows the preparation of even or odd chain lengths and the incorporation of a variety of fun ctional groups. The synthesis of phenyl-capped heptaaniline through de caaniline, of four end-functionalized octaaniline derivatives, and of phenyl-capped 16-mer and 24-mer is described. The effects of chain len gth and substitution upon oligomer behavior have been investigated by electronic absorption spectroscopy and cyclic voltammetry.