Towards crystal engineering of solid-state polymerization in dibromothiophenes

Three new dibromothiophene monomers for solid-state polymerization have been synthesized and their solid-state structure was studied by X-ray crystallography. The substituents in the thiophene ring are introduced to induce an anti-orientation of the monomer to resemble the s-trans structure of the polythiophene. The details of the solid-state packing of the new monomers are compared to those of the previously studied 2,5-dibromo(3,4-ethylenedioxythiophene) and related to their reactivity and to the conductivity of the resulting polymers. The same polymers have also been prepared by electrooxidative polymerization on the surface of an electrode.