Synthesis and characterization of soluble poly (ferrocenylenearylene)s from condensation of dilithio bis(alkylcyclopentadienide) arenes with iron(II) halides: A general route to conjugated poly(metallocene)s

Bis(alkylcyclopentadienyl)arenes have been prepared by sequential lithiation/alkylation of dibromoarenes with alkylcyclopenta-2-en-1-ones. The resulting dicarbinols were dehydrated with p-toluenesulfonic acid to give the bis(alkylcyclopentadienyl)arene. Poly(alkyl-1,1'-ferrocenylenearylene)s were prepared by the reaction of dilithio bis(alkylcyclopentadienide)arenes and iron(II) salts in THF. The resulting polymers were oxidized with iodine to give the fully oxidized polyionomers. The polyionomers were found to give mixed-valence polymers when allowed to equilibrate with neutral polymers in solution, provided the degree of oxidation, N, lies between ca. 0.55 and 1.0. For degrees of oxidation 0.0 < N < 0.55, disproportionation occurs to give neutral polymer and polymer with N approximate to 0.55. The oxidized polymers showed small to moderate antiferromagnetic interactions, and some were found to follow non-Curie-Weiss behavior that is ascribed to the complex magnetic properties of individual ferrocenium centers rather than to any type of magnetic ordering. The organic bridging ligands and polymers were characterized by TGA-DSC, GPC, NR, CV, FT-IR, and UV-vis techniques. The fully oxidized and mixed-valence polymers were characterized by magnetic susceptibility, FT-IR, EPR,Mossbauer, and UV-vis spectroscopies.