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 lithiatio n/alkylation of dibromoarenes with alkylcyclopenta-2-en-1-ones. The resulti ng dicarbinols were dehydrated with p-toluenesulfonic acid to give the bis( alkylcyclopentadienyl)arene. Poly(alkyl-1,1'-ferrocenylenearylene)s were pr epared by the reaction of dilithio bis(alkylcyclopentadienide)arenes and ir on(II) salts in THF. The resulting polymers were oxidized with iodine to gi ve the fully oxidized polyionomers. The polyionomers were found to give mix ed-valence polymers when allowed to equilibrate with neutral polymers in so lution, 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 polym ers showed small to moderate antiferromagnetic interactions, and some were found to follow non-Curie-Weiss behavior that is ascribed to the complex ma gnetic properties of individual ferrocenium centers rather than to any type of magnetic ordering. The organic bridging ligands and polymers were chara cterized by TGA-DSC, GPC, NR, CV, FT-IR, and UV-vis techniques. The fully o xidized and mixed-valence polymers were characterized by magnetic susceptib ility, FT-IR, EPR,Mossbauer, and UV-vis spectroscopies.