Synthesis, characterization and electrochemical properties of an iron cyclopentadienyl complex of poly(n-hexylphenylene)

An iron cyclopentadienyl complex of a conducting polymer, poly(n-hexylphenylene) (abbreviated as PHP), was prepared by a reaction of PHP with ferrocene, Al and AlCl3 followed by an anion exchange using NH4PF6. Cyclic voltammetry of the complex thus formed with a formula, {(C6H3C6H13)1.6[(η6-C6H3C6H13)Fe(η5-C5H5)]PF6}n (abbreviated as PHP-[FeCp]PF6, Cp = η5-cyclopentadienyl), has indicated that it is reduced with a moderate chemical reversibility in Bu4NBF4-THF at E0′ = − 1.7 V versus Ag/Ag+. Spectroelectrochemical measurements have suggested that the chemical reaction of the reduced form is a coupling reaction of phenylene rings coordinated to iron, resulting in a formation of insoluble thin network polymer film on the electrode surface. Photoluminescence of PHP is modified in intensity and maximum emission wavelength by coordinating the FeCp moiety.