Electrochromic poly(acetylene)s with switchable visible/near-IR absorption characteristics

Abstract

Ferrocene is incorporated into a poly(acetylene) derivative via the postpolymerization amidation of a polymer precursor bearing pentafluorophenyl ester-leaving groups with aminoferrocene. While the neutral polymer exhibits a strong absorbance at 553 nm due to its conjugated backbone, oxidation of the ferrocene moieties with silver tetrafluoroborate causes the material to absorb in the near-IR (λmax ≈1215 nm). Subsequent reduction of the oxidized polymer with decamethylferrocene restores the initial absorbance profile, demonstrating that the material features switchable visible/near-IR absorption characteristics. Ferrocene-functionalized polyacetylenes are synthesized via the postpolymerization amidation of a precursor that features activated ester-leaving groups. Upon oxidation, the absorption profile of the copolymer shifts to the near-IR. The process is found to be reversible, and renders the polymer as an attractive candidate for use in electro-optic switching and related applications. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.