Abstract
A new method for the fabrication of soluble polyacetylene derivatives was developed based on bromination–dehydrobromination of bicyclic diene polymers. High molecular weight polymer precursors were synthesized by radical 1,4-polymerization of the corresponding dienes, which contained a bicyclo[2.2.2]octane skeleton. Polymer precursors with narrow molecular distributions were prepared by nitroxide-mediated polymerization of the bicyclic diene monomers. Regioselective elimination from the brominated polymer afforded a polyacetylene derivative contaning bicyclic substituents, which was readily soluble in common organic solvents. The polymer electronic bandgap, obtained by optical and electrochemical measurements, was in the range 1.4–1.7 eV. Low bandgap values were attributed to the conformational inflexibility of the bicyclic substituent forcing coplanar orientation of the backbone double bonds. Solid-state conductivity of the produced polymer in the undoped form was measured to be 1.5 × 10–5 S/m. This new synthetic method allows for the chain-growth production of polyacetylene derivatives that possess favorable electronic properties and superior solubility characteristics to pristine polyacetylene.
