We describe the synthesis and characterization of a novel set of conjugated polymers that may be doped through simple post-polymerization acid/base chemistry. Dopability arises from incorporation of aryl-imidazole units which are easily protonated or deprotonated (pKa’s of ~6.4 and 12) placing a positive or negative charge in conjugation with the polymeric backbone. We hypothesized that acid-doping would increase the system’s electron affinity while base-doping would decrease the ionization potential. This hypothesis came about by drawing analogies between our system and the inorganic Group IV semiconductors where p-doping effectively creates holes just below the conduction band (LUMO) and n-doping adds electrons to the system in electronic states just above the valence band (HOMO). Indeed, these materials show interesting opto-electronic properties upon doping, including highly variable band structures and fluorescence emission profiles. We quantify the effects of doping through cyclic voltammetry and a variety of spectroscopies including: UV/Vis, fluorescence, and <sup>1</sup>H NMR. Previously, the effects of doping have been attributed to steric collisions affecting backbone planarity; we demonstrate through the synthesis and characterization of vinylene and ethynylene linked polymers that there is more to the observed phenomena than changes due to sterics, lending credibility to the concept of inducing electronic changes upon doping.

Incorporation and use of imidazoles as a dually dopable moiety in conjugated polymers

249th National Meeting (2015)

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