Variable band gap poly(arylene ethynylene) conjugated polyelectrolytes

A series of poly(arylene ethynylene) (PAE) conjugated polyelectrolytes (CPEs) have been prepared using palladium-mediated (Sonogashira) coupling chemistry. The series consists of five pairs of polymers that share the same poly(arylene ethynylene) backbone. One member of each pair contains anionic sulfonate (R−SO3-) side groups, whereas the other member contains cationic bis-alkylammonium (R-N+−R-N+−R) side groups. The repeat unit structure of the poly(arylene ethynylene) backbone consists of a bis(alkoxy)phenylene-1,4-ethynylene unit alternating with a second arylene ethynylene moiety, and five different arylenes were used, Ar = 1,4-phenyl, 2,5-pyridyl (Py), 2,5-thienyl (Th), 2,5-(3,4-ethylenedioxy)thienyl (EDOT), and 1,4-benzo[2,1,3]thiodiazole (BDT). The different arylene units induce variation in the HOMO−LUMO band gap across the series of polymers, resulting in a series of materials that display absorption maxima at wavelengths ranging from 400 to 550 nm and fluorescence maxima ranging from 440 to 600...