Ladder-Type Polymers and Ladder-Type Polyelectrolytes with On-Chain Dibenz[a,h]anthracene Chromophores

The alternating copolymerization of fluorene and diethynyl benzene building blocks and postpolymerization electrophilic cyclization result in the generation of well-defined ladder poly­(dibenz­[a,h]­anthracene)­s (PLDBAs). PLDBAs combine the specific optical properties of the aromatic building blocks with well-resolved, vibronically structured photoluminescence spectra and a small Stokes shift (5 nm), as typical characteristics of ladder polymers, with an excellent solubility in organic solvents. Success of the ladderization step was confirmed by NMR- and IR-spectroscopies. The presence of syn- and anti-isomeric repeat units along the polymer backbone was proven by an investigation of corresponding model compounds. In addition, this concept was used for the synthesis of the corresponding ladder polyelectrolytes, bearing cationic imidazolium groups in their sidechains. The polyelectrolytes show very similar optical and electronical properties if compared to their noncharged counterparts but are now soluble in protic, polar solvents as methanol.