Indolo[3,2-b]carbazole-based poly(arylene ethynylene)s through Sonogashira coupling for optoelectronic and sensing applications

Two indolo[3,2-b]carbazole (ICZ)-based polymers have been designed and synthesized using Sonogashira cross-coupling based on dibromoindolo[3,2-b]carbazoles and 2,7-diethynylfluorene or 9,10-diethynylanthracene. The 2, 8 positions of the ICZ moiety has been used for the bridging of arylene ethynylene structure to form the polymer backbone. The characterization has been done by Fourier transform infrared, proton nuclear magnetic resonance, ultraviolet-visible and (UV-vis) fluorescence spectroscopic methods. The polymers, moderately soluble in aprotic and chlorinated solvents, have been found to possess thermal stability above 300 degrees C. The band gap examinations, executed through cyclic voltammetry and complemented by UV-vis studies, indicated their semiconducting nature and the possibility for their utilization for the fabrication of polymer solar cells and for optical switching applications. Interestingly, the new diethynylindolocarbazole systems have been found to act as Bronsted acid sensors as well as a Hg2+ receptors. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46940