Furan and benzochalcogenodiazole based multichromic polymers via a donor–acceptor approach

Two new furan and benzochalcogenodiazole based monomers, namely 4,7-di(furan-2-yl)benzo[c][1,2,5]selenadiazole (FSeF) and 4,7-di(furan-2-yl)benzo[c][1,2,5]thiadiazole (FSF), were designed and synthesized via a donor–acceptor–donor approach. The monomers were electrochemically polymerized via potentiodynamic or potentiostatic methods. The monomers and their polymers exhibited lower oxidation potentials (1.16 V and 1.06 V for monomers; 0.93 V and 0.80 V for polymers vs. Ag/AgCl) and red shifts of the whole dual-band absorption spectra upon moving from S to Se. Intramolecular charge transfer properties of the monomers and the polymers were demonstrated by using electroanalytical and optical methods. Also, the polymers PFSeF and PFSF were multicolored at different redox states and have low band gaps of 1.43 eV and 1.61 eV, respectively.