Synthesis of New Benzotellurodiazole Based Inorganic-Organic Hybrid Electroactive Monomers

In this study, the synthesis, characterization and polymerization of six different electron donor-acceptor-donor (D-A-D) type monomers based on benzotelluradiazole and benzimidazole units were tried to be reported. Whereas benzotelluradiazole based D-A-D monomers couldn’t synthesized successfully, benzoimidazole based D-A-D monomers were successfully synthesized, characterized and polymerized electrochemically. Just as benzothiadiazole and benzoselenadiazole analogues, polymers bearing benzimidazole acceptor units combined with thiophene and 3,4-alkylenedioxythiophenes donor units have narrow band gaps in a range between 1.50 eV and 1.57 eV, and showed electrochromic properties under applied external potentials. On the other hand, the applied procedures reported previously elsewhere for benzotelluradiazole analogues did not work for the synthesis of benzotelluradiazole based D-A-D monomers in this study. Unfortunately, the procedures in literature used for the transformation of the polymers containing benzothiadiazole or benzoselenadiazole units into the polymer bearing benzotelluradiazole units also did not work for the monomers and oligomers. Conversely, theoretical studies showed that the synthesis of benzotelluradiazole based D-A-D type monomers and oligomers are stable substances at room temperature and they can give lower band gap polymers when compared to their other electron acceptor analogues. As a result, in order to synthesize benzotelluradiazole based monomers, unlike known procedures, new strategies and procedures must be applied. Work in this line is in progress.