Thienopyrrole and selenophenopyrrole donor fused with benzotriazole acceptor: microwave assisted synthesis and electrochemical polymerization

Thieno-/selenophenopyrrole fused substituted benzotriazoles were synthesized by microwave assisted cyclization which dramatically reduced the reaction time. Incorporation of benzotriazole as an acceptor moiety in a fused system was studied for the first time. Single crystal X-ray crystallographic studies were performed on thienopyrrole and selenophenopyrrole fused benzotriazoles 4, 5, 6 and 7. Compound 4 and 5 crystalize via hydrogen bonding with an ethyl acetate molecule from the solvent. N-Methyl substituted compounds 6 and 7 were electrochemically polymerized and characterized by spectroelectrochemistry. The effects of changing the heteroatom of the terminally fused heterocycles on their photophysical and electrochemical properties were also explored in this report. Emission spectra of compound 6 and 7 showed solvatochromic effects with a large Stokes shift.