Control of the optical properties upon a reversible [2+2] cycloaddition of 3-(4-N,N-dibutylamino)-styryl)-3’-(dicyanovinyl)-bithiophene

Abstract

In the course of our studies of D-π-A push-pull chromophores we have envisioned the design of the novel 3-(4-N,N-dibutylamino)-styryl)-3’-(dicyanovinyl)-bithiophene derivative as a potential building block for optoelectronic applications. However, during the synthesis of this chromophore, a cycloadduct compound confirmed by X-ray structure was obtained by an intramolecular [2 + 2] cycloaddition reaction. The retro cycloaddition reaction carried out in thermal conditions and followed by UV–Visible absorption spectrophotometry afforded quantitively the target chromophore. Electrochemical properties recorded are in good agreement with open and close compounds. Mechanism involves cis/trans isomerization was proposed to explain the complete conversion.