Photophysical Properties and Metal-Free Synthesis of Thiophene-Based D─π─A Stilbenes with Enhanced Stokes Shift

Abstract

A straightforward and practical nucleophile-induced synthetic route for the synthesis of thermally stable, fluorescently active, functionalized stilbenes has been developed. The described synthetic method involves nucleophile-induced, base-promoted ring transformation reactions following a more traditional approach. All reactions occur at room temperature, yielding high amounts of the desired product with minimal byproducts. Due to the inclusion of a donor-π-acceptor system, all the produced stilbenes exhibited impressive emission characteristics. The resulting band gaps ranged from 3.37 to 3.93 eV, indicating a notable redshift. Solvatochromic investigations underscored these positive impacts. Furthermore, the TG-DTA analysis indicated a single-step evaporation process, and the compounds exhibited stability up to 375 °C.