Extending the Conjugation of Pechmann Lactone Thienyl Derivatives: A New Class of Small Molecules for Organic Electronics Application

The preparation and spectroscopic characterization of some symmetrical small molecules containing the disubstituted (E)-3,3?-bifuranylidene-2,2?-dione chromophore (the so-called Pechmann lactone) and featuring an extended conjugation are reported. The synthetic approach of such compounds is based on the Stille-Migita coupling reaction, which is carried out in very mild conditions, suitable to be applied with the very sensitive Pechmann core. The absorption and emission spectra of the new molecules obtained have been recorded in solution and clearly show how their photophysical properties can be modulated by a proper choice of the (hetero)aromatic terminal groups. The compounds prepared in this study (or close analogues thereof) have interesting optical properties and could find application as semiconductors in organic electronics or as near-IR fluorescent dyes.