Synthesis and Physicochemical Properties of New Chalcones Containing a 2-Chloroimidazo[1,2-a]pyridine Fragment

New chalcones containing a 2-chloroimidazo[1,2-a]pyridine fragment have been synthesized, and their optical properties have been studied. The Stokes shifts, forbidden band gap widths, molar absorption coefficients, and fluorescence quantum yields have been determined on the basis of their absorption and emission spectra. Introduction of an additional thiophene fragment into the chalcone molecules produced an increase of the Stokes shift, red shift of the emission maximum, and sharp increase of the quantum yield (up to 22%). The synthesized chalcones showed high thermal stability and good film-forming properties, and films obtained therefrom exhibited an ordered structure.