New possibilities of 2-pyranone derivatives – Thermal, optical and electrochemical properties

Highlights: • A series of 2-pyranone derivatives were synthesized. • The influence of the pyranone bridge on the stability, luminescent and (spectro)electrochemical behaviour was studied. • The polymers obtained present stability during both multiple n- and p-doping. • Electrochemical impedance spectroscopy of polymeric films was measured and evaluated. The paper contains a comprehensive study regarding the new possibilities of using 2-pyranone derivatives. In this work, six compounds of this type (including three electropolymerisable bithiophenyl's monomers) were synthesized in a one-step reaction with high yields ranging from 57% to 81%. The synthesized monomers of Bt-py-Bt (where Bt = 2,2′-bithiophene-5-yl, py = pyranone moiety) type were transformed into conducting polymers in an electrochemical oxidation process. The influence of the pyranone bridge on the stability, luminescent and (spectro)electrochemical behaviour was thoroughly studied. The polymers present extraordinary stability during both multiple n- and p-doping. The experimental results were also investigated theoretically, using the DFT approach. Calculations of the frontier orbital energies and the corresponding E_g value were done for each polymer using periodic boundary conditions. Finally, the electrochemical impedance spectroscopy measurements of polymeric films were done and evaluated.