Synthesis, optical and electrochemical study of bipolar heterocyclic systems, including 1,2,4-oxadiazole moiety

Abstract

AbstractTwo new 3,5-dihetarylsubstituted 1,2,4- oxadiazoles 8 a,b, including N-alkyl substituted carbazole and thiophene moieties, were synthesized as potential components of materials for organic electronics devices. Optical and electrochemical properties of all new compounds were investigated. On the basis of the experimental UV absorption data, the values of bandgap energies equal to 3.44 eV (8a) and 3.05 eV (8b) were determined. The values of their ionization potentials, HOMO levels (−5.62 eV for 8a, −5.46 eV – for 8b), as well as their electron affinity levels, LUMO levels (−2.2 eV for 8a, −2.4 eV – for 8b), were calculated from the results of electrochemical studies. The energy of the triplet excited states of 8 a,b was defined with the help of time-dependent density functional theory (TD-DFT), comprising 2.68 eV (8a) and 2.32 eV (8b), where the greatest value of this parameter was for the compound with a shorter conjugation chain.