The synthesis and spectral study of thiazolo[5,4-d]thiazole based small molecules using 1,3,4-oxadiazole as a linker for organic electronics

Abstract

The present research explores the experimental and theoretical study of seven new asymmetric derivatives with thiazolo[5,4-d]thiazole acceptor block and para substituted phenyl functional donor and acceptor groups linked with oxadiazole unit. We present one pot preparation of small organic molecules by simple condensation of commercially available tetrazoles and easily synthesized acyl chloride of thiazolo[5,4-d]thiazole unit. For a deeper examination of the products, UV-Vis, steady-state, and time-correlated fluorescence spectroscopy in chloroform solutions were used to study the correlation between the structure and the spectroscopic behavior of prepared compounds. The electronic properties of these derivatives were experimentally studied by cyclic voltammetry. The molecules were further investigated by quantum chemical calculations. It is almost certain, that studied compounds with weak electron-donor and medium to strong electron acceptor ability are not low band gap electron transport materials because UV–Vis and cyclic voltammetry results supported by the theoretical study show a wide band gap between their HOMO and LUMO orbitals. However, they may be useful in wide-bandgap semiconductors. Derivatives with electron donor moieties show low band gap and intramolecular charge transfer in the visible light region which makes them promising candidates for organic electronics. This study lays the groundwork for future research of thiazolo[5,4-d] thiazole molecules with 1,3,4-oxadiazole linkers.