Low-molar-mass and oligomeric derivatives of carbazole and triphenylamine containing thiazolo[5,4-d]thiazole moieties

Polymers and low-molar-mass-compounds containing donor and acceptor moieties are recently of great interest for the application in organic light-emitting diodes and other optoelectronic devices. Here, we report on the synthesis of oligomers containing carbazole or triphenylamine units as donors and thiazolo[5,4-d]thiazole as an acceptor moiety and on the corresponding low-molar-mass model compounds. In order to control the molecular weights and solubility of oligomeric compounds obtained via condensation reaction, the different ratios of mono- and diformyl derivatives were chosen. Thermal, optical, photophysical and electrochemical properties of the synthesized compounds were investigated. The initial thermal decomposition temperatures of the synthesized oligomeric compounds were in the range of 218–289 °C. Glass transition temperatures of the synthesized oligomeric compounds ranged from 109 to 174 °C. They absorb light in the range of 402–442 nm and emit in the region from 472 to 533 nm. The ionization potential values of the synthesized compounds ranged from 5.29 to 5.48 eV as it was established by cyclic voltammetry. Relatively wide ranges of the characteristics obtained show that purposeful manipulation of the conditions of the synthesis of the donor disubstituted thiazolo[5,4-d]thiazoles can lead to the preparation of the electroactive compounds with the desired sets of the properties.