Studies of electron-withdrawing systems based on chalcogenadiazoles continue at the ZIOC

In recent years, condensed heterocyclic systems containing many nitrogen and chalcogen (mainly sulfur) atoms in the cycles, which have pronounced acceptor properties, have attracted great interest. Electron-withdrawing fragments are widely present in π-conjugated organic molecules in various combinations with electron donors and π-conjugated bridges. These organic chromophores are widely used in semiconductor devices such as dye-sensitized solar cells (DSSC), organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and electrochromic devices (ECDs). An important place among such heterocycles is occupied by benzothiadiazole derivatives due to their excellent properties, such as strong electron-withdrawing properties, intense light absorption and good photochemical stability.

The Laboratory of Polysulfur-Nitrogen Heterocycles of the Zelinsky Institute actively studies electron-withdrawing systems based on chalcogenadiazoles, one of the striking examples of which is benzbisthiadiazole. In a recent joint study by scientists from the ZIOC and INEOS RAS, the electronic structure and electron density delocalization in this compound, as well as in its 4-bromo and 4,8-dibromo derivatives, were studied using X-ray diffraction analysis. Quantum mechanical calculations have shown that the introduction of bromine atoms increases the electron deficiency of this heterocyclic system, practically without affecting its aromaticity, which increases the reactivity of these compounds in aromatic nucleophilic substitution reactions and, on the other hand, does not reduce the ability to cross-coupling reactions. The 4-bromo benzobisthiadiazole derivative has been introduced into nucleophilic aromatic substitution and palladium-catalyzed cross-coupling reactions to form various heterocyclic structures. The resulting structures are of interest for the synthesis of organic compounds in order to create optoelectronic devices based on organic semiconductors.
 

Source:

Timofey N. Chmovzh, Daria A. Alekhina, Timofey A. Kudryashev, Rinat. R. Aysin, Alexander A. Korlyukov, Oleg A. Rakitin Benzo[1,2-d:4,5-d′]bis([1,2,3]thiadiazole) and Its Bromo Derivatives: Molecular Structure and Reactivity // Int. J. Mol. Sci. 2023, 24, 8835. DOI: 10.3390/ijms24108835.