Symmetrical and Unsymmetrical 4,7-Bis-arylvinyl-benzo-2,1,3-chalcogenodiazoles: Synthesis, Photophysical and Electrochemical Properties and Biomolecular Interaction Studies

Double Heck cross-coupling reactions for the synthesis of 4,7-bis-arylvinyl-benzo-2,1,3-chalcogenodiazole derivatives starting from 4,7-dibromobenzo[c][1,2,5]chalcogenodiazoles and functionalized styrenes are described. Compounds were obtained in moderate to excellent yields by using 10 mol-% of Pd(OAc)(2) as a catalyst and the reaction scope involved symmetrical and unsymmetrical benzo-2,1,3-chalcogenodiazoles. The prepared compounds were investigated regarding their photophysical properties in solution as well as their electrochemical behavior. The findings were corroborated using TD-DFT calculations. In general, 4,7-bis-arylvinyl-benzo-2,1,3-chalcogenodiazoles present strong absorption bands at the UV/Vis region and red emission depending on the substituents. In all derivatives, the HOMO-LUMO transitions have no significant dependence on the type of chalcogen atom. The oxidation process attributed to the chalcogen atom was observed using electrochemical analysis (CV and DPV techniques). Spectroscopic studies and molecular docking calculations evinced the ability of each 4,7-bis-arylvinyl-benzo-2,1,3-chalcogenodiazole derivative to establish interactions with calf-thymus DNA (ct-DNA) and human serum albumin (HSA).