Trifurcated Chalcogen Bond: Design and Synthesis

Compared with monofurcated chalcogen bonds and bifurcated chalcogen bonds, the theoretical and experimental studies on trifurcated chalcogen bonds and other multifurcated chalcogen bonds remain relatively underexplored. In this study, we first designed a series of trifurcated chalcogen bonds using 2,1,3-benzoselenadiazole and its derivatives as trifurcated chalcogen bond donors and pyridine-2,6-dicarboxylic acid as the trifurcated chalcogen bond acceptor. Then, through quantum chemical calculations, we conducted a detailed investigation into the structures, energies, and nature of these trifurcated chalcogen bonds. The results demonstrate that these trifurcated chalcogen bonds are primarily held together by attractive electrostatic forces; introducing electron-withdrawing substituents into the 2,1,3-benzoselenadiazole molecule strengthens the trifurcated chalcogen bonds. Finally, based on the computational design, we successfully synthesized the trifurcated chalcogen bonds via crystallographic experiments. Theory and experiment are perfectly integrated. This study establishes a solid foundation for subsequent research on trifurcated chalcogen bonds and other multifurcated chalcogen bonds.