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.