Comparison of Anion‐Anion Halogen Bonds with Neutral‐Anion Halogen Bonds in the Gas Phase and Polar Solvents.

In recent years, anion‐anion halogen bonds and neutral‐anion halogen bonds have received extensive attention. In this work, the possibility of halogen bonding of neutral and anionic forms of para‐substituted iodine derivatives of dithiobenzoic acid and its Se‐ and Te‐based congeners with halide anions has been investigated. The anion‐anion complexes are not favorable in the gas phase because of the repulsive effect between anionic halogen bond donors and acceptors. A local minimum is present in the potential energy surface between the −S2CC6H4I and X (X=F−, Cl−, Br−), and the anion‐anion complexes −S2CC6H4I ⋅⋅⋅ X(X=F−, Cl−, Br−) are metastable in the gas phase. Solvation is beneficial to the formation of the anion‐anion complexes. The neutral‐anion complexes are stable in both the gas phase and the polar solvents. The anion‐anion halogen bonds tend to be stable in polar solvents, while the neutral‐anion halogen bonds are stronger in the gas phase than in solvents. [ABSTRACT FROM AUTHOR]