Weak energetic effects between X–π and X–N halogen bonds: CSD search and theoretical study

MP2 and M05-2x calculations have been carried out to investigate the interplay between X–π and X–N halogen bonds. Weak cooperative or diminutive effects are observed in the complexes where the two interactions coexist. For comparison, the mutual influence between H–π interactions and halogen bonds was also examined and the same energetic effects take place. These effects have been analyzed in detail by the structural, energetic, and AIM properties of the complexes. In addition, some crystal structures extracted from the Cambridge Structural Database were selected to provide experimental evidence of the combination of the two interactions.