Halogen–Halogen Nonbonded Interactions

Abstract

Halogen–halogen nonbonded interactions were studied for methyl halides and phenyl halides using both B3LYP and MP2 along with 6-311+G* and aug-cc-pVTZ. With the methyl halides, the linear approach was found to lead to little stabilization, whereas the “90°” approach gave 1–2 kcal/mol. This modest stabilization was due to long-range electron correlation effects. The lowest-energy arrangement had the molecules side-by-side, with the major stabilization being derived from halogen–hydrogen interactions. The results for methyl bromide were quite similar. Chlorobenzene dimer with the 90° orientation gave a small stabilization energy, but the best arrangement had the two benzene rings oriented over each other. The meta orientation of the chlorines had a lower energy than ortho or para. The dimerization energy was larger than that for two benzene rings sitting directly above each other, suggesting that whereas Cl···Cl interaction is not very important, the effect of the halogen on the electron distribution does have an effect. This suggests that much of the crystallographic results for these compounds may not be due to halogen–halogen interactions but rather the interaction between the substituted benzene rings along with crystal forces.

Hydrogen Bonding versus Halogen Bonding: Spectroscopic Investigation of Gas‐Phase Complexes Involving Bromide and Chloromethanes

“…[81] The four Br * •••CH 3 Cl complexes found in this study have similar binding motifs to those found in a study pertaining to CH 3 Cl dimer complexes, where instead of the CH 3 Cl moiety interacting with atomic bromine, the interaction occurs with the chlorine atom of the other CH 3 Cl molecule. [82] The lone Br * •••CCl 3 Br neutral structure shown in a study by Bowen and co-workers features atomic bromine interacting with the bromine atom of CCl 3 Br, [68] an interaction similar to what is shown in this study for the Br * •••CCl 4 (AXB1) complex.…”

Unveiling the energetic complexity of noncovalent interactions in halogenated dimers

“…The quantum theory of the atom in molecules (AIM) is considered an authoritative tool for gaining insight into the nature of intermolecular interactions [42]. The AIM analysis was performed to identify the presence of halogen⋯halogen interactions by generating bond critical points (BCPs) and bond paths (BPs) [43, 44]. Each of these methods offers unique insights into the nature and characteristics of these interactions.…”