Characteristics of a σ-Hole and the Nature of a Halogen Bond

摘要: The nature of halogen bonding in 128 complexes was investigated using advanced quantum mechanical calculations. First, isolated donors were studied and their σ-holes described terms size magnitude. Later, both partners the complex considered interaction DFT-SAPT decomposition. whole set under study split into two categories on basis stabilisation energy. first subset with 38 possesses energies range 7–32 kcal/mol, while second 90 has smaller than 7 kcal/mol. is characterised by small intermolecular distances (less 2.5 A) a significant contraction van der Waals (vdW) distance (sum vdW radii). Here polarisation/electrostatic energy dominant, mostly followed induction dispersion energies. importance reflects charge-transfer character respective bonds. Intermolecular are large upon formation bond much smaller. polarisation Considering complexes, we conclude that characteristic features bonds arise from concerted action neither these can be as dominant. Finally, magnitude σ-hole correlates only weakly within complexes.