On Halogen Bond Nature in OC∙∙∙XY Systems from the Energy Decomposition
In this work have been presented the theoretical studies of the halogen
bond nature based on six model complexes of O≡C∙∙∙X–Y type, where X and
Y are halogen atoms. In these investigations, Local Molecular Orbital
Energy Decomposition Analysis (LMOEDA) and Quantum Theory Atom in
Molecules have been used as well as geometrical parameters and energy of
intermolecular interaction and Molecular Electrostatic Potential (MESP).
LMOEDA studies reveal a strong dependency on results on calculation
methods. Some techniques have been given very consistence results with
expectations; however, Grimme’s dispersion corrections and some
long-range separated functions in DFT do not work with used
decomposition energy procedure. Electron density and Laplacian values
confirm linear dependencies in connection to halogen bond energy than in
the case of ΔEint=f(RC∙∙∙X). MEP calculations clearly
indicate that for studied complexes the σ-hole theory is very useful to
halogen bond description.