The nature of halogen bond in model OC∙∙∙XY systems from the energy decomposition analysis perspective

Abstract This work represents the theoretical study results of the halogen bond's nature, based upon six model complexes of O C∙∙∙X Y type, in which X and Y are halogen atoms. Local Molecular Orbital Energy Decomposition Analysis (LMOEDA), Quantum Theory Atom in Molecules (QTAIM), including geometrical parameters, the values and energy of intermolecular interaction and Molecular Electrostatic Potential (MESP) have been referred to in this investigation. A critical assessment of the LMOEDA studies is also presented. This shows a strong dependency of the results on calculation methods. Some DFT methods have as expected given very consistent results; however, Grimme’s dispersion corrections and some long-range separated functions in DFT do not work with the 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). MESP calculations also confirm the usefulness of σ-hole theory.