Dissecting the nature of halogen bonding interactions from energy decomposition and wavefunction analysis

Halogen-bonded complexes: CF3X···A(CH3)n where X = Cl, Br, I; A = N, P or O, S; n = 0, 1, 2, 3 are investigated through the total energy decomposition analysis (EDA), quantum theory of atoms in molecules (QTAIM). QTAIM results show that the closed-shell interactions are characteristic of a halogen bond. EDA results indicate the predominant role of the exchange–correlation energy rather than the electrostatic potential; compared with the electrostatic potential, the steric energy makes less important contributions to the total interaction energy.