Theoretical investigation on the interplay of hydrogen bond and halogen bond in HX⋯(BrCl)n (X = F, Cl, Br and n = 1, 2) complexes

Quantum chemical calculations at the MP2 level with the aug-cc-pVTZ basis set were used to investigate the HX center dot center dot center dot(BrCl)(n) (X = F, Cl, Br and n = 1, 2) complexes. They are connected via hydrogen bond or halogen bond in dimers and together in trimers. Molecular geometries, interaction energies, cooperative energies and atomic charge of dyads and triads have been studied at the Mp2/aug-cc-pVTZ computational level. All studied trimers show cooperativity with the simultaneous presence of a hydrogen and one or two halogen bond. The molecular electrostatic potential has been employed to explore the formation mechanisms of these molecular complexes. The AIM analysis has been performed at the Mp2/aug-cc-pVTZ level to examine the topological characteristics, confirming the coexistence of hydrogen bonds and one or two halogen bond for each complex.