Cooperativity between the hydrogen bonding and halogen bonding in F3CX...NCH(CNH)...NCH(CNH) complexes (X=Cl, Br)
MP2 calculations with the cc-pVTZ basis set were used to analyse the intermolecular interactions in F3CX ··· NCH(CNH) ··· NCH(CNH) triads (X=Cl, Br), which are connected via hydrogen and halogen bonds. Molecular geometries, binding energies, and infrared spectra of the dyads and triads were investigated at the MP2/cc-pVTZ computational level. Particular attention was given to parameters such as the cooperative energies, cooperative dipole moments, and many-body interaction energies. All studied complexes, with the simultaneous presence of a halogen bond and a hydrogen bond, show cooperativity with energy values ranging between −1.32 and −2.88 kJ mol−1. The electronic properties of the complexes were analysed using the Molecular Electrostatic Potential (MEP), electron density shift maps and the parameters derived from the Atoms in Molecules (AIM) methodology.