The influence of substituent effect on noncovalent interactions in ternary complexes stabilized by hydrogen-bonding and halogen-bonding

The ternary complexes stabilized by three types of noncovalent interactions, that is, H-bonding, X-bonding and N…C interaction, were investigated. In all investigated systems the bromine atom plays a dual Lewis acid–Lewis base role. The acidity/basicity of the Br-moiety is modulated by the substituent effect. Substituents attached to the benzene ring in para-position with respect to Br atom change the ability of that atom to interact through H- and X-bonding. The structural, energetic and electron-density based properties of the systems were investigated. The three-body contributions to interaction energies were estimated in order to assess the cooperative or anticooperative character of interrelation between three types of interactions present in the investigated systems. It was found that rather anticooperative effect is present for all variously substituted systems.