Mutual enhancing effects of the σ-hole interactions and halogen/hydrogen-bonded interactions in the iodine-ylide containing complexes

The region of positive electrostatic potentials (σ-hole) has been found along the extension of the C–I bond in the iodine-ylide CH 2 IH, which suggests that the iodine-ylide could interact with nucleophiles to form weak, directional noncovalent interactions. MP2 calculations confirmed that the I···N σ-hole interaction exists in the CH 2 IH···NCX (X = H, F, Cl, Br, I) bimolecular complexes. The NCCl···CH 2 IH···NCX (X = H, F, Cl, Br, I) termolecular complexes were constructed to investigate the weakly bonded σ-hole interactions to be strengthened by Cl···C halogen bond. And then, the NCY···CH 2 IH···NCCl (Y = H, F, Cl, Br, I) termolecular complexes were designed to investigate the enhancing effects of the I···N σ-hole interaction on the Y···C halogen/hydrogen-bonded interactions. Accompany with the mutual enhancing processes of the σ-hole interactions and halogen/hydrogen-bonded interactions in the iodine-ylide containing termolecular complexes, both the I···N σ-hole interactions and Y···C halogen/hydrogen-bonded interactions become more polarizable.