The aim of this work is to study cooperative effects between the π-hole and dihydrogen bond (DHB) interactions in the ternary X3B···NCH···HM complexes, where X= H, F and M= Li, Na, BeH, BeF, BeCH3, MgH, MgF, MgCH3. The properties of the resulting complexes are studied by molecular electrostatic potential, noncovalent interaction index and natural bond orbital analyses. It is found that there is a substantial shortening of H···H bond distances in the X3B···NCH···HM complexes, especially in M=Li and Na. Such remarkable variation in the H···H binding distances has not been reported for the DHB interactions previously. The formation of a H···H interaction in the H3B···NCH···HM and F3B···NCH···HM complexes makes an increase in the interaction energy of B···N bonds by 3–22% and 9–320%, respectively. The cooperative effects in the ternary complexes make a sizable increase in the 15N chemical shielding and total spin-spin coupling constants across the B···N bonding, which can be regarded as an evidence for the reinforce of π-hole interactions in the ternary complexes with respect to the corresponding binary systems.
