In this work, the interplay between the tetrel bond and the dihydrogen bond is investigated in ternary XH3Si•••NCH•••HM complexes, where X=H, F, Cl, Br and M=Li, Na, BeH, MgH. The nature of Si···N and H···H interactions is studied by molecular electrostatic potential (MEP), noncovalent interaction (NCI) and electron localization function (ELF) analyses. All binding distances in the ternary complexes are shorter than those of isolated XH3Si•••NCH and NCH•••HM systems. That is, the two types of interactions have a cooperative effect on each other. The results of the MEP analysis indicate that the enhancement of the Si···N and H···H bonds can mainly be attributed to the electrostatic interaction. The plot of the reduced density gradient (RDG) versus sign (λ2)ρ indicates that the location of the spike associated with each interaction in the ternary systems moves slightly towards the negative (λ2)ρ values with respect to the binary systems. This confirms that both Si•••N and H•••H interactions in the ternary complexes are strengthened by the presence of other. Besides, cooperative effects lead to a considerable change in the 14N nuclear quadrupole coupling constant values of the ternary complexes relative to the XH3Si•••NCH complexes.
