A theoretical study of the HnF4−nSi:N‑base (n = 1–4) tetrel‑bonded complexes
Tetrel-bonded complexes of HnF4−nSi with a N-base for n = 0–4 were explored by MP2 calculations. Configurations with H–Si···N and F–Si···N linear or nearly linear alignment in complexes were considered. Nine sp3 hybridized nitrogen bases NH3, NH2Cl, NH2F, NHCl2, NCl3, NFCl2, NHF2, NF2Cl, NF3 and nine sp ones NCNH2, NCCH3, NCOH, NP, NCCl, NCH, NCF, NCCN, N2 have been studied. It is shown that binding energies of the complexes depend strongly on the nature of the base involved in the complex. Complexes with NH3 bases present the highest binding energies. In the stronger complexes, the silicon molecules suffer important geometrical distortions. NBO and AIM methodologies have been applied in order to describe properly the intermolecular Si···N contact. F atoms in equatorial position at silicon acid provoke a deviation from linearity of the Si···N electron density bond path trajectory.