Comparison of σ‐hole and π‐hole tetrel bonds in complexes of borazine with TH3F and F2TO/H2TO (T = C, Si, Ge)

The complexes between borazine and TH3F/F2TO/H2TO (T = C, Si, Ge) are investigated with high‐level quantum chemical calculations. Borazine has three sites of negative electrostatic potential: the N atom, the ring center, and the H atom of the BH bond, whereas TH3F and F2TO/H2TO provide the σ‐hole and π‐hole, respectively, for the tetrel bond. The N atom of borazine is the favored site for both the σ and π‐hole tetrel bonds. Less‐stable dimers include a σ‐tetrel bond to the borazine ring center and to the BH proton. The π‐hole tetrel‐bonded complexes are more strongly bound than are their σ‐hole counterparts. Due to the coexistence of both T···N tetrel and B···O triel bonding, the complexes of borazine with F2TO/H2TO (T = Si and Ge) are very stable, with interaction energies up to −108 kcal/mol. The strongly bonded complexes are accompanied by substantial net charge transfer from F2TO/H2TO to borazine.