Noncovalent interactions in model molecular clusters containing the tetrel atoms Si and Ge

An MP2 computational study was undertaken for the XF···LiF-TF3CN (X = Li, H, Cl: T = Si, Ge) and LiF-TF3CN···XF (T = Si, Ge; XF = BeF2, BF3, SF2, PH2F, SiH3F, LiF, HF, ClF) series of complexes involving a strongly bound LiF-TF3CN molecular subunit, characterised by a strong bonding motif with an Si-F (or Ge-F) bond perpendicular to the LiF molecule. The effect of attachment of XF, to either the LiF or the CN end of the LiF-TF3CN moiety, was investigated and rationalised with the aid of the natural bond orbital (NBO) analyses and localised molecular orbital-energy decomposition analyses (LMO-EDA). These analyses allow for a comparison of the bonding features in these complexes and the relative strengths of the noncovalent interactions introduced by the model Lewis acids XF.