Pnicogen-Hydride Interaction between FH2X (X = P and As) and HM (M = ZnH, BeH, MgH, Li, and Na)

A pnicogen-hydride interaction has been predicted and characterized in FH2P-HM and FH2As-HM (M = ZnH, BeH, MgH, Li, and Na) complexes at the M22/aug-cc-pVTZ level. For the complexes analyzed here, P(As) and HM are treated as a Lewis acid and a Lewis base, respectively. This interaction is moderate or strong since, for the strongest interaction of the FH2As-HNa complex, the interaction energy amounts to -24.79 kcal/mol, and the binding distance is equal to about 1.7 angstrom, much less than the sum of the corresponding van der Waals radii. By comparison with some related systems, it is concluded that the pnicogen-hydride interactions are stronger than dihydrogen bonds and lithium hydride interactions. This interaction has been analyzed with natural bond orbitals, atoms in molecules, electron localization function, and symmetry adapted perturbation theory methods.