Dipole-bound anions supported by charge-transfer interaction: valence- and dipole-bound anionic states of H 3N→BF 3

Abstract

The possibility of electron binding to H 3NBF 3 was studied at the coupled cluster level of theory with single, double and non-iterative triple excitations. The neutral complex involves a dative bond that is responsible for a significant polarization of this species and generates a large dipole moment (6.53 D). As a consequence, H 3NBF 3 supports an electronically stable dipole-bound anionic state whose vertical electron detachment energy was calculated to be 2039 cm −1. In addition, a potential energy surface scan of the (H 3NBH 3) − indicates (for large separations between NH 3 and BF 3) the existence of a stable valence anion in which the excess electron is localized on the BF 3 monomer. These two anionic states (i.e., dipole- and valence-bound) can co-exist in some regions of the potential energy surface, and the dipole-bound state is more stable at the equilibrium geometry of the complex, while the valence anion is lower in energy at larger monomer–monomer separation.