Dihydrogen bond cooperativity in aza-borane derivatives

A theoretical study of the dihydrogen-bonded clusters of three aza-borane derivatives, H-N....B-H, has been carried out using DFT, M05-2X, computational methods. Clusters consisting of up to 10 monomers have been considered. The energetic results show an increment of the average interaction energy per monomer as the size of the cluster increases. Similarly, a shortening of the intermolecular distances up to 0.1 A is observed. Among the electrostatic properties, an increment of the dipole moment and the absolute values of the molecular electrostatic potential at the interacting point of the cluster are observed. Finally, the orbital interaction responsible for the dihydrogen bond follows the same pattern observed for the bond distances. Thus, it can be concluded that these systems show behavior, with respect to cooperativity, similar to those observed in standard hydrogen bonds.