A new insight on hydrogen bond donor property of bridged B–H–B protons in the interaction of diborane with some hydrogen bond acceptor molecules

Abstract

Ab initio calculations at the MP2/6-311++G(d,p) computational level were used to analyze the interactions between a molecule of B2H6 with some small molecules which often have both hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) abilities. Interaction of B2H6 with amine derivatives (NH3, NH2Me, NHMe2, NMe3) as well as H2O, MeOH, OMe2, and CH3CN occurs through its bridged protons (Hb) to form a Hb···X (X = N or O) hydrogen bond complex. On the other hand, interaction of B2H6 with HCN could be as Ht···H dihydrogen bond or Hb···N hydrogen bonding. Topological analyses of the electron density of optimized structures have been carried out using the atoms in molecules (AIMs) methodology. AIM calculations are indicating the HBD characteristic of Hb of B2H6 in its hydrogen bond interaction with X atom of HBA molecules. Stability of the predicted clusters depends on the kind of HBA molecule. In addition, our calculations have been used to determine the Drago–Wayland coefficients of diborane and stabilization energy of adducts formed by the association of the diborane and HBAs.