Systematic kinetic study of H₂ release from the dimer of lithium amidoborane (LiNH₂BH₃)₂

The four-step dehydrogenation of lithium amidoborane dimer (LiNH ₂BH₃)₂ has been systematically simulated for the first time, and the respective rate constants have been calculated. Density functional theory has been used to optimize the molecular structure and ab initio direct kinetic theory has been applied to identify dehydrogenation mechanisms. The transition states were confirmed by intrinsic reaction coordinate calculations to insure the validity of our simulation and the barrier associated with each reaction was calculated. The Arrhenius equations of the four-step reactions (two pathways in all) were then obtained. The result indicated the dissociation maybe dimer way different from the traditional views. Our study has indicated a lower activation energy for dehydrogenation of the dimer compared to that of the monomer. The simulation is consistent with experimental observation because each step of the process requires increasingly higher energy. The study provides useful information on the properties and dehydrogenation mechanisms of metal-amidoborane compounds.